Added e3cfsprogs and ext3cow-tools. Ext3cow is a stand-alone disk file system, (e.g. ReiserFS, HFS, NTFS) based on ext3, that supports versioning through copy-on-write and a time-shifting interface.

svn path=/nixpkgs/trunk/; revision=9010

1 files changed, 18428 insertions, 0 deletions

diff --git a/pkgs/os-specific/linux/kernel/linux-2.6.20.3-ext3cow.patch b/pkgs/os-specific/linux/kernel/linux-2.6.20.3-ext3cow.patch
new file mode 100644
index 00000000000..5ce03fa0434
--- /dev/null
+++ b/pkgs/os-specific/linux/kernel/linux-2.6.20.3-ext3cow.patch
@@ -0,0 +1,18428 @@
+diff -ruN linux-2.6.20.3/fs/Kconfig linux-2.6.20.3-ext3cow/fs/Kconfig
+--- linux-2.6.20.3/fs/Kconfig	2007-03-13 14:27:08.000000000 -0400
++++ linux-2.6.20.3-ext3cow/fs/Kconfig	2007-04-07 14:23:46.000000000 -0400
+@@ -136,6 +136,77 @@
+ 	  If you are not using a security module that requires using
+ 	  extended attributes for file security labels, say N.
+ 
++
++
++config EXT3COW_FS
++	tristate "Ext3cow journalling and versioning file system support"
++	select JBD
++	help
++	  This is the journalling version of the Second extended file system
++	  (often called ext3), the de facto standard Linux file system
++	  (method to organize files on a storage device) for hard disks.
++
++	  The journalling code included in this driver means you do not have
++	  to run e2fsck (file system checker) on your file systems after a
++	  crash.  The journal keeps track of any changes that were being made
++	  at the time the system crashed, and can ensure that your file system
++	  is consistent without the need for a lengthy check.
++
++	  Other than adding the journal to the file system, the on-disk format
++	  of ext3 is identical to ext2.  It is possible to freely switch
++	  between using the ext3 driver and the ext2 driver, as long as the
++	  file system has been cleanly unmounted, or e2fsck is run on the file
++	  system.
++
++	  To add a journal on an existing ext2 file system or change the
++	  behavior of ext3 file systems, you can use the tune2fs utility ("man
++	  tune2fs").  To modify attributes of files and directories on ext3
++	  file systems, use chattr ("man chattr").  You need to be using
++	  e2fsprogs version 1.20 or later in order to create ext3 journals
++	  (available at <http://sourceforge.net/projects/e2fsprogs/>).
++
++	  To compile this file system support as a module, choose M here: the
++	  module will be called ext3.
++
++config EXT3COW_FS_XATTR
++	bool "Ext3cow extended attributes"
++	depends on EXT3COW_FS
++	default y
++	help
++	  Extended attributes are name:value pairs associated with inodes by
++	  the kernel or by users (see the attr(5) manual page, or visit
++	  <http://acl.bestbits.at/> for details).
++
++	  If unsure, say N.
++
++	  You need this for POSIX ACL support on ext3cow.
++
++config EXT3COW_FS_POSIX_ACL
++	bool "Ext3cow POSIX Access Control Lists"
++	depends on EXT3COW_FS_XATTR
++	select FS_POSIX_ACL
++	help
++	  Posix Access Control Lists (ACLs) support permissions for users and
++	  groups beyond the owner/group/world scheme.
++
++	  To learn more about Access Control Lists, visit the Posix ACLs for
++	  Linux website <http://acl.bestbits.at/>.
++
++	  If you don't know what Access Control Lists are, say N
++
++config EXT3COW_FS_SECURITY
++	bool "Ext3cow Security Labels"
++	depends on EXT3COW_FS_XATTR
++	help
++	  Security labels support alternative access control models
++	  implemented by security modules like SELinux.  This option
++	  enables an extended attribute handler for file security
++	  labels in the ext3cow filesystem.
++
++	  If you are not using a security module that requires using
++	  extended attributes for file security labels, say N.
++
++
+ config EXT4DEV_FS
+ 	tristate "Ext4dev/ext4 extended fs support development (EXPERIMENTAL)"
+ 	depends on EXPERIMENTAL
+@@ -205,23 +276,23 @@
+ 	tristate
+ 	help
+ 	  This is a generic journalling layer for block devices.  It is
+-	  currently used by the ext3 and OCFS2 file systems, but it could
++	  currently used by the ext3, ext3cow and OCFS2 file systems, but it could
+ 	  also be used to add journal support to other file systems or block
+ 	  devices such as RAID or LVM.
+ 
+-	  If you are using the ext3 or OCFS2 file systems, you need to
++	  If you are using the ext3, ext3cow or OCFS2 file systems, you need to
+ 	  say Y here. If you are not using ext3 OCFS2 then you will probably
+ 	  want to say N.
+ 
+ 	  To compile this device as a module, choose M here: the module will be
+-	  called jbd.  If you are compiling ext3 or OCFS2 into the kernel,
++	  called jbd.  If you are compiling ext3, ext3cow or OCFS2 into the kernel,
+ 	  you cannot compile this code as a module.
+ 
+ config JBD_DEBUG
+ 	bool "JBD (ext3) debugging support"
+ 	depends on JBD
+ 	help
+-	  If you are using the ext3 journaled file system (or potentially any
++	  If you are using the ext3 or ext3cow journaled file system (or potentially any
+ 	  other file system/device using JBD), this option allows you to
+ 	  enable debugging output while the system is running, in order to
+ 	  help track down any problems you are having.  By default the
+@@ -266,11 +337,12 @@
+ 	  "echo 0 > /proc/sys/fs/jbd2-debug".
+ 
+ config FS_MBCACHE
+-# Meta block cache for Extended Attributes (ext2/ext3/ext4)
++# Meta block cache for Extended Attributes (ext2/ext3(cow)/ext4)
+ 	tristate
+-	depends on EXT2_FS_XATTR || EXT3_FS_XATTR || EXT4DEV_FS_XATTR
+-	default y if EXT2_FS=y || EXT3_FS=y || EXT4DEV_FS=y
+-	default m if EXT2_FS=m || EXT3_FS=m || EXT4DEV_FS=m
++	depends on EXT2_FS_XATTR || EXT3_FS_XATTR || EXT3COW_FS_XATTR || EXT4DEV_FS_XATTR
++	default y if EXT2_FS=y || EXT3_FS=y || EXT3COW_FS=y || EXT4DEV_FS=y
++	default m if EXT2_FS=m || EXT3_FS=m || EXT3COW_FS=m || EXT4DEV_FS=m
++
+ 
+ config REISERFS_FS
+ 	tristate "Reiserfs support"
+diff -ruN linux-2.6.20.3/fs/Makefile linux-2.6.20.3-ext3cow/fs/Makefile
+--- linux-2.6.20.3/fs/Makefile	2007-03-13 14:27:08.000000000 -0400
++++ linux-2.6.20.3-ext3cow/fs/Makefile	2007-04-07 14:23:46.000000000 -0400
+@@ -63,6 +63,7 @@
+ # Do not add any filesystems before this line
+ obj-$(CONFIG_REISERFS_FS)	+= reiserfs/
+ obj-$(CONFIG_EXT3_FS)		+= ext3/ # Before ext2 so root fs can be ext3
++obj-$(CONFIG_EXT3COW_FS)		+= ext3cow/ # Before ext2 so root fs can be ext3
+ obj-$(CONFIG_EXT4DEV_FS)	+= ext4/ # Before ext2 so root fs can be ext4dev
+ obj-$(CONFIG_JBD)		+= jbd/
+ obj-$(CONFIG_JBD2)		+= jbd2/
+diff -ruN linux-2.6.20.3/fs/ext3cow/Makefile linux-2.6.20.3-ext3cow/fs/ext3cow/Makefile
+--- linux-2.6.20.3/fs/ext3cow/Makefile	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/Makefile	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,12 @@
++#
++# Makefile for the linux ext3cow-filesystem routines.
++#
++
++obj-$(CONFIG_EXT3COW_FS) += ext3cow.o
++
++ext3cow-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
++	   ioctl.o namei.o super.o symlink.o hash.o resize.o ext3cow_jbd.o
++
++ext3cow-$(CONFIG_EXT3COW_FS_XATTR)	 += xattr.o xattr_user.o xattr_trusted.o
++ext3cow-$(CONFIG_EXT3COW_FS_POSIX_ACL) += acl.o
++ext3cow-$(CONFIG_EXT3COW_FS_SECURITY)	 += xattr_security.o
+diff -ruN linux-2.6.20.3/fs/ext3cow/acl.c linux-2.6.20.3-ext3cow/fs/ext3cow/acl.c
+--- linux-2.6.20.3/fs/ext3cow/acl.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/acl.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,551 @@
++/*
++ * linux/fs/ext3cow/acl.c
++ *
++ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
++ */
++
++#include <linux/init.h>
++#include <linux/sched.h>
++#include <linux/slab.h>
++#include <linux/capability.h>
++#include <linux/fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/ext3cow_fs.h>
++#include "xattr.h"
++#include "acl.h"
++
++/*
++ * Convert from filesystem to in-memory representation.
++ */
++static struct posix_acl *
++ext3cow_acl_from_disk(const void *value, size_t size)
++{
++	const char *end = (char *)value + size;
++	int n, count;
++	struct posix_acl *acl;
++
++	if (!value)
++		return NULL;
++	if (size < sizeof(ext3cow_acl_header))
++		 return ERR_PTR(-EINVAL);
++	if (((ext3cow_acl_header *)value)->a_version !=
++	    cpu_to_le32(EXT3COW_ACL_VERSION))
++		return ERR_PTR(-EINVAL);
++	value = (char *)value + sizeof(ext3cow_acl_header);
++	count = ext3cow_acl_count(size);
++	if (count < 0)
++		return ERR_PTR(-EINVAL);
++	if (count == 0)
++		return NULL;
++	acl = posix_acl_alloc(count, GFP_KERNEL);
++	if (!acl)
++		return ERR_PTR(-ENOMEM);
++	for (n=0; n < count; n++) {
++		ext3cow_acl_entry *entry =
++			(ext3cow_acl_entry *)value;
++		if ((char *)value + sizeof(ext3cow_acl_entry_short) > end)
++			goto fail;
++		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
++		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
++		switch(acl->a_entries[n].e_tag) {
++			case ACL_USER_OBJ:
++			case ACL_GROUP_OBJ:
++			case ACL_MASK:
++			case ACL_OTHER:
++				value = (char *)value +
++					sizeof(ext3cow_acl_entry_short);
++				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
++				break;
++
++			case ACL_USER:
++			case ACL_GROUP:
++				value = (char *)value + sizeof(ext3cow_acl_entry);
++				if ((char *)value > end)
++					goto fail;
++				acl->a_entries[n].e_id =
++					le32_to_cpu(entry->e_id);
++				break;
++
++			default:
++				goto fail;
++		}
++	}
++	if (value != end)
++		goto fail;
++	return acl;
++
++fail:
++	posix_acl_release(acl);
++	return ERR_PTR(-EINVAL);
++}
++
++/*
++ * Convert from in-memory to filesystem representation.
++ */
++static void *
++ext3cow_acl_to_disk(const struct posix_acl *acl, size_t *size)
++{
++	ext3cow_acl_header *ext_acl;
++	char *e;
++	size_t n;
++
++	*size = ext3cow_acl_size(acl->a_count);
++	ext_acl = kmalloc(sizeof(ext3cow_acl_header) + acl->a_count *
++			sizeof(ext3cow_acl_entry), GFP_KERNEL);
++	if (!ext_acl)
++		return ERR_PTR(-ENOMEM);
++	ext_acl->a_version = cpu_to_le32(EXT3COW_ACL_VERSION);
++	e = (char *)ext_acl + sizeof(ext3cow_acl_header);
++	for (n=0; n < acl->a_count; n++) {
++		ext3cow_acl_entry *entry = (ext3cow_acl_entry *)e;
++		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
++		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
++		switch(acl->a_entries[n].e_tag) {
++			case ACL_USER:
++			case ACL_GROUP:
++				entry->e_id =
++					cpu_to_le32(acl->a_entries[n].e_id);
++				e += sizeof(ext3cow_acl_entry);
++				break;
++
++			case ACL_USER_OBJ:
++			case ACL_GROUP_OBJ:
++			case ACL_MASK:
++			case ACL_OTHER:
++				e += sizeof(ext3cow_acl_entry_short);
++				break;
++
++			default:
++				goto fail;
++		}
++	}
++	return (char *)ext_acl;
++
++fail:
++	kfree(ext_acl);
++	return ERR_PTR(-EINVAL);
++}
++
++static inline struct posix_acl *
++ext3cow_iget_acl(struct inode *inode, struct posix_acl **i_acl)
++{
++	struct posix_acl *acl = EXT3COW_ACL_NOT_CACHED;
++
++	spin_lock(&inode->i_lock);
++	if (*i_acl != EXT3COW_ACL_NOT_CACHED)
++		acl = posix_acl_dup(*i_acl);
++	spin_unlock(&inode->i_lock);
++
++	return acl;
++}
++
++static inline void
++ext3cow_iset_acl(struct inode *inode, struct posix_acl **i_acl,
++                  struct posix_acl *acl)
++{
++	spin_lock(&inode->i_lock);
++	if (*i_acl != EXT3COW_ACL_NOT_CACHED)
++		posix_acl_release(*i_acl);
++	*i_acl = posix_acl_dup(acl);
++	spin_unlock(&inode->i_lock);
++}
++
++/*
++ * Inode operation get_posix_acl().
++ *
++ * inode->i_mutex: don't care
++ */
++static struct posix_acl *
++ext3cow_get_acl(struct inode *inode, int type)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	int name_index;
++	char *value = NULL;
++	struct posix_acl *acl;
++	int retval;
++
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return NULL;
++
++	switch(type) {
++		case ACL_TYPE_ACCESS:
++			acl = ext3cow_iget_acl(inode, &ei->i_acl);
++			if (acl != EXT3COW_ACL_NOT_CACHED)
++				return acl;
++			name_index = EXT3COW_XATTR_INDEX_POSIX_ACL_ACCESS;
++			break;
++
++		case ACL_TYPE_DEFAULT:
++			acl = ext3cow_iget_acl(inode, &ei->i_default_acl);
++			if (acl != EXT3COW_ACL_NOT_CACHED)
++				return acl;
++			name_index = EXT3COW_XATTR_INDEX_POSIX_ACL_DEFAULT;
++			break;
++
++		default:
++			return ERR_PTR(-EINVAL);
++	}
++	retval = ext3cow_xattr_get(inode, name_index, "", NULL, 0);
++	if (retval > 0) {
++		value = kmalloc(retval, GFP_KERNEL);
++		if (!value)
++			return ERR_PTR(-ENOMEM);
++		retval = ext3cow_xattr_get(inode, name_index, "", value, retval);
++	}
++	if (retval > 0)
++		acl = ext3cow_acl_from_disk(value, retval);
++	else if (retval == -ENODATA || retval == -ENOSYS)
++		acl = NULL;
++	else
++		acl = ERR_PTR(retval);
++	kfree(value);
++
++	if (!IS_ERR(acl)) {
++		switch(type) {
++			case ACL_TYPE_ACCESS:
++				ext3cow_iset_acl(inode, &ei->i_acl, acl);
++				break;
++
++			case ACL_TYPE_DEFAULT:
++				ext3cow_iset_acl(inode, &ei->i_default_acl, acl);
++				break;
++		}
++	}
++	return acl;
++}
++
++/*
++ * Set the access or default ACL of an inode.
++ *
++ * inode->i_mutex: down unless called from ext3cow_new_inode
++ */
++static int
++ext3cow_set_acl(handle_t *handle, struct inode *inode, int type,
++	     struct posix_acl *acl)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	int name_index;
++	void *value = NULL;
++	size_t size = 0;
++	int error;
++
++	if (S_ISLNK(inode->i_mode))
++		return -EOPNOTSUPP;
++
++	switch(type) {
++		case ACL_TYPE_ACCESS:
++			name_index = EXT3COW_XATTR_INDEX_POSIX_ACL_ACCESS;
++			if (acl) {
++				mode_t mode = inode->i_mode;
++				error = posix_acl_equiv_mode(acl, &mode);
++				if (error < 0)
++					return error;
++				else {
++					inode->i_mode = mode;
++					ext3cow_mark_inode_dirty(handle, inode);
++					if (error == 0)
++						acl = NULL;
++				}
++			}
++			break;
++
++		case ACL_TYPE_DEFAULT:
++			name_index = EXT3COW_XATTR_INDEX_POSIX_ACL_DEFAULT;
++			if (!S_ISDIR(inode->i_mode))
++				return acl ? -EACCES : 0;
++			break;
++
++		default:
++			return -EINVAL;
++	}
++	if (acl) {
++		value = ext3cow_acl_to_disk(acl, &size);
++		if (IS_ERR(value))
++			return (int)PTR_ERR(value);
++	}
++
++	error = ext3cow_xattr_set_handle(handle, inode, name_index, "",
++				      value, size, 0);
++
++	kfree(value);
++	if (!error) {
++		switch(type) {
++			case ACL_TYPE_ACCESS:
++				ext3cow_iset_acl(inode, &ei->i_acl, acl);
++				break;
++
++			case ACL_TYPE_DEFAULT:
++				ext3cow_iset_acl(inode, &ei->i_default_acl, acl);
++				break;
++		}
++	}
++	return error;
++}
++
++static int
++ext3cow_check_acl(struct inode *inode, int mask)
++{
++	struct posix_acl *acl = ext3cow_get_acl(inode, ACL_TYPE_ACCESS);
++
++	if (IS_ERR(acl))
++		return PTR_ERR(acl);
++	if (acl) {
++		int error = posix_acl_permission(inode, acl, mask);
++		posix_acl_release(acl);
++		return error;
++	}
++
++	return -EAGAIN;
++}
++
++int
++ext3cow_permission(struct inode *inode, int mask, struct nameidata *nd)
++{
++	return generic_permission(inode, mask, ext3cow_check_acl);
++}
++
++/*
++ * Initialize the ACLs of a new inode. Called from ext3cow_new_inode.
++ *
++ * dir->i_mutex: down
++ * inode->i_mutex: up (access to inode is still exclusive)
++ */
++int
++ext3cow_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
++{
++	struct posix_acl *acl = NULL;
++	int error = 0;
++
++	if (!S_ISLNK(inode->i_mode)) {
++		if (test_opt(dir->i_sb, POSIX_ACL)) {
++			acl = ext3cow_get_acl(dir, ACL_TYPE_DEFAULT);
++			if (IS_ERR(acl))
++				return PTR_ERR(acl);
++		}
++		if (!acl)
++			inode->i_mode &= ~current->fs->umask;
++	}
++	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
++		struct posix_acl *clone;
++		mode_t mode;
++
++		if (S_ISDIR(inode->i_mode)) {
++			error = ext3cow_set_acl(handle, inode,
++					     ACL_TYPE_DEFAULT, acl);
++			if (error)
++				goto cleanup;
++		}
++		clone = posix_acl_clone(acl, GFP_KERNEL);
++		error = -ENOMEM;
++		if (!clone)
++			goto cleanup;
++
++		mode = inode->i_mode;
++		error = posix_acl_create_masq(clone, &mode);
++		if (error >= 0) {
++			inode->i_mode = mode;
++			if (error > 0) {
++				/* This is an extended ACL */
++				error = ext3cow_set_acl(handle, inode,
++						     ACL_TYPE_ACCESS, clone);
++			}
++		}
++		posix_acl_release(clone);
++	}
++cleanup:
++	posix_acl_release(acl);
++	return error;
++}
++
++/*
++ * Does chmod for an inode that may have an Access Control List. The
++ * inode->i_mode field must be updated to the desired value by the caller
++ * before calling this function.
++ * Returns 0 on success, or a negative error number.
++ *
++ * We change the ACL rather than storing some ACL entries in the file
++ * mode permission bits (which would be more efficient), because that
++ * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
++ * for directories) are added. There are no more bits available in the
++ * file mode.
++ *
++ * inode->i_mutex: down
++ */
++int
++ext3cow_acl_chmod(struct inode *inode)
++{
++	struct posix_acl *acl, *clone;
++        int error;
++
++	if (S_ISLNK(inode->i_mode))
++		return -EOPNOTSUPP;
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return 0;
++	acl = ext3cow_get_acl(inode, ACL_TYPE_ACCESS);
++	if (IS_ERR(acl) || !acl)
++		return PTR_ERR(acl);
++	clone = posix_acl_clone(acl, GFP_KERNEL);
++	posix_acl_release(acl);
++	if (!clone)
++		return -ENOMEM;
++	error = posix_acl_chmod_masq(clone, inode->i_mode);
++	if (!error) {
++		handle_t *handle;
++		int retries = 0;
++
++	retry:
++		handle = ext3cow_journal_start(inode,
++				EXT3COW_DATA_TRANS_BLOCKS(inode->i_sb));
++		if (IS_ERR(handle)) {
++			error = PTR_ERR(handle);
++			ext3cow_std_error(inode->i_sb, error);
++			goto out;
++		}
++		error = ext3cow_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
++		ext3cow_journal_stop(handle);
++		if (error == -ENOSPC &&
++		    ext3cow_should_retry_alloc(inode->i_sb, &retries))
++			goto retry;
++	}
++out:
++	posix_acl_release(clone);
++	return error;
++}
++
++/*
++ * Extended attribute handlers
++ */
++static size_t
++ext3cow_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
++			   const char *name, size_t name_len)
++{
++	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
++
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return 0;
++	if (list && size <= list_len)
++		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
++	return size;
++}
++
++static size_t
++ext3cow_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
++			    const char *name, size_t name_len)
++{
++	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
++
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return 0;
++	if (list && size <= list_len)
++		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
++	return size;
++}
++
++static int
++ext3cow_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
++{
++	struct posix_acl *acl;
++	int error;
++
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return -EOPNOTSUPP;
++
++	acl = ext3cow_get_acl(inode, type);
++	if (IS_ERR(acl))
++		return PTR_ERR(acl);
++	if (acl == NULL)
++		return -ENODATA;
++	error = posix_acl_to_xattr(acl, buffer, size);
++	posix_acl_release(acl);
++
++	return error;
++}
++
++static int
++ext3cow_xattr_get_acl_access(struct inode *inode, const char *name,
++			  void *buffer, size_t size)
++{
++	if (strcmp(name, "") != 0)
++		return -EINVAL;
++	return ext3cow_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
++}
++
++static int
++ext3cow_xattr_get_acl_default(struct inode *inode, const char *name,
++			   void *buffer, size_t size)
++{
++	if (strcmp(name, "") != 0)
++		return -EINVAL;
++	return ext3cow_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
++}
++
++static int
++ext3cow_xattr_set_acl(struct inode *inode, int type, const void *value,
++		   size_t size)
++{
++	handle_t *handle;
++	struct posix_acl *acl;
++	int error, retries = 0;
++
++	if (!test_opt(inode->i_sb, POSIX_ACL))
++		return -EOPNOTSUPP;
++	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
++		return -EPERM;
++
++	if (value) {
++		acl = posix_acl_from_xattr(value, size);
++		if (IS_ERR(acl))
++			return PTR_ERR(acl);
++		else if (acl) {
++			error = posix_acl_valid(acl);
++			if (error)
++				goto release_and_out;
++		}
++	} else
++		acl = NULL;
++
++retry:
++	handle = ext3cow_journal_start(inode, EXT3COW_DATA_TRANS_BLOCKS(inode->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	error = ext3cow_set_acl(handle, inode, type, acl);
++	ext3cow_journal_stop(handle);
++	if (error == -ENOSPC && ext3cow_should_retry_alloc(inode->i_sb, &retries))
++		goto retry;
++
++release_and_out:
++	posix_acl_release(acl);
++	return error;
++}
++
++static int
++ext3cow_xattr_set_acl_access(struct inode *inode, const char *name,
++			  const void *value, size_t size, int flags)
++{
++	if (strcmp(name, "") != 0)
++		return -EINVAL;
++	return ext3cow_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
++}
++
++static int
++ext3cow_xattr_set_acl_default(struct inode *inode, const char *name,
++			   const void *value, size_t size, int flags)
++{
++	if (strcmp(name, "") != 0)
++		return -EINVAL;
++	return ext3cow_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
++}
++
++struct xattr_handler ext3cow_xattr_acl_access_handler = {
++	.prefix	= POSIX_ACL_XATTR_ACCESS,
++	.list	= ext3cow_xattr_list_acl_access,
++	.get	= ext3cow_xattr_get_acl_access,
++	.set	= ext3cow_xattr_set_acl_access,
++};
++
++struct xattr_handler ext3cow_xattr_acl_default_handler = {
++	.prefix	= POSIX_ACL_XATTR_DEFAULT,
++	.list	= ext3cow_xattr_list_acl_default,
++	.get	= ext3cow_xattr_get_acl_default,
++	.set	= ext3cow_xattr_set_acl_default,
++};
+diff -ruN linux-2.6.20.3/fs/ext3cow/acl.h linux-2.6.20.3-ext3cow/fs/ext3cow/acl.h
+--- linux-2.6.20.3/fs/ext3cow/acl.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/acl.h	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,81 @@
++/*
++  File: fs/ext3cow/acl.h
++
++  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
++*/
++
++#include <linux/posix_acl_xattr.h>
++
++#define EXT3COW_ACL_VERSION	0x0001
++
++typedef struct {
++	__le16		e_tag;
++	__le16		e_perm;
++	__le32		e_id;
++} ext3cow_acl_entry;
++
++typedef struct {
++	__le16		e_tag;
++	__le16		e_perm;
++} ext3cow_acl_entry_short;
++
++typedef struct {
++	__le32		a_version;
++} ext3cow_acl_header;
++
++static inline size_t ext3cow_acl_size(int count)
++{
++	if (count <= 4) {
++		return sizeof(ext3cow_acl_header) +
++		       count * sizeof(ext3cow_acl_entry_short);
++	} else {
++		return sizeof(ext3cow_acl_header) +
++		       4 * sizeof(ext3cow_acl_entry_short) +
++		       (count - 4) * sizeof(ext3cow_acl_entry);
++	}
++}
++
++static inline int ext3cow_acl_count(size_t size)
++{
++	ssize_t s;
++	size -= sizeof(ext3cow_acl_header);
++	s = size - 4 * sizeof(ext3cow_acl_entry_short);
++	if (s < 0) {
++		if (size % sizeof(ext3cow_acl_entry_short))
++			return -1;
++		return size / sizeof(ext3cow_acl_entry_short);
++	} else {
++		if (s % sizeof(ext3cow_acl_entry))
++			return -1;
++		return s / sizeof(ext3cow_acl_entry) + 4;
++	}
++}
++
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++
++/* Value for inode->u.ext3cow_i.i_acl and inode->u.ext3cow_i.i_default_acl
++   if the ACL has not been cached */
++#define EXT3COW_ACL_NOT_CACHED ((void *)-1)
++
++/* acl.c */
++extern int ext3cow_permission (struct inode *, int, struct nameidata *);
++extern int ext3cow_acl_chmod (struct inode *);
++extern int ext3cow_init_acl (handle_t *, struct inode *, struct inode *);
++
++#else  /* CONFIG_EXT3COW_FS_POSIX_ACL */
++#include <linux/sched.h>
++#define ext3cow_permission NULL
++
++static inline int
++ext3cow_acl_chmod(struct inode *inode)
++{
++	return 0;
++}
++
++static inline int
++ext3cow_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
++{
++	return 0;
++}
++#endif  /* CONFIG_EXT3COW_FS_POSIX_ACL */
++
+diff -ruN linux-2.6.20.3/fs/ext3cow/balloc.c linux-2.6.20.3-ext3cow/fs/ext3cow/balloc.c
+--- linux-2.6.20.3/fs/ext3cow/balloc.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/balloc.c	2007-04-14 11:40:48.000000000 -0400
+@@ -0,0 +1,1823 @@
++/*
++ *  linux/fs/ext3cow/balloc.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ */
++
++#include <linux/time.h>
++#include <linux/capability.h>
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/quotaops.h>
++#include <linux/buffer_head.h>
++
++/*
++ * balloc.c contains the blocks allocation and deallocation routines
++ */
++
++/*
++ * The free blocks are managed by bitmaps.  A file system contains several
++ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
++ * block for inodes, N blocks for the inode table and data blocks.
++ *
++ * The file system contains group descriptors which are located after the
++ * super block.  Each descriptor contains the number of the bitmap block and
++ * the free blocks count in the block.  The descriptors are loaded in memory
++ * when a file system is mounted (see ext3cow_read_super).
++ */
++
++
++#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
++
++/**
++ * ext3cow_get_group_desc() -- load group descriptor from disk
++ * @sb:			super block
++ * @block_group:	given block group
++ * @bh:			pointer to the buffer head to store the block
++ *			group descriptor
++ */
++struct ext3cow_group_desc * ext3cow_get_group_desc(struct super_block * sb,
++					     unsigned int block_group,
++					     struct buffer_head ** bh)
++{
++	unsigned long group_desc;
++	unsigned long offset;
++	struct ext3cow_group_desc * desc;
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++
++	if (block_group >= sbi->s_groups_count) {
++		ext3cow_error (sb, "ext3cow_get_group_desc",
++			    "block_group >= groups_count - "
++			    "block_group = %d, groups_count = %lu",
++			    block_group, sbi->s_groups_count);
++
++		return NULL;
++	}
++	smp_rmb();
++
++	group_desc = block_group >> EXT3COW_DESC_PER_BLOCK_BITS(sb);
++	offset = block_group & (EXT3COW_DESC_PER_BLOCK(sb) - 1);
++	if (!sbi->s_group_desc[group_desc]) {
++		ext3cow_error (sb, "ext3cow_get_group_desc",
++			    "Group descriptor not loaded - "
++			    "block_group = %d, group_desc = %lu, desc = %lu",
++			     block_group, group_desc, offset);
++		return NULL;
++	}
++
++	desc = (struct ext3cow_group_desc *) sbi->s_group_desc[group_desc]->b_data;
++	if (bh)
++		*bh = sbi->s_group_desc[group_desc];
++	return desc + offset;
++}
++
++/**
++ * read_block_bitmap()
++ * @sb:			super block
++ * @block_group:	given block group
++ *
++ * Read the bitmap for a given block_group, reading into the specified
++ * slot in the superblock's bitmap cache.
++ *
++ * Return buffer_head on success or NULL in case of failure.
++ */
++static struct buffer_head *
++read_block_bitmap(struct super_block *sb, unsigned int block_group)
++{
++	struct ext3cow_group_desc * desc;
++	struct buffer_head * bh = NULL;
++
++	desc = ext3cow_get_group_desc (sb, block_group, NULL);
++	if (!desc)
++		goto error_out;
++	bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
++	if (!bh)
++		ext3cow_error (sb, "read_block_bitmap",
++			    "Cannot read block bitmap - "
++			    "block_group = %d, block_bitmap = %u",
++			    block_group, le32_to_cpu(desc->bg_block_bitmap));
++error_out:
++	return bh;
++}
++/*
++ * The reservation window structure operations
++ * --------------------------------------------
++ * Operations include:
++ * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
++ *
++ * We use a red-black tree to represent per-filesystem reservation
++ * windows.
++ *
++ */
++
++/**
++ * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
++ * @rb_root:		root of per-filesystem reservation rb tree
++ * @verbose:		verbose mode
++ * @fn:			function which wishes to dump the reservation map
++ *
++ * If verbose is turned on, it will print the whole block reservation
++ * windows(start, end).	Otherwise, it will only print out the "bad" windows,
++ * those windows that overlap with their immediate neighbors.
++ */
++#if 1
++static void __rsv_window_dump(struct rb_root *root, int verbose,
++			      const char *fn)
++{
++	struct rb_node *n;
++	struct ext3cow_reserve_window_node *rsv, *prev;
++	int bad;
++
++restart:
++	n = rb_first(root);
++	bad = 0;
++	prev = NULL;
++
++	printk("Block Allocation Reservation Windows Map (%s):\n", fn);
++	while (n) {
++		rsv = rb_entry(n, struct ext3cow_reserve_window_node, rsv_node);
++		if (verbose)
++			printk("reservation window 0x%p "
++			       "start:  %lu, end:  %lu\n",
++			       rsv, rsv->rsv_start, rsv->rsv_end);
++		if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
++			printk("Bad reservation %p (start >= end)\n",
++			       rsv);
++			bad = 1;
++		}
++		if (prev && prev->rsv_end >= rsv->rsv_start) {
++			printk("Bad reservation %p (prev->end >= start)\n",
++			       rsv);
++			bad = 1;
++		}
++		if (bad) {
++			if (!verbose) {
++				printk("Restarting reservation walk in verbose mode\n");
++				verbose = 1;
++				goto restart;
++			}
++		}
++		n = rb_next(n);
++		prev = rsv;
++	}
++	printk("Window map complete.\n");
++	if (bad)
++		BUG();
++}
++#define rsv_window_dump(root, verbose) \
++	__rsv_window_dump((root), (verbose), __FUNCTION__)
++#else
++#define rsv_window_dump(root, verbose) do {} while (0)
++#endif
++
++/**
++ * goal_in_my_reservation()
++ * @rsv:		inode's reservation window
++ * @grp_goal:		given goal block relative to the allocation block group
++ * @group:		the current allocation block group
++ * @sb:			filesystem super block
++ *
++ * Test if the given goal block (group relative) is within the file's
++ * own block reservation window range.
++ *
++ * If the reservation window is outside the goal allocation group, return 0;
++ * grp_goal (given goal block) could be -1, which means no specific
++ * goal block. In this case, always return 1.
++ * If the goal block is within the reservation window, return 1;
++ * otherwise, return 0;
++ */
++static int
++goal_in_my_reservation(struct ext3cow_reserve_window *rsv, ext3cow_grpblk_t grp_goal,
++			unsigned int group, struct super_block * sb)
++{
++	ext3cow_fsblk_t group_first_block, group_last_block;
++
++	group_first_block = ext3cow_group_first_block_no(sb, group);
++	group_last_block = group_first_block + (EXT3COW_BLOCKS_PER_GROUP(sb) - 1);
++
++	if ((rsv->_rsv_start > group_last_block) ||
++	    (rsv->_rsv_end < group_first_block))
++		return 0;
++	if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
++		|| (grp_goal + group_first_block > rsv->_rsv_end)))
++		return 0;
++	return 1;
++}
++
++/**
++ * search_reserve_window()
++ * @rb_root:		root of reservation tree
++ * @goal:		target allocation block
++ *
++ * Find the reserved window which includes the goal, or the previous one
++ * if the goal is not in any window.
++ * Returns NULL if there are no windows or if all windows start after the goal.
++ */
++static struct ext3cow_reserve_window_node *
++search_reserve_window(struct rb_root *root, ext3cow_fsblk_t goal)
++{
++	struct rb_node *n = root->rb_node;
++	struct ext3cow_reserve_window_node *rsv;
++
++	if (!n)
++		return NULL;
++
++	do {
++		rsv = rb_entry(n, struct ext3cow_reserve_window_node, rsv_node);
++
++		if (goal < rsv->rsv_start)
++			n = n->rb_left;
++		else if (goal > rsv->rsv_end)
++			n = n->rb_right;
++		else
++			return rsv;
++	} while (n);
++	/*
++	 * We've fallen off the end of the tree: the goal wasn't inside
++	 * any particular node.  OK, the previous node must be to one
++	 * side of the interval containing the goal.  If it's the RHS,
++	 * we need to back up one.
++	 */
++	if (rsv->rsv_start > goal) {
++		n = rb_prev(&rsv->rsv_node);
++		rsv = rb_entry(n, struct ext3cow_reserve_window_node, rsv_node);
++	}
++	return rsv;
++}
++
++/**
++ * ext3cow_rsv_window_add() -- Insert a window to the block reservation rb tree.
++ * @sb:			super block
++ * @rsv:		reservation window to add
++ *
++ * Must be called with rsv_lock hold.
++ */
++void ext3cow_rsv_window_add(struct super_block *sb,
++		    struct ext3cow_reserve_window_node *rsv)
++{
++	struct rb_root *root = &EXT3COW_SB(sb)->s_rsv_window_root;
++	struct rb_node *node = &rsv->rsv_node;
++	ext3cow_fsblk_t start = rsv->rsv_start;
++
++	struct rb_node ** p = &root->rb_node;
++	struct rb_node * parent = NULL;
++	struct ext3cow_reserve_window_node *this;
++
++	while (*p)
++	{
++		parent = *p;
++		this = rb_entry(parent, struct ext3cow_reserve_window_node, rsv_node);
++
++		if (start < this->rsv_start)
++			p = &(*p)->rb_left;
++		else if (start > this->rsv_end)
++			p = &(*p)->rb_right;
++		else {
++			rsv_window_dump(root, 1);
++			BUG();
++		}
++	}
++
++	rb_link_node(node, parent, p);
++	rb_insert_color(node, root);
++}
++
++/**
++ * ext3cow_rsv_window_remove() -- unlink a window from the reservation rb tree
++ * @sb:			super block
++ * @rsv:		reservation window to remove
++ *
++ * Mark the block reservation window as not allocated, and unlink it
++ * from the filesystem reservation window rb tree. Must be called with
++ * rsv_lock hold.
++ */
++static void rsv_window_remove(struct super_block *sb,
++			      struct ext3cow_reserve_window_node *rsv)
++{
++	rsv->rsv_start = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++	rsv->rsv_end = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++	rsv->rsv_alloc_hit = 0;
++	rb_erase(&rsv->rsv_node, &EXT3COW_SB(sb)->s_rsv_window_root);
++}
++
++/*
++ * rsv_is_empty() -- Check if the reservation window is allocated.
++ * @rsv:		given reservation window to check
++ *
++ * returns 1 if the end block is EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED.
++ */
++static inline int rsv_is_empty(struct ext3cow_reserve_window *rsv)
++{
++	/* a valid reservation end block could not be 0 */
++	return rsv->_rsv_end == EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++}
++
++/**
++ * ext3cow_init_block_alloc_info()
++ * @inode:		file inode structure
++ *
++ * Allocate and initialize the	reservation window structure, and
++ * link the window to the ext3cow inode structure at last
++ *
++ * The reservation window structure is only dynamically allocated
++ * and linked to ext3cow inode the first time the open file
++ * needs a new block. So, before every ext3cow_new_block(s) call, for
++ * regular files, we should check whether the reservation window
++ * structure exists or not. In the latter case, this function is called.
++ * Fail to do so will result in block reservation being turned off for that
++ * open file.
++ *
++ * This function is called from ext3cow_get_blocks_handle(), also called
++ * when setting the reservation window size through ioctl before the file
++ * is open for write (needs block allocation).
++ *
++ * Needs truncate_mutex protection prior to call this function.
++ */
++void ext3cow_init_block_alloc_info(struct inode *inode)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	struct ext3cow_block_alloc_info *block_i = ei->i_block_alloc_info;
++	struct super_block *sb = inode->i_sb;
++
++	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
++	if (block_i) {
++		struct ext3cow_reserve_window_node *rsv = &block_i->rsv_window_node;
++
++		rsv->rsv_start = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++		rsv->rsv_end = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++
++		/*
++		 * if filesystem is mounted with NORESERVATION, the goal
++		 * reservation window size is set to zero to indicate
++		 * block reservation is off
++		 */
++		if (!test_opt(sb, RESERVATION))
++			rsv->rsv_goal_size = 0;
++		else
++			rsv->rsv_goal_size = EXT3COW_DEFAULT_RESERVE_BLOCKS;
++		rsv->rsv_alloc_hit = 0;
++		block_i->last_alloc_logical_block = 0;
++		block_i->last_alloc_physical_block = 0;
++	}
++	ei->i_block_alloc_info = block_i;
++}
++
++/**
++ * ext3cow_discard_reservation()
++ * @inode:		inode
++ *
++ * Discard(free) block reservation window on last file close, or truncate
++ * or at last iput().
++ *
++ * It is being called in three cases:
++ *	ext3cow_release_file(): last writer close the file
++ *	ext3cow_clear_inode(): last iput(), when nobody link to this file.
++ *	ext3cow_truncate(): when the block indirect map is about to change.
++ *
++ */
++void ext3cow_discard_reservation(struct inode *inode)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	struct ext3cow_block_alloc_info *block_i = ei->i_block_alloc_info;
++	struct ext3cow_reserve_window_node *rsv;
++	spinlock_t *rsv_lock = &EXT3COW_SB(inode->i_sb)->s_rsv_window_lock;
++
++	if (!block_i)
++		return;
++
++	rsv = &block_i->rsv_window_node;
++	if (!rsv_is_empty(&rsv->rsv_window)) {
++		spin_lock(rsv_lock);
++		if (!rsv_is_empty(&rsv->rsv_window))
++			rsv_window_remove(inode->i_sb, rsv);
++		spin_unlock(rsv_lock);
++	}
++}
++
++/**
++ * ext3cow_free_blocks_sb() -- Free given blocks and update quota
++ * @handle:			handle to this transaction
++ * @sb:				super block
++ * @block:			start physcial block to free
++ * @count:			number of blocks to free
++ * @pdquot_freed_blocks:	pointer to quota
++ */
++void ext3cow_free_blocks_sb(handle_t *handle, struct super_block *sb,
++			 ext3cow_fsblk_t block, unsigned long count,
++			 unsigned long *pdquot_freed_blocks)
++{
++	struct buffer_head *bitmap_bh = NULL;
++	struct buffer_head *gd_bh;
++	unsigned long block_group;
++	ext3cow_grpblk_t bit;
++	unsigned long i;
++	unsigned long overflow;
++	struct ext3cow_group_desc * desc;
++	struct ext3cow_super_block * es;
++	struct ext3cow_sb_info *sbi;
++	int err = 0, ret;
++	ext3cow_grpblk_t group_freed;
++
++	*pdquot_freed_blocks = 0;
++	sbi = EXT3COW_SB(sb);
++	es = sbi->s_es;
++	if (block < le32_to_cpu(es->s_first_data_block) ||
++	    block + count < block ||
++	    block + count > le32_to_cpu(es->s_blocks_count)) {
++		ext3cow_error (sb, "ext3cow_free_blocks",
++			    "Freeing blocks not in datazone - "
++			    "block = "E3FSBLK", count = %lu", block, count);
++		goto error_return;
++	}
++
++  //TODO: Remove:
++  printk(KERN_INFO "freeing block(s) %lu-%lu\n", block, block + count - 1);
++	ext3cow_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
++
++do_more:
++	overflow = 0;
++	block_group = (block - le32_to_cpu(es->s_first_data_block)) /
++		      EXT3COW_BLOCKS_PER_GROUP(sb);
++	bit = (block - le32_to_cpu(es->s_first_data_block)) %
++		      EXT3COW_BLOCKS_PER_GROUP(sb);
++	/*
++	 * Check to see if we are freeing blocks across a group
++	 * boundary.
++	 */
++	if (bit + count > EXT3COW_BLOCKS_PER_GROUP(sb)) {
++		overflow = bit + count - EXT3COW_BLOCKS_PER_GROUP(sb);
++		count -= overflow;
++	}
++	brelse(bitmap_bh);
++	bitmap_bh = read_block_bitmap(sb, block_group);
++	if (!bitmap_bh)
++		goto error_return;
++	desc = ext3cow_get_group_desc (sb, block_group, &gd_bh);
++	if (!desc)
++		goto error_return;
++
++	if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
++	    in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
++	    in_range (block, le32_to_cpu(desc->bg_inode_table),
++		      sbi->s_itb_per_group) ||
++	    in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
++		      sbi->s_itb_per_group))
++		ext3cow_error (sb, "ext3cow_free_blocks",
++			    "Freeing blocks in system zones - "
++			    "Block = "E3FSBLK", count = %lu",
++			    block, count);
++
++	/*
++	 * We are about to start releasing blocks in the bitmap,
++	 * so we need undo access.
++	 */
++	/* @@@ check errors */
++	BUFFER_TRACE(bitmap_bh, "getting undo access");
++	err = ext3cow_journal_get_undo_access(handle, bitmap_bh);
++	if (err)
++		goto error_return;
++
++	/*
++	 * We are about to modify some metadata.  Call the journal APIs
++	 * to unshare ->b_data if a currently-committing transaction is
++	 * using it
++	 */
++	BUFFER_TRACE(gd_bh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, gd_bh);
++	if (err)
++		goto error_return;
++
++	jbd_lock_bh_state(bitmap_bh);
++
++	for (i = 0, group_freed = 0; i < count; i++) {
++		/*
++		 * An HJ special.  This is expensive...
++		 */
++#ifdef CONFIG_JBD_DEBUG
++		jbd_unlock_bh_state(bitmap_bh);
++		{
++			struct buffer_head *debug_bh;
++			debug_bh = sb_find_get_block(sb, block + i);
++			if (debug_bh) {
++				BUFFER_TRACE(debug_bh, "Deleted!");
++				if (!bh2jh(bitmap_bh)->b_committed_data)
++					BUFFER_TRACE(debug_bh,
++						"No commited data in bitmap");
++				BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
++				__brelse(debug_bh);
++			}
++		}
++		jbd_lock_bh_state(bitmap_bh);
++#endif
++		if (need_resched()) {
++			jbd_unlock_bh_state(bitmap_bh);
++			cond_resched();
++			jbd_lock_bh_state(bitmap_bh);
++		}
++		/* @@@ This prevents newly-allocated data from being
++		 * freed and then reallocated within the same
++		 * transaction.
++		 *
++		 * Ideally we would want to allow that to happen, but to
++		 * do so requires making journal_forget() capable of
++		 * revoking the queued write of a data block, which
++		 * implies blocking on the journal lock.  *forget()
++		 * cannot block due to truncate races.
++		 *
++		 * Eventually we can fix this by making journal_forget()
++		 * return a status indicating whether or not it was able
++		 * to revoke the buffer.  On successful revoke, it is
++		 * safe not to set the allocation bit in the committed
++		 * bitmap, because we know that there is no outstanding
++		 * activity on the buffer any more and so it is safe to
++		 * reallocate it.
++		 */
++		BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
++		J_ASSERT_BH(bitmap_bh,
++				bh2jh(bitmap_bh)->b_committed_data != NULL);
++		ext3cow_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
++				bh2jh(bitmap_bh)->b_committed_data);
++
++		/*
++		 * We clear the bit in the bitmap after setting the committed
++		 * data bit, because this is the reverse order to that which
++		 * the allocator uses.
++		 */
++		BUFFER_TRACE(bitmap_bh, "clear bit");
++		if (!ext3cow_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
++						bit + i, bitmap_bh->b_data)) {
++			jbd_unlock_bh_state(bitmap_bh);
++			ext3cow_error(sb, __FUNCTION__,
++				"bit already cleared for block "E3FSBLK,
++				 block + i);
++			jbd_lock_bh_state(bitmap_bh);
++			BUFFER_TRACE(bitmap_bh, "bit already cleared");
++		} else {
++			group_freed++;
++		}
++	}
++	jbd_unlock_bh_state(bitmap_bh);
++
++	spin_lock(sb_bgl_lock(sbi, block_group));
++	desc->bg_free_blocks_count =
++		cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
++			group_freed);
++	spin_unlock(sb_bgl_lock(sbi, block_group));
++	percpu_counter_mod(&sbi->s_freeblocks_counter, count);
++
++	/* We dirtied the bitmap block */
++	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
++	err = ext3cow_journal_dirty_metadata(handle, bitmap_bh);
++
++	/* And the group descriptor block */
++	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
++	ret = ext3cow_journal_dirty_metadata(handle, gd_bh);
++	if (!err) err = ret;
++	*pdquot_freed_blocks += group_freed;
++
++	if (overflow && !err) {
++		block += count;
++		count = overflow;
++		goto do_more;
++	}
++	sb->s_dirt = 1;
++error_return:
++	brelse(bitmap_bh);
++	ext3cow_std_error(sb, err);
++	return;
++}
++
++/**
++ * ext3cow_free_blocks() -- Free given blocks and update quota
++ * @handle:		handle for this transaction
++ * @inode:		inode
++ * @block:		start physical block to free
++ * @count:		number of blocks to count
++ */
++void ext3cow_free_blocks(handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t block, unsigned long count)
++{
++	struct super_block * sb;
++	unsigned long dquot_freed_blocks;
++
++	sb = inode->i_sb;
++	if (!sb) {
++		printk ("ext3cow_free_blocks: nonexistent device");
++		return;
++	}
++	ext3cow_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
++	if (dquot_freed_blocks)
++		DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
++	return;
++}
++
++/**
++ * ext3cow_test_allocatable()
++ * @nr:			given allocation block group
++ * @bh:			bufferhead contains the bitmap of the given block group
++ *
++ * For ext3cow allocations, we must not reuse any blocks which are
++ * allocated in the bitmap buffer's "last committed data" copy.  This
++ * prevents deletes from freeing up the page for reuse until we have
++ * committed the delete transaction.
++ *
++ * If we didn't do this, then deleting something and reallocating it as
++ * data would allow the old block to be overwritten before the
++ * transaction committed (because we force data to disk before commit).
++ * This would lead to corruption if we crashed between overwriting the
++ * data and committing the delete.
++ *
++ * @@@ We may want to make this allocation behaviour conditional on
++ * data-writes at some point, and disable it for metadata allocations or
++ * sync-data inodes.
++ */
++static int ext3cow_test_allocatable(ext3cow_grpblk_t nr, struct buffer_head *bh)
++{
++	int ret;
++	struct journal_head *jh = bh2jh(bh);
++
++	if (ext3cow_test_bit(nr, bh->b_data))
++		return 0;
++
++	jbd_lock_bh_state(bh);
++	if (!jh->b_committed_data)
++		ret = 1;
++	else
++		ret = !ext3cow_test_bit(nr, jh->b_committed_data);
++	jbd_unlock_bh_state(bh);
++	return ret;
++}
++
++/**
++ * bitmap_search_next_usable_block()
++ * @start:		the starting block (group relative) of the search
++ * @bh:			bufferhead contains the block group bitmap
++ * @maxblocks:		the ending block (group relative) of the reservation
++ *
++ * The bitmap search --- search forward alternately through the actual
++ * bitmap on disk and the last-committed copy in journal, until we find a
++ * bit free in both bitmaps.
++ */
++static ext3cow_grpblk_t
++bitmap_search_next_usable_block(ext3cow_grpblk_t start, struct buffer_head *bh,
++					ext3cow_grpblk_t maxblocks)
++{
++	ext3cow_grpblk_t next;
++	struct journal_head *jh = bh2jh(bh);
++
++	while (start < maxblocks) {
++		next = ext3cow_find_next_zero_bit(bh->b_data, maxblocks, start);
++		if (next >= maxblocks)
++			return -1;
++		if (ext3cow_test_allocatable(next, bh))
++			return next;
++		jbd_lock_bh_state(bh);
++		if (jh->b_committed_data)
++			start = ext3cow_find_next_zero_bit(jh->b_committed_data,
++							maxblocks, next);
++		jbd_unlock_bh_state(bh);
++	}
++	return -1;
++}
++
++/**
++ * find_next_usable_block()
++ * @start:		the starting block (group relative) to find next
++ *			allocatable block in bitmap.
++ * @bh:			bufferhead contains the block group bitmap
++ * @maxblocks:		the ending block (group relative) for the search
++ *
++ * Find an allocatable block in a bitmap.  We honor both the bitmap and
++ * its last-committed copy (if that exists), and perform the "most
++ * appropriate allocation" algorithm of looking for a free block near
++ * the initial goal; then for a free byte somewhere in the bitmap; then
++ * for any free bit in the bitmap.
++ */
++static ext3cow_grpblk_t
++find_next_usable_block(ext3cow_grpblk_t start, struct buffer_head *bh,
++			ext3cow_grpblk_t maxblocks)
++{
++	ext3cow_grpblk_t here, next;
++	char *p, *r;
++
++	if (start > 0) {
++		/*
++		 * The goal was occupied; search forward for a free
++		 * block within the next XX blocks.
++		 *
++		 * end_goal is more or less random, but it has to be
++		 * less than EXT3COW_BLOCKS_PER_GROUP. Aligning up to the
++		 * next 64-bit boundary is simple..
++		 */
++		ext3cow_grpblk_t end_goal = (start + 63) & ~63;
++		if (end_goal > maxblocks)
++			end_goal = maxblocks;
++		here = ext3cow_find_next_zero_bit(bh->b_data, end_goal, start);
++		if (here < end_goal && ext3cow_test_allocatable(here, bh))
++			return here;
++		ext3cow_debug("Bit not found near goal\n");
++	}
++
++	here = start;
++	if (here < 0)
++		here = 0;
++
++	p = ((char *)bh->b_data) + (here >> 3);
++	r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3));
++	next = (r - ((char *)bh->b_data)) << 3;
++
++	if (next < maxblocks && next >= start && ext3cow_test_allocatable(next, bh))
++		return next;
++
++	/*
++	 * The bitmap search --- search forward alternately through the actual
++	 * bitmap and the last-committed copy until we find a bit free in
++	 * both
++	 */
++	here = bitmap_search_next_usable_block(here, bh, maxblocks);
++	return here;
++}
++
++/**
++ * claim_block()
++ * @block:		the free block (group relative) to allocate
++ * @bh:			the bufferhead containts the block group bitmap
++ *
++ * We think we can allocate this block in this bitmap.  Try to set the bit.
++ * If that succeeds then check that nobody has allocated and then freed the
++ * block since we saw that is was not marked in b_committed_data.  If it _was_
++ * allocated and freed then clear the bit in the bitmap again and return
++ * zero (failure).
++ */
++static inline int
++claim_block(spinlock_t *lock, ext3cow_grpblk_t block, struct buffer_head *bh)
++{
++	struct journal_head *jh = bh2jh(bh);
++	int ret;
++
++	if (ext3cow_set_bit_atomic(lock, block, bh->b_data))
++		return 0;
++	jbd_lock_bh_state(bh);
++	if (jh->b_committed_data && ext3cow_test_bit(block,jh->b_committed_data)) {
++		ext3cow_clear_bit_atomic(lock, block, bh->b_data);
++		ret = 0;
++	} else {
++		ret = 1;
++	}
++	jbd_unlock_bh_state(bh);
++	return ret;
++}
++
++/**
++ * ext3cow_try_to_allocate()
++ * @sb:			superblock
++ * @handle:		handle to this transaction
++ * @group:		given allocation block group
++ * @bitmap_bh:		bufferhead holds the block bitmap
++ * @grp_goal:		given target block within the group
++ * @count:		target number of blocks to allocate
++ * @my_rsv:		reservation window
++ *
++ * Attempt to allocate blocks within a give range. Set the range of allocation
++ * first, then find the first free bit(s) from the bitmap (within the range),
++ * and at last, allocate the blocks by claiming the found free bit as allocated.
++ *
++ * To set the range of this allocation:
++ *	if there is a reservation window, only try to allocate block(s) from the
++ *	file's own reservation window;
++ *	Otherwise, the allocation range starts from the give goal block, ends at
++ *	the block group's last block.
++ *
++ * If we failed to allocate the desired block then we may end up crossing to a
++ * new bitmap.  In that case we must release write access to the old one via
++ * ext3cow_journal_release_buffer(), else we'll run out of credits.
++ */
++static ext3cow_grpblk_t
++ext3cow_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
++			struct buffer_head *bitmap_bh, ext3cow_grpblk_t grp_goal,
++			unsigned long *count, struct ext3cow_reserve_window *my_rsv)
++{
++	ext3cow_fsblk_t group_first_block;
++	ext3cow_grpblk_t start, end;
++	unsigned long num = 0;
++
++	/* we do allocation within the reservation window if we have a window */
++	if (my_rsv) {
++		group_first_block = ext3cow_group_first_block_no(sb, group);
++		if (my_rsv->_rsv_start >= group_first_block)
++			start = my_rsv->_rsv_start - group_first_block;
++		else
++			/* reservation window cross group boundary */
++			start = 0;
++		end = my_rsv->_rsv_end - group_first_block + 1;
++		if (end > EXT3COW_BLOCKS_PER_GROUP(sb))
++			/* reservation window crosses group boundary */
++			end = EXT3COW_BLOCKS_PER_GROUP(sb);
++		if ((start <= grp_goal) && (grp_goal < end))
++			start = grp_goal;
++		else
++			grp_goal = -1;
++	} else {
++		if (grp_goal > 0)
++			start = grp_goal;
++		else
++			start = 0;
++		end = EXT3COW_BLOCKS_PER_GROUP(sb);
++	}
++
++	BUG_ON(start > EXT3COW_BLOCKS_PER_GROUP(sb));
++
++repeat:
++	if (grp_goal < 0 || !ext3cow_test_allocatable(grp_goal, bitmap_bh)) {
++		grp_goal = find_next_usable_block(start, bitmap_bh, end);
++		if (grp_goal < 0)
++			goto fail_access;
++		if (!my_rsv) {
++			int i;
++
++			for (i = 0; i < 7 && grp_goal > start &&
++					ext3cow_test_allocatable(grp_goal - 1,
++								bitmap_bh);
++					i++, grp_goal--)
++				;
++		}
++	}
++	start = grp_goal;
++
++	if (!claim_block(sb_bgl_lock(EXT3COW_SB(sb), group),
++		grp_goal, bitmap_bh)) {
++		/*
++		 * The block was allocated by another thread, or it was
++		 * allocated and then freed by another thread
++		 */
++		start++;
++		grp_goal++;
++		if (start >= end)
++			goto fail_access;
++		goto repeat;
++	}
++	num++;
++	grp_goal++;
++	while (num < *count && grp_goal < end
++		&& ext3cow_test_allocatable(grp_goal, bitmap_bh)
++		&& claim_block(sb_bgl_lock(EXT3COW_SB(sb), group),
++				grp_goal, bitmap_bh)) {
++		num++;
++		grp_goal++;
++	}
++	*count = num;
++	return grp_goal - num;
++fail_access:
++	*count = num;
++	return -1;
++}
++
++/**
++ *	find_next_reservable_window():
++ *		find a reservable space within the given range.
++ *		It does not allocate the reservation window for now:
++ *		alloc_new_reservation() will do the work later.
++ *
++ *	@search_head: the head of the searching list;
++ *		This is not necessarily the list head of the whole filesystem
++ *
++ *		We have both head and start_block to assist the search
++ *		for the reservable space. The list starts from head,
++ *		but we will shift to the place where start_block is,
++ *		then start from there, when looking for a reservable space.
++ *
++ *	@size: the target new reservation window size
++ *
++ *	@group_first_block: the first block we consider to start
++ *			the real search from
++ *
++ *	@last_block:
++ *		the maximum block number that our goal reservable space
++ *		could start from. This is normally the last block in this
++ *		group. The search will end when we found the start of next
++ *		possible reservable space is out of this boundary.
++ *		This could handle the cross boundary reservation window
++ *		request.
++ *
++ *	basically we search from the given range, rather than the whole
++ *	reservation double linked list, (start_block, last_block)
++ *	to find a free region that is of my size and has not
++ *	been reserved.
++ *
++ */
++static int find_next_reservable_window(
++				struct ext3cow_reserve_window_node *search_head,
++				struct ext3cow_reserve_window_node *my_rsv,
++				struct super_block * sb,
++				ext3cow_fsblk_t start_block,
++				ext3cow_fsblk_t last_block)
++{
++	struct rb_node *next;
++	struct ext3cow_reserve_window_node *rsv, *prev;
++	ext3cow_fsblk_t cur;
++	int size = my_rsv->rsv_goal_size;
++
++	/* TODO: make the start of the reservation window byte-aligned */
++	/* cur = *start_block & ~7;*/
++	cur = start_block;
++	rsv = search_head;
++	if (!rsv)
++		return -1;
++
++	while (1) {
++		if (cur <= rsv->rsv_end)
++			cur = rsv->rsv_end + 1;
++
++		/* TODO?
++		 * in the case we could not find a reservable space
++		 * that is what is expected, during the re-search, we could
++		 * remember what's the largest reservable space we could have
++		 * and return that one.
++		 *
++		 * For now it will fail if we could not find the reservable
++		 * space with expected-size (or more)...
++		 */
++		if (cur > last_block)
++			return -1;		/* fail */
++
++		prev = rsv;
++		next = rb_next(&rsv->rsv_node);
++		rsv = rb_entry(next,struct ext3cow_reserve_window_node,rsv_node);
++
++		/*
++		 * Reached the last reservation, we can just append to the
++		 * previous one.
++		 */
++		if (!next)
++			break;
++
++		if (cur + size <= rsv->rsv_start) {
++			/*
++			 * Found a reserveable space big enough.  We could
++			 * have a reservation across the group boundary here
++			 */
++			break;
++		}
++	}
++	/*
++	 * we come here either :
++	 * when we reach the end of the whole list,
++	 * and there is empty reservable space after last entry in the list.
++	 * append it to the end of the list.
++	 *
++	 * or we found one reservable space in the middle of the list,
++	 * return the reservation window that we could append to.
++	 * succeed.
++	 */
++
++	if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
++		rsv_window_remove(sb, my_rsv);
++
++	/*
++	 * Let's book the whole avaliable window for now.  We will check the
++	 * disk bitmap later and then, if there are free blocks then we adjust
++	 * the window size if it's larger than requested.
++	 * Otherwise, we will remove this node from the tree next time
++	 * call find_next_reservable_window.
++	 */
++	my_rsv->rsv_start = cur;
++	my_rsv->rsv_end = cur + size - 1;
++	my_rsv->rsv_alloc_hit = 0;
++
++	if (prev != my_rsv)
++		ext3cow_rsv_window_add(sb, my_rsv);
++
++	return 0;
++}
++
++/**
++ *	alloc_new_reservation()--allocate a new reservation window
++ *
++ *		To make a new reservation, we search part of the filesystem
++ *		reservation list (the list that inside the group). We try to
++ *		allocate a new reservation window near the allocation goal,
++ *		or the beginning of the group, if there is no goal.
++ *
++ *		We first find a reservable space after the goal, then from
++ *		there, we check the bitmap for the first free block after
++ *		it. If there is no free block until the end of group, then the
++ *		whole group is full, we failed. Otherwise, check if the free
++ *		block is inside the expected reservable space, if so, we
++ *		succeed.
++ *		If the first free block is outside the reservable space, then
++ *		start from the first free block, we search for next available
++ *		space, and go on.
++ *
++ *	on succeed, a new reservation will be found and inserted into the list
++ *	It contains at least one free block, and it does not overlap with other
++ *	reservation windows.
++ *
++ *	failed: we failed to find a reservation window in this group
++ *
++ *	@rsv: the reservation
++ *
++ *	@grp_goal: The goal (group-relative).  It is where the search for a
++ *		free reservable space should start from.
++ *		if we have a grp_goal(grp_goal >0 ), then start from there,
++ *		no grp_goal(grp_goal = -1), we start from the first block
++ *		of the group.
++ *
++ *	@sb: the super block
++ *	@group: the group we are trying to allocate in
++ *	@bitmap_bh: the block group block bitmap
++ *
++ */
++static int alloc_new_reservation(struct ext3cow_reserve_window_node *my_rsv,
++		ext3cow_grpblk_t grp_goal, struct super_block *sb,
++		unsigned int group, struct buffer_head *bitmap_bh)
++{
++	struct ext3cow_reserve_window_node *search_head;
++	ext3cow_fsblk_t group_first_block, group_end_block, start_block;
++	ext3cow_grpblk_t first_free_block;
++	struct rb_root *fs_rsv_root = &EXT3COW_SB(sb)->s_rsv_window_root;
++	unsigned long size;
++	int ret;
++	spinlock_t *rsv_lock = &EXT3COW_SB(sb)->s_rsv_window_lock;
++
++	group_first_block = ext3cow_group_first_block_no(sb, group);
++	group_end_block = group_first_block + (EXT3COW_BLOCKS_PER_GROUP(sb) - 1);
++
++	if (grp_goal < 0)
++		start_block = group_first_block;
++	else
++		start_block = grp_goal + group_first_block;
++
++	size = my_rsv->rsv_goal_size;
++
++	if (!rsv_is_empty(&my_rsv->rsv_window)) {
++		/*
++		 * if the old reservation is cross group boundary
++		 * and if the goal is inside the old reservation window,
++		 * we will come here when we just failed to allocate from
++		 * the first part of the window. We still have another part
++		 * that belongs to the next group. In this case, there is no
++		 * point to discard our window and try to allocate a new one
++		 * in this group(which will fail). we should
++		 * keep the reservation window, just simply move on.
++		 *
++		 * Maybe we could shift the start block of the reservation
++		 * window to the first block of next group.
++		 */
++
++		if ((my_rsv->rsv_start <= group_end_block) &&
++				(my_rsv->rsv_end > group_end_block) &&
++				(start_block >= my_rsv->rsv_start))
++			return -1;
++
++		if ((my_rsv->rsv_alloc_hit >
++		     (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
++			/*
++			 * if the previously allocation hit ratio is
++			 * greater than 1/2, then we double the size of
++			 * the reservation window the next time,
++			 * otherwise we keep the same size window
++			 */
++			size = size * 2;
++			if (size > EXT3COW_MAX_RESERVE_BLOCKS)
++				size = EXT3COW_MAX_RESERVE_BLOCKS;
++			my_rsv->rsv_goal_size= size;
++		}
++	}
++
++	spin_lock(rsv_lock);
++	/*
++	 * shift the search start to the window near the goal block
++	 */
++	search_head = search_reserve_window(fs_rsv_root, start_block);
++
++	/*
++	 * find_next_reservable_window() simply finds a reservable window
++	 * inside the given range(start_block, group_end_block).
++	 *
++	 * To make sure the reservation window has a free bit inside it, we
++	 * need to check the bitmap after we found a reservable window.
++	 */
++retry:
++	ret = find_next_reservable_window(search_head, my_rsv, sb,
++						start_block, group_end_block);
++
++	if (ret == -1) {
++		if (!rsv_is_empty(&my_rsv->rsv_window))
++			rsv_window_remove(sb, my_rsv);
++		spin_unlock(rsv_lock);
++		return -1;
++	}
++
++	/*
++	 * On success, find_next_reservable_window() returns the
++	 * reservation window where there is a reservable space after it.
++	 * Before we reserve this reservable space, we need
++	 * to make sure there is at least a free block inside this region.
++	 *
++	 * searching the first free bit on the block bitmap and copy of
++	 * last committed bitmap alternatively, until we found a allocatable
++	 * block. Search start from the start block of the reservable space
++	 * we just found.
++	 */
++	spin_unlock(rsv_lock);
++	first_free_block = bitmap_search_next_usable_block(
++			my_rsv->rsv_start - group_first_block,
++			bitmap_bh, group_end_block - group_first_block + 1);
++
++	if (first_free_block < 0) {
++		/*
++		 * no free block left on the bitmap, no point
++		 * to reserve the space. return failed.
++		 */
++		spin_lock(rsv_lock);
++		if (!rsv_is_empty(&my_rsv->rsv_window))
++			rsv_window_remove(sb, my_rsv);
++		spin_unlock(rsv_lock);
++		return -1;		/* failed */
++	}
++
++	start_block = first_free_block + group_first_block;
++	/*
++	 * check if the first free block is within the
++	 * free space we just reserved
++	 */
++	if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end)
++		return 0;		/* success */
++	/*
++	 * if the first free bit we found is out of the reservable space
++	 * continue search for next reservable space,
++	 * start from where the free block is,
++	 * we also shift the list head to where we stopped last time
++	 */
++	search_head = my_rsv;
++	spin_lock(rsv_lock);
++	goto retry;
++}
++
++/**
++ * try_to_extend_reservation()
++ * @my_rsv:		given reservation window
++ * @sb:			super block
++ * @size:		the delta to extend
++ *
++ * Attempt to expand the reservation window large enough to have
++ * required number of free blocks
++ *
++ * Since ext3cow_try_to_allocate() will always allocate blocks within
++ * the reservation window range, if the window size is too small,
++ * multiple blocks allocation has to stop at the end of the reservation
++ * window. To make this more efficient, given the total number of
++ * blocks needed and the current size of the window, we try to
++ * expand the reservation window size if necessary on a best-effort
++ * basis before ext3cow_new_blocks() tries to allocate blocks,
++ */
++static void try_to_extend_reservation(struct ext3cow_reserve_window_node *my_rsv,
++			struct super_block *sb, int size)
++{
++	struct ext3cow_reserve_window_node *next_rsv;
++	struct rb_node *next;
++	spinlock_t *rsv_lock = &EXT3COW_SB(sb)->s_rsv_window_lock;
++
++	if (!spin_trylock(rsv_lock))
++		return;
++
++	next = rb_next(&my_rsv->rsv_node);
++
++	if (!next)
++		my_rsv->rsv_end += size;
++	else {
++		next_rsv = rb_entry(next, struct ext3cow_reserve_window_node, rsv_node);
++
++		if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
++			my_rsv->rsv_end += size;
++		else
++			my_rsv->rsv_end = next_rsv->rsv_start - 1;
++	}
++	spin_unlock(rsv_lock);
++}
++
++/**
++ * ext3cow_try_to_allocate_with_rsv()
++ * @sb:			superblock
++ * @handle:		handle to this transaction
++ * @group:		given allocation block group
++ * @bitmap_bh:		bufferhead holds the block bitmap
++ * @grp_goal:		given target block within the group
++ * @count:		target number of blocks to allocate
++ * @my_rsv:		reservation window
++ * @errp:		pointer to store the error code
++ *
++ * This is the main function used to allocate a new block and its reservation
++ * window.
++ *
++ * Each time when a new block allocation is need, first try to allocate from
++ * its own reservation.  If it does not have a reservation window, instead of
++ * looking for a free bit on bitmap first, then look up the reservation list to
++ * see if it is inside somebody else's reservation window, we try to allocate a
++ * reservation window for it starting from the goal first. Then do the block
++ * allocation within the reservation window.
++ *
++ * This will avoid keeping on searching the reservation list again and
++ * again when somebody is looking for a free block (without
++ * reservation), and there are lots of free blocks, but they are all
++ * being reserved.
++ *
++ * We use a red-black tree for the per-filesystem reservation list.
++ *
++ */
++static ext3cow_grpblk_t
++ext3cow_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
++			unsigned int group, struct buffer_head *bitmap_bh,
++			ext3cow_grpblk_t grp_goal,
++			struct ext3cow_reserve_window_node * my_rsv,
++			unsigned long *count, int *errp)
++{
++	ext3cow_fsblk_t group_first_block, group_last_block;
++	ext3cow_grpblk_t ret = 0;
++	int fatal;
++	unsigned long num = *count;
++
++	*errp = 0;
++
++	/*
++	 * Make sure we use undo access for the bitmap, because it is critical
++	 * that we do the frozen_data COW on bitmap buffers in all cases even
++	 * if the buffer is in BJ_Forget state in the committing transaction.
++	 */
++	BUFFER_TRACE(bitmap_bh, "get undo access for new block");
++	fatal = ext3cow_journal_get_undo_access(handle, bitmap_bh);
++	if (fatal) {
++		*errp = fatal;
++		return -1;
++	}
++
++	/*
++	 * we don't deal with reservation when
++	 * filesystem is mounted without reservation
++	 * or the file is not a regular file
++	 * or last attempt to allocate a block with reservation turned on failed
++	 */
++	if (my_rsv == NULL ) {
++		ret = ext3cow_try_to_allocate(sb, handle, group, bitmap_bh,
++						grp_goal, count, NULL);
++		goto out;
++	}
++	/*
++	 * grp_goal is a group relative block number (if there is a goal)
++	 * 0 <= grp_goal < EXT3COW_BLOCKS_PER_GROUP(sb)
++	 * first block is a filesystem wide block number
++	 * first block is the block number of the first block in this group
++	 */
++	group_first_block = ext3cow_group_first_block_no(sb, group);
++	group_last_block = group_first_block + (EXT3COW_BLOCKS_PER_GROUP(sb) - 1);
++
++	/*
++	 * Basically we will allocate a new block from inode's reservation
++	 * window.
++	 *
++	 * We need to allocate a new reservation window, if:
++	 * a) inode does not have a reservation window; or
++	 * b) last attempt to allocate a block from existing reservation
++	 *    failed; or
++	 * c) we come here with a goal and with a reservation window
++	 *
++	 * We do not need to allocate a new reservation window if we come here
++	 * at the beginning with a goal and the goal is inside the window, or
++	 * we don't have a goal but already have a reservation window.
++	 * then we could go to allocate from the reservation window directly.
++	 */
++	while (1) {
++		if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
++			!goal_in_my_reservation(&my_rsv->rsv_window,
++						grp_goal, group, sb)) {
++			if (my_rsv->rsv_goal_size < *count)
++				my_rsv->rsv_goal_size = *count;
++			ret = alloc_new_reservation(my_rsv, grp_goal, sb,
++							group, bitmap_bh);
++			if (ret < 0)
++				break;			/* failed */
++
++			if (!goal_in_my_reservation(&my_rsv->rsv_window,
++							grp_goal, group, sb))
++				grp_goal = -1;
++		} else if (grp_goal >= 0) {
++			int curr = my_rsv->rsv_end -
++					(grp_goal + group_first_block) + 1;
++
++			if (curr < *count)
++				try_to_extend_reservation(my_rsv, sb,
++							*count - curr);
++		}
++
++		if ((my_rsv->rsv_start > group_last_block) ||
++				(my_rsv->rsv_end < group_first_block)) {
++			rsv_window_dump(&EXT3COW_SB(sb)->s_rsv_window_root, 1);
++			BUG();
++		}
++		ret = ext3cow_try_to_allocate(sb, handle, group, bitmap_bh,
++					   grp_goal, &num, &my_rsv->rsv_window);
++		if (ret >= 0) {
++			my_rsv->rsv_alloc_hit += num;
++			*count = num;
++			break;				/* succeed */
++		}
++		num = *count;
++	}
++out:
++	if (ret >= 0) {
++		BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
++					"bitmap block");
++		fatal = ext3cow_journal_dirty_metadata(handle, bitmap_bh);
++		if (fatal) {
++			*errp = fatal;
++			return -1;
++		}
++		return ret;
++	}
++
++	BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
++	ext3cow_journal_release_buffer(handle, bitmap_bh);
++	return ret;
++}
++
++/**
++ * ext3cow_has_free_blocks()
++ * @sbi:		in-core super block structure.
++ *
++ * Check if filesystem has at least 1 free block available for allocation.
++ */
++static int ext3cow_has_free_blocks(struct ext3cow_sb_info *sbi)
++{
++	ext3cow_fsblk_t free_blocks, root_blocks;
++
++	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
++	root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
++	if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
++		sbi->s_resuid != current->fsuid &&
++		(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
++		return 0;
++	}
++	return 1;
++}
++
++/**
++ * ext3cow_should_retry_alloc()
++ * @sb:			super block
++ * @retries		number of attemps has been made
++ *
++ * ext3cow_should_retry_alloc() is called when ENOSPC is returned, and if
++ * it is profitable to retry the operation, this function will wait
++ * for the current or commiting transaction to complete, and then
++ * return TRUE.
++ *
++ * if the total number of retries exceed three times, return FALSE.
++ */
++int ext3cow_should_retry_alloc(struct super_block *sb, int *retries)
++{
++	if (!ext3cow_has_free_blocks(EXT3COW_SB(sb)) || (*retries)++ > 3)
++		return 0;
++
++	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
++
++	return journal_force_commit_nested(EXT3COW_SB(sb)->s_journal);
++}
++
++/**
++ * ext3cow_new_blocks() -- core block(s) allocation function
++ * @handle:		handle to this transaction
++ * @inode:		file inode
++ * @goal:		given target block(filesystem wide)
++ * @count:		target number of blocks to allocate
++ * @errp:		error code
++ *
++ * ext3cow_new_blocks uses a goal block to assist allocation.  It tries to
++ * allocate block(s) from the block group contains the goal block first. If that
++ * fails, it will try to allocate block(s) from other block groups without
++ * any specific goal block.
++ *
++ */
++ext3cow_fsblk_t ext3cow_new_blocks(handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t goal, unsigned long *count, int *errp)
++{
++	struct buffer_head *bitmap_bh = NULL;
++	struct buffer_head *gdp_bh;
++	int group_no;
++	int goal_group;
++	ext3cow_grpblk_t grp_target_blk;	/* blockgroup relative goal block */
++	ext3cow_grpblk_t grp_alloc_blk;	/* blockgroup-relative allocated block*/
++	ext3cow_fsblk_t ret_block;		/* filesyetem-wide allocated block */
++	int bgi;			/* blockgroup iteration index */
++	int fatal = 0, err;
++	int performed_allocation = 0;
++	ext3cow_grpblk_t free_blocks;	/* number of free blocks in a group */
++	struct super_block *sb;
++	struct ext3cow_group_desc *gdp;
++	struct ext3cow_super_block *es;
++	struct ext3cow_sb_info *sbi;
++	struct ext3cow_reserve_window_node *my_rsv = NULL;
++	struct ext3cow_block_alloc_info *block_i;
++	unsigned short windowsz = 0;
++#ifdef EXT3COWFS_DEBUG
++	static int goal_hits, goal_attempts;
++#endif
++	unsigned long ngroups;
++	unsigned long num = *count;
++
++	*errp = -ENOSPC;
++	sb = inode->i_sb;
++	if (!sb) {
++		printk("ext3cow_new_block: nonexistent device");
++		return 0;
++	}
++
++	/*
++	 * Check quota for allocation of this block.
++	 */
++	if (DQUOT_ALLOC_BLOCK(inode, num)) {
++		*errp = -EDQUOT;
++		return 0;
++	}
++
++	sbi = EXT3COW_SB(sb);
++	es = EXT3COW_SB(sb)->s_es;
++	ext3cow_debug("goal=%lu.\n", goal);
++	/*
++	 * Allocate a block from reservation only when
++	 * filesystem is mounted with reservation(default,-o reservation), and
++	 * it's a regular file, and
++	 * the desired window size is greater than 0 (One could use ioctl
++	 * command EXT3COW_IOC_SETRSVSZ to set the window size to 0 to turn off
++	 * reservation on that particular file)
++	 */
++	block_i = EXT3COW_I(inode)->i_block_alloc_info;
++	if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
++		my_rsv = &block_i->rsv_window_node;
++
++	if (!ext3cow_has_free_blocks(sbi)) {
++		*errp = -ENOSPC;
++		goto out;
++	}
++
++	/*
++	 * First, test whether the goal block is free.
++	 */
++	if (goal < le32_to_cpu(es->s_first_data_block) ||
++	    goal >= le32_to_cpu(es->s_blocks_count))
++		goal = le32_to_cpu(es->s_first_data_block);
++	group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
++			EXT3COW_BLOCKS_PER_GROUP(sb);
++	goal_group = group_no;
++retry_alloc:
++	gdp = ext3cow_get_group_desc(sb, group_no, &gdp_bh);
++	if (!gdp)
++		goto io_error;
++
++	free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
++	/*
++	 * if there is not enough free blocks to make a new resevation
++	 * turn off reservation for this allocation
++	 */
++	if (my_rsv && (free_blocks < windowsz)
++		&& (rsv_is_empty(&my_rsv->rsv_window)))
++		my_rsv = NULL;
++
++	if (free_blocks > 0) {
++		grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
++				EXT3COW_BLOCKS_PER_GROUP(sb));
++		bitmap_bh = read_block_bitmap(sb, group_no);
++		if (!bitmap_bh)
++			goto io_error;
++		grp_alloc_blk = ext3cow_try_to_allocate_with_rsv(sb, handle,
++					group_no, bitmap_bh, grp_target_blk,
++					my_rsv,	&num, &fatal);
++		if (fatal)
++			goto out;
++		if (grp_alloc_blk >= 0)
++			goto allocated;
++	}
++
++	ngroups = EXT3COW_SB(sb)->s_groups_count;
++	smp_rmb();
++
++	/*
++	 * Now search the rest of the groups.  We assume that
++	 * i and gdp correctly point to the last group visited.
++	 */
++	for (bgi = 0; bgi < ngroups; bgi++) {
++		group_no++;
++		if (group_no >= ngroups)
++			group_no = 0;
++		gdp = ext3cow_get_group_desc(sb, group_no, &gdp_bh);
++		if (!gdp)
++			goto io_error;
++		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
++		/*
++		 * skip this group if the number of
++		 * free blocks is less than half of the reservation
++		 * window size.
++		 */
++		if (free_blocks <= (windowsz/2))
++			continue;
++
++		brelse(bitmap_bh);
++		bitmap_bh = read_block_bitmap(sb, group_no);
++		if (!bitmap_bh)
++			goto io_error;
++		/*
++		 * try to allocate block(s) from this group, without a goal(-1).
++		 */
++		grp_alloc_blk = ext3cow_try_to_allocate_with_rsv(sb, handle,
++					group_no, bitmap_bh, -1, my_rsv,
++					&num, &fatal);
++		if (fatal)
++			goto out;
++		if (grp_alloc_blk >= 0)
++			goto allocated;
++	}
++	/*
++	 * We may end up a bogus ealier ENOSPC error due to
++	 * filesystem is "full" of reservations, but
++	 * there maybe indeed free blocks avaliable on disk
++	 * In this case, we just forget about the reservations
++	 * just do block allocation as without reservations.
++	 */
++	if (my_rsv) {
++		my_rsv = NULL;
++		windowsz = 0;
++		group_no = goal_group;
++		goto retry_alloc;
++	}
++	/* No space left on the device */
++	*errp = -ENOSPC;
++	goto out;
++
++allocated:
++
++	ext3cow_debug("using block group %d(%d)\n",
++			group_no, gdp->bg_free_blocks_count);
++
++	BUFFER_TRACE(gdp_bh, "get_write_access");
++	fatal = ext3cow_journal_get_write_access(handle, gdp_bh);
++	if (fatal)
++		goto out;
++
++	ret_block = grp_alloc_blk + ext3cow_group_first_block_no(sb, group_no);
++
++	if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
++	    in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
++	    in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
++		      EXT3COW_SB(sb)->s_itb_per_group) ||
++	    in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
++		      EXT3COW_SB(sb)->s_itb_per_group))
++		ext3cow_error(sb, "ext3cow_new_block",
++			    "Allocating block in system zone - "
++			    "blocks from "E3FSBLK", length %lu",
++			     ret_block, num);
++
++	performed_allocation = 1;
++
++#ifdef CONFIG_JBD_DEBUG
++	{
++		struct buffer_head *debug_bh;
++
++		/* Record bitmap buffer state in the newly allocated block */
++		debug_bh = sb_find_get_block(sb, ret_block);
++		if (debug_bh) {
++			BUFFER_TRACE(debug_bh, "state when allocated");
++			BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
++			brelse(debug_bh);
++		}
++	}
++	jbd_lock_bh_state(bitmap_bh);
++	spin_lock(sb_bgl_lock(sbi, group_no));
++	if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
++		int i;
++
++		for (i = 0; i < num; i++) {
++			if (ext3cow_test_bit(grp_alloc_blk+i,
++					bh2jh(bitmap_bh)->b_committed_data)) {
++				printk("%s: block was unexpectedly set in "
++					"b_committed_data\n", __FUNCTION__);
++			}
++		}
++	}
++	ext3cow_debug("found bit %d\n", grp_alloc_blk);
++	spin_unlock(sb_bgl_lock(sbi, group_no));
++	jbd_unlock_bh_state(bitmap_bh);
++#endif
++
++	if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
++		ext3cow_error(sb, "ext3cow_new_block",
++			    "block("E3FSBLK") >= blocks count(%d) - "
++			    "block_group = %d, es == %p ", ret_block,
++			le32_to_cpu(es->s_blocks_count), group_no, es);
++		goto out;
++	}
++
++	/*
++	 * It is up to the caller to add the new buffer to a journal
++	 * list of some description.  We don't know in advance whether
++	 * the caller wants to use it as metadata or data.
++	 */
++	ext3cow_debug("allocating block %lu. Goal hits %d of %d.\n",
++			ret_block, goal_hits, goal_attempts);
++
++	spin_lock(sb_bgl_lock(sbi, group_no));
++	gdp->bg_free_blocks_count =
++			cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
++	spin_unlock(sb_bgl_lock(sbi, group_no));
++	percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
++
++	BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
++	err = ext3cow_journal_dirty_metadata(handle, gdp_bh);
++	if (!fatal)
++		fatal = err;
++
++	sb->s_dirt = 1;
++	if (fatal)
++		goto out;
++
++	*errp = 0;
++	brelse(bitmap_bh);
++	DQUOT_FREE_BLOCK(inode, *count-num);
++	*count = num;
++	return ret_block;
++
++io_error:
++	*errp = -EIO;
++out:
++	if (fatal) {
++		*errp = fatal;
++		ext3cow_std_error(sb, fatal);
++	}
++	/*
++	 * Undo the block allocation
++	 */
++	if (!performed_allocation)
++		DQUOT_FREE_BLOCK(inode, *count);
++	brelse(bitmap_bh);
++	return 0;
++}
++
++ext3cow_fsblk_t ext3cow_new_block(handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t goal, int *errp)
++{
++	unsigned long count = 1;
++
++	return ext3cow_new_blocks(handle, inode, goal, &count, errp);
++}
++
++/**
++ * ext3cow_count_free_blocks() -- count filesystem free blocks
++ * @sb:		superblock
++ *
++ * Adds up the number of free blocks from each block group.
++ */
++ext3cow_fsblk_t ext3cow_count_free_blocks(struct super_block *sb)
++{
++	ext3cow_fsblk_t desc_count;
++	struct ext3cow_group_desc *gdp;
++	int i;
++	unsigned long ngroups = EXT3COW_SB(sb)->s_groups_count;
++#ifdef EXT3COWFS_DEBUG
++	struct ext3cow_super_block *es;
++	ext3cow_fsblk_t bitmap_count;
++	unsigned long x;
++	struct buffer_head *bitmap_bh = NULL;
++
++	es = EXT3COW_SB(sb)->s_es;
++	desc_count = 0;
++	bitmap_count = 0;
++	gdp = NULL;
++
++	smp_rmb();
++	for (i = 0; i < ngroups; i++) {
++		gdp = ext3cow_get_group_desc(sb, i, NULL);
++		if (!gdp)
++			continue;
++		desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
++		brelse(bitmap_bh);
++		bitmap_bh = read_block_bitmap(sb, i);
++		if (bitmap_bh == NULL)
++			continue;
++
++		x = ext3cow_count_free(bitmap_bh, sb->s_blocksize);
++		printk("group %d: stored = %d, counted = %lu\n",
++			i, le16_to_cpu(gdp->bg_free_blocks_count), x);
++		bitmap_count += x;
++	}
++	brelse(bitmap_bh);
++	printk("ext3cow_count_free_blocks: stored = "E3FSBLK
++		", computed = "E3FSBLK", "E3FSBLK"\n",
++	       le32_to_cpu(es->s_free_blocks_count),
++		desc_count, bitmap_count);
++	return bitmap_count;
++#else
++	desc_count = 0;
++	smp_rmb();
++	for (i = 0; i < ngroups; i++) {
++		gdp = ext3cow_get_group_desc(sb, i, NULL);
++		if (!gdp)
++			continue;
++		desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
++	}
++
++	return desc_count;
++#endif
++}
++
++static inline int
++block_in_use(ext3cow_fsblk_t block, struct super_block *sb, unsigned char *map)
++{
++	return ext3cow_test_bit ((block -
++		le32_to_cpu(EXT3COW_SB(sb)->s_es->s_first_data_block)) %
++			 EXT3COW_BLOCKS_PER_GROUP(sb), map);
++}
++
++static inline int test_root(int a, int b)
++{
++	int num = b;
++
++	while (a > num)
++		num *= b;
++	return num == a;
++}
++
++static int ext3cow_group_sparse(int group)
++{
++	if (group <= 1)
++		return 1;
++	if (!(group & 1))
++		return 0;
++	return (test_root(group, 7) || test_root(group, 5) ||
++		test_root(group, 3));
++}
++
++/**
++ *	ext3cow_bg_has_super - number of blocks used by the superblock in group
++ *	@sb: superblock for filesystem
++ *	@group: group number to check
++ *
++ *	Return the number of blocks used by the superblock (primary or backup)
++ *	in this group.  Currently this will be only 0 or 1.
++ */
++int ext3cow_bg_has_super(struct super_block *sb, int group)
++{
++	if (EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++				EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
++			!ext3cow_group_sparse(group))
++		return 0;
++	return 1;
++}
++
++static unsigned long ext3cow_bg_num_gdb_meta(struct super_block *sb, int group)
++{
++	unsigned long metagroup = group / EXT3COW_DESC_PER_BLOCK(sb);
++	unsigned long first = metagroup * EXT3COW_DESC_PER_BLOCK(sb);
++	unsigned long last = first + EXT3COW_DESC_PER_BLOCK(sb) - 1;
++
++	if (group == first || group == first + 1 || group == last)
++		return 1;
++	return 0;
++}
++
++static unsigned long ext3cow_bg_num_gdb_nometa(struct super_block *sb, int group)
++{
++	if (EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++				EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
++			!ext3cow_group_sparse(group))
++		return 0;
++	return EXT3COW_SB(sb)->s_gdb_count;
++}
++
++/**
++ *	ext3cow_bg_num_gdb - number of blocks used by the group table in group
++ *	@sb: superblock for filesystem
++ *	@group: group number to check
++ *
++ *	Return the number of blocks used by the group descriptor table
++ *	(primary or backup) in this group.  In the future there may be a
++ *	different number of descriptor blocks in each group.
++ */
++unsigned long ext3cow_bg_num_gdb(struct super_block *sb, int group)
++{
++	unsigned long first_meta_bg =
++			le32_to_cpu(EXT3COW_SB(sb)->s_es->s_first_meta_bg);
++	unsigned long metagroup = group / EXT3COW_DESC_PER_BLOCK(sb);
++
++	if (!EXT3COW_HAS_INCOMPAT_FEATURE(sb,EXT3COW_FEATURE_INCOMPAT_META_BG) ||
++			metagroup < first_meta_bg)
++		return ext3cow_bg_num_gdb_nometa(sb,group);
++
++	return ext3cow_bg_num_gdb_meta(sb,group);
++
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/bitmap.c linux-2.6.20.3-ext3cow/fs/ext3cow/bitmap.c
+--- linux-2.6.20.3/fs/ext3cow/bitmap.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/bitmap.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,32 @@
++/*
++ *  linux/fs/ext3/bitmap.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ */
++
++#include <linux/buffer_head.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++
++#ifdef EXT3COWFS_DEBUG
++
++static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
++
++unsigned long ext3cow_count_free (struct buffer_head * map, unsigned int numchars)
++{
++	unsigned int i;
++	unsigned long sum = 0;
++
++	if (!map)
++		return (0);
++	for (i = 0; i < numchars; i++)
++		sum += nibblemap[map->b_data[i] & 0xf] +
++			nibblemap[(map->b_data[i] >> 4) & 0xf];
++	return (sum);
++}
++
++#endif  /*  EXT3COWFS_DEBUG  */
++
+diff -ruN linux-2.6.20.3/fs/ext3cow/dir.c linux-2.6.20.3-ext3cow/fs/ext3cow/dir.c
+--- linux-2.6.20.3/fs/ext3cow/dir.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/dir.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,732 @@
++/*
++ *  linux/fs/ext3cow/dir.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/dir.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  ext3cow directory handling functions
++ *
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ *
++ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
++ *
++ */
++
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/buffer_head.h>
++#include <linux/smp_lock.h>
++#include <linux/slab.h>
++#include <linux/rbtree.h>
++
++static unsigned char ext3cow_filetype_table[] = {
++	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
++};
++
++static int ext3cow_readdir(struct file *, void *, filldir_t);
++static int ext3cow_dx_readdir(struct file * filp,
++			   void * dirent, filldir_t filldir);
++static int ext3cow_release_dir (struct inode * inode,
++				struct file * filp);
++
++const struct file_operations ext3cow_dir_operations = {
++	.llseek		= generic_file_llseek,
++	.read		= generic_read_dir,
++	.readdir	= ext3cow_readdir,		/* we take BKL. needed?*/
++	.ioctl		= ext3cow_ioctl,		/* BKL held */
++#ifdef CONFIG_COMPAT
++	.compat_ioctl	= ext3cow_compat_ioctl,
++#endif
++	.fsync		= ext3cow_sync_file,	/* BKL held */
++#ifdef CONFIG_EXT3COW_INDEX
++	.release	= ext3cow_release_dir,
++#endif
++};
++
++
++static unsigned char get_dtype(struct super_block *sb, int filetype)
++{
++	if (!EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_FILETYPE) ||
++	    (filetype >= EXT3COW_FT_MAX))
++		return DT_UNKNOWN;
++
++	return (ext3cow_filetype_table[filetype]);
++}
++
++static int ext3cow_readversions(struct file * filp, void * dirent, 
++                                filldir_t filldir)
++{
++  int error = 0;
++  unsigned long offset;
++  int i, stored;
++  struct buffer_head *bh;
++  struct ext3cow_dir_entry_2 * de;
++  struct super_block * sb;
++  int err;
++  struct inode *dir = filp->f_dentry->d_inode;
++  char *at;
++  unsigned long ino;
++  int ref_len = filp->f_dentry->d_name.len -1;
++  
++  sb = dir->i_sb;
++  
++  stored = 0;
++  bh = NULL;
++  offset = filp->f_pos & (sb->s_blocksize - 1);
++  
++  at = strrchr(filp->f_dentry->d_name.name, EXT3COW_FLUX_TOKEN);
++  
++  while (!error && !stored && filp->f_pos < dir->i_size) {
++    unsigned long blk = (filp->f_pos) >> EXT3COW_BLOCK_SIZE_BITS(sb);
++    struct buffer_head map_bh;
++
++    bh = NULL;
++    map_bh.b_state = 0;
++		err = ext3cow_get_blocks_handle(NULL, dir, blk, 1,
++						&map_bh, 0, 0);
++		if (err > 0) {
++			page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
++				&filp->f_ra,
++				filp,
++				map_bh.b_blocknr >>
++					(PAGE_CACHE_SHIFT - dir->i_blkbits),
++				1);
++			bh = ext3cow_bread(NULL, dir, blk, 0, &err);
++		}
++
++		/*
++		 * We ignore I/O errors on directories so users have a chance
++		 * of recovering data when there's a bad sector
++		 */
++    if (!bh) {
++      ext3cow_error (sb, "ext3cow_readdir",
++                     "directory #%lu contains a hole at offset %lu",
++                     dir->i_ino, (unsigned long)filp->f_pos);
++      /* corrupt size?  Maybe no more blocks to read */
++			if (filp->f_pos > dir->i_blocks << 9)
++				break;
++      filp->f_pos += sb->s_blocksize - offset;
++      continue;
++    }
++    
++  ver_revalidate:
++    /* If the dir block has changed since the last call to
++     * readdir(2), then we might be pointing to an invalid
++     * dirent right now.  Scan from the start of the block
++     * to make sure. */
++    if (filp->f_version != dir->i_version) {
++      for (i = 0; i < sb->s_blocksize && i < offset; ) {
++        de = (struct ext3cow_dir_entry_2 *) 
++          (bh->b_data + i);
++				/* It's too expensive to do a full
++				 * dirent test each time round this
++				 * loop, but we do have to test at
++				 * least that it is non-zero.  A
++				 * failure will be detected in the
++				 * dirent test below. */
++        if (le16_to_cpu(de->rec_len) <
++            EXT3COW_DIR_REC_LEN(1))
++          break;
++        i += le16_to_cpu(de->rec_len);
++      }
++      offset = i;
++      filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
++        | offset;
++      filp->f_version = dir->i_version;
++    }
++    
++    while (!error && filp->f_pos < dir->i_size 
++           && offset < sb->s_blocksize) {
++      de = (struct ext3cow_dir_entry_2 *) (bh->b_data + offset);
++      if (!ext3cow_check_dir_entry ("ext3cow_readdir", dir, de,
++                                    bh, offset)) {
++				/* On error, skip the f_pos to the
++           next block. */
++        filp->f_pos = (filp->f_pos |
++                       (sb->s_blocksize - 1)) + 1;
++        brelse (bh);
++        return stored;
++      }
++      offset += le16_to_cpu(de->rec_len);
++      
++      if (le32_to_cpu(de->inode)){
++        unsigned long version = filp->f_version;
++        unsigned char d_type = DT_UNKNOWN;
++        
++        /* We might block in the next section
++         * if the data destination is
++         * currently swapped out.  So, use a
++         * version stamp to detect whether or
++         * not the directory has been modified
++         * during the copy operation.
++         */
++        
++        if (EXT3COW_HAS_INCOMPAT_FEATURE(sb,
++                                         EXT3COW_FEATURE_INCOMPAT_FILETYPE)
++            && de->file_type < EXT3COW_FT_MAX)
++          d_type =
++            ext3cow_filetype_table[de->file_type];
++        if (de->name_len == ref_len
++            && strncmp(filp->f_dentry->d_name.name, de->name, ref_len)==0) {
++          
++          struct inode * inde;
++          char * name;
++          
++          name = kmalloc(EXT3COW_NAME_LEN, GFP_KERNEL);
++          strncpy(name, de->name, de->name_len);
++          inde = iget(dir->i_sb, de->inode);
++          
++          if (de->death_epoch!=0 && de->birth_epoch!=de->death_epoch) {
++            name[de->name_len]='\0';
++            sprintf(name,"%s@%d",name, de->death_epoch);
++            error = filldir(dirent, name,
++                            strlen(name),
++                            filp->f_pos,
++                            le32_to_cpu(inde->i_ino),
++                            d_type);
++            stored++;
++          }
++          
++          while (EXT3COW_I(inde)->i_next_inode!=0) {
++            name[de->name_len]='\0';
++            sprintf(name,"%s@%d",name, EXT3COW_I_EPOCHNUMBER(inde));
++            error = filldir(dirent, name,
++                            strlen(name),
++                            filp->f_pos,
++                            le32_to_cpu(inde->i_ino),
++                            d_type);
++            ino = EXT3COW_I(inde)->i_next_inode;
++            iput(inde);
++            inde = iget(dir->i_sb, ino);
++            stored++;
++          }
++          
++          kfree(name);
++          iput(inde);
++                    
++          if (error)
++            break;
++          
++          if (!stored && 
++              EXT3COW_IS_DIRENT_SCOPED(de, EXT3COW_I_EPOCHNUMBER(dir))) {
++            error = filldir(dirent, de->name,
++                            de->name_len,
++                            filp->f_pos,
++                            le32_to_cpu(de->inode),
++                            d_type);
++          }
++            
++          if (error)
++            break;
++          if (version != filp->f_version)
++            goto ver_revalidate;
++          stored ++;
++        }
++      }
++      
++      filp->f_pos += le16_to_cpu(de->rec_len);
++    }
++    offset = 0;
++    brelse (bh);
++  }
++  return 0;
++}
++
++
++int ext3cow_check_dir_entry (const char * function, struct inode * dir,
++			  struct ext3cow_dir_entry_2 * de,
++			  struct buffer_head * bh,
++			  unsigned long offset)
++{
++	const char * error_msg = NULL;
++	const int rlen = le16_to_cpu(de->rec_len);
++  unsigned int current_epoch = EXT3COW_S_EPOCHNUMBER(dir->i_sb);
++
++	if (rlen < EXT3COW_DIR_REC_LEN(1))
++		error_msg = "rec_len is smaller than minimal";
++	else if (rlen % 4 != 0)
++		error_msg = "rec_len % 4 != 0";
++	else if (rlen < EXT3COW_DIR_REC_LEN(de->name_len))
++		error_msg = "rec_len is too small for name_len";
++	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
++		error_msg = "directory entry across blocks";
++	else if (le32_to_cpu(de->inode) >
++			le32_to_cpu(EXT3COW_SB(dir->i_sb)->s_es->s_inodes_count))
++		error_msg = "inode out of bounds";
++  /* Some bounds on versioned entries -znjp*/
++  else if (le32_to_cpu(de->death_epoch) != EXT3COW_DIRENT_ALIVE && 
++           le32_to_cpu(de->birth_epoch) > le32_to_cpu(de->death_epoch))
++    error_msg = "entry died before it was born";
++  else if (le32_to_cpu(de->birth_epoch) > current_epoch)
++    error_msg = "entry was born in the future";
++  else if (le32_to_cpu(de->death_epoch) > current_epoch)
++    error_msg = "entry has already died in the future";
++
++	if (error_msg != NULL)
++		ext3cow_error (dir->i_sb, function,
++			"bad entry in directory #%lu: %s - "
++			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d, "
++      "birth_epoch=%d death_epoch=%d",
++			dir->i_ino, error_msg, offset,
++			(unsigned long) le32_to_cpu(de->inode),
++                   rlen, de->name_len, de->birth_epoch, de->death_epoch);
++	return error_msg == NULL ? 1 : 0;
++}
++
++static int ext3cow_readdir(struct file * filp,
++			 void * dirent, filldir_t filldir)
++{
++	int error = 0;
++	unsigned long offset;
++	int i, stored;
++	struct ext3cow_dir_entry_2 *de;
++	struct super_block *sb;
++	int err;
++	struct inode *inode = filp->f_path.dentry->d_inode;
++	int ret = 0;
++  
++  /* is this a version listing? */
++  if (filp->f_dentry->d_name.name[filp->f_dentry->d_name.len-1] ==  
++      EXT3COW_FLUX_TOKEN)
++    return ext3cow_readversions(filp, dirent, filldir);
++  
++	sb = inode->i_sb;
++
++#ifdef CONFIG_EXT3COW_INDEX
++	if (EXT3COW_HAS_COMPAT_FEATURE(inode->i_sb, 
++                                 EXT3COW_FEATURE_COMPAT_DIR_INDEX) &&
++	    ((EXT3COW_I(inode)->i_flags & EXT3COW_INDEX_FL) ||
++	     ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
++
++		err = ext3cow_dx_readdir(filp, dirent, filldir);
++		if (err != ERR_BAD_DX_DIR) {
++			ret = err;
++			goto out;
++		}
++		/*
++		 * We don't set the inode dirty flag since it's not
++		 * critical that it get flushed back to the disk.
++		 */
++		EXT3COW_I(filp->f_path.dentry->d_inode)->i_flags &= ~EXT3COW_INDEX_FL;
++	}
++#endif
++	stored = 0;
++	offset = filp->f_pos & (sb->s_blocksize - 1);
++
++	while (!error && !stored && filp->f_pos < inode->i_size) {
++		unsigned long blk = filp->f_pos >> EXT3COW_BLOCK_SIZE_BITS(sb);
++		struct buffer_head map_bh;
++		struct buffer_head *bh = NULL;
++
++		map_bh.b_state = 0;
++		err = ext3cow_get_blocks_handle(NULL, inode, blk, 1,
++						&map_bh, 0, 0);
++		if (err > 0) {
++			page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
++				&filp->f_ra,
++				filp,
++				map_bh.b_blocknr >>
++					(PAGE_CACHE_SHIFT - inode->i_blkbits),
++				1);
++			bh = ext3cow_bread(NULL, inode, blk, 0, &err);
++		}
++
++		/*
++		 * We ignore I/O errors on directories so users have a chance
++		 * of recovering data when there's a bad sector
++		 */
++		if (!bh) {
++			ext3cow_error (sb, "ext3cow_readdir",
++				"directory #%lu contains a hole at offset %lu",
++				inode->i_ino, (unsigned long)filp->f_pos);
++			/* corrupt size?  Maybe no more blocks to read */
++			if (filp->f_pos > inode->i_blocks << 9)
++				break;
++			filp->f_pos += sb->s_blocksize - offset;
++			continue;
++		}
++
++revalidate:
++		/* If the dir block has changed since the last call to
++		 * readdir(2), then we might be pointing to an invalid
++		 * dirent right now.  Scan from the start of the block
++		 * to make sure. */
++		if (filp->f_version != inode->i_version) {
++			for (i = 0; i < sb->s_blocksize && i < offset; ) {
++				de = (struct ext3cow_dir_entry_2 *)
++					(bh->b_data + i);
++				/* It's too expensive to do a full
++				 * dirent test each time round this
++				 * loop, but we do have to test at
++				 * least that it is non-zero.  A
++				 * failure will be detected in the
++				 * dirent test below. */
++				if (le16_to_cpu(de->rec_len) <
++						EXT3COW_DIR_REC_LEN(1))
++					break;
++				i += le16_to_cpu(de->rec_len);
++			}
++			offset = i;
++			filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
++				| offset;
++			filp->f_version = inode->i_version;
++		}
++
++		while (!error && filp->f_pos < inode->i_size
++		       && offset < sb->s_blocksize) {
++			de = (struct ext3cow_dir_entry_2 *) (bh->b_data + offset);
++			if (!ext3cow_check_dir_entry ("ext3cow_readdir", inode, de,
++						   bh, offset)) {
++				/* On error, skip the f_pos to the
++                                   next block. */
++				filp->f_pos = (filp->f_pos |
++						(sb->s_blocksize - 1)) + 1;
++				brelse (bh);
++				ret = stored;
++				goto out;
++			}
++			offset += le16_to_cpu(de->rec_len);
++    /*
++        printk("Inode %ld Epoch number %u: is 
++        dir %d -> %s be %d de %d scoped? %d\n",
++        dir->i_ino,
++        EXT3COW_I_EPOCHNUMBER(dir),
++        de->inode,
++        de->name,
++        de->birth_epoch,
++        de->death_epoch,
++        EXT3COW_IS_DIRENT_SCOPED(de, EXT3COW_I_EPOCHNUMBER(dir)));
++      */
++
++      /* Only add scoped dirents - znjp */
++			if (le32_to_cpu(de->inode)  && 
++          EXT3COW_IS_DIRENT_SCOPED(de, EXT3COW_I_EPOCHNUMBER(inode))) {
++				/* We might block in the next section
++				 * if the data destination is
++				 * currently swapped out.  So, use a
++				 * version stamp to detect whether or
++				 * not the directory has been modified
++				 * during the copy operation.
++				 */
++				unsigned long version = filp->f_version;
++
++				error = filldir(dirent, de->name,
++						de->name_len,
++						filp->f_pos,
++						le32_to_cpu(de->inode),
++						get_dtype(sb, de->file_type));
++				if (error)
++					break;
++				if (version != filp->f_version)
++					goto revalidate;
++				stored ++;
++			}
++			filp->f_pos += le16_to_cpu(de->rec_len);
++		}
++		offset = 0;
++		brelse (bh);
++	}
++out:
++	return ret;
++}
++
++#ifdef CONFIG_EXT3COW_INDEX
++/*
++ * These functions convert from the major/minor hash to an f_pos
++ * value.
++ *
++ * Currently we only use major hash numer.  This is unfortunate, but
++ * on 32-bit machines, the same VFS interface is used for lseek and
++ * llseek, so if we use the 64 bit offset, then the 32-bit versions of
++ * lseek/telldir/seekdir will blow out spectacularly, and from within
++ * the ext2 low-level routine, we don't know if we're being called by
++ * a 64-bit version of the system call or the 32-bit version of the
++ * system call.  Worse yet, NFSv2 only allows for a 32-bit readdir
++ * cookie.  Sigh.
++ */
++#define hash2pos(major, minor)	(major >> 1)
++#define pos2maj_hash(pos)	((pos << 1) & 0xffffffff)
++#define pos2min_hash(pos)	(0)
++
++/*
++ * This structure holds the nodes of the red-black tree used to store
++ * the directory entry in hash order.
++ */
++struct fname {
++	__u32		hash;
++	__u32		minor_hash;
++	struct rb_node	rb_hash;
++	struct fname	*next;
++	__u32		inode;
++	__u8		name_len;
++	__u8		file_type;
++	char		name[0];
++};
++
++/*
++ * This functoin implements a non-recursive way of freeing all of the
++ * nodes in the red-black tree.
++ */
++static void free_rb_tree_fname(struct rb_root *root)
++{
++	struct rb_node	*n = root->rb_node;
++	struct rb_node	*parent;
++	struct fname	*fname;
++
++	while (n) {
++		/* Do the node's children first */
++		if ((n)->rb_left) {
++			n = n->rb_left;
++			continue;
++		}
++		if (n->rb_right) {
++			n = n->rb_right;
++			continue;
++		}
++		/*
++		 * The node has no children; free it, and then zero
++		 * out parent's link to it.  Finally go to the
++		 * beginning of the loop and try to free the parent
++		 * node.
++		 */
++		parent = rb_parent(n);
++		fname = rb_entry(n, struct fname, rb_hash);
++		while (fname) {
++			struct fname * old = fname;
++			fname = fname->next;
++			kfree (old);
++		}
++		if (!parent)
++			root->rb_node = NULL;
++		else if (parent->rb_left == n)
++			parent->rb_left = NULL;
++		else if (parent->rb_right == n)
++			parent->rb_right = NULL;
++		n = parent;
++	}
++	root->rb_node = NULL;
++}
++
++
++static struct dir_private_info *create_dir_info(loff_t pos)
++{
++	struct dir_private_info *p;
++
++	p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
++	if (!p)
++		return NULL;
++	p->root.rb_node = NULL;
++	p->curr_node = NULL;
++	p->extra_fname = NULL;
++	p->last_pos = 0;
++	p->curr_hash = pos2maj_hash(pos);
++	p->curr_minor_hash = pos2min_hash(pos);
++	p->next_hash = 0;
++	return p;
++}
++
++void ext3cow_htree_free_dir_info(struct dir_private_info *p)
++{
++	free_rb_tree_fname(&p->root);
++	kfree(p);
++}
++
++/*
++ * Given a directory entry, enter it into the fname rb tree.
++ */
++int ext3cow_htree_store_dirent(struct file *dir_file, __u32 hash,
++			     __u32 minor_hash,
++			     struct ext3cow_dir_entry_2 *dirent)
++{
++	struct rb_node **p, *parent = NULL;
++	struct fname * fname, *new_fn;
++	struct dir_private_info *info;
++	int len;
++
++	info = (struct dir_private_info *) dir_file->private_data;
++	p = &info->root.rb_node;
++
++	/* Create and allocate the fname structure */
++	len = sizeof(struct fname) + dirent->name_len + 1;
++	new_fn = kzalloc(len, GFP_KERNEL);
++	if (!new_fn)
++		return -ENOMEM;
++	new_fn->hash = hash;
++	new_fn->minor_hash = minor_hash;
++	new_fn->inode = le32_to_cpu(dirent->inode);
++	new_fn->name_len = dirent->name_len;
++	new_fn->file_type = dirent->file_type;
++	memcpy(new_fn->name, dirent->name, dirent->name_len);
++	new_fn->name[dirent->name_len] = 0;
++
++	while (*p) {
++		parent = *p;
++		fname = rb_entry(parent, struct fname, rb_hash);
++
++		/*
++		 * If the hash and minor hash match up, then we put
++		 * them on a linked list.  This rarely happens...
++		 */
++		if ((new_fn->hash == fname->hash) &&
++		    (new_fn->minor_hash == fname->minor_hash)) {
++			new_fn->next = fname->next;
++			fname->next = new_fn;
++			return 0;
++		}
++
++		if (new_fn->hash < fname->hash)
++			p = &(*p)->rb_left;
++		else if (new_fn->hash > fname->hash)
++			p = &(*p)->rb_right;
++		else if (new_fn->minor_hash < fname->minor_hash)
++			p = &(*p)->rb_left;
++		else /* if (new_fn->minor_hash > fname->minor_hash) */
++			p = &(*p)->rb_right;
++	}
++
++	rb_link_node(&new_fn->rb_hash, parent, p);
++	rb_insert_color(&new_fn->rb_hash, &info->root);
++	return 0;
++}
++
++
++
++/*
++ * This is a helper function for ext3cow_dx_readdir.  It calls filldir
++ * for all entres on the fname linked list.  (Normally there is only
++ * one entry on the linked list, unless there are 62 bit hash collisions.)
++ */
++static int call_filldir(struct file * filp, void * dirent,
++			filldir_t filldir, struct fname *fname)
++{
++	struct dir_private_info *info = filp->private_data;
++	loff_t	curr_pos;
++	struct inode *inode = filp->f_path.dentry->d_inode;
++	struct super_block * sb;
++	int error;
++
++	sb = inode->i_sb;
++
++  printk(KERN_INFO, "Got %s\n", filp->f_path.dentry->d_name.name);
++
++	if (!fname) {
++		printk("call_filldir: called with null fname?!?\n");
++		return 0;
++	}
++	curr_pos = hash2pos(fname->hash, fname->minor_hash);
++	while (fname) {
++		error = filldir(dirent, fname->name,
++				fname->name_len, curr_pos,
++				fname->inode,
++				get_dtype(sb, fname->file_type));
++		if (error) {
++			filp->f_pos = curr_pos;
++			info->extra_fname = fname->next;
++			return error;
++		}
++		fname = fname->next;
++	}
++	return 0;
++}
++
++static int ext3cow_dx_readdir(struct file * filp,
++			 void * dirent, filldir_t filldir)
++{
++	struct dir_private_info *info = filp->private_data;
++	struct inode *inode = filp->f_path.dentry->d_inode;
++	struct fname *fname;
++	int	ret;
++
++	if (!info) {
++		info = create_dir_info(filp->f_pos);
++		if (!info)
++			return -ENOMEM;
++		filp->private_data = info;
++	}
++
++	if (filp->f_pos == EXT3COW_HTREE_EOF)
++		return 0;	/* EOF */
++
++	/* Some one has messed with f_pos; reset the world */
++	if (info->last_pos != filp->f_pos) {
++		free_rb_tree_fname(&info->root);
++		info->curr_node = NULL;
++		info->extra_fname = NULL;
++		info->curr_hash = pos2maj_hash(filp->f_pos);
++		info->curr_minor_hash = pos2min_hash(filp->f_pos);
++	}
++
++	/*
++	 * If there are any leftover names on the hash collision
++	 * chain, return them first.
++	 */
++	if (info->extra_fname &&
++	    call_filldir(filp, dirent, filldir, info->extra_fname))
++		goto finished;
++
++	if (!info->curr_node)
++		info->curr_node = rb_first(&info->root);
++
++	while (1) {
++		/*
++		 * Fill the rbtree if we have no more entries,
++		 * or the inode has changed since we last read in the
++		 * cached entries.
++		 */
++		if ((!info->curr_node) ||
++		    (filp->f_version != inode->i_version)) {
++			info->curr_node = NULL;
++			free_rb_tree_fname(&info->root);
++			filp->f_version = inode->i_version;
++			ret = ext3cow_htree_fill_tree(filp, info->curr_hash,
++						   info->curr_minor_hash,
++						   &info->next_hash);
++			if (ret < 0)
++				return ret;
++			if (ret == 0) {
++				filp->f_pos = EXT3COW_HTREE_EOF;
++				break;
++			}
++			info->curr_node = rb_first(&info->root);
++		}
++
++		fname = rb_entry(info->curr_node, struct fname, rb_hash);
++		info->curr_hash = fname->hash;
++		info->curr_minor_hash = fname->minor_hash;
++		if (call_filldir(filp, dirent, filldir, fname))
++			break;
++
++		info->curr_node = rb_next(info->curr_node);
++		if (!info->curr_node) {
++			if (info->next_hash == ~0) {
++				filp->f_pos = EXT3COW_HTREE_EOF;
++				break;
++			}
++			info->curr_hash = info->next_hash;
++			info->curr_minor_hash = 0;
++		}
++	}
++finished:
++	info->last_pos = filp->f_pos;
++	return 0;
++}
++
++static int ext3cow_release_dir (struct inode * inode, struct file * filp)
++{
++       if (filp->private_data)
++		ext3cow_htree_free_dir_info(filp->private_data);
++
++	return 0;
++}
++
++#endif
+diff -ruN linux-2.6.20.3/fs/ext3cow/ext3cow_jbd.c linux-2.6.20.3-ext3cow/fs/ext3cow/ext3cow_jbd.c
+--- linux-2.6.20.3/fs/ext3cow/ext3cow_jbd.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/ext3cow_jbd.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,59 @@
++/*
++ * Interface between ext3cow and JBD
++ */
++
++#include <linux/ext3cow_jbd.h>
++
++int __ext3cow_journal_get_undo_access(const char *where, handle_t *handle,
++				struct buffer_head *bh)
++{
++	int err = journal_get_undo_access(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
++
++int __ext3cow_journal_get_write_access(const char *where, handle_t *handle,
++				struct buffer_head *bh)
++{
++	int err = journal_get_write_access(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
++
++int __ext3cow_journal_forget(const char *where, handle_t *handle,
++				struct buffer_head *bh)
++{
++	int err = journal_forget(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
++
++int __ext3cow_journal_revoke(const char *where, handle_t *handle,
++				unsigned long blocknr, struct buffer_head *bh)
++{
++	int err = journal_revoke(handle, blocknr, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
++
++int __ext3cow_journal_get_create_access(const char *where,
++				handle_t *handle, struct buffer_head *bh)
++{
++	int err = journal_get_create_access(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
++
++int __ext3cow_journal_dirty_metadata(const char *where,
++				handle_t *handle, struct buffer_head *bh)
++{
++	int err = journal_dirty_metadata(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
++	return err;
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/file.c linux-2.6.20.3-ext3cow/fs/ext3cow/file.c
+--- linux-2.6.20.3/fs/ext3cow/file.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/file.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,147 @@
++/*
++ *  linux/fs/ext3cow/file.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/file.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  ext3cow fs regular file handling primitives
++ *
++ *  64-bit file support on 64-bit platforms by Jakub Jelinek
++ *	(jj@sunsite.ms.mff.cuni.cz)
++ */
++
++#include <linux/time.h>
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include "xattr.h"
++#include "acl.h"
++
++/*
++ * Called when an inode is released. Note that this is different
++ * from ext3cow_file_open: open gets called at every open, but release
++ * gets called only when /all/ the files are closed.
++ */
++static int ext3cow_release_file (struct inode * inode, struct file * filp)
++{
++	/* if we are the last writer on the inode, drop the block reservation */
++	if ((filp->f_mode & FMODE_WRITE) &&
++			(atomic_read(&inode->i_writecount) == 1))
++	{
++		mutex_lock(&EXT3COW_I(inode)->truncate_mutex);
++		ext3cow_discard_reservation(inode);
++		mutex_unlock(&EXT3COW_I(inode)->truncate_mutex);
++	}
++	if (is_dx(inode) && filp->private_data)
++		ext3cow_htree_free_dir_info(filp->private_data);
++
++	return 0;
++}
++
++static ssize_t
++ext3cow_file_write(struct kiocb *iocb, const struct iovec *iov,
++		unsigned long nr_segs, loff_t pos)
++{
++	struct file *file = iocb->ki_filp;
++	struct inode *inode = file->f_path.dentry->d_inode;
++  struct inode *dir   = file->f_path.dentry->d_parent->d_inode;
++	ssize_t ret = 0;
++	int err = 0;
++  
++  /* This is the place where we create a new version on write -znjp */
++  if(EXT3COW_S_EPOCHNUMBER(inode->i_sb) > EXT3COW_I_EPOCHNUMBER(inode)){
++    err = ext3cow_dup_inode(dir, inode);
++    if(err)
++      return err;
++  }
++
++	ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
++
++	/*
++	 * Skip flushing if there was an error, or if nothing was written.
++	 */
++	if (ret <= 0)
++		return ret;
++
++	/*
++	 * If the inode is IS_SYNC, or is O_SYNC and we are doing data
++	 * journalling then we need to make sure that we force the transaction
++	 * to disk to keep all metadata uptodate synchronously.
++	 */
++	if (file->f_flags & O_SYNC) {
++		/*
++		 * If we are non-data-journaled, then the dirty data has
++		 * already been flushed to backing store by generic_osync_inode,
++		 * and the inode has been flushed too if there have been any
++		 * modifications other than mere timestamp updates.
++		 *
++		 * Open question --- do we care about flushing timestamps too
++		 * if the inode is IS_SYNC?
++		 */
++		if (!ext3cow_should_journal_data(inode))
++			return ret;
++
++		goto force_commit;
++	}
++
++	/*
++	 * So we know that there has been no forced data flush.  If the inode
++	 * is marked IS_SYNC, we need to force one ourselves.
++	 */
++	if (!IS_SYNC(inode))
++		return ret;
++
++	/*
++	 * Open question #2 --- should we force data to disk here too?  If we
++	 * don't, the only impact is that data=writeback filesystems won't
++	 * flush data to disk automatically on IS_SYNC, only metadata (but
++	 * historically, that is what ext2 has done.)
++	 */
++
++force_commit:
++	err = ext3cow_force_commit(inode->i_sb);
++	if (err)
++		return err;
++	return ret;
++}
++
++const struct file_operations ext3cow_file_operations = {
++	.llseek		= generic_file_llseek,
++	.read		= do_sync_read,
++	.write		= do_sync_write,
++	.aio_read	= generic_file_aio_read,
++	.aio_write	= ext3cow_file_write,
++	.ioctl		= ext3cow_ioctl,
++#ifdef CONFIG_COMPAT
++	.compat_ioctl	= ext3cow_compat_ioctl,
++#endif
++	.mmap		= generic_file_mmap,
++	.open		= generic_file_open,
++	.release	= ext3cow_release_file,
++	.fsync		= ext3cow_sync_file,
++	.sendfile	= generic_file_sendfile,
++	.splice_read	= generic_file_splice_read,
++	.splice_write	= generic_file_splice_write,
++};
++
++struct inode_operations ext3cow_file_inode_operations = {
++	.truncate	= ext3cow_truncate,
++	.setattr	= ext3cow_setattr,
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	.setxattr	= generic_setxattr,
++	.getxattr	= generic_getxattr,
++	.listxattr	= ext3cow_listxattr,
++	.removexattr	= generic_removexattr,
++#endif
++	.permission	= ext3cow_permission,
++};
++
+diff -ruN linux-2.6.20.3/fs/ext3cow/fsync.c linux-2.6.20.3-ext3cow/fs/ext3cow/fsync.c
+--- linux-2.6.20.3/fs/ext3cow/fsync.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/fsync.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,88 @@
++/*
++ *  linux/fs/ext3cow/fsync.c
++ *
++ *  Copyright (C) 1993  Stephen Tweedie (sct@redhat.com)
++ *  from
++ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
++ *                      Laboratoire MASI - Institut Blaise Pascal
++ *                      Universite Pierre et Marie Curie (Paris VI)
++ *  from
++ *  linux/fs/minix/truncate.c   Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  ext3cowfs fsync primitive
++ *
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ *
++ *  Removed unnecessary code duplication for little endian machines
++ *  and excessive __inline__s.
++ *        Andi Kleen, 1997
++ *
++ * Major simplications and cleanup - we only need to do the metadata, because
++ * we can depend on generic_block_fdatasync() to sync the data blocks.
++ */
++
++#include <linux/time.h>
++#include <linux/fs.h>
++#include <linux/sched.h>
++#include <linux/writeback.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++
++/*
++ * akpm: A new design for ext3cow_sync_file().
++ *
++ * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
++ * There cannot be a transaction open by this task.
++ * Another task could have dirtied this inode.  Its data can be in any
++ * state in the journalling system.
++ *
++ * What we do is just kick off a commit and wait on it.  This will snapshot the
++ * inode to disk.
++ */
++
++int ext3cow_sync_file(struct file * file, struct dentry *dentry, int datasync)
++{
++	struct inode *inode = dentry->d_inode;
++	int ret = 0;
++
++	J_ASSERT(ext3cow_journal_current_handle() == 0);
++
++	/*
++	 * data=writeback:
++	 *  The caller's filemap_fdatawrite()/wait will sync the data.
++	 *  sync_inode() will sync the metadata
++	 *
++	 * data=ordered:
++	 *  The caller's filemap_fdatawrite() will write the data and
++	 *  sync_inode() will write the inode if it is dirty.  Then the caller's
++	 *  filemap_fdatawait() will wait on the pages.
++	 *
++	 * data=journal:
++	 *  filemap_fdatawrite won't do anything (the buffers are clean).
++	 *  ext3cow_force_commit will write the file data into the journal and
++	 *  will wait on that.
++	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
++	 *  (they were dirtied by commit).  But that's OK - the blocks are
++	 *  safe in-journal, which is all fsync() needs to ensure.
++	 */
++	if (ext3cow_should_journal_data(inode)) {
++		ret = ext3cow_force_commit(inode->i_sb);
++		goto out;
++	}
++
++	/*
++	 * The VFS has written the file data.  If the inode is unaltered
++	 * then we need not start a commit.
++	 */
++	if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
++		struct writeback_control wbc = {
++			.sync_mode = WB_SYNC_ALL,
++			.nr_to_write = 0, /* sys_fsync did this */
++		};
++		ret = sync_inode(inode, &wbc);
++	}
++out:
++	return ret;
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/hash.c linux-2.6.20.3-ext3cow/fs/ext3cow/hash.c
+--- linux-2.6.20.3/fs/ext3cow/hash.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/hash.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,152 @@
++/*
++ *  linux/fs/ext3cow/hash.c
++ *
++ * Copyright (C) 2002 by Theodore Ts'o
++ *
++ * This file is released under the GPL v2.
++ *
++ * This file may be redistributed under the terms of the GNU Public
++ * License.
++ */
++
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/sched.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/cryptohash.h>
++
++#define DELTA 0x9E3779B9
++
++static void TEA_transform(__u32 buf[4], __u32 const in[])
++{
++	__u32	sum = 0;
++	__u32	b0 = buf[0], b1 = buf[1];
++	__u32	a = in[0], b = in[1], c = in[2], d = in[3];
++	int	n = 16;
++
++	do {
++		sum += DELTA;
++		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
++		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
++	} while(--n);
++
++	buf[0] += b0;
++	buf[1] += b1;
++}
++
++
++/* The old legacy hash */
++static __u32 dx_hack_hash (const char *name, int len)
++{
++	__u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
++	while (len--) {
++		__u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
++
++		if (hash & 0x80000000) hash -= 0x7fffffff;
++		hash1 = hash0;
++		hash0 = hash;
++	}
++	return (hash0 << 1);
++}
++
++static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
++{
++	__u32	pad, val;
++	int	i;
++
++	pad = (__u32)len | ((__u32)len << 8);
++	pad |= pad << 16;
++
++	val = pad;
++	if (len > num*4)
++		len = num * 4;
++	for (i=0; i < len; i++) {
++		if ((i % 4) == 0)
++			val = pad;
++		val = msg[i] + (val << 8);
++		if ((i % 4) == 3) {
++			*buf++ = val;
++			val = pad;
++			num--;
++		}
++	}
++	if (--num >= 0)
++		*buf++ = val;
++	while (--num >= 0)
++		*buf++ = pad;
++}
++
++/*
++ * Returns the hash of a filename.  If len is 0 and name is NULL, then
++ * this function can be used to test whether or not a hash version is
++ * supported.
++ *
++ * The seed is an 4 longword (32 bits) "secret" which can be used to
++ * uniquify a hash.  If the seed is all zero's, then some default seed
++ * may be used.
++ *
++ * A particular hash version specifies whether or not the seed is
++ * represented, and whether or not the returned hash is 32 bits or 64
++ * bits.  32 bit hashes will return 0 for the minor hash.
++ */
++int ext3cowfs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
++{
++	__u32	hash;
++	__u32	minor_hash = 0;
++	const char	*p;
++	int		i;
++	__u32		in[8], buf[4];
++
++	/* Initialize the default seed for the hash checksum functions */
++	buf[0] = 0x67452301;
++	buf[1] = 0xefcdab89;
++	buf[2] = 0x98badcfe;
++	buf[3] = 0x10325476;
++
++	/* Check to see if the seed is all zero's */
++	if (hinfo->seed) {
++		for (i=0; i < 4; i++) {
++			if (hinfo->seed[i])
++				break;
++		}
++		if (i < 4)
++			memcpy(buf, hinfo->seed, sizeof(buf));
++	}
++
++	switch (hinfo->hash_version) {
++	case DX_HASH_LEGACY:
++		hash = dx_hack_hash(name, len);
++		break;
++	case DX_HASH_HALF_MD4:
++		p = name;
++		while (len > 0) {
++			str2hashbuf(p, len, in, 8);
++			half_md4_transform(buf, in);
++			len -= 32;
++			p += 32;
++		}
++		minor_hash = buf[2];
++		hash = buf[1];
++		break;
++	case DX_HASH_TEA:
++		p = name;
++		while (len > 0) {
++			str2hashbuf(p, len, in, 4);
++			TEA_transform(buf, in);
++			len -= 16;
++			p += 16;
++		}
++		hash = buf[0];
++		minor_hash = buf[1];
++		break;
++	default:
++		hinfo->hash = 0;
++		return -1;
++	}
++	hash = hash & ~1;
++	if (hash == (EXT3COW_HTREE_EOF << 1))
++		hash = (EXT3COW_HTREE_EOF-1) << 1;
++	hinfo->hash = hash;
++	hinfo->minor_hash = minor_hash;
++	return 0;
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/ialloc.c linux-2.6.20.3-ext3cow/fs/ext3cow/ialloc.c
+--- linux-2.6.20.3/fs/ext3cow/ialloc.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/ialloc.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,763 @@
++/*
++ *  linux/fs/ext3cow/ialloc.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  BSD ufs-inspired inode and directory allocation by
++ *  Stephen Tweedie (sct@redhat.com), 1993
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ */
++
++#include <linux/time.h>
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/stat.h>
++#include <linux/string.h>
++#include <linux/quotaops.h>
++#include <linux/buffer_head.h>
++#include <linux/random.h>
++#include <linux/bitops.h>
++
++#include <asm/byteorder.h>
++
++#include "xattr.h"
++#include "acl.h"
++
++/*
++ * ialloc.c contains the inodes allocation and deallocation routines
++ */
++
++/*
++ * The free inodes are managed by bitmaps.  A file system contains several
++ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
++ * block for inodes, N blocks for the inode table and data blocks.
++ *
++ * The file system contains group descriptors which are located after the
++ * super block.  Each descriptor contains the number of the bitmap block and
++ * the free blocks count in the block.
++ */
++
++
++/*
++ * Read the inode allocation bitmap for a given block_group, reading
++ * into the specified slot in the superblock's bitmap cache.
++ *
++ * Return buffer_head of bitmap on success or NULL.
++ */
++static struct buffer_head *
++read_inode_bitmap(struct super_block * sb, unsigned long block_group)
++{
++	struct ext3cow_group_desc *desc;
++	struct buffer_head *bh = NULL;
++
++	desc = ext3cow_get_group_desc(sb, block_group, NULL);
++	if (!desc)
++		goto error_out;
++
++	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
++	if (!bh)
++		ext3cow_error(sb, "read_inode_bitmap",
++			    "Cannot read inode bitmap - "
++			    "block_group = %lu, inode_bitmap = %u",
++			    block_group, le32_to_cpu(desc->bg_inode_bitmap));
++error_out:
++	return bh;
++}
++
++/*
++ * NOTE! When we get the inode, we're the only people
++ * that have access to it, and as such there are no
++ * race conditions we have to worry about. The inode
++ * is not on the hash-lists, and it cannot be reached
++ * through the filesystem because the directory entry
++ * has been deleted earlier.
++ *
++ * HOWEVER: we must make sure that we get no aliases,
++ * which means that we have to call "clear_inode()"
++ * _before_ we mark the inode not in use in the inode
++ * bitmaps. Otherwise a newly created file might use
++ * the same inode number (not actually the same pointer
++ * though), and then we'd have two inodes sharing the
++ * same inode number and space on the harddisk.
++ */
++void ext3cow_free_inode (handle_t *handle, struct inode * inode)
++{
++	struct super_block * sb = inode->i_sb;
++	int is_directory;
++	unsigned long ino;
++	struct buffer_head *bitmap_bh = NULL;
++	struct buffer_head *bh2;
++	unsigned long block_group;
++	unsigned long bit;
++	struct ext3cow_group_desc * gdp;
++	struct ext3cow_super_block * es;
++	struct ext3cow_sb_info *sbi;
++	int fatal = 0, err;
++
++	if (atomic_read(&inode->i_count) > 1) {
++		printk ("ext3cow_free_inode: inode has count=%d\n",
++					atomic_read(&inode->i_count));
++		return;
++	}
++	if (inode->i_nlink) {
++		printk ("ext3cow_free_inode: inode has nlink=%d\n",
++			inode->i_nlink);
++		return;
++	}
++	if (!sb) {
++		printk("ext3cow_free_inode: inode on nonexistent device\n");
++		return;
++	}
++	sbi = EXT3COW_SB(sb);
++
++	ino = inode->i_ino;
++	ext3cow_debug ("freeing inode %lu\n", ino);
++
++	/*
++	 * Note: we must free any quota before locking the superblock,
++	 * as writing the quota to disk may need the lock as well.
++	 */
++	DQUOT_INIT(inode);
++	ext3cow_xattr_delete_inode(handle, inode);
++	DQUOT_FREE_INODE(inode);
++	DQUOT_DROP(inode);
++
++	is_directory = S_ISDIR(inode->i_mode);
++
++	/* Do this BEFORE marking the inode not in use or returning an error */
++	clear_inode (inode);
++
++	es = EXT3COW_SB(sb)->s_es;
++	if (ino < EXT3COW_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
++		ext3cow_error (sb, "ext3cow_free_inode",
++			    "reserved or nonexistent inode %lu", ino);
++		goto error_return;
++	}
++	block_group = (ino - 1) / EXT3COW_INODES_PER_GROUP(sb);
++	bit = (ino - 1) % EXT3COW_INODES_PER_GROUP(sb);
++	bitmap_bh = read_inode_bitmap(sb, block_group);
++	if (!bitmap_bh)
++		goto error_return;
++
++	BUFFER_TRACE(bitmap_bh, "get_write_access");
++	fatal = ext3cow_journal_get_write_access(handle, bitmap_bh);
++	if (fatal)
++		goto error_return;
++
++	/* Ok, now we can actually update the inode bitmaps.. */
++	if (!ext3cow_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
++					bit, bitmap_bh->b_data))
++		ext3cow_error (sb, "ext3cow_free_inode",
++			      "bit already cleared for inode %lu", ino);
++	else {
++		gdp = ext3cow_get_group_desc (sb, block_group, &bh2);
++
++		BUFFER_TRACE(bh2, "get_write_access");
++		fatal = ext3cow_journal_get_write_access(handle, bh2);
++		if (fatal) goto error_return;
++
++		if (gdp) {
++			spin_lock(sb_bgl_lock(sbi, block_group));
++			gdp->bg_free_inodes_count = cpu_to_le16(
++				le16_to_cpu(gdp->bg_free_inodes_count) + 1);
++			if (is_directory)
++				gdp->bg_used_dirs_count = cpu_to_le16(
++				  le16_to_cpu(gdp->bg_used_dirs_count) - 1);
++			spin_unlock(sb_bgl_lock(sbi, block_group));
++			percpu_counter_inc(&sbi->s_freeinodes_counter);
++			if (is_directory)
++				percpu_counter_dec(&sbi->s_dirs_counter);
++
++		}
++		BUFFER_TRACE(bh2, "call ext3cow_journal_dirty_metadata");
++		err = ext3cow_journal_dirty_metadata(handle, bh2);
++		if (!fatal) fatal = err;
++	}
++	BUFFER_TRACE(bitmap_bh, "call ext3cow_journal_dirty_metadata");
++	err = ext3cow_journal_dirty_metadata(handle, bitmap_bh);
++	if (!fatal)
++		fatal = err;
++	sb->s_dirt = 1;
++error_return:
++	brelse(bitmap_bh);
++	ext3cow_std_error(sb, fatal);
++}
++
++/*
++ * There are two policies for allocating an inode.  If the new inode is
++ * a directory, then a forward search is made for a block group with both
++ * free space and a low directory-to-inode ratio; if that fails, then of
++ * the groups with above-average free space, that group with the fewest
++ * directories already is chosen.
++ *
++ * For other inodes, search forward from the parent directory\'s block
++ * group to find a free inode.
++ */
++static int find_group_dir(struct super_block *sb, struct inode *parent)
++{
++	int ngroups = EXT3COW_SB(sb)->s_groups_count;
++	unsigned int freei, avefreei;
++	struct ext3cow_group_desc *desc, *best_desc = NULL;
++	struct buffer_head *bh;
++	int group, best_group = -1;
++
++	freei = percpu_counter_read_positive(&EXT3COW_SB(sb)->s_freeinodes_counter);
++	avefreei = freei / ngroups;
++
++	for (group = 0; group < ngroups; group++) {
++		desc = ext3cow_get_group_desc (sb, group, &bh);
++		if (!desc || !desc->bg_free_inodes_count)
++			continue;
++		if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
++			continue;
++		if (!best_desc ||
++		    (le16_to_cpu(desc->bg_free_blocks_count) >
++		     le16_to_cpu(best_desc->bg_free_blocks_count))) {
++			best_group = group;
++			best_desc = desc;
++		}
++	}
++	return best_group;
++}
++
++/*
++ * Orlov's allocator for directories.
++ *
++ * We always try to spread first-level directories.
++ *
++ * If there are blockgroups with both free inodes and free blocks counts
++ * not worse than average we return one with smallest directory count.
++ * Otherwise we simply return a random group.
++ *
++ * For the rest rules look so:
++ *
++ * It's OK to put directory into a group unless
++ * it has too many directories already (max_dirs) or
++ * it has too few free inodes left (min_inodes) or
++ * it has too few free blocks left (min_blocks) or
++ * it's already running too large debt (max_debt).
++ * Parent's group is prefered, if it doesn't satisfy these
++ * conditions we search cyclically through the rest. If none
++ * of the groups look good we just look for a group with more
++ * free inodes than average (starting at parent's group).
++ *
++ * Debt is incremented each time we allocate a directory and decremented
++ * when we allocate an inode, within 0--255.
++ */
++
++#define INODE_COST 64
++#define BLOCK_COST 256
++
++static int find_group_orlov(struct super_block *sb, struct inode *parent)
++{
++	int parent_group = EXT3COW_I(parent)->i_block_group;
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	struct ext3cow_super_block *es = sbi->s_es;
++	int ngroups = sbi->s_groups_count;
++	int inodes_per_group = EXT3COW_INODES_PER_GROUP(sb);
++	unsigned int freei, avefreei;
++	ext3cow_fsblk_t freeb, avefreeb;
++	ext3cow_fsblk_t blocks_per_dir;
++	unsigned int ndirs;
++	int max_debt, max_dirs, min_inodes;
++	ext3cow_grpblk_t min_blocks;
++	int group = -1, i;
++	struct ext3cow_group_desc *desc;
++	struct buffer_head *bh;
++
++	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
++	avefreei = freei / ngroups;
++	freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
++	avefreeb = freeb / ngroups;
++	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
++
++	if ((parent == sb->s_root->d_inode) ||
++	    (EXT3COW_I(parent)->i_flags & EXT3COW_TOPDIR_FL)) {
++		int best_ndir = inodes_per_group;
++		int best_group = -1;
++
++		get_random_bytes(&group, sizeof(group));
++		parent_group = (unsigned)group % ngroups;
++		for (i = 0; i < ngroups; i++) {
++			group = (parent_group + i) % ngroups;
++			desc = ext3cow_get_group_desc (sb, group, &bh);
++			if (!desc || !desc->bg_free_inodes_count)
++				continue;
++			if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
++				continue;
++			if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
++				continue;
++			if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
++				continue;
++			best_group = group;
++			best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
++		}
++		if (best_group >= 0)
++			return best_group;
++		goto fallback;
++	}
++
++	blocks_per_dir = (le32_to_cpu(es->s_blocks_count) - freeb) / ndirs;
++
++	max_dirs = ndirs / ngroups + inodes_per_group / 16;
++	min_inodes = avefreei - inodes_per_group / 4;
++	min_blocks = avefreeb - EXT3COW_BLOCKS_PER_GROUP(sb) / 4;
++
++	max_debt = EXT3COW_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, (ext3cow_fsblk_t)BLOCK_COST);
++	if (max_debt * INODE_COST > inodes_per_group)
++		max_debt = inodes_per_group / INODE_COST;
++	if (max_debt > 255)
++		max_debt = 255;
++	if (max_debt == 0)
++		max_debt = 1;
++
++	for (i = 0; i < ngroups; i++) {
++		group = (parent_group + i) % ngroups;
++		desc = ext3cow_get_group_desc (sb, group, &bh);
++		if (!desc || !desc->bg_free_inodes_count)
++			continue;
++		if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
++			continue;
++		if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
++			continue;
++		if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
++			continue;
++		return group;
++	}
++
++fallback:
++	for (i = 0; i < ngroups; i++) {
++		group = (parent_group + i) % ngroups;
++		desc = ext3cow_get_group_desc (sb, group, &bh);
++		if (!desc || !desc->bg_free_inodes_count)
++			continue;
++		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
++			return group;
++	}
++
++	if (avefreei) {
++		/*
++		 * The free-inodes counter is approximate, and for really small
++		 * filesystems the above test can fail to find any blockgroups
++		 */
++		avefreei = 0;
++		goto fallback;
++	}
++
++	return -1;
++}
++
++static int find_group_other(struct super_block *sb, struct inode *parent)
++{
++	int parent_group = EXT3COW_I(parent)->i_block_group;
++	int ngroups = EXT3COW_SB(sb)->s_groups_count;
++	struct ext3cow_group_desc *desc;
++	struct buffer_head *bh;
++	int group, i;
++
++	/*
++	 * Try to place the inode in its parent directory
++	 */
++	group = parent_group;
++	desc = ext3cow_get_group_desc (sb, group, &bh);
++	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
++			le16_to_cpu(desc->bg_free_blocks_count))
++		return group;
++
++	/*
++	 * We're going to place this inode in a different blockgroup from its
++	 * parent.  We want to cause files in a common directory to all land in
++	 * the same blockgroup.  But we want files which are in a different
++	 * directory which shares a blockgroup with our parent to land in a
++	 * different blockgroup.
++	 *
++	 * So add our directory's i_ino into the starting point for the hash.
++	 */
++	group = (group + parent->i_ino) % ngroups;
++
++	/*
++	 * Use a quadratic hash to find a group with a free inode and some free
++	 * blocks.
++	 */
++	for (i = 1; i < ngroups; i <<= 1) {
++		group += i;
++		if (group >= ngroups)
++			group -= ngroups;
++		desc = ext3cow_get_group_desc (sb, group, &bh);
++		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
++				le16_to_cpu(desc->bg_free_blocks_count))
++			return group;
++	}
++
++	/*
++	 * That failed: try linear search for a free inode, even if that group
++	 * has no free blocks.
++	 */
++	group = parent_group;
++	for (i = 0; i < ngroups; i++) {
++		if (++group >= ngroups)
++			group = 0;
++		desc = ext3cow_get_group_desc (sb, group, &bh);
++		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
++			return group;
++	}
++
++	return -1;
++}
++
++/*
++ * There are two policies for allocating an inode.  If the new inode is
++ * a directory, then a forward search is made for a block group with both
++ * free space and a low directory-to-inode ratio; if that fails, then of
++ * the groups with above-average free space, that group with the fewest
++ * directories already is chosen.
++ *
++ * For other inodes, search forward from the parent directory's block
++ * group to find a free inode.
++ */
++struct inode *ext3cow_new_inode(handle_t *handle, struct inode * dir, int mode)
++{
++	struct super_block *sb;
++	struct buffer_head *bitmap_bh = NULL;
++	struct buffer_head *bh2;
++	int group;
++	unsigned long ino = 0;
++	struct inode * inode;
++	struct ext3cow_group_desc * gdp = NULL;
++	struct ext3cow_super_block * es;
++	struct ext3cow_inode_info *ei;
++	struct ext3cow_sb_info *sbi;
++	int err = 0;
++	struct inode *ret;
++	int i;
++
++	/* Cannot create files in a deleted directory */
++	if (!dir || !dir->i_nlink)
++		return ERR_PTR(-EPERM);
++
++	sb = dir->i_sb;
++	inode = new_inode(sb);
++	if (!inode)
++		return ERR_PTR(-ENOMEM);
++	ei = EXT3COW_I(inode);
++
++	sbi = EXT3COW_SB(sb);
++	es = sbi->s_es;
++	if (S_ISDIR(mode)) {
++		if (test_opt (sb, OLDALLOC))
++			group = find_group_dir(sb, dir);
++		else
++			group = find_group_orlov(sb, dir);
++	} else
++		group = find_group_other(sb, dir);
++
++	err = -ENOSPC;
++	if (group == -1)
++		goto out;
++
++	for (i = 0; i < sbi->s_groups_count; i++) {
++		err = -EIO;
++
++		gdp = ext3cow_get_group_desc(sb, group, &bh2);
++		if (!gdp)
++			goto fail;
++
++		brelse(bitmap_bh);
++		bitmap_bh = read_inode_bitmap(sb, group);
++		if (!bitmap_bh)
++			goto fail;
++
++		ino = 0;
++
++repeat_in_this_group:
++		ino = ext3cow_find_next_zero_bit((unsigned long *)
++				bitmap_bh->b_data, EXT3COW_INODES_PER_GROUP(sb), ino);
++		if (ino < EXT3COW_INODES_PER_GROUP(sb)) {
++
++			BUFFER_TRACE(bitmap_bh, "get_write_access");
++			err = ext3cow_journal_get_write_access(handle, bitmap_bh);
++			if (err)
++				goto fail;
++
++			if (!ext3cow_set_bit_atomic(sb_bgl_lock(sbi, group),
++						ino, bitmap_bh->b_data)) {
++				/* we won it */
++				BUFFER_TRACE(bitmap_bh,
++					"call ext3cow_journal_dirty_metadata");
++				err = ext3cow_journal_dirty_metadata(handle,
++								bitmap_bh);
++				if (err)
++					goto fail;
++				goto got;
++			}
++			/* we lost it */
++			journal_release_buffer(handle, bitmap_bh);
++
++			if (++ino < EXT3COW_INODES_PER_GROUP(sb))
++				goto repeat_in_this_group;
++		}
++
++		/*
++		 * This case is possible in concurrent environment.  It is very
++		 * rare.  We cannot repeat the find_group_xxx() call because
++		 * that will simply return the same blockgroup, because the
++		 * group descriptor metadata has not yet been updated.
++		 * So we just go onto the next blockgroup.
++		 */
++		if (++group == sbi->s_groups_count)
++			group = 0;
++	}
++	err = -ENOSPC;
++	goto out;
++
++got:
++	ino += group * EXT3COW_INODES_PER_GROUP(sb) + 1;
++	if (ino < EXT3COW_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
++		ext3cow_error (sb, "ext3cow_new_inode",
++			    "reserved inode or inode > inodes count - "
++			    "block_group = %d, inode=%lu", group, ino);
++		err = -EIO;
++		goto fail;
++	}
++
++	BUFFER_TRACE(bh2, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, bh2);
++	if (err) goto fail;
++	spin_lock(sb_bgl_lock(sbi, group));
++	gdp->bg_free_inodes_count =
++		cpu_to_le16(le16_to_cpu(gdp->bg_free_inodes_count) - 1);
++	if (S_ISDIR(mode)) {
++		gdp->bg_used_dirs_count =
++			cpu_to_le16(le16_to_cpu(gdp->bg_used_dirs_count) + 1);
++	}
++	spin_unlock(sb_bgl_lock(sbi, group));
++	BUFFER_TRACE(bh2, "call ext3cow_journal_dirty_metadata");
++	err = ext3cow_journal_dirty_metadata(handle, bh2);
++	if (err) goto fail;
++
++	percpu_counter_dec(&sbi->s_freeinodes_counter);
++	if (S_ISDIR(mode))
++		percpu_counter_inc(&sbi->s_dirs_counter);
++	sb->s_dirt = 1;
++
++	inode->i_uid = current->fsuid;
++	if (test_opt (sb, GRPID))
++		inode->i_gid = dir->i_gid;
++	else if (dir->i_mode & S_ISGID) {
++		inode->i_gid = dir->i_gid;
++		if (S_ISDIR(mode))
++			mode |= S_ISGID;
++	} else
++		inode->i_gid = current->fsgid;
++	inode->i_mode = mode;
++
++	inode->i_ino = ino;
++	/* This is the optimal IO size (for stat), not the fs block size */
++	inode->i_blocks = 0;
++	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
++
++  /* For versioning -znjp */
++  ei->i_cow_bitmap   = 0x0000;
++  ei->i_epoch_number = EXT3COW_S_EPOCHNUMBER(dir->i_sb);
++  ei->i_next_inode   = 0;
++
++	memset(ei->i_data, 0, sizeof(ei->i_data));
++	ei->i_dir_start_lookup = 0;
++	ei->i_disksize = 0;
++
++	ei->i_flags = EXT3COW_I(dir)->i_flags & ~EXT3COW_INDEX_FL;
++	if (S_ISLNK(mode))
++		ei->i_flags &= ~(EXT3COW_IMMUTABLE_FL|EXT3COW_APPEND_FL);
++	/* dirsync only applies to directories */
++	if (!S_ISDIR(mode))
++		ei->i_flags &= ~EXT3COW_DIRSYNC_FL;
++#ifdef EXT3COW_FRAGMENTS
++	ei->i_faddr = 0;
++	ei->i_frag_no = 0;
++	ei->i_frag_size = 0;
++#endif
++	ei->i_file_acl = 0;
++	ei->i_dir_acl = 0;
++	ei->i_dtime = 0;
++	ei->i_block_alloc_info = NULL;
++	ei->i_block_group = group;
++
++	ext3cow_set_inode_flags(inode);
++	if (IS_DIRSYNC(inode))
++		handle->h_sync = 1;
++	insert_inode_hash(inode);
++	spin_lock(&sbi->s_next_gen_lock);
++	inode->i_generation = sbi->s_next_generation++;
++	spin_unlock(&sbi->s_next_gen_lock);
++
++	ei->i_state = EXT3COW_STATE_NEW;
++	ei->i_extra_isize =
++		(EXT3COW_INODE_SIZE(inode->i_sb) > EXT3COW_GOOD_OLD_INODE_SIZE) ?
++		sizeof(struct ext3cow_inode) - EXT3COW_GOOD_OLD_INODE_SIZE : 0;
++
++	ret = inode;
++	if(DQUOT_ALLOC_INODE(inode)) {
++		err = -EDQUOT;
++		goto fail_drop;
++	}
++
++	err = ext3cow_init_acl(handle, inode, dir);
++	if (err)
++		goto fail_free_drop;
++
++	err = ext3cow_init_security(handle,inode, dir);
++	if (err)
++		goto fail_free_drop;
++
++	err = ext3cow_mark_inode_dirty(handle, inode);
++	if (err) {
++		ext3cow_std_error(sb, err);
++		goto fail_free_drop;
++	}
++
++	ext3cow_debug("allocating inode %lu\n", inode->i_ino);
++	goto really_out;
++fail:
++	ext3cow_std_error(sb, err);
++out:
++	iput(inode);
++	ret = ERR_PTR(err);
++really_out:
++	brelse(bitmap_bh);
++	return ret;
++
++fail_free_drop:
++	DQUOT_FREE_INODE(inode);
++
++fail_drop:
++	DQUOT_DROP(inode);
++	inode->i_flags |= S_NOQUOTA;
++	inode->i_nlink = 0;
++	iput(inode);
++	brelse(bitmap_bh);
++	return ERR_PTR(err);
++}
++
++/* Verify that we are loading a valid orphan from disk */
++struct inode *ext3cow_orphan_get(struct super_block *sb, unsigned long ino)
++{
++	unsigned long max_ino = le32_to_cpu(EXT3COW_SB(sb)->s_es->s_inodes_count);
++	unsigned long block_group;
++	int bit;
++	struct buffer_head *bitmap_bh = NULL;
++	struct inode *inode = NULL;
++
++	/* Error cases - e2fsck has already cleaned up for us */
++	if (ino > max_ino) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "bad orphan ino %lu!  e2fsck was run?", ino);
++		goto out;
++	}
++
++	block_group = (ino - 1) / EXT3COW_INODES_PER_GROUP(sb);
++	bit = (ino - 1) % EXT3COW_INODES_PER_GROUP(sb);
++	bitmap_bh = read_inode_bitmap(sb, block_group);
++	if (!bitmap_bh) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "inode bitmap error for orphan %lu", ino);
++		goto out;
++	}
++
++	/* Having the inode bit set should be a 100% indicator that this
++	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
++	 * inodes that were being truncated, so we can't check i_nlink==0.
++	 */
++	if (!ext3cow_test_bit(bit, bitmap_bh->b_data) ||
++			!(inode = iget(sb, ino)) || is_bad_inode(inode) ||
++			NEXT_ORPHAN(inode) > max_ino) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "bad orphan inode %lu!  e2fsck was run?", ino);
++		printk(KERN_NOTICE "ext3cow_test_bit(bit=%d, block=%llu) = %d\n",
++		       bit, (unsigned long long)bitmap_bh->b_blocknr,
++		       ext3cow_test_bit(bit, bitmap_bh->b_data));
++		printk(KERN_NOTICE "inode=%p\n", inode);
++		if (inode) {
++			printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
++			       is_bad_inode(inode));
++			printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
++			       NEXT_ORPHAN(inode));
++			printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
++		}
++		/* Avoid freeing blocks if we got a bad deleted inode */
++		if (inode && inode->i_nlink == 0)
++			inode->i_blocks = 0;
++		iput(inode);
++		inode = NULL;
++	}
++out:
++	brelse(bitmap_bh);
++	return inode;
++}
++
++unsigned long ext3cow_count_free_inodes (struct super_block * sb)
++{
++	unsigned long desc_count;
++	struct ext3cow_group_desc *gdp;
++	int i;
++#ifdef EXT3COWFS_DEBUG
++	struct ext3cow_super_block *es;
++	unsigned long bitmap_count, x;
++	struct buffer_head *bitmap_bh = NULL;
++
++	es = EXT3COW_SB(sb)->s_es;
++	desc_count = 0;
++	bitmap_count = 0;
++	gdp = NULL;
++	for (i = 0; i < EXT3COW_SB(sb)->s_groups_count; i++) {
++		gdp = ext3cow_get_group_desc (sb, i, NULL);
++		if (!gdp)
++			continue;
++		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
++		brelse(bitmap_bh);
++		bitmap_bh = read_inode_bitmap(sb, i);
++		if (!bitmap_bh)
++			continue;
++
++		x = ext3cow_count_free(bitmap_bh, EXT3COW_INODES_PER_GROUP(sb) / 8);
++		printk("group %d: stored = %d, counted = %lu\n",
++			i, le16_to_cpu(gdp->bg_free_inodes_count), x);
++		bitmap_count += x;
++	}
++	brelse(bitmap_bh);
++	printk("ext3cow_count_free_inodes: stored = %u, computed = %lu, %lu\n",
++		le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
++	return desc_count;
++#else
++	desc_count = 0;
++	for (i = 0; i < EXT3COW_SB(sb)->s_groups_count; i++) {
++		gdp = ext3cow_get_group_desc (sb, i, NULL);
++		if (!gdp)
++			continue;
++		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
++		cond_resched();
++	}
++	return desc_count;
++#endif
++}
++
++/* Called at mount-time, super-block is locked */
++unsigned long ext3cow_count_dirs (struct super_block * sb)
++{
++	unsigned long count = 0;
++	int i;
++
++	for (i = 0; i < EXT3COW_SB(sb)->s_groups_count; i++) {
++		struct ext3cow_group_desc *gdp = ext3cow_get_group_desc (sb, i, NULL);
++		if (!gdp)
++			continue;
++		count += le16_to_cpu(gdp->bg_used_dirs_count);
++	}
++	return count;
++}
++
+diff -ruN linux-2.6.20.3/fs/ext3cow/inode.c linux-2.6.20.3-ext3cow/fs/ext3cow/inode.c
+--- linux-2.6.20.3/fs/ext3cow/inode.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/inode.c	2007-04-17 11:34:02.000000000 -0400
+@@ -0,0 +1,3474 @@
++/*
++ *  linux/fs/ext3cow/inode.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/inode.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  Goal-directed block allocation by Stephen Tweedie
++ *	(sct@redhat.com), 1993, 1998
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ *  64-bit file support on 64-bit platforms by Jakub Jelinek
++ *	(jj@sunsite.ms.mff.cuni.cz)
++ *
++ *  Assorted race fixes, rewrite of ext3cow_get_block() by Al Viro, 2000
++ */
++
++#include <linux/module.h>
++#include <linux/fs.h>
++#include <linux/time.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/jbd.h>
++#include <linux/smp_lock.h>
++#include <linux/highuid.h>
++#include <linux/pagemap.h>
++#include <linux/quotaops.h>
++#include <linux/string.h>
++#include <linux/buffer_head.h>
++#include <linux/writeback.h>
++#include <linux/mpage.h>
++#include <linux/uio.h>
++#include <linux/bio.h>
++#include "xattr.h"
++#include "acl.h"
++
++static int ext3cow_writepage_trans_blocks(struct inode *inode);
++
++/*
++ * Test whether an inode is a fast symlink.
++ */
++static int ext3cow_inode_is_fast_symlink(struct inode *inode)
++{
++	int ea_blocks = EXT3COW_I(inode)->i_file_acl ?
++		(inode->i_sb->s_blocksize >> 9) : 0;
++
++	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
++}
++
++/*
++ * The ext3cow forget function must perform a revoke if we are freeing data
++ * which has been journaled.  Metadata (eg. indirect blocks) must be
++ * revoked in all cases.
++ *
++ * "bh" may be NULL: a metadata block may have been freed from memory
++ * but there may still be a record of it in the journal, and that record
++ * still needs to be revoked.
++ */
++int ext3cow_forget(handle_t *handle, int is_metadata, struct inode *inode,
++			struct buffer_head *bh, ext3cow_fsblk_t blocknr)
++{
++	int err;
++
++	might_sleep();
++
++	BUFFER_TRACE(bh, "enter");
++
++	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
++		  "data mode %lx\n",
++		  bh, is_metadata, inode->i_mode,
++		  test_opt(inode->i_sb, DATA_FLAGS));
++
++	/* Never use the revoke function if we are doing full data
++	 * journaling: there is no need to, and a V1 superblock won't
++	 * support it.  Otherwise, only skip the revoke on un-journaled
++	 * data blocks. */
++
++	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3COW_MOUNT_JOURNAL_DATA ||
++	    (!is_metadata && !ext3cow_should_journal_data(inode))) {
++		if (bh) {
++			BUFFER_TRACE(bh, "call journal_forget");
++			return ext3cow_journal_forget(handle, bh);
++		}
++		return 0;
++	}
++
++	/*
++	 * data!=journal && (is_metadata || should_journal_data(inode))
++	 */
++	BUFFER_TRACE(bh, "call ext3cow_journal_revoke");
++	err = ext3cow_journal_revoke(handle, blocknr, bh);
++	if (err)
++		ext3cow_abort(inode->i_sb, __FUNCTION__,
++			   "error %d when attempting revoke", err);
++	BUFFER_TRACE(bh, "exit");
++	return err;
++}
++
++/*
++ * Work out how many blocks we need to proceed with the next chunk of a
++ * truncate transaction.
++ */
++static unsigned long blocks_for_truncate(struct inode *inode)
++{
++	unsigned long needed;
++
++	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
++
++	/* Give ourselves just enough room to cope with inodes in which
++	 * i_blocks is corrupt: we've seen disk corruptions in the past
++	 * which resulted in random data in an inode which looked enough
++	 * like a regular file for ext3cow to try to delete it.  Things
++	 * will go a bit crazy if that happens, but at least we should
++	 * try not to panic the whole kernel. */
++	if (needed < 2)
++		needed = 2;
++
++	/* But we need to bound the transaction so we don't overflow the
++	 * journal. */
++	if (needed > EXT3COW_MAX_TRANS_DATA)
++		needed = EXT3COW_MAX_TRANS_DATA;
++
++	return EXT3COW_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
++}
++
++/*
++ * Truncate transactions can be complex and absolutely huge.  So we need to
++ * be able to restart the transaction at a conventient checkpoint to make
++ * sure we don't overflow the journal.
++ *
++ * start_transaction gets us a new handle for a truncate transaction,
++ * and extend_transaction tries to extend the existing one a bit.  If
++ * extend fails, we need to propagate the failure up and restart the
++ * transaction in the top-level truncate loop. --sct
++ */
++static handle_t *start_transaction(struct inode *inode)
++{
++	handle_t *result;
++
++	result = ext3cow_journal_start(inode, blocks_for_truncate(inode));
++	if (!IS_ERR(result))
++		return result;
++
++	ext3cow_std_error(inode->i_sb, PTR_ERR(result));
++	return result;
++}
++
++/*
++ * Try to extend this transaction for the purposes of truncation.
++ *
++ * Returns 0 if we managed to create more room.  If we can't create more
++ * room, and the transaction must be restarted we return 1.
++ */
++static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
++{
++	if (handle->h_buffer_credits > EXT3COW_RESERVE_TRANS_BLOCKS)
++		return 0;
++	if (!ext3cow_journal_extend(handle, blocks_for_truncate(inode)))
++		return 0;
++	return 1;
++}
++
++/*
++ * Restart the transaction associated with *handle.  This does a commit,
++ * so before we call here everything must be consistently dirtied against
++ * this transaction.
++ */
++static int ext3cow_journal_test_restart(handle_t *handle, struct inode *inode)
++{
++	jbd_debug(2, "restarting handle %p\n", handle);
++	return ext3cow_journal_restart(handle, blocks_for_truncate(inode));
++}
++
++/*
++ * Called at the last iput() if i_nlink is zero.
++ */
++void ext3cow_delete_inode (struct inode * inode)
++{
++	handle_t *handle;
++
++	truncate_inode_pages(&inode->i_data, 0);
++
++	if (is_bad_inode(inode))
++		goto no_delete;
++
++	handle = start_transaction(inode);
++	if (IS_ERR(handle)) {
++		/*
++		 * If we're going to skip the normal cleanup, we still need to
++		 * make sure that the in-core orphan linked list is properly
++		 * cleaned up.
++		 */
++		ext3cow_orphan_del(NULL, inode);
++		goto no_delete;
++	}
++
++	if (IS_SYNC(inode))
++		handle->h_sync = 1;
++	inode->i_size = 0;
++	if (inode->i_blocks)
++		ext3cow_truncate(inode);
++	/*
++	 * Kill off the orphan record which ext3cow_truncate created.
++	 * AKPM: I think this can be inside the above `if'.
++	 * Note that ext3cow_orphan_del() has to be able to cope with the
++	 * deletion of a non-existent orphan - this is because we don't
++	 * know if ext3cow_truncate() actually created an orphan record.
++	 * (Well, we could do this if we need to, but heck - it works)
++	 */
++	ext3cow_orphan_del(handle, inode);
++	EXT3COW_I(inode)->i_dtime	= get_seconds();
++
++	/*
++	 * One subtle ordering requirement: if anything has gone wrong
++	 * (transaction abort, IO errors, whatever), then we can still
++	 * do these next steps (the fs will already have been marked as
++	 * having errors), but we can't free the inode if the mark_dirty
++	 * fails.
++	 */
++	if (ext3cow_mark_inode_dirty(handle, inode))
++		/* If that failed, just do the required in-core inode clear. */
++		clear_inode(inode);
++	else
++		ext3cow_free_inode(handle, inode);
++	ext3cow_journal_stop(handle);
++	return;
++no_delete:
++	clear_inode(inode);	/* We must guarantee clearing of inode... */
++}
++
++typedef struct {
++	__le32	*p;
++	__le32	key;
++	struct buffer_head *bh;
++} Indirect;
++
++static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
++{
++	p->key = *(p->p = v);
++	p->bh = bh;
++}
++
++static int verify_chain(Indirect *from, Indirect *to)
++{
++	while (from <= to && from->key == *from->p)
++		from++;
++	return (from > to);
++}
++
++//TODO: Delete at some point
++/* znjp - used for bitmap testing */
++
++ static void printbin(u32 val, int size) {
++  u32 mask;
++  
++  mask=(1UL << (size-1));
++  while (mask) {
++    if (mask & val) 
++      printk("1");
++    else 
++      printk("0");
++    mask /= 2;
++  }
++  printk("\n");
++ 
++ }
++
++
++/**
++ *	ext3cow_block_to_path - parse the block number into array of offsets
++ *	@inode: inode in question (we are only interested in its superblock)
++ *	@i_block: block number to be parsed
++ *	@offsets: array to store the offsets in
++ *      @boundary: set this non-zero if the referred-to block is likely to be
++ *             followed (on disk) by an indirect block.
++ *
++ *	To store the locations of file's data ext3cow uses a data structure common
++ *	for UNIX filesystems - tree of pointers anchored in the inode, with
++ *	data blocks at leaves and indirect blocks in intermediate nodes.
++ *	This function translates the block number into path in that tree -
++ *	return value is the path length and @offsets[n] is the offset of
++ *	pointer to (n+1)th node in the nth one. If @block is out of range
++ *	(negative or too large) warning is printed and zero returned.
++ *
++ *	Note: function doesn't find node addresses, so no IO is needed. All
++ *	we need to know is the capacity of indirect blocks (taken from the
++ *	inode->i_sb).
++ */
++
++/*
++ * Portability note: the last comparison (check that we fit into triple
++ * indirect block) is spelled differently, because otherwise on an
++ * architecture with 32-bit longs and 8Kb pages we might get into trouble
++ * if our filesystem had 8Kb blocks. We might use long long, but that would
++ * kill us on x86. Oh, well, at least the sign propagation does not matter -
++ * i_block would have to be negative in the very beginning, so we would not
++ * get there at all.
++ */
++
++static int ext3cow_block_to_path(struct inode *inode,
++			long i_block, int offsets[4], int *boundary)
++{
++  /* TODO: Check for efficientcy -znjp */
++	int ptrs = EXT3COW_ADDR_PER_BLOCK(inode->i_sb);
++	const long direct_blocks = EXT3COW_NDIR_BLOCKS,
++		indirect_blocks = ptrs,
++    double_blocks = (ptrs * ptrs);
++		//double_blocks = (1 << (ptrs_bits * 2));
++	int n = 0;
++	int final = 0;
++
++	if (i_block < 0) {
++		ext3cow_warning (inode->i_sb, "ext3cow_block_to_path", "block < 0");
++	} else if (i_block < direct_blocks) {
++		offsets[n++] = i_block;
++		final = direct_blocks;
++	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
++		offsets[n++] = EXT3COW_IND_BLOCK;
++		offsets[n++] = i_block;
++		final = ptrs;
++	} else if ((i_block -= indirect_blocks) < double_blocks) {
++		offsets[n++] = EXT3COW_DIND_BLOCK;
++		offsets[n++] = (i_block/ptrs); //i_block >> ptrs_bits;
++		offsets[n++] = (i_block%ptrs); //i_block & (ptrs - 1);
++		final = ptrs;
++	} else if (((i_block -= double_blocks)/(double_blocks)) < ptrs) {
++    //	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
++		offsets[n++] = EXT3COW_TIND_BLOCK;
++		offsets[n++] = (i_block/double_blocks); //i_block >> (ptrs_bits * 2);
++		offsets[n++] = (i_block/double_blocks)%ptrs; //(i_block >> ptrs_bits) & (ptrs - 1);
++		offsets[n++] = i_block%ptrs; //i_block & (ptrs - 1);
++		final = ptrs;
++	} else {
++		ext3cow_warning(inode->i_sb, "ext3cow_block_to_path", "block > big");
++	}
++	if (boundary)
++		*boundary = final - 1 - (i_block & (ptrs - 1));
++	return n;
++}
++
++/**
++ *	ext3cow_get_branch - read the chain of indirect blocks leading to data
++ *	@inode: inode in question
++ *	@depth: depth of the chain (1 - direct pointer, etc.)
++ *	@offsets: offsets of pointers in inode/indirect blocks
++ *	@chain: place to store the result
++ *	@err: here we store the error value
++ *
++ *	Function fills the array of triples <key, p, bh> and returns %NULL
++ *	if everything went OK or the pointer to the last filled triple
++ *	(incomplete one) otherwise. Upon the return chain[i].key contains
++ *	the number of (i+1)-th block in the chain (as it is stored in memory,
++ *	i.e. little-endian 32-bit), chain[i].p contains the address of that
++ *	number (it points into struct inode for i==0 and into the bh->b_data
++ *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
++ *	block for i>0 and NULL for i==0. In other words, it holds the block
++ *	numbers of the chain, addresses they were taken from (and where we can
++ *	verify that chain did not change) and buffer_heads hosting these
++ *	numbers.
++ *
++ *	Function stops when it stumbles upon zero pointer (absent block)
++ *		(pointer to last triple returned, *@err == 0)
++ *	or when it gets an IO error reading an indirect block
++ *		(ditto, *@err == -EIO)
++ *	or when it notices that chain had been changed while it was reading
++ *		(ditto, *@err == -EAGAIN)
++ *	or when it reads all @depth-1 indirect blocks successfully and finds
++ *	the whole chain, all way to the data (returns %NULL, *err == 0).
++ *  If this is COW we set the cow field to 1.  We know if it's COW
++ *  because there will already be a key.  We need this field so we
++ *  zero out the data already in the buffer.
++ *  The create flag let's us know if were just looking for a block
++ *  to read, or a block to write.  We only set the bitmap when
++ *  we're looking for a block to write, either on new allocation
++ *  or on COWing. -znjp
++ */
++static Indirect *ext3cow_get_branch(struct inode *inode, int depth, 
++                                    int *offsets,
++                                    Indirect chain[4], int *err, int *cow,
++                                    int create)
++{
++	struct super_block *sb = inode->i_sb;
++	Indirect *p = chain;
++	struct buffer_head *bh;
++  u32* bitmap_w;
++  int ptrs = EXT3COW_ADDR_PER_BLOCK(inode->i_sb);
++  int nbitsperword = (sizeof(u32) * 8);
++
++	*err = 0;
++  *cow = 0;
++	/* i_data is not going away, no lock needed */
++	add_chain (chain, NULL, EXT3COW_I(inode)->i_data + *offsets);
++	if (!p->key){
++    /* Set the bitmap on allocation - znjp */
++    if(create)
++      EXT3COW_I(inode)->i_cow_bitmap |= (1UL << *offsets);
++		goto no_block;
++  }
++
++  /* Are we COWing any direct blocks? -znjp */
++  if(create && !(EXT3COW_I(inode)->i_cow_bitmap & (1UL << *offsets))){    
++    printk(KERN_INFO "COWing direct block\n");
++    *(p->p) = 0;
++    p->key = 0;
++    /* Set the bitamp when COWing -znjp */
++    EXT3COW_I(inode)->i_cow_bitmap |= (1UL << *offsets);
++    *cow = 1;
++    goto no_block;
++  }
++
++	while (--depth) {
++		bh = sb_bread(sb, le32_to_cpu(p->key));
++		if (!bh)
++			goto failure;
++
++		/* Reader: pointers */
++		if (!verify_chain(chain, p))
++			goto changed;
++		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
++		/* Reader: end */
++    /* Find correct bitamp word */
++    bitmap_w = (u32*)bh->b_data + ptrs + (*offsets/nbitsperword);
++		if (!p->key){
++      /* Set the bitmap when allocating -znjp */
++      if(create)
++       *bitmap_w = (u32)*bitmap_w | (u32)(1UL << (int)(*offsets%nbitsperword));
++			goto no_block;
++    }
++
++    /* Are we COWing any indirect blocks? -znjp */
++    if(create && !((1UL << (int)(*offsets%nbitsperword)) & 
++         le32_to_cpu((u32)*bitmap_w))){
++      printk(KERN_INFO "COWing indirect block\n");
++      *(p->p) = 0;
++      p->key = 0;
++      /* Set the bitmap -znjp */
++      *bitmap_w = (u32)*bitmap_w | (u32)(1UL << (int)(*offsets%nbitsperword));
++      *cow = 1;
++      goto no_block;
++    }
++	}
++	return NULL;
++
++changed:
++	brelse(bh);
++	*err = -EAGAIN;
++	goto no_block;
++failure:
++	*err = -EIO;
++no_block:
++	return p;
++}
++
++/**
++ *	ext3cow_find_near - find a place for allocation with sufficient locality
++ *	@inode: owner
++ *	@ind: descriptor of indirect block.
++ *
++ *	This function returns the prefered place for block allocation.
++ *	It is used when heuristic for sequential allocation fails.
++ *	Rules are:
++ *	  + if there is a block to the left of our position - allocate near it.
++ *	  + if pointer will live in indirect block - allocate near that block.
++ *	  + if pointer will live in inode - allocate in the same
++ *	    cylinder group.
++ *
++ * In the latter case we colour the starting block by the callers PID to
++ * prevent it from clashing with concurrent allocations for a different inode
++ * in the same block group.   The PID is used here so that functionally related
++ * files will be close-by on-disk.
++ *
++ *	Caller must make sure that @ind is valid and will stay that way.
++ */
++static ext3cow_fsblk_t ext3cow_find_near(struct inode *inode, Indirect *ind)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
++	__le32 *p;
++	ext3cow_fsblk_t bg_start;
++	ext3cow_grpblk_t colour;
++
++	/* Try to find previous block */
++	for (p = ind->p - 1; p >= start; p--) {
++		if (*p)
++			return le32_to_cpu(*p);
++	}
++
++	/* No such thing, so let's try location of indirect block */
++	if (ind->bh)
++		return ind->bh->b_blocknr;
++
++	/*
++	 * It is going to be referred to from the inode itself? OK, just put it
++	 * into the same cylinder group then.
++	 */
++	bg_start = ext3cow_group_first_block_no(inode->i_sb, ei->i_block_group);
++	colour = (current->pid % 16) *
++			(EXT3COW_BLOCKS_PER_GROUP(inode->i_sb) / 16);
++	return bg_start + colour;
++}
++
++/**
++ *	ext3cow_find_goal - find a prefered place for allocation.
++ *	@inode: owner
++ *	@block:  block we want
++ *	@chain:  chain of indirect blocks
++ *	@partial: pointer to the last triple within a chain
++ *	@goal:	place to store the result.
++ *
++ *	Normally this function find the prefered place for block allocation,
++ *	stores it in *@goal and returns zero.
++ */
++
++static ext3cow_fsblk_t ext3cow_find_goal(struct inode *inode, long block,
++		Indirect chain[4], Indirect *partial)
++{
++	struct ext3cow_block_alloc_info *block_i;
++
++	block_i =  EXT3COW_I(inode)->i_block_alloc_info;
++
++	/*
++	 * try the heuristic for sequential allocation,
++	 * failing that at least try to get decent locality.
++	 */
++	if (block_i && (block == block_i->last_alloc_logical_block + 1)
++		&& (block_i->last_alloc_physical_block != 0)) {
++		return block_i->last_alloc_physical_block + 1;
++	}
++
++	return ext3cow_find_near(inode, partial);
++}
++
++/**
++ *	ext3cow_blks_to_allocate: Look up the block map and count the number
++ *	of direct blocks need to be allocated for the given branch.
++ *
++ *	@branch: chain of indirect blocks
++ *	@k: number of blocks need for indirect blocks
++ *	@blks: number of data blocks to be mapped.
++ *	@blocks_to_boundary:  the offset in the indirect block
++ *
++ *	return the total number of blocks to be allocate, including the
++ *	direct and indirect blocks.
++ */
++static int ext3cow_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
++		int blocks_to_boundary)
++{
++	unsigned long count = 0;
++
++	/*
++	 * Simple case, [t,d]Indirect block(s) has not allocated yet
++	 * then it's clear blocks on that path have not allocated
++	 */
++	if (k > 0) {
++		/* right now we don't handle cross boundary allocation */
++		if (blks < blocks_to_boundary + 1)
++			count += blks;
++		else
++			count += blocks_to_boundary + 1;
++		return count;
++	}
++
++	count++;
++	while (count < blks && count <= blocks_to_boundary &&
++		le32_to_cpu(*(branch[0].p + count)) == 0) {
++		count++;
++	}
++	return count;
++}
++
++/**
++ *	ext3cow_alloc_blocks: multiple allocate blocks needed for a branch
++ *	@indirect_blks: the number of blocks need to allocate for indirect
++ *			blocks
++ *
++ *	@new_blocks: on return it will store the new block numbers for
++ *	the indirect blocks(if needed) and the first direct block,
++ *	@blks:	on return it will store the total number of allocated
++ *		direct blocks
++ */
++static int ext3cow_alloc_blocks(handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t goal, int indirect_blks, int blks,
++			ext3cow_fsblk_t new_blocks[4], int *err)
++{
++	int target, i;
++	unsigned long count = 0;
++	int index = 0;
++	ext3cow_fsblk_t current_block = 0;
++	int ret = 0;
++
++	/*
++	 * Here we try to allocate the requested multiple blocks at once,
++	 * on a best-effort basis.
++	 * To build a branch, we should allocate blocks for
++	 * the indirect blocks(if not allocated yet), and at least
++	 * the first direct block of this branch.  That's the
++	 * minimum number of blocks need to allocate(required)
++	 */
++	target = blks + indirect_blks;
++
++	while (1) {
++		count = target;
++		/* allocating blocks for indirect blocks and direct blocks */
++		current_block = ext3cow_new_blocks(handle,inode,goal,&count,err);
++		if (*err)
++			goto failed_out;
++
++		target -= count;
++		/* allocate blocks for indirect blocks */
++		while (index < indirect_blks && count) {
++			new_blocks[index++] = current_block++;
++			count--;
++		}
++
++		if (count > 0)
++			break;
++	}
++
++	/* save the new block number for the first direct block */
++	new_blocks[index] = current_block;
++
++	/* total number of blocks allocated for direct blocks */
++	ret = count;
++	*err = 0;
++	return ret;
++failed_out:
++	for (i = 0; i <index; i++)
++		ext3cow_free_blocks(handle, inode, new_blocks[i], 1);
++	return ret;
++}
++
++/**
++ *	ext3cow_alloc_branch - allocate and set up a chain of blocks.
++ *	@inode: owner
++ *	@indirect_blks: number of allocated indirect blocks
++ *	@blks: number of allocated direct blocks
++ *	@offsets: offsets (in the blocks) to store the pointers to next.
++ *	@branch: place to store the chain in.
++ *
++ *	This function allocates blocks, zeroes out all but the last one,
++ *	links them into chain and (if we are synchronous) writes them to disk.
++ *	In other words, it prepares a branch that can be spliced onto the
++ *	inode. It stores the information about that chain in the branch[], in
++ *	the same format as ext3cow_get_branch() would do. We are calling it after
++ *	we had read the existing part of chain and partial points to the last
++ *	triple of that (one with zero ->key). Upon the exit we have the same
++ *	picture as after the successful ext3cow_get_block(), except that in one
++ *	place chain is disconnected - *branch->p is still zero (we did not
++ *	set the last link), but branch->key contains the number that should
++ *	be placed into *branch->p to fill that gap.
++ *
++ *	If allocation fails we free all blocks we've allocated (and forget
++ *	their buffer_heads) and return the error value the from failed
++ *	ext3cow_alloc_block() (normally -ENOSPC). Otherwise we set the chain
++ *	as described above and return 0.
++ */
++static int ext3cow_alloc_branch(handle_t *handle, struct inode *inode,
++			int indirect_blks, int *blks, ext3cow_fsblk_t goal,
++			int *offsets, Indirect *branch)
++{
++	int blocksize = inode->i_sb->s_blocksize;
++	int i, n = 0;
++	int err = 0;
++	struct buffer_head *bh;
++	int num;
++	ext3cow_fsblk_t new_blocks[4];
++	ext3cow_fsblk_t current_block;
++
++	num = ext3cow_alloc_blocks(handle, inode, goal, indirect_blks,
++				*blks, new_blocks, &err);
++	if (err)
++		return err;
++
++	branch[0].key = cpu_to_le32(new_blocks[0]);
++	/*
++	 * metadata blocks and data blocks are allocated.
++	 */
++	for (n = 1; n <= indirect_blks;  n++) {
++		/*
++		 * Get buffer_head for parent block, zero it out
++		 * and set the pointer to new one, then send
++		 * parent to disk.
++		 */
++		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
++		branch[n].bh = bh;
++		lock_buffer(bh);
++		BUFFER_TRACE(bh, "call get_create_access");
++		err = ext3cow_journal_get_create_access(handle, bh);
++		if (err) {
++			unlock_buffer(bh);
++			brelse(bh);
++			goto failed;
++		}
++
++		memset(bh->b_data, 0, blocksize);
++		branch[n].p = (__le32 *) bh->b_data + offsets[n];
++		branch[n].key = cpu_to_le32(new_blocks[n]);
++		*branch[n].p = branch[n].key;
++		if ( n == indirect_blks) {
++			current_block = new_blocks[n];
++			/*
++			 * End of chain, update the last new metablock of
++			 * the chain to point to the new allocated
++			 * data blocks numbers
++			 */
++			for (i=1; i < num; i++)
++				*(branch[n].p + i) = cpu_to_le32(++current_block);
++		}
++		BUFFER_TRACE(bh, "marking uptodate");
++		set_buffer_uptodate(bh);
++		unlock_buffer(bh);
++
++		BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++		err = ext3cow_journal_dirty_metadata(handle, bh);
++		if (err)
++			goto failed;
++	}
++	*blks = num;
++	return err;
++failed:
++	/* Allocation failed, free what we already allocated */
++	for (i = 1; i <= n ; i++) {
++		BUFFER_TRACE(branch[i].bh, "call journal_forget");
++		ext3cow_journal_forget(handle, branch[i].bh);
++	}
++	for (i = 0; i <indirect_blks; i++)
++		ext3cow_free_blocks(handle, inode, new_blocks[i], 1);
++
++	ext3cow_free_blocks(handle, inode, new_blocks[i], num);
++
++	return err;
++}
++
++/**
++ * ext3cow_splice_branch - splice the allocated branch onto inode.
++ * @inode: owner
++ * @block: (logical) number of block we are adding
++ * @chain: chain of indirect blocks (with a missing link - see
++ *	ext3cow_alloc_branch)
++ * @where: location of missing link
++ * @num:   number of indirect blocks we are adding
++ * @blks:  number of direct blocks we are adding
++ *
++ * This function fills the missing link and does all housekeeping needed in
++ * inode (->i_blocks, etc.). In case of success we end up with the full
++ * chain to new block and return 0.
++ */
++static int ext3cow_splice_branch(handle_t *handle, struct inode *inode,
++			long block, Indirect *where, int num, int blks)
++{
++	int i;
++	int err = 0;
++	struct ext3cow_block_alloc_info *block_i;
++	ext3cow_fsblk_t current_block;
++
++	block_i = EXT3COW_I(inode)->i_block_alloc_info;
++	/*
++	 * If we're splicing into a [td]indirect block (as opposed to the
++	 * inode) then we need to get write access to the [td]indirect block
++	 * before the splice.
++	 */
++	if (where->bh) {
++		BUFFER_TRACE(where->bh, "get_write_access");
++		err = ext3cow_journal_get_write_access(handle, where->bh);
++		if (err)
++			goto err_out;
++	}
++	/* That's it */
++
++	*where->p = where->key;
++
++	/*
++	 * Update the host buffer_head or inode to point to more just allocated
++	 * direct blocks blocks
++	 */
++	if (num == 0 && blks > 1) {
++		current_block = le32_to_cpu(where->key) + 1;
++		for (i = 1; i < blks; i++)
++			*(where->p + i ) = cpu_to_le32(current_block++);
++	}
++
++	/*
++	 * update the most recently allocated logical & physical block
++	 * in i_block_alloc_info, to assist find the proper goal block for next
++	 * allocation
++	 */
++	if (block_i) {
++		block_i->last_alloc_logical_block = block + blks - 1;
++		block_i->last_alloc_physical_block =
++				le32_to_cpu(where[num].key) + blks - 1;
++	}
++
++	/* We are done with atomic stuff, now do the rest of housekeeping */
++
++	inode->i_ctime = CURRENT_TIME_SEC;
++	ext3cow_mark_inode_dirty(handle, inode);
++
++	/* had we spliced it onto indirect block? */
++	if (where->bh) {
++		/*
++		 * If we spliced it onto an indirect block, we haven't
++		 * altered the inode.  Note however that if it is being spliced
++		 * onto an indirect block at the very end of the file (the
++		 * file is growing) then we *will* alter the inode to reflect
++		 * the new i_size.  But that is not done here - it is done in
++		 * generic_commit_write->__mark_inode_dirty->ext3cow_dirty_inode.
++		 */
++		jbd_debug(5, "splicing indirect only\n");
++		BUFFER_TRACE(where->bh, "call ext3cow_journal_dirty_metadata");
++		err = ext3cow_journal_dirty_metadata(handle, where->bh);
++		if (err)
++			goto err_out;
++	} else {
++		/*
++		 * OK, we spliced it into the inode itself on a direct block.
++		 * Inode was dirtied above.
++		 */
++		jbd_debug(5, "splicing direct\n");
++	}
++	return err;
++
++err_out:
++	for (i = 1; i <= num; i++) {
++		BUFFER_TRACE(where[i].bh, "call journal_forget");
++		ext3cow_journal_forget(handle, where[i].bh);
++		ext3cow_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
++	}
++	ext3cow_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
++
++	return err;
++}
++
++/*
++ * Allocation strategy is simple: if we have to allocate something, we will
++ * have to go the whole way to leaf. So let's do it before attaching anything
++ * to tree, set linkage between the newborn blocks, write them if sync is
++ * required, recheck the path, free and repeat if check fails, otherwise
++ * set the last missing link (that will protect us from any truncate-generated
++ * removals - all blocks on the path are immune now) and possibly force the
++ * write on the parent block.
++ * That has a nice additional property: no special recovery from the failed
++ * allocations is needed - we simply release blocks and do not touch anything
++ * reachable from inode.
++ *
++ * `handle' can be NULL if create == 0.
++ *
++ * The BKL may not be held on entry here.  Be sure to take it early.
++ * return > 0, # of blocks mapped or allocated.
++ * return = 0, if plain lookup failed.
++ * return < 0, error case.
++ */
++int ext3cow_get_blocks_handle(handle_t *handle, struct inode *inode,
++		sector_t iblock, unsigned long maxblocks,
++		struct buffer_head *bh_result,
++		int create, int extend_disksize)
++{
++	int err = -EIO;
++	int offsets[4];
++	Indirect chain[4];
++	Indirect *partial;
++	ext3cow_fsblk_t goal;
++	int indirect_blks;
++	int blocks_to_boundary = 0;
++	int depth;
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	int count = 0;
++	ext3cow_fsblk_t first_block = 0;
++  int cow = 0; /* To determine wether we clear the buffer of not -znjp */
++
++
++	J_ASSERT(handle != NULL || create == 0);
++	depth = ext3cow_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
++
++	if (depth == 0)
++		goto out;
++
++	partial = ext3cow_get_branch(inode, depth, offsets, 
++                               chain, &err, &cow, create);
++
++	/* Simplest case - block found, no allocation needed */
++	if (!partial) {
++		first_block = le32_to_cpu(chain[depth - 1].key);
++    if(!cow) /* Don't clear the buffer if it's a COW allocation -znjp */
++      clear_buffer_new(bh_result);
++		count++;
++		/*map more blocks*/
++		while (count < maxblocks && count <= blocks_to_boundary) {
++			ext3cow_fsblk_t blk;
++
++			if (!verify_chain(chain, partial)) {
++				/*
++				 * Indirect block might be removed by
++				 * truncate while we were reading it.
++				 * Handling of that case: forget what we've
++				 * got now. Flag the err as EAGAIN, so it
++				 * will reread.
++				 */
++				err = -EAGAIN;
++				count = 0;
++				break;
++			}
++			blk = le32_to_cpu(*(chain[depth-1].p + count));
++
++			if (blk == first_block + count)
++				count++;
++			else
++				break;
++		}
++		if (err != -EAGAIN)
++			goto got_it;
++	}
++
++	/* Next simple case - plain lookup or failed read of indirect block */
++	if (!create || err == -EIO)
++		goto cleanup;
++
++	mutex_lock(&ei->truncate_mutex);
++
++	/*
++	 * If the indirect block is missing while we are reading
++	 * the chain(ext3cow_get_branch() returns -EAGAIN err), or
++	 * if the chain has been changed after we grab the semaphore,
++	 * (either because another process truncated this branch, or
++	 * another get_block allocated this branch) re-grab the chain to see if
++	 * the request block has been allocated or not.
++	 *
++	 * Since we already block the truncate/other get_block
++	 * at this point, we will have the current copy of the chain when we
++	 * splice the branch into the tree.
++	 */
++	if (err == -EAGAIN || !verify_chain(chain, partial)) {
++		while (partial > chain) {
++			brelse(partial->bh);
++			partial--;
++		}
++		partial = ext3cow_get_branch(inode, depth, offsets, 
++                                 chain, &err, &cow, create);
++		if (!partial) {
++			count++;
++			mutex_unlock(&ei->truncate_mutex);
++			if (err)
++				goto cleanup;
++      /* Don't clear the buffer if we're COWing it -znjp */
++      if(!cow)
++        clear_buffer_new(bh_result);
++			goto got_it;
++		}
++	}
++
++	/*
++	 * Okay, we need to do block allocation.  Lazily initialize the block
++	 * allocation info here if necessary
++	*/
++	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
++		ext3cow_init_block_alloc_info(inode);
++
++	goal = ext3cow_find_goal(inode, iblock, chain, partial);
++
++	/* the number of blocks need to allocate for [d,t]indirect blocks */
++	indirect_blks = (chain + depth) - partial - 1;
++
++	/*
++	 * Next look up the indirect map to count the totoal number of
++	 * direct blocks to allocate for this branch.
++	 */
++	count = ext3cow_blks_to_allocate(partial, indirect_blks,
++					maxblocks, blocks_to_boundary);
++	/*
++	 * Block out ext3cow_truncate while we alter the tree
++	 */
++	err = ext3cow_alloc_branch(handle, inode, indirect_blks, &count, goal,
++				offsets + (partial - chain), partial);
++
++	/*
++	 * The ext3cow_splice_branch call will free and forget any buffers
++	 * on the new chain if there is a failure, but that risks using
++	 * up transaction credits, especially for bitmaps where the
++	 * credits cannot be returned.  Can we handle this somehow?  We
++	 * may need to return -EAGAIN upwards in the worst case.  --sct
++	 */
++	if (!err)
++		err = ext3cow_splice_branch(handle, inode, iblock,
++					partial, indirect_blks, count);
++	/*
++	 * i_disksize growing is protected by truncate_mutex.  Don't forget to
++	 * protect it if you're about to implement concurrent
++	 * ext3cow_get_block() -bzzz
++	*/
++	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
++		ei->i_disksize = inode->i_size;
++	mutex_unlock(&ei->truncate_mutex);
++	if (err)
++		goto cleanup;
++
++	set_buffer_new(bh_result);
++got_it:
++	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
++	if (count > blocks_to_boundary)
++		set_buffer_boundary(bh_result);
++	err = count;
++	/* Clean up and exit */
++	partial = chain + depth - 1;	/* the whole chain */
++cleanup:
++	while (partial > chain) {
++		BUFFER_TRACE(partial->bh, "call brelse");
++		brelse(partial->bh);
++		partial--;
++	}
++	BUFFER_TRACE(bh_result, "returned");
++out:
++	return err;
++}
++
++#define DIO_CREDITS (EXT3COW_RESERVE_TRANS_BLOCKS + 32)
++
++static int ext3cow_get_block(struct inode *inode, sector_t iblock,
++			struct buffer_head *bh_result, int create)
++{
++	handle_t *handle = journal_current_handle();
++	int ret = 0;
++	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
++
++	if (!create)
++		goto get_block;		/* A read */
++
++	if (max_blocks == 1)
++		goto get_block;		/* A single block get */
++
++	if (handle->h_transaction->t_state == T_LOCKED) {
++		/*
++		 * Huge direct-io writes can hold off commits for long
++		 * periods of time.  Let this commit run.
++		 */
++		ext3cow_journal_stop(handle);
++		handle = ext3cow_journal_start(inode, DIO_CREDITS);
++		if (IS_ERR(handle))
++			ret = PTR_ERR(handle);
++		goto get_block;
++	}
++
++	if (handle->h_buffer_credits <= EXT3COW_RESERVE_TRANS_BLOCKS) {
++		/*
++		 * Getting low on buffer credits...
++		 */
++		ret = ext3cow_journal_extend(handle, DIO_CREDITS);
++		if (ret > 0) {
++			/*
++			 * Couldn't extend the transaction.  Start a new one.
++			 */
++			ret = ext3cow_journal_restart(handle, DIO_CREDITS);
++		}
++	}
++
++get_block:
++	if (ret == 0) {
++		ret = ext3cow_get_blocks_handle(handle, inode, iblock,
++					max_blocks, bh_result, create, 0);
++		if (ret > 0) {
++			bh_result->b_size = (ret << inode->i_blkbits);
++			ret = 0;
++		}
++	}
++	return ret;
++}
++
++/*
++ * `handle' can be NULL if create is zero
++ */
++struct buffer_head *ext3cow_getblk(handle_t *handle, struct inode *inode,
++				long block, int create, int *errp)
++{
++	struct buffer_head dummy;
++	int fatal = 0, err;
++
++	J_ASSERT(handle != NULL || create == 0);
++
++	dummy.b_state = 0;
++	dummy.b_blocknr = -1000;
++	buffer_trace_init(&dummy.b_history);
++	err = ext3cow_get_blocks_handle(handle, inode, block, 1,
++					&dummy, create, 1);
++	/*
++	 * ext3cow_get_blocks_handle() returns number of blocks
++	 * mapped. 0 in case of a HOLE.
++	 */
++	if (err > 0) {
++		if (err > 1)
++			WARN_ON(1);
++		err = 0;
++	}
++	*errp = err;
++	if (!err && buffer_mapped(&dummy)) {
++		struct buffer_head *bh;
++		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
++		if (!bh) {
++			*errp = -EIO;
++			goto err;
++		}
++		if (buffer_new(&dummy)) {
++			J_ASSERT(create != 0);
++			J_ASSERT(handle != 0);
++
++			/*
++			 * Now that we do not always journal data, we should
++			 * keep in mind whether this should always journal the
++			 * new buffer as metadata.  For now, regular file
++			 * writes use ext3cow_get_block instead, so it's not a
++			 * problem.
++			 */
++			lock_buffer(bh);
++			BUFFER_TRACE(bh, "call get_create_access");
++			fatal = ext3cow_journal_get_create_access(handle, bh);
++			if (!fatal && !buffer_uptodate(bh)) {
++				memset(bh->b_data,0,inode->i_sb->s_blocksize);
++				set_buffer_uptodate(bh);
++			}
++			unlock_buffer(bh);
++			BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++			err = ext3cow_journal_dirty_metadata(handle, bh);
++			if (!fatal)
++				fatal = err;
++		} else {
++			BUFFER_TRACE(bh, "not a new buffer");
++		}
++		if (fatal) {
++			*errp = fatal;
++			brelse(bh);
++			bh = NULL;
++		}
++		return bh;
++	}
++err:
++	return NULL;
++}
++
++struct buffer_head *ext3cow_bread(handle_t *handle, struct inode *inode,
++			       int block, int create, int *err)
++{
++	struct buffer_head * bh;
++
++	bh = ext3cow_getblk(handle, inode, block, create, err);
++	if (!bh)
++		return bh;
++	if (buffer_uptodate(bh))
++		return bh;
++	ll_rw_block(READ_META, 1, &bh);
++	wait_on_buffer(bh);
++	if (buffer_uptodate(bh))
++		return bh;
++	put_bh(bh);
++	*err = -EIO;
++	return NULL;
++}
++
++static int walk_page_buffers(	handle_t *handle,
++				struct buffer_head *head,
++				unsigned from,
++				unsigned to,
++				int *partial,
++				int (*fn)(	handle_t *handle,
++						struct buffer_head *bh))
++{
++	struct buffer_head *bh;
++	unsigned block_start, block_end;
++	unsigned blocksize = head->b_size;
++	int err, ret = 0;
++	struct buffer_head *next;
++
++	for (	bh = head, block_start = 0;
++		ret == 0 && (bh != head || !block_start);
++		block_start = block_end, bh = next)
++	{
++		next = bh->b_this_page;
++		block_end = block_start + blocksize;
++		if (block_end <= from || block_start >= to) {
++			if (partial && !buffer_uptodate(bh))
++				*partial = 1;
++			continue;
++		}
++		err = (*fn)(handle, bh);
++		if (!ret)
++			ret = err;
++	}
++	return ret;
++}
++
++/*
++ * To preserve ordering, it is essential that the hole instantiation and
++ * the data write be encapsulated in a single transaction.  We cannot
++ * close off a transaction and start a new one between the ext3cow_get_block()
++ * and the commit_write().  So doing the journal_start at the start of
++ * prepare_write() is the right place.
++ *
++ * Also, this function can nest inside ext3cow_writepage() ->
++ * block_write_full_page(). In that case, we *know* that ext3cow_writepage()
++ * has generated enough buffer credits to do the whole page.  So we won't
++ * block on the journal in that case, which is good, because the caller may
++ * be PF_MEMALLOC.
++ *
++ * By accident, ext3cow can be reentered when a transaction is open via
++ * quota file writes.  If we were to commit the transaction while thus
++ * reentered, there can be a deadlock - we would be holding a quota
++ * lock, and the commit would never complete if another thread had a
++ * transaction open and was blocking on the quota lock - a ranking
++ * violation.
++ *
++ * So what we do is to rely on the fact that journal_stop/journal_start
++ * will _not_ run commit under these circumstances because handle->h_ref
++ * is elevated.  We'll still have enough credits for the tiny quotafile
++ * write.
++ */
++static int do_journal_get_write_access(handle_t *handle,
++					struct buffer_head *bh)
++{
++	if (!buffer_mapped(bh) || buffer_freed(bh))
++		return 0;
++	return ext3cow_journal_get_write_access(handle, bh);
++}
++
++/*
++ * The idea of this helper function is following:
++ * if prepare_write has allocated some blocks, but not all of them, the
++ * transaction must include the content of the newly allocated blocks.
++ * This content is expected to be set to zeroes by block_prepare_write().
++ * 2006/10/14  SAW
++ */
++static int ext3cow_prepare_failure(struct file *file, struct page *page,
++				unsigned from, unsigned to)
++{
++	struct address_space *mapping;
++	struct buffer_head *bh, *head, *next;
++	unsigned block_start, block_end;
++	unsigned blocksize;
++	int ret;
++	handle_t *handle = ext3cow_journal_current_handle();
++
++	mapping = page->mapping;
++	if (ext3cow_should_writeback_data(mapping->host)) {
++		/* optimization: no constraints about data */
++skip:
++		return ext3cow_journal_stop(handle);
++	}
++
++	head = page_buffers(page);
++	blocksize = head->b_size;
++	for (	bh = head, block_start = 0;
++		bh != head || !block_start;
++	    	block_start = block_end, bh = next)
++	{
++		next = bh->b_this_page;
++		block_end = block_start + blocksize;
++		if (block_end <= from)
++			continue;
++		if (block_start >= to) {
++			block_start = to;
++			break;
++		}
++		if (!buffer_mapped(bh))
++		/* prepare_write failed on this bh */
++			break;
++		if (ext3cow_should_journal_data(mapping->host)) {
++			ret = do_journal_get_write_access(handle, bh);
++			if (ret) {
++				ext3cow_journal_stop(handle);
++				return ret;
++			}
++		}
++	/*
++	 * block_start here becomes the first block where the current iteration
++	 * of prepare_write failed.
++	 */
++	}
++	if (block_start <= from)
++		goto skip;
++
++	/* commit allocated and zeroed buffers */
++	return mapping->a_ops->commit_write(file, page, from, block_start);
++}
++
++/* Used to quickly unmap all buffers in a page for COWing -znjp */
++static int ext3cow_clear_buffer_mapped(handle_t *handle, 
++                                       struct buffer_head *bh)
++{
++  clear_buffer_mapped(bh);
++  return 0;
++}
++
++static int ext3cow_prepare_write(struct file *file, struct page *page,
++			      unsigned from, unsigned to)
++{
++	struct inode *inode = page->mapping->host;
++	int ret, ret2;
++	int needed_blocks = ext3cow_writepage_trans_blocks(inode);
++	handle_t *handle;
++	int retries = 0;
++
++retry:
++	handle = ext3cow_journal_start(inode, needed_blocks);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++  /* Unset the BH_Mapped flag so get_block is always called -znjp */
++  if(page_has_buffers(page))
++    ret = walk_page_buffers(handle, page_buffers(page),
++                            from, to, NULL, ext3cow_clear_buffer_mapped);
++
++	if (test_opt(inode->i_sb, NOBH) && ext3cow_should_writeback_data(inode))
++		ret = nobh_prepare_write(page, from, to, ext3cow_get_block);
++	else
++		ret = block_prepare_write(page, from, to, ext3cow_get_block);
++	if (ret)
++		goto failure;
++
++	if (ext3cow_should_journal_data(inode)) {
++		ret = walk_page_buffers(handle, page_buffers(page),
++				from, to, NULL, do_journal_get_write_access);
++		if (ret)
++			/* fatal error, just put the handle and return */
++			journal_stop(handle);
++	}
++	return ret;
++
++failure:
++	ret2 = ext3cow_prepare_failure(file, page, from, to);
++	if (ret2 < 0)
++		return ret2;
++	if (ret == -ENOSPC && ext3cow_should_retry_alloc(inode->i_sb, &retries))
++		goto retry;
++	/* retry number exceeded, or other error like -EDQUOT */
++	return ret;
++}
++
++int ext3cow_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
++{
++	int err = journal_dirty_data(handle, bh);
++	if (err)
++		ext3cow_journal_abort_handle(__FUNCTION__, __FUNCTION__,
++						bh, handle,err);
++	return err;
++}
++
++/* For commit_write() in data=journal mode */
++static int commit_write_fn(handle_t *handle, struct buffer_head *bh)
++{
++	if (!buffer_mapped(bh) || buffer_freed(bh))
++		return 0;
++	set_buffer_uptodate(bh);
++	return ext3cow_journal_dirty_metadata(handle, bh);
++}
++
++/*
++ * We need to pick up the new inode size which generic_commit_write gave us
++ * `file' can be NULL - eg, when called from page_symlink().
++ *
++ * ext3cow never places buffers on inode->i_mapping->private_list.  metadata
++ * buffers are managed internally.
++ */
++static int ext3cow_ordered_commit_write(struct file *file, struct page *page,
++			     unsigned from, unsigned to)
++{
++	handle_t *handle = ext3cow_journal_current_handle();
++	struct inode *inode = page->mapping->host;
++	int ret = 0, ret2;
++
++	ret = walk_page_buffers(handle, page_buffers(page),
++		from, to, NULL, ext3cow_journal_dirty_data);
++
++	if (ret == 0) {
++		/*
++		 * generic_commit_write() will run mark_inode_dirty() if i_size
++		 * changes.  So let's piggyback the i_disksize mark_inode_dirty
++		 * into that.
++		 */
++		loff_t new_i_size;
++
++		new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
++		if (new_i_size > EXT3COW_I(inode)->i_disksize)
++			EXT3COW_I(inode)->i_disksize = new_i_size;
++		ret = generic_commit_write(file, page, from, to);
++	}
++	ret2 = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = ret2;
++	return ret;
++}
++
++static int ext3cow_writeback_commit_write(struct file *file, struct page *page,
++			     unsigned from, unsigned to)
++{
++	handle_t *handle = ext3cow_journal_current_handle();
++	struct inode *inode = page->mapping->host;
++	int ret = 0, ret2;
++	loff_t new_i_size;
++
++	new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
++	if (new_i_size > EXT3COW_I(inode)->i_disksize)
++		EXT3COW_I(inode)->i_disksize = new_i_size;
++
++	if (test_opt(inode->i_sb, NOBH) && ext3cow_should_writeback_data(inode))
++		ret = nobh_commit_write(file, page, from, to);
++	else
++		ret = generic_commit_write(file, page, from, to);
++
++	ret2 = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = ret2;
++	return ret;
++}
++
++static int ext3cow_journalled_commit_write(struct file *file,
++			struct page *page, unsigned from, unsigned to)
++{
++	handle_t *handle = ext3cow_journal_current_handle();
++	struct inode *inode = page->mapping->host;
++	int ret = 0, ret2;
++	int partial = 0;
++	loff_t pos;
++
++	/*
++	 * Here we duplicate the generic_commit_write() functionality
++	 */
++	pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
++
++	ret = walk_page_buffers(handle, page_buffers(page), from,
++				to, &partial, commit_write_fn);
++	if (!partial)
++		SetPageUptodate(page);
++	if (pos > inode->i_size)
++		i_size_write(inode, pos);
++	EXT3COW_I(inode)->i_state |= EXT3COW_STATE_JDATA;
++	if (inode->i_size > EXT3COW_I(inode)->i_disksize) {
++		EXT3COW_I(inode)->i_disksize = inode->i_size;
++		ret2 = ext3cow_mark_inode_dirty(handle, inode);
++		if (!ret)
++			ret = ret2;
++	}
++	ret2 = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = ret2;
++	return ret;
++}
++
++/*
++ * bmap() is special.  It gets used by applications such as lilo and by
++ * the swapper to find the on-disk block of a specific piece of data.
++ *
++ * Naturally, this is dangerous if the block concerned is still in the
++ * journal.  If somebody makes a swapfile on an ext3cow data-journaling
++ * filesystem and enables swap, then they may get a nasty shock when the
++ * data getting swapped to that swapfile suddenly gets overwritten by
++ * the original zero's written out previously to the journal and
++ * awaiting writeback in the kernel's buffer cache.
++ *
++ * So, if we see any bmap calls here on a modified, data-journaled file,
++ * take extra steps to flush any blocks which might be in the cache.
++ */
++static sector_t ext3cow_bmap(struct address_space *mapping, sector_t block)
++{
++	struct inode *inode = mapping->host;
++	journal_t *journal;
++	int err;
++
++	if (EXT3COW_I(inode)->i_state & EXT3COW_STATE_JDATA) {
++		/*
++		 * This is a REALLY heavyweight approach, but the use of
++		 * bmap on dirty files is expected to be extremely rare:
++		 * only if we run lilo or swapon on a freshly made file
++		 * do we expect this to happen.
++		 *
++		 * (bmap requires CAP_SYS_RAWIO so this does not
++		 * represent an unprivileged user DOS attack --- we'd be
++		 * in trouble if mortal users could trigger this path at
++		 * will.)
++		 *
++		 * NB. EXT3COW_STATE_JDATA is not set on files other than
++		 * regular files.  If somebody wants to bmap a directory
++		 * or symlink and gets confused because the buffer
++		 * hasn't yet been flushed to disk, they deserve
++		 * everything they get.
++		 */
++
++		EXT3COW_I(inode)->i_state &= ~EXT3COW_STATE_JDATA;
++		journal = EXT3COW_JOURNAL(inode);
++		journal_lock_updates(journal);
++		err = journal_flush(journal);
++		journal_unlock_updates(journal);
++
++		if (err)
++			return 0;
++	}
++
++	return generic_block_bmap(mapping,block,ext3cow_get_block);
++}
++
++static int bget_one(handle_t *handle, struct buffer_head *bh)
++{
++	get_bh(bh);
++	return 0;
++}
++
++static int bput_one(handle_t *handle, struct buffer_head *bh)
++{
++	put_bh(bh);
++	return 0;
++}
++
++static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
++{
++	if (buffer_mapped(bh))
++		return ext3cow_journal_dirty_data(handle, bh);
++	return 0;
++}
++
++/*
++ * Note that we always start a transaction even if we're not journalling
++ * data.  This is to preserve ordering: any hole instantiation within
++ * __block_write_full_page -> ext3cow_get_block() should be journalled
++ * along with the data so we don't crash and then get metadata which
++ * refers to old data.
++ *
++ * In all journalling modes block_write_full_page() will start the I/O.
++ *
++ * Problem:
++ *
++ *	ext3cow_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
++ *		ext3cow_writepage()
++ *
++ * Similar for:
++ *
++ *	ext3cow_file_write() -> generic_file_write() -> __alloc_pages() -> ...
++ *
++ * Same applies to ext3cow_get_block().  We will deadlock on various things like
++ * lock_journal and i_truncate_mutex.
++ *
++ * Setting PF_MEMALLOC here doesn't work - too many internal memory
++ * allocations fail.
++ *
++ * 16May01: If we're reentered then journal_current_handle() will be
++ *	    non-zero. We simply *return*.
++ *
++ * 1 July 2001: @@@ FIXME:
++ *   In journalled data mode, a data buffer may be metadata against the
++ *   current transaction.  But the same file is part of a shared mapping
++ *   and someone does a writepage() on it.
++ *
++ *   We will move the buffer onto the async_data list, but *after* it has
++ *   been dirtied. So there's a small window where we have dirty data on
++ *   BJ_Metadata.
++ *
++ *   Note that this only applies to the last partial page in the file.  The
++ *   bit which block_write_full_page() uses prepare/commit for.  (That's
++ *   broken code anyway: it's wrong for msync()).
++ *
++ *   It's a rare case: affects the final partial page, for journalled data
++ *   where the file is subject to bith write() and writepage() in the same
++ *   transction.  To fix it we'll need a custom block_write_full_page().
++ *   We'll probably need that anyway for journalling writepage() output.
++ *
++ * We don't honour synchronous mounts for writepage().  That would be
++ * disastrous.  Any write() or metadata operation will sync the fs for
++ * us.
++ *
++ * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
++ * we don't need to open a transaction here.
++ */
++static int ext3cow_ordered_writepage(struct page *page,
++				struct writeback_control *wbc)
++{
++	struct inode *inode = page->mapping->host;
++	struct buffer_head *page_bufs;
++	handle_t *handle = NULL;
++	int ret = 0;
++	int err;
++
++	J_ASSERT(PageLocked(page));
++
++	/*
++	 * We give up here if we're reentered, because it might be for a
++	 * different filesystem.
++	 */
++	if (ext3cow_journal_current_handle())
++		goto out_fail;
++
++	handle = ext3cow_journal_start(inode, ext3cow_writepage_trans_blocks(inode));
++
++	if (IS_ERR(handle)) {
++		ret = PTR_ERR(handle);
++		goto out_fail;
++	}
++
++	if (!page_has_buffers(page)) {
++		create_empty_buffers(page, inode->i_sb->s_blocksize,
++				(1 << BH_Dirty)|(1 << BH_Uptodate));
++	}
++	page_bufs = page_buffers(page);
++	walk_page_buffers(handle, page_bufs, 0,
++			PAGE_CACHE_SIZE, NULL, bget_one);
++
++	ret = block_write_full_page(page, ext3cow_get_block, wbc);
++
++	/*
++	 * The page can become unlocked at any point now, and
++	 * truncate can then come in and change things.  So we
++	 * can't touch *page from now on.  But *page_bufs is
++	 * safe due to elevated refcount.
++	 */
++
++	/*
++	 * And attach them to the current transaction.  But only if
++	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
++	 * and generally junk.
++	 */
++	if (ret == 0) {
++		err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
++					NULL, journal_dirty_data_fn);
++		if (!ret)
++			ret = err;
++	}
++	walk_page_buffers(handle, page_bufs, 0,
++			PAGE_CACHE_SIZE, NULL, bput_one);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++
++out_fail:
++	redirty_page_for_writepage(wbc, page);
++	unlock_page(page);
++	return ret;
++}
++
++static int ext3cow_writeback_writepage(struct page *page,
++				struct writeback_control *wbc)
++{
++	struct inode *inode = page->mapping->host;
++	handle_t *handle = NULL;
++	int ret = 0;
++	int err;
++
++	if (ext3cow_journal_current_handle())
++		goto out_fail;
++
++	handle = ext3cow_journal_start(inode, ext3cow_writepage_trans_blocks(inode));
++	if (IS_ERR(handle)) {
++		ret = PTR_ERR(handle);
++		goto out_fail;
++	}
++
++	if (test_opt(inode->i_sb, NOBH) && ext3cow_should_writeback_data(inode))
++		ret = nobh_writepage(page, ext3cow_get_block, wbc);
++	else
++		ret = block_write_full_page(page, ext3cow_get_block, wbc);
++
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++
++out_fail:
++	redirty_page_for_writepage(wbc, page);
++	unlock_page(page);
++	return ret;
++}
++
++static int ext3cow_journalled_writepage(struct page *page,
++				struct writeback_control *wbc)
++{
++	struct inode *inode = page->mapping->host;
++	handle_t *handle = NULL;
++	int ret = 0;
++	int err;
++
++	if (ext3cow_journal_current_handle())
++		goto no_write;
++
++	handle = ext3cow_journal_start(inode, ext3cow_writepage_trans_blocks(inode));
++	if (IS_ERR(handle)) {
++		ret = PTR_ERR(handle);
++		goto no_write;
++	}
++
++	if (!page_has_buffers(page) || PageChecked(page)) {
++		/*
++		 * It's mmapped pagecache.  Add buffers and journal it.  There
++		 * doesn't seem much point in redirtying the page here.
++		 */
++		ClearPageChecked(page);
++		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
++					ext3cow_get_block);
++		if (ret != 0) {
++			ext3cow_journal_stop(handle);
++			goto out_unlock;
++		}
++		ret = walk_page_buffers(handle, page_buffers(page), 0,
++			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
++
++		err = walk_page_buffers(handle, page_buffers(page), 0,
++				PAGE_CACHE_SIZE, NULL, commit_write_fn);
++		if (ret == 0)
++			ret = err;
++		EXT3COW_I(inode)->i_state |= EXT3COW_STATE_JDATA;
++		unlock_page(page);
++	} else {
++		/*
++		 * It may be a page full of checkpoint-mode buffers.  We don't
++		 * really know unless we go poke around in the buffer_heads.
++		 * But block_write_full_page will do the right thing.
++		 */
++		ret = block_write_full_page(page, ext3cow_get_block, wbc);
++	}
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++out:
++	return ret;
++
++no_write:
++	redirty_page_for_writepage(wbc, page);
++out_unlock:
++	unlock_page(page);
++	goto out;
++}
++
++static int ext3cow_readpage(struct file *file, struct page *page)
++{
++	return mpage_readpage(page, ext3cow_get_block);
++}
++
++static int
++ext3cow_readpages(struct file *file, struct address_space *mapping,
++		struct list_head *pages, unsigned nr_pages)
++{
++	return mpage_readpages(mapping, pages, nr_pages, ext3cow_get_block);
++}
++
++static void ext3cow_invalidatepage(struct page *page, unsigned long offset)
++{
++	journal_t *journal = EXT3COW_JOURNAL(page->mapping->host);
++
++	/*
++	 * If it's a full truncate we just forget about the pending dirtying
++	 */
++	if (offset == 0)
++		ClearPageChecked(page);
++
++	journal_invalidatepage(journal, page, offset);
++}
++
++static int ext3cow_releasepage(struct page *page, gfp_t wait)
++{
++	journal_t *journal = EXT3COW_JOURNAL(page->mapping->host);
++
++	WARN_ON(PageChecked(page));
++	if (!page_has_buffers(page))
++		return 0;
++	return journal_try_to_free_buffers(journal, page, wait);
++}
++
++/*
++ * If the O_DIRECT write will extend the file then add this inode to the
++ * orphan list.  So recovery will truncate it back to the original size
++ * if the machine crashes during the write.
++ *
++ * If the O_DIRECT write is intantiating holes inside i_size and the machine
++ * crashes then stale disk data _may_ be exposed inside the file.
++ */
++static ssize_t ext3cow_direct_IO(int rw, struct kiocb *iocb,
++			const struct iovec *iov, loff_t offset,
++			unsigned long nr_segs)
++{
++	struct file *file = iocb->ki_filp;
++	struct inode *inode = file->f_mapping->host;
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	handle_t *handle = NULL;
++	ssize_t ret;
++	int orphan = 0;
++	size_t count = iov_length(iov, nr_segs);
++
++	if (rw == WRITE) {
++		loff_t final_size = offset + count;
++
++		handle = ext3cow_journal_start(inode, DIO_CREDITS);
++		if (IS_ERR(handle)) {
++			ret = PTR_ERR(handle);
++			goto out;
++		}
++		if (final_size > inode->i_size) {
++			ret = ext3cow_orphan_add(handle, inode);
++			if (ret)
++				goto out_stop;
++			orphan = 1;
++			ei->i_disksize = inode->i_size;
++		}
++	}
++
++	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
++				 offset, nr_segs,
++				 ext3cow_get_block, NULL);
++
++	/*
++	 * Reacquire the handle: ext3cow_get_block() can restart the transaction
++	 */
++	handle = journal_current_handle();
++
++out_stop:
++	if (handle) {
++		int err;
++
++		if (orphan && inode->i_nlink)
++			ext3cow_orphan_del(handle, inode);
++		if (orphan && ret > 0) {
++			loff_t end = offset + ret;
++			if (end > inode->i_size) {
++				ei->i_disksize = end;
++				i_size_write(inode, end);
++				/*
++				 * We're going to return a positive `ret'
++				 * here due to non-zero-length I/O, so there's
++				 * no way of reporting error returns from
++				 * ext3cow_mark_inode_dirty() to userspace.  So
++				 * ignore it.
++				 */
++				ext3cow_mark_inode_dirty(handle, inode);
++			}
++		}
++		err = ext3cow_journal_stop(handle);
++		if (ret == 0)
++			ret = err;
++	}
++out:
++	return ret;
++}
++
++/*
++ * Pages can be marked dirty completely asynchronously from ext3cow's journalling
++ * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
++ * much here because ->set_page_dirty is called under VFS locks.  The page is
++ * not necessarily locked.
++ *
++ * We cannot just dirty the page and leave attached buffers clean, because the
++ * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
++ * or jbddirty because all the journalling code will explode.
++ *
++ * So what we do is to mark the page "pending dirty" and next time writepage
++ * is called, propagate that into the buffers appropriately.
++ */
++static int ext3cow_journalled_set_page_dirty(struct page *page)
++{
++	SetPageChecked(page);
++	return __set_page_dirty_nobuffers(page);
++}
++
++static const struct address_space_operations ext3cow_ordered_aops = {
++	.readpage	= ext3cow_readpage,
++	.readpages	= ext3cow_readpages,
++	.writepage	= ext3cow_ordered_writepage,
++	.sync_page	= block_sync_page,
++	.prepare_write	= ext3cow_prepare_write,
++	.commit_write	= ext3cow_ordered_commit_write,
++	.bmap		= ext3cow_bmap,
++	.invalidatepage	= ext3cow_invalidatepage,
++	.releasepage	= ext3cow_releasepage,
++	.direct_IO	= ext3cow_direct_IO,
++	.migratepage	= buffer_migrate_page,
++};
++
++static const struct address_space_operations ext3cow_writeback_aops = {
++	.readpage	= ext3cow_readpage,
++	.readpages	= ext3cow_readpages,
++	.writepage	= ext3cow_writeback_writepage,
++	.sync_page	= block_sync_page,
++	.prepare_write	= ext3cow_prepare_write,
++	.commit_write	= ext3cow_writeback_commit_write,
++	.bmap		= ext3cow_bmap,
++	.invalidatepage	= ext3cow_invalidatepage,
++	.releasepage	= ext3cow_releasepage,
++	.direct_IO	= ext3cow_direct_IO,
++	.migratepage	= buffer_migrate_page,
++};
++
++static const struct address_space_operations ext3cow_journalled_aops = {
++	.readpage	= ext3cow_readpage,
++	.readpages	= ext3cow_readpages,
++	.writepage	= ext3cow_journalled_writepage,
++	.sync_page	= block_sync_page,
++	.prepare_write	= ext3cow_prepare_write,
++	.commit_write	= ext3cow_journalled_commit_write,
++	.set_page_dirty	= ext3cow_journalled_set_page_dirty,
++	.bmap		= ext3cow_bmap,
++	.invalidatepage	= ext3cow_invalidatepage,
++	.releasepage	= ext3cow_releasepage,
++};
++
++void ext3cow_set_aops(struct inode *inode)
++{
++	if (ext3cow_should_order_data(inode))
++		inode->i_mapping->a_ops = &ext3cow_ordered_aops;
++	else if (ext3cow_should_writeback_data(inode))
++		inode->i_mapping->a_ops = &ext3cow_writeback_aops;
++	else
++		inode->i_mapping->a_ops = &ext3cow_journalled_aops;
++}
++
++/*
++ * ext3cow_block_truncate_page() zeroes out a mapping from file offset `from'
++ * up to the end of the block which corresponds to `from'.
++ * This required during truncate. We need to physically zero the tail end
++ * of that block so it doesn't yield old data if the file is later grown.
++ */
++static int ext3cow_block_truncate_page(handle_t *handle, struct page *page,
++		struct address_space *mapping, loff_t from)
++{
++	ext3cow_fsblk_t index = from >> PAGE_CACHE_SHIFT;
++	unsigned offset = from & (PAGE_CACHE_SIZE-1);
++	unsigned blocksize, iblock, length, pos;
++	struct inode *inode = mapping->host;
++	struct buffer_head *bh;
++	int err = 0;
++	void *kaddr;
++
++	blocksize = inode->i_sb->s_blocksize;
++	length = blocksize - (offset & (blocksize - 1));
++	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
++
++	/*
++	 * For "nobh" option,  we can only work if we don't need to
++	 * read-in the page - otherwise we create buffers to do the IO.
++	 */
++	if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
++	     ext3cow_should_writeback_data(inode) && PageUptodate(page)) {
++		kaddr = kmap_atomic(page, KM_USER0);
++		memset(kaddr + offset, 0, length);
++		flush_dcache_page(page);
++		kunmap_atomic(kaddr, KM_USER0);
++		set_page_dirty(page);
++		goto unlock;
++	}
++
++	if (!page_has_buffers(page))
++		create_empty_buffers(page, blocksize, 0);
++
++	/* Find the buffer that contains "offset" */
++	bh = page_buffers(page);
++	pos = blocksize;
++	while (offset >= pos) {
++		bh = bh->b_this_page;
++		iblock++;
++		pos += blocksize;
++	}
++
++	err = 0;
++	if (buffer_freed(bh)) {
++		BUFFER_TRACE(bh, "freed: skip");
++		goto unlock;
++	}
++
++	if (!buffer_mapped(bh)) {
++		BUFFER_TRACE(bh, "unmapped");
++		ext3cow_get_block(inode, iblock, bh, 0);
++		/* unmapped? It's a hole - nothing to do */
++		if (!buffer_mapped(bh)) {
++			BUFFER_TRACE(bh, "still unmapped");
++			goto unlock;
++		}
++	}
++
++	/* Ok, it's mapped. Make sure it's up-to-date */
++	if (PageUptodate(page))
++		set_buffer_uptodate(bh);
++
++	if (!buffer_uptodate(bh)) {
++		err = -EIO;
++		ll_rw_block(READ, 1, &bh);
++		wait_on_buffer(bh);
++		/* Uhhuh. Read error. Complain and punt. */
++		if (!buffer_uptodate(bh))
++			goto unlock;
++	}
++
++	if (ext3cow_should_journal_data(inode)) {
++		BUFFER_TRACE(bh, "get write access");
++		err = ext3cow_journal_get_write_access(handle, bh);
++		if (err)
++			goto unlock;
++	}
++
++	kaddr = kmap_atomic(page, KM_USER0);
++	memset(kaddr + offset, 0, length);
++	flush_dcache_page(page);
++	kunmap_atomic(kaddr, KM_USER0);
++
++	BUFFER_TRACE(bh, "zeroed end of block");
++
++	err = 0;
++	if (ext3cow_should_journal_data(inode)) {
++		err = ext3cow_journal_dirty_metadata(handle, bh);
++	} else {
++		if (ext3cow_should_order_data(inode))
++			err = ext3cow_journal_dirty_data(handle, bh);
++		mark_buffer_dirty(bh);
++	}
++
++unlock:
++	unlock_page(page);
++	page_cache_release(page);
++	return err;
++}
++
++/*
++ * Probably it should be a library function... search for first non-zero word
++ * or memcmp with zero_page, whatever is better for particular architecture.
++ * Linus?
++ */
++static inline int all_zeroes(__le32 *p, __le32 *q)
++{
++	while (p < q)
++		if (*p++)
++			return 0;
++	return 1;
++}
++
++/**
++ *	ext3cow_find_shared - find the indirect blocks for partial truncation.
++ *	@inode:	  inode in question
++ *	@depth:	  depth of the affected branch
++ *	@offsets: offsets of pointers in that branch (see ext3cow_block_to_path)
++ *	@chain:	  place to store the pointers to partial indirect blocks
++ *	@top:	  place to the (detached) top of branch
++ *
++ *	This is a helper function used by ext3cow_truncate().
++ *
++ *	When we do truncate() we may have to clean the ends of several
++ *	indirect blocks but leave the blocks themselves alive. Block is
++ *	partially truncated if some data below the new i_size is refered
++ *	from it (and it is on the path to the first completely truncated
++ *	data block, indeed).  We have to free the top of that path along
++ *	with everything to the right of the path. Since no allocation
++ *	past the truncation point is possible until ext3cow_truncate()
++ *	finishes, we may safely do the latter, but top of branch may
++ *	require special attention - pageout below the truncation point
++ *	might try to populate it.
++ *
++ *	We atomically detach the top of branch from the tree, store the
++ *	block number of its root in *@top, pointers to buffer_heads of
++ *	partially truncated blocks - in @chain[].bh and pointers to
++ *	their last elements that should not be removed - in
++ *	@chain[].p. Return value is the pointer to last filled element
++ *	of @chain.
++ *
++ *	The work left to caller to do the actual freeing of subtrees:
++ *		a) free the subtree starting from *@top
++ *		b) free the subtrees whose roots are stored in
++ *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
++ *		c) free the subtrees growing from the inode past the @chain[0].
++ *			(no partially truncated stuff there).  */
++
++static Indirect *ext3cow_find_shared(struct inode *inode, int depth,
++			int offsets[4], Indirect chain[4], __le32 *top)
++{
++	Indirect *partial, *p;
++	int k, err, cow;
++
++	*top = 0;
++	/* Make k index the deepest non-null offest + 1 */
++	for (k = depth; k > 1 && !offsets[k-1]; k--)
++		;
++	partial = ext3cow_get_branch(inode, k, offsets, chain, &err, &cow, 0);
++	/* Writer: pointers */
++	if (!partial)
++		partial = chain + k-1;
++	/*
++	 * If the branch acquired continuation since we've looked at it -
++	 * fine, it should all survive and (new) top doesn't belong to us.
++	 */
++	if (!partial->key && *partial->p)
++		/* Writer: end */
++		goto no_top;
++	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
++		;
++	/*
++	 * OK, we've found the last block that must survive. The rest of our
++	 * branch should be detached before unlocking. However, if that rest
++	 * of branch is all ours and does not grow immediately from the inode
++	 * it's easier to cheat and just decrement partial->p.
++	 */
++	if (p == chain + k - 1 && p > chain) {
++		p->p--;
++	} else {
++		*top = *p->p;
++		/* Nope, don't do this in ext3cow.  Must leave the tree intact */
++#if 0
++		*p->p = 0;
++#endif
++	}
++	/* Writer: end */
++
++	while(partial > p) {
++		brelse(partial->bh);
++		partial--;
++	}
++no_top:
++	return partial;
++}
++
++/*
++ * Zero a number of block pointers in either an inode or an indirect block.
++ * If we restart the transaction we must again get write access to the
++ * indirect block for further modification.
++ *
++ * We release `count' blocks on disk, but (last - first) may be greater
++ * than `count' because there can be holes in there.
++ */
++static void ext3cow_clear_blocks(handle_t *handle, struct inode *inode,
++		struct buffer_head *bh, ext3cow_fsblk_t block_to_free,
++		unsigned long count, __le32 *first, __le32 *last)
++{
++	__le32 *p;
++	if (try_to_extend_transaction(handle, inode)) {
++		if (bh) {
++			BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++			ext3cow_journal_dirty_metadata(handle, bh);
++		}
++		ext3cow_mark_inode_dirty(handle, inode);
++		ext3cow_journal_test_restart(handle, inode);
++		if (bh) {
++			BUFFER_TRACE(bh, "retaking write access");
++			ext3cow_journal_get_write_access(handle, bh);
++		}
++	}
++
++	/*
++	 * Any buffers which are on the journal will be in memory. We find
++	 * them on the hash table so journal_revoke() will run journal_forget()
++	 * on them.  We've already detached each block from the file, so
++	 * bforget() in journal_forget() should be safe.
++	 *
++	 * AKPM: turn on bforget in journal_forget()!!!
++	 */
++	for (p = first; p < last; p++) {
++		u32 nr = le32_to_cpu(*p);
++		if (nr) {
++			struct buffer_head *bh;
++
++			*p = 0;
++			bh = sb_find_get_block(inode->i_sb, nr);
++			ext3cow_forget(handle, 0, inode, bh, nr);
++		}
++	}
++
++	ext3cow_free_blocks(handle, inode, block_to_free, count);
++}
++
++/**
++ * ext3cow_free_data - free a list of data blocks
++ * @handle:	handle for this transaction
++ * @inode:	inode we are dealing with
++ * @this_bh:	indirect buffer_head which contains *@first and *@last
++ * @first:	array of block numbers
++ * @last:	points immediately past the end of array
++ *
++ * We are freeing all blocks refered from that array (numbers are stored as
++ * little-endian 32-bit) and updating @inode->i_blocks appropriately.
++ *
++ * We accumulate contiguous runs of blocks to free.  Conveniently, if these
++ * blocks are contiguous then releasing them at one time will only affect one
++ * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
++ * actually use a lot of journal space.
++ *
++ * @this_bh will be %NULL if @first and @last point into the inode's direct
++ * block pointers.
++ */
++static void ext3cow_free_data(handle_t *handle, struct inode *inode,
++			   struct buffer_head *this_bh,
++			   __le32 *first, __le32 *last)
++{
++	ext3cow_fsblk_t block_to_free = 0;    /* Starting block # of a run */
++	unsigned long count = 0;	    /* Number of blocks in the run */
++	__le32 *block_to_free_p = NULL;	    /* Pointer into inode/ind
++					       corresponding to
++					       block_to_free */
++	ext3cow_fsblk_t nr;		    /* Current block # */
++	__le32 *p;			    /* Pointer into inode/ind
++					       for current block */
++	int err;
++
++	if (this_bh) {				/* For indirect block */
++		BUFFER_TRACE(this_bh, "get_write_access");
++		err = ext3cow_journal_get_write_access(handle, this_bh);
++		/* Important: if we can't update the indirect pointers
++		 * to the blocks, we can't free them. */
++		if (err)
++			return;
++	}
++
++	for (p = first; p < last; p++) {
++		nr = le32_to_cpu(*p);
++		if (nr) {
++			/* accumulate blocks to free if they're contiguous */
++			if (count == 0) {
++				block_to_free = nr;
++				block_to_free_p = p;
++				count = 1;
++			} else if (nr == block_to_free + count) {
++				count++;
++			} else {
++				ext3cow_clear_blocks(handle, inode, this_bh,
++						  block_to_free,
++						  count, block_to_free_p, p);
++				block_to_free = nr;
++				block_to_free_p = p;
++				count = 1;
++			}
++		}
++	}
++
++	if (count > 0)
++		ext3cow_clear_blocks(handle, inode, this_bh, block_to_free,
++				  count, block_to_free_p, p);
++
++	if (this_bh) {
++		BUFFER_TRACE(this_bh, "call ext3cow_journal_dirty_metadata");
++		ext3cow_journal_dirty_metadata(handle, this_bh);
++	}
++}
++
++/**
++ *	ext3cow_free_branches - free an array of branches
++ *	@handle: JBD handle for this transaction
++ *	@inode:	inode we are dealing with
++ *	@parent_bh: the buffer_head which contains *@first and *@last
++ *	@first:	array of block numbers
++ *	@last:	pointer immediately past the end of array
++ *	@depth:	depth of the branches to free
++ *
++ *	We are freeing all blocks refered from these branches (numbers are
++ *	stored as little-endian 32-bit) and updating @inode->i_blocks
++ *	appropriately.
++ */
++static void ext3cow_free_branches(handle_t *handle, struct inode *inode,
++			       struct buffer_head *parent_bh,
++			       __le32 *first, __le32 *last, int depth)
++{
++	ext3cow_fsblk_t nr;
++	__le32 *p;
++
++	if (is_handle_aborted(handle))
++		return;
++
++	if (depth--) {
++		struct buffer_head *bh;
++		int addr_per_block = EXT3COW_ADDR_PER_BLOCK(inode->i_sb);
++    u32 *bitmap_word = NULL, *first_block = NULL;
++    unsigned int count = 0, cur = 0, bcount = 0;
++    int i = 0;
++		p = last;
++		while (--p >= first) {
++			nr = le32_to_cpu(*p);
++			if (!nr)
++				continue;		/* A hole */
++
++			/* Go read the buffer for the next level down */
++			bh = sb_bread(inode->i_sb, nr);
++
++			/*
++			 * A read failure? Report error and clear slot
++			 * (should be rare).
++			 */
++			if (!bh) {
++				ext3cow_error(inode->i_sb, "ext3cow_free_branches",
++					   "Read failure, inode=%lu, block="E3FSBLK,
++					   inode->i_ino, nr);
++				continue;
++			}
++      /* Only free the branches that have been newly allocated - znjp */
++      cur = 0;
++      count = 0;
++      bitmap_word = (u32*)bh->b_data + addr_per_block;
++      
++      for(bcount = 0; bcount < EXT3COW_COWBITMAPS_PER_IBLOCK(inode->i_sb);
++          bcount++){
++        for(i = 0; i < EXT3COW_COWBITMAP_SIZE; i++, cur++){
++          if(cur >= addr_per_block)
++            goto free;
++          if(le32_to_cpu(*bitmap_word) & (1UL << i)){
++            if(count == 0){
++              first_block = (u32*)bh->b_data + cur;
++              count = 1;
++            }else if((u32*)first_block + count == (u32*)bh->b_data + cur){
++              count++;
++            }else{
++              BUFFER_TRACE(bh, "free child branches");
++              ext3cow_free_branches(handle, inode, bh, (u32*)first_block,
++                                    (u32*)first_block + count, depth);
++              first_block = (u32*)bh->b_data + cur;
++              count = 1;
++            }
++          }
++        }
++        (u32*)bitmap_word++;
++      }   
++    free:
++      if(count){
++        BUFFER_TRACE(bh, "free child branches");
++        ext3cow_free_branches(handle, inode, bh, (u32*)first_block,
++                              (u32*)first_block + count, depth);
++      }
++
++			/*
++			 * We've probably journalled the indirect block several
++			 * times during the truncate.  But it's no longer
++			 * needed and we now drop it from the transaction via
++			 * journal_revoke().
++			 *
++			 * That's easy if it's exclusively part of this
++			 * transaction.  But if it's part of the committing
++			 * transaction then journal_forget() will simply
++			 * brelse() it.  That means that if the underlying
++			 * block is reallocated in ext3cow_get_block(),
++			 * unmap_underlying_metadata() will find this block
++			 * and will try to get rid of it.  damn, damn.
++			 *
++			 * If this block has already been committed to the
++			 * journal, a revoke record will be written.  And
++			 * revoke records must be emitted *before* clearing
++			 * this block's bit in the bitmaps.
++			 */
++			ext3cow_forget(handle, 1, inode, bh, bh->b_blocknr);
++
++			/*
++			 * Everything below this this pointer has been
++			 * released.  Now let this top-of-subtree go.
++			 *
++			 * We want the freeing of this indirect block to be
++			 * atomic in the journal with the updating of the
++			 * bitmap block which owns it.  So make some room in
++			 * the journal.
++			 *
++			 * We zero the parent pointer *after* freeing its
++			 * pointee in the bitmaps, so if extend_transaction()
++			 * for some reason fails to put the bitmap changes and
++			 * the release into the same transaction, recovery
++			 * will merely complain about releasing a free block,
++			 * rather than leaking blocks.
++			 */
++			if (is_handle_aborted(handle))
++				return;
++			if (try_to_extend_transaction(handle, inode)) {
++				ext3cow_mark_inode_dirty(handle, inode);
++				ext3cow_journal_test_restart(handle, inode);
++			}
++
++			ext3cow_free_blocks(handle, inode, nr, 1);
++
++			if (parent_bh) {
++				/*
++				 * The block which we have just freed is
++				 * pointed to by an indirect block: journal it
++				 */
++				BUFFER_TRACE(parent_bh, "get_write_access");
++				if (!ext3cow_journal_get_write_access(handle,
++								   parent_bh)){
++					*p = 0;
++					BUFFER_TRACE(parent_bh,
++					"call ext3cow_journal_dirty_metadata");
++					ext3cow_journal_dirty_metadata(handle,
++								    parent_bh);
++				}
++			}
++		}
++	} else {
++		/* We have reached the bottom of the tree. */
++		BUFFER_TRACE(parent_bh, "free data blocks");
++		ext3cow_free_data(handle, inode, parent_bh, first, last);
++	}
++}
++
++/*
++ * ext3cow_truncate()
++ *
++ * We block out ext3cow_get_block() block instantiations across the entire
++ * transaction, and VFS/VM ensures that ext3cow_truncate() cannot run
++ * simultaneously on behalf of the same inode.
++ *
++ * As we work through the truncate and commmit bits of it to the journal there
++ * is one core, guiding principle: the file's tree must always be consistent on
++ * disk.  We must be able to restart the truncate after a crash.
++ *
++ * The file's tree may be transiently inconsistent in memory (although it
++ * probably isn't), but whenever we close off and commit a journal transaction,
++ * the contents of (the filesystem + the journal) must be consistent and
++ * restartable.  It's pretty simple, really: bottom up, right to left (although
++ * left-to-right works OK too).
++ *
++ * Note that at recovery time, journal replay occurs *before* the restart of
++ * truncate against the orphan inode list.
++ *
++ * The committed inode has the new, desired i_size (which is the same as
++ * i_disksize in this case).  After a crash, ext3cow_orphan_cleanup() will see
++ * that this inode's truncate did not complete and it will again call
++ * ext3cow_truncate() to have another go.  So there will be instantiated blocks
++ * to the right of the truncation point in a crashed ext3cow filesystem.  But
++ * that's fine - as long as they are linked from the inode, the post-crash
++ * ext3cow_truncate() run will find them and release them.
++ */
++void ext3cow_truncate(struct inode *inode)
++{
++	handle_t *handle;
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	__le32 *i_data = ei->i_data;
++	int addr_per_block = EXT3COW_ADDR_PER_BLOCK(inode->i_sb);
++	struct address_space *mapping = inode->i_mapping;
++	int offsets[4];
++	Indirect chain[4];
++	Indirect *partial;
++	__le32 nr = 0;
++	int n;
++	long last_block;
++	unsigned blocksize = inode->i_sb->s_blocksize;
++	struct page *page;
++
++
++	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
++	    S_ISLNK(inode->i_mode)))
++		return;
++	if (ext3cow_inode_is_fast_symlink(inode))
++		return;
++	if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || 
++      EXT3COW_IS_UNCHANGEABLE(inode)) /* znjp */
++		return;
++
++  /* If the inode needs to be dup'd, then there are no blocks
++   * to truncate; they all are part of the previous version.
++   * - znjp */
++  if(EXT3COW_S_EPOCHNUMBER(inode->i_sb) > EXT3COW_I_EPOCHNUMBER(inode)){
++    ext3cow_dup_inode(NULL, inode);
++    return;
++  }
++
++	/*
++	 * We have to lock the EOF page here, because lock_page() nests
++	 * outside journal_start().
++	 */
++	if ((inode->i_size & (blocksize - 1)) == 0) {
++		/* Block boundary? Nothing to do */
++		page = NULL;
++	} else {
++		page = grab_cache_page(mapping,
++				inode->i_size >> PAGE_CACHE_SHIFT);
++		if (!page)
++			return;
++	}
++
++	handle = start_transaction(inode);
++	if (IS_ERR(handle)) {
++		if (page) {
++			clear_highpage(page);
++			flush_dcache_page(page);
++			unlock_page(page);
++			page_cache_release(page);
++		}
++		return;		/* AKPM: return what? */
++	}
++
++	last_block = (inode->i_size + blocksize-1)
++					>> EXT3COW_BLOCK_SIZE_BITS(inode->i_sb);
++
++	if (page)
++		ext3cow_block_truncate_page(handle, page, mapping, inode->i_size);
++
++	n = ext3cow_block_to_path(inode, last_block, offsets, NULL);
++	if (n == 0)
++		goto out_stop;	/* error */
++
++	/*
++	 * OK.  This truncate is going to happen.  We add the inode to the
++	 * orphan list, so that if this truncate spans multiple transactions,
++	 * and we crash, we will resume the truncate when the filesystem
++	 * recovers.  It also marks the inode dirty, to catch the new size.
++	 *
++	 * Implication: the file must always be in a sane, consistent
++	 * truncatable state while each transaction commits.
++	 */
++	if (ext3cow_orphan_add(handle, inode))
++		goto out_stop;
++
++	/*
++	 * The orphan list entry will now protect us from any crash which
++	 * occurs before the truncate completes, so it is now safe to propagate
++	 * the new, shorter inode size (held for now in i_size) into the
++	 * on-disk inode. We do this via i_disksize, which is the value which
++	 * ext3cow *really* writes onto the disk inode.
++	 */
++	ei->i_disksize = inode->i_size;
++
++	/*
++	 * From here we block out all ext3cow_get_block() callers who want to
++	 * modify the block allocation tree.
++	 */
++	mutex_lock(&ei->truncate_mutex);
++
++	if (n == 1) {		/* direct blocks */
++    unsigned int count = 0;
++    unsigned long block_to_free = 0;
++    unsigned long b = 0; 
++
++    /* We only want to remove blocks that were allocated in this
++     * epoch, i.e., have 1 bit in the bitmap. -znjp */
++    for(b = offsets[0]; b < EXT3COW_NDIR_BLOCKS; b++){
++      if(EXT3COW_I(inode)->i_cow_bitmap & (1UL << b)){
++        if(count == 0){
++          block_to_free = b;
++          count = 1;
++        }else if(b == block_to_free + count){
++          count++;
++        }else{
++          ext3cow_free_data(handle, inode, NULL, i_data + (int)block_to_free,
++                            i_data + (int)(block_to_free + count));
++          block_to_free = b;
++          count = 1;
++        }
++      }
++    }
++    if(count > 0)
++      ext3cow_free_data(handle, inode, NULL, i_data+(int)block_to_free,
++                        i_data + (int)(block_to_free + count));
++		goto do_indirects;
++	}
++
++	partial = ext3cow_find_shared(inode, n, offsets, chain, &nr);
++	/* Kill the top of shared branch (not detached) */
++	if (nr) {
++		if (partial == chain) {
++			/* Shared branch grows from the inode */
++			ext3cow_free_branches(handle, inode, NULL,
++					   &nr, &nr+1, (chain+n-1) - partial);
++			*partial->p = 0;
++			/*
++			 * We mark the inode dirty prior to restart,
++			 * and prior to stop.  No need for it here.
++			 */
++		} else {
++			/* Shared branch grows from an indirect block */
++			BUFFER_TRACE(partial->bh, "get_write_access");
++			ext3cow_free_branches(handle, inode, partial->bh,
++					partial->p,
++					partial->p+1, (chain+n-1) - partial);
++		}
++	}
++	/* Clear the ends of indirect blocks on the shared branch */
++	while (partial > chain) {
++		ext3cow_free_branches(handle, inode, partial->bh, partial->p + 1,
++				   (__le32*)partial->bh->b_data+addr_per_block,
++				   (chain+n-1) - partial);
++		BUFFER_TRACE(partial->bh, "call brelse");
++		brelse (partial->bh);
++		partial--;
++	}
++do_indirects:
++	/* Kill the remaining (whole) subtrees */
++  /* Unless we don't have to.  If the indirect block has a 0 bit
++   * then all of the children do too, so we can skip the branch - znjp
++   */
++	switch (offsets[0]) {
++	default:
++   if(EXT3COW_I(inode)->i_cow_bitmap & (1UL << EXT3COW_IND_BLOCK)){
++     nr = i_data[EXT3COW_IND_BLOCK];
++     if (nr) {
++       ext3cow_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
++       i_data[EXT3COW_IND_BLOCK] = 0;
++     }
++   }
++	case EXT3COW_IND_BLOCK:
++   if(EXT3COW_I(inode)->i_cow_bitmap & (1UL << EXT3COW_DIND_BLOCK)){
++     nr = i_data[EXT3COW_DIND_BLOCK];
++     if (nr) {
++       ext3cow_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
++       i_data[EXT3COW_DIND_BLOCK] = 0;
++     }
++   }
++	case EXT3COW_DIND_BLOCK:
++   if(EXT3COW_I(inode)->i_cow_bitmap & (1UL << EXT3COW_TIND_BLOCK)){
++     nr = i_data[EXT3COW_TIND_BLOCK];
++     if (nr) {
++       ext3cow_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
++       i_data[EXT3COW_TIND_BLOCK] = 0;
++     }
++   }
++	case EXT3COW_TIND_BLOCK:
++		;
++	}
++
++	ext3cow_discard_reservation(inode);
++
++	mutex_unlock(&ei->truncate_mutex);
++	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
++	ext3cow_mark_inode_dirty(handle, inode);
++
++	/*
++	 * In a multi-transaction truncate, we only make the final transaction
++	 * synchronous
++	 */
++	if (IS_SYNC(inode))
++		handle->h_sync = 1;
++out_stop:
++	/*
++	 * If this was a simple ftruncate(), and the file will remain alive
++	 * then we need to clear up the orphan record which we created above.
++	 * However, if this was a real unlink then we were called by
++	 * ext3cow_delete_inode(), and we allow that function to clean up the
++	 * orphan info for us.
++	 */
++	if (inode->i_nlink)
++		ext3cow_orphan_del(handle, inode);
++
++	ext3cow_journal_stop(handle);
++}
++
++static ext3cow_fsblk_t ext3cow_get_inode_block(struct super_block *sb,
++		unsigned long ino, struct ext3cow_iloc *iloc)
++{
++	unsigned long desc, group_desc, block_group;
++	unsigned long offset;
++	ext3cow_fsblk_t block;
++	struct buffer_head *bh;
++	struct ext3cow_group_desc * gdp;
++
++	if (!ext3cow_valid_inum(sb, ino)) {
++		/*
++		 * This error is already checked for in namei.c unless we are
++		 * looking at an NFS filehandle, in which case no error
++		 * report is needed
++		 */
++		return 0;
++	}
++
++	block_group = (ino - 1) / EXT3COW_INODES_PER_GROUP(sb);
++	if (block_group >= EXT3COW_SB(sb)->s_groups_count) {
++		ext3cow_error(sb,"ext3cow_get_inode_block","group >= groups count");
++		return 0;
++	}
++	smp_rmb();
++	group_desc = block_group >> EXT3COW_DESC_PER_BLOCK_BITS(sb);
++	desc = block_group & (EXT3COW_DESC_PER_BLOCK(sb) - 1);
++	bh = EXT3COW_SB(sb)->s_group_desc[group_desc];
++	if (!bh) {
++		ext3cow_error (sb, "ext3cow_get_inode_block",
++			    "Descriptor not loaded");
++		return 0;
++	}
++
++	gdp = (struct ext3cow_group_desc *)bh->b_data;
++	/*
++	 * Figure out the offset within the block group inode table
++	 */
++	offset = ((ino - 1) % EXT3COW_INODES_PER_GROUP(sb)) *
++		EXT3COW_INODE_SIZE(sb);
++	block = le32_to_cpu(gdp[desc].bg_inode_table) +
++		(offset >> EXT3COW_BLOCK_SIZE_BITS(sb));
++
++	iloc->block_group = block_group;
++	iloc->offset = offset & (EXT3COW_BLOCK_SIZE(sb) - 1);
++	return block;
++}
++
++/*
++ * ext3cow_get_inode_loc returns with an extra refcount against the inode's
++ * underlying buffer_head on success. If 'in_mem' is true, we have all
++ * data in memory that is needed to recreate the on-disk version of this
++ * inode.
++ */
++static int __ext3cow_get_inode_loc(struct inode *inode,
++				struct ext3cow_iloc *iloc, int in_mem)
++{
++	ext3cow_fsblk_t block;
++	struct buffer_head *bh;
++
++	block = ext3cow_get_inode_block(inode->i_sb, inode->i_ino, iloc);
++	if (!block)
++		return -EIO;
++
++	bh = sb_getblk(inode->i_sb, block);
++	if (!bh) {
++		ext3cow_error (inode->i_sb, "ext3cow_get_inode_loc",
++				"unable to read inode block - "
++				"inode=%lu, block="E3FSBLK,
++				 inode->i_ino, block);
++		return -EIO;
++	}
++	if (!buffer_uptodate(bh)) {
++		lock_buffer(bh);
++		if (buffer_uptodate(bh)) {
++			/* someone brought it uptodate while we waited */
++			unlock_buffer(bh);
++			goto has_buffer;
++		}
++
++		/*
++		 * If we have all information of the inode in memory and this
++		 * is the only valid inode in the block, we need not read the
++		 * block.
++		 */
++		if (in_mem) {
++			struct buffer_head *bitmap_bh;
++			struct ext3cow_group_desc *desc;
++			int inodes_per_buffer;
++			int inode_offset, i;
++			int block_group;
++			int start;
++
++			block_group = (inode->i_ino - 1) /
++					EXT3COW_INODES_PER_GROUP(inode->i_sb);
++			inodes_per_buffer = bh->b_size /
++				EXT3COW_INODE_SIZE(inode->i_sb);
++			inode_offset = ((inode->i_ino - 1) %
++					EXT3COW_INODES_PER_GROUP(inode->i_sb));
++			start = inode_offset & ~(inodes_per_buffer - 1);
++
++			/* Is the inode bitmap in cache? */
++			desc = ext3cow_get_group_desc(inode->i_sb,
++						block_group, NULL);
++			if (!desc)
++				goto make_io;
++
++			bitmap_bh = sb_getblk(inode->i_sb,
++					le32_to_cpu(desc->bg_inode_bitmap));
++			if (!bitmap_bh)
++				goto make_io;
++
++			/*
++			 * If the inode bitmap isn't in cache then the
++			 * optimisation may end up performing two reads instead
++			 * of one, so skip it.
++			 */
++			if (!buffer_uptodate(bitmap_bh)) {
++				brelse(bitmap_bh);
++				goto make_io;
++			}
++			for (i = start; i < start + inodes_per_buffer; i++) {
++				if (i == inode_offset)
++					continue;
++				if (ext3cow_test_bit(i, bitmap_bh->b_data))
++					break;
++			}
++			brelse(bitmap_bh);
++			if (i == start + inodes_per_buffer) {
++				/* all other inodes are free, so skip I/O */
++				memset(bh->b_data, 0, bh->b_size);
++				set_buffer_uptodate(bh);
++				unlock_buffer(bh);
++				goto has_buffer;
++			}
++		}
++
++make_io:
++		/*
++		 * There are other valid inodes in the buffer, this inode
++		 * has in-inode xattrs, or we don't have this inode in memory.
++		 * Read the block from disk.
++		 */
++		get_bh(bh);
++		bh->b_end_io = end_buffer_read_sync;
++		submit_bh(READ_META, bh);
++		wait_on_buffer(bh);
++		if (!buffer_uptodate(bh)) {
++			ext3cow_error(inode->i_sb, "ext3cow_get_inode_loc",
++					"unable to read inode block - "
++					"inode=%lu, block="E3FSBLK,
++					inode->i_ino, block);
++			brelse(bh);
++			return -EIO;
++		}
++	}
++has_buffer:
++	iloc->bh = bh;
++	return 0;
++}
++
++int ext3cow_get_inode_loc(struct inode *inode, struct ext3cow_iloc *iloc)
++{
++	/* We have all inode data except xattrs in memory here. */
++	return __ext3cow_get_inode_loc(inode, iloc,
++		!(EXT3COW_I(inode)->i_state & EXT3COW_STATE_XATTR));
++}
++
++void ext3cow_set_inode_flags(struct inode *inode)
++{
++	unsigned int flags = EXT3COW_I(inode)->i_flags;
++
++	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
++	if (flags & EXT3COW_SYNC_FL)
++		inode->i_flags |= S_SYNC;
++	if (flags & EXT3COW_APPEND_FL)
++		inode->i_flags |= S_APPEND;
++	if (flags & EXT3COW_IMMUTABLE_FL)
++		inode->i_flags |= S_IMMUTABLE;
++	if (flags & EXT3COW_NOATIME_FL)
++		inode->i_flags |= S_NOATIME;
++	if (flags & EXT3COW_DIRSYNC_FL)
++		inode->i_flags |= S_DIRSYNC;
++}
++
++void ext3cow_read_inode(struct inode * inode)
++{
++	struct ext3cow_iloc iloc;
++	struct ext3cow_inode *raw_inode;
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	struct buffer_head *bh;
++	int block;
++
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	ei->i_acl = EXT3COW_ACL_NOT_CACHED;
++	ei->i_default_acl = EXT3COW_ACL_NOT_CACHED;
++#endif
++	ei->i_block_alloc_info = NULL;
++
++	if (__ext3cow_get_inode_loc(inode, &iloc, 0))
++		goto bad_inode;
++	bh = iloc.bh;
++	raw_inode = ext3cow_raw_inode(&iloc);
++	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
++	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
++	inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
++  /* Taken out for versioning -znjp
++	if(!(test_opt (inode->i_sb, NO_UID32))) {
++		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
++		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
++	}
++  */
++	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
++	inode->i_size = le32_to_cpu(raw_inode->i_size);
++	inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime);
++	inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime);
++	inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime);
++	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
++
++	ei->i_state = 0;
++	ei->i_dir_start_lookup = 0;
++	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
++	/* We now have enough fields to check if the inode was active or not.
++	 * This is needed because nfsd might try to access dead inodes
++	 * the test is that same one that e2fsck uses
++	 * NeilBrown 1999oct15
++	 */
++	if (inode->i_nlink == 0) {
++		if (inode->i_mode == 0 ||
++		    !(EXT3COW_SB(inode->i_sb)->s_mount_state & EXT3COW_ORPHAN_FS)) {
++			/* this inode is deleted */
++			brelse (bh);
++			goto bad_inode;
++		}
++		/* The only unlinked inodes we let through here have
++		 * valid i_mode and are being read by the orphan
++		 * recovery code: that's fine, we're about to complete
++		 * the process of deleting those. */
++	}
++	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
++	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
++  /* For versioning -znjp */
++  ei->i_cow_bitmap   = le32_to_cpu(raw_inode->i_cowbitmap);
++  ei->i_epoch_number = le32_to_cpu(raw_inode->i_epch_number);
++  ei->i_next_inode   = le32_to_cpu(raw_inode->i_nxt_inode);
++  
++#ifdef EXT3COW_FRAGMENTS
++	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
++	ei->i_frag_no = raw_inode->i_frag;
++	ei->i_frag_size = raw_inode->i_fsize;
++#endif
++	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
++	if (!S_ISREG(inode->i_mode)) {
++		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
++	} else {
++		inode->i_size |=
++			((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
++	}
++	ei->i_disksize = inode->i_size;
++	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
++	ei->i_block_group = iloc.block_group;
++	/*
++	 * NOTE! The in-memory inode i_data array is in little-endian order
++	 * even on big-endian machines: we do NOT byteswap the block numbers!
++	 */
++	for (block = 0; block < EXT3COW_N_BLOCKS; block++)
++		ei->i_data[block] = raw_inode->i_block[block];
++	INIT_LIST_HEAD(&ei->i_orphan);
++
++	if (inode->i_ino >= EXT3COW_FIRST_INO(inode->i_sb) + 1 &&
++	    EXT3COW_INODE_SIZE(inode->i_sb) > EXT3COW_GOOD_OLD_INODE_SIZE) {
++		/*
++		 * When mke2fs creates big inodes it does not zero out
++		 * the unused bytes above EXT3COW_GOOD_OLD_INODE_SIZE,
++		 * so ignore those first few inodes.
++		 */
++		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
++		if (EXT3COW_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
++		    EXT3COW_INODE_SIZE(inode->i_sb))
++			goto bad_inode;
++		if (ei->i_extra_isize == 0) {
++			/* The extra space is currently unused. Use it. */
++			ei->i_extra_isize = sizeof(struct ext3cow_inode) -
++					    EXT3COW_GOOD_OLD_INODE_SIZE;
++		} else {
++			__le32 *magic = (void *)raw_inode +
++					EXT3COW_GOOD_OLD_INODE_SIZE +
++					ei->i_extra_isize;
++			if (*magic == cpu_to_le32(EXT3COW_XATTR_MAGIC))
++				 ei->i_state |= EXT3COW_STATE_XATTR;
++		}
++	} else
++		ei->i_extra_isize = 0;
++
++	if (S_ISREG(inode->i_mode)) {
++		inode->i_op = &ext3cow_file_inode_operations;
++		inode->i_fop = &ext3cow_file_operations;
++		ext3cow_set_aops(inode);
++	} else if (S_ISDIR(inode->i_mode)) {
++		inode->i_op = &ext3cow_dir_inode_operations;
++		inode->i_fop = &ext3cow_dir_operations;
++	} else if (S_ISLNK(inode->i_mode)) {
++		if (ext3cow_inode_is_fast_symlink(inode))
++			inode->i_op = &ext3cow_fast_symlink_inode_operations;
++		else {
++			inode->i_op = &ext3cow_symlink_inode_operations;
++			ext3cow_set_aops(inode);
++		}
++	} else {
++		inode->i_op = &ext3cow_special_inode_operations;
++		if (raw_inode->i_block[0])
++			init_special_inode(inode, inode->i_mode,
++			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
++		else
++			init_special_inode(inode, inode->i_mode,
++			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
++	}
++	brelse (iloc.bh);
++	ext3cow_set_inode_flags(inode);
++	return;
++
++bad_inode:
++	make_bad_inode(inode);
++	return;
++}
++
++/*
++ * Post the struct inode info into an on-disk inode location in the
++ * buffer-cache.  This gobbles the caller's reference to the
++ * buffer_head in the inode location struct.
++ *
++ * The caller must have write access to iloc->bh.
++ */
++static int ext3cow_do_update_inode(handle_t *handle,
++				struct inode *inode,
++				struct ext3cow_iloc *iloc)
++{
++	struct ext3cow_inode *raw_inode = ext3cow_raw_inode(iloc);
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	struct buffer_head *bh = iloc->bh;
++	int err = 0, rc, block;
++
++	/* For fields not not tracking in the in-memory inode,
++	 * initialise them to zero for new inodes. */
++	if (ei->i_state & EXT3COW_STATE_NEW)
++		memset(raw_inode, 0, EXT3COW_SB(inode->i_sb)->s_inode_size);
++
++	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
++
++  /* Taken out for versioning  -znjp
++	if(!(test_opt(inode->i_sb, NO_UID32))) {
++		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
++		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
++*
++ * Fix up interoperability with old kernels. Otherwise, old inodes get
++ * re-used with the upper 16 bits of the uid/gid intact
++ *
++
++		if(!ei->i_dtime) {
++			raw_inode->i_uid_high =
++				cpu_to_le16(high_16_bits(inode->i_uid));
++			raw_inode->i_gid_high =
++				cpu_to_le16(high_16_bits(inode->i_gid));
++		} else {
++			raw_inode->i_uid_high = 0;
++			raw_inode->i_gid_high = 0;
++		}
++    
++	} else {
++		raw_inode->i_uid_low =
++			cpu_to_le16(fs_high2lowuid(inode->i_uid));
++		raw_inode->i_gid_low =
++			cpu_to_le16(fs_high2lowgid(inode->i_gid));
++		raw_inode->i_uid_high = 0;
++		raw_inode->i_gid_high = 0;
++	}
++  */
++	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
++	raw_inode->i_size = cpu_to_le32(ei->i_disksize);
++	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
++	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
++	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
++	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
++	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
++	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
++  /* For versioning -znjp */
++  raw_inode->i_cowbitmap   = cpu_to_le16(EXT3COW_I(inode)->i_cow_bitmap);
++  raw_inode->i_epch_number = cpu_to_le32(EXT3COW_I(inode)->i_epoch_number);
++  raw_inode->i_nxt_inode   = cpu_to_le32(EXT3COW_I(inode)->i_next_inode);
++
++#ifdef EXT3COW_FRAGMENTS
++	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
++	raw_inode->i_frag = ei->i_frag_no;
++	raw_inode->i_fsize = ei->i_frag_size;
++#endif
++	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
++	if (!S_ISREG(inode->i_mode)) {
++		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
++	} else {
++		raw_inode->i_size_high =
++			cpu_to_le32(ei->i_disksize >> 32);
++		if (ei->i_disksize > 0x7fffffffULL) {
++			struct super_block *sb = inode->i_sb;
++			if (!EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++					EXT3COW_FEATURE_RO_COMPAT_LARGE_FILE) ||
++			    EXT3COW_SB(sb)->s_es->s_rev_level ==
++					cpu_to_le32(EXT3COW_GOOD_OLD_REV)) {
++			       /* If this is the first large file
++				* created, add a flag to the superblock.
++				*/
++				err = ext3cow_journal_get_write_access(handle,
++						EXT3COW_SB(sb)->s_sbh);
++				if (err)
++					goto out_brelse;
++				ext3cow_update_dynamic_rev(sb);
++				EXT3COW_SET_RO_COMPAT_FEATURE(sb,
++					EXT3COW_FEATURE_RO_COMPAT_LARGE_FILE);
++				sb->s_dirt = 1;
++				handle->h_sync = 1;
++				err = ext3cow_journal_dirty_metadata(handle,
++						EXT3COW_SB(sb)->s_sbh);
++			}
++		}
++	}
++	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
++	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
++		if (old_valid_dev(inode->i_rdev)) {
++			raw_inode->i_block[0] =
++				cpu_to_le32(old_encode_dev(inode->i_rdev));
++			raw_inode->i_block[1] = 0;
++		} else {
++			raw_inode->i_block[0] = 0;
++			raw_inode->i_block[1] =
++				cpu_to_le32(new_encode_dev(inode->i_rdev));
++			raw_inode->i_block[2] = 0;
++		}
++	} else for (block = 0; block < EXT3COW_N_BLOCKS; block++)
++		raw_inode->i_block[block] = ei->i_data[block];
++
++	if (ei->i_extra_isize)
++		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
++
++	BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++	rc = ext3cow_journal_dirty_metadata(handle, bh);
++	if (!err)
++		err = rc;
++	ei->i_state &= ~EXT3COW_STATE_NEW;
++
++out_brelse:
++	brelse (bh);
++	ext3cow_std_error(inode->i_sb, err);
++	return err;
++}
++
++/*
++ * ext3cow_write_inode()
++ *
++ * We are called from a few places:
++ *
++ * - Within generic_file_write() for O_SYNC files.
++ *   Here, there will be no transaction running. We wait for any running
++ *   trasnaction to commit.
++ *
++ * - Within sys_sync(), kupdate and such.
++ *   We wait on commit, if tol to.
++ *
++ * - Within prune_icache() (PF_MEMALLOC == true)
++ *   Here we simply return.  We can't afford to block kswapd on the
++ *   journal commit.
++ *
++ * In all cases it is actually safe for us to return without doing anything,
++ * because the inode has been copied into a raw inode buffer in
++ * ext3cow_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
++ * knfsd.
++ *
++ * Note that we are absolutely dependent upon all inode dirtiers doing the
++ * right thing: they *must* call mark_inode_dirty() after dirtying info in
++ * which we are interested.
++ *
++ * It would be a bug for them to not do this.  The code:
++ *
++ *	mark_inode_dirty(inode)
++ *	stuff();
++ *	inode->i_size = expr;
++ *
++ * is in error because a kswapd-driven write_inode() could occur while
++ * `stuff()' is running, and the new i_size will be lost.  Plus the inode
++ * will no longer be on the superblock's dirty inode list.
++ */
++int ext3cow_write_inode(struct inode *inode, int wait)
++{
++	if (current->flags & PF_MEMALLOC)
++		return 0;
++
++	if (ext3cow_journal_current_handle()) {
++		jbd_debug(0, "called recursively, non-PF_MEMALLOC!\n");
++		dump_stack();
++		return -EIO;
++	}
++
++	if (!wait)
++		return 0;
++
++	return ext3cow_force_commit(inode->i_sb);
++}
++
++/*
++ * ext3cow_setattr()
++ *
++ * Called from notify_change.
++ *
++ * We want to trap VFS attempts to truncate the file as soon as
++ * possible.  In particular, we want to make sure that when the VFS
++ * shrinks i_size, we put the inode on the orphan list and modify
++ * i_disksize immediately, so that during the subsequent flushing of
++ * dirty pages and freeing of disk blocks, we can guarantee that any
++ * commit will leave the blocks being flushed in an unused state on
++ * disk.  (On recovery, the inode will get truncated and the blocks will
++ * be freed, so we have a strong guarantee that no future commit will
++ * leave these blocks visible to the user.)
++ *
++ * Called with inode->sem down.
++ */
++int ext3cow_setattr(struct dentry *dentry, struct iattr *attr)
++{
++	struct inode *inode = dentry->d_inode;
++	int error, rc = 0;
++	const unsigned int ia_valid = attr->ia_valid;
++
++	error = inode_change_ok(inode, attr);
++	if (error)
++		return error;
++
++  /* For versioning -znjp */
++  if(is_unchangeable(inode, dentry)){
++    error = -EROFS;
++    goto err_out;
++  }
++  
++  if(EXT3COW_S_EPOCHNUMBER(inode->i_sb) > EXT3COW_I_EPOCHNUMBER(inode)){
++    error = ext3cow_dup_inode(dentry->d_parent->d_inode, inode);
++    if(error)
++      goto err_out;
++  }
++  
++	if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
++		(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
++		handle_t *handle;
++
++		/* (user+group)*(old+new) structure, inode write (sb,
++		 * inode block, ? - but truncate inode update has it) */
++		handle = ext3cow_journal_start(inode, 2*(EXT3COW_QUOTA_INIT_BLOCKS(inode->i_sb)+
++					EXT3COW_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
++		if (IS_ERR(handle)) {
++			error = PTR_ERR(handle);
++			goto err_out;
++		}
++		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
++		if (error) {
++			ext3cow_journal_stop(handle);
++			return error;
++		}
++		/* Update corresponding info in inode so that everything is in
++		 * one transaction */
++		if (attr->ia_valid & ATTR_UID)
++			inode->i_uid = attr->ia_uid;
++		if (attr->ia_valid & ATTR_GID)
++			inode->i_gid = attr->ia_gid;
++		error = ext3cow_mark_inode_dirty(handle, inode);
++		ext3cow_journal_stop(handle);
++	}
++
++	if (S_ISREG(inode->i_mode) &&
++	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
++		handle_t *handle;
++
++		handle = ext3cow_journal_start(inode, 3);
++		if (IS_ERR(handle)) {
++			error = PTR_ERR(handle);
++			goto err_out;
++		}
++
++		error = ext3cow_orphan_add(handle, inode);
++		EXT3COW_I(inode)->i_disksize = attr->ia_size;
++		rc = ext3cow_mark_inode_dirty(handle, inode);
++		if (!error)
++			error = rc;
++		ext3cow_journal_stop(handle);
++	}
++
++	rc = inode_setattr(inode, attr);
++
++	/* If inode_setattr's call to ext3cow_truncate failed to get a
++	 * transaction handle at all, we need to clean up the in-core
++	 * orphan list manually. */
++	if (inode->i_nlink)
++		ext3cow_orphan_del(NULL, inode);
++
++	if (!rc && (ia_valid & ATTR_MODE))
++		rc = ext3cow_acl_chmod(inode);
++
++err_out:
++	ext3cow_std_error(inode->i_sb, error);
++	if (!error)
++		error = rc;
++	return error;
++}
++
++
++/*
++ * How many blocks doth make a writepage()?
++ *
++ * With N blocks per page, it may be:
++ * N data blocks
++ * 2 indirect block
++ * 2 dindirect
++ * 1 tindirect
++ * N+5 bitmap blocks (from the above)
++ * N+5 group descriptor summary blocks
++ * 1 inode block
++ * 1 superblock.
++ * 2 * EXT3COW_SINGLEDATA_TRANS_BLOCKS for the quote files
++ *
++ * 3 * (N + 5) + 2 + 2 * EXT3COW_SINGLEDATA_TRANS_BLOCKS
++ *
++ * With ordered or writeback data it's the same, less the N data blocks.
++ *
++ * If the inode's direct blocks can hold an integral number of pages then a
++ * page cannot straddle two indirect blocks, and we can only touch one indirect
++ * and dindirect block, and the "5" above becomes "3".
++ *
++ * This still overestimates under most circumstances.  If we were to pass the
++ * start and end offsets in here as well we could do block_to_path() on each
++ * block and work out the exact number of indirects which are touched.  Pah.
++ */
++
++static int ext3cow_writepage_trans_blocks(struct inode *inode)
++{
++	int bpp = ext3cow_journal_blocks_per_page(inode);
++	int indirects = (EXT3COW_NDIR_BLOCKS % bpp) ? 5 : 3;
++	int ret;
++
++	if (ext3cow_should_journal_data(inode))
++		ret = 3 * (bpp + indirects) + 2;
++	else
++		ret = 2 * (bpp + indirects) + 2;
++
++#ifdef CONFIG_QUOTA
++	/* We know that structure was already allocated during DQUOT_INIT so
++	 * we will be updating only the data blocks + inodes */
++	ret += 2*EXT3COW_QUOTA_TRANS_BLOCKS(inode->i_sb);
++#endif
++
++	return ret;
++}
++
++/*
++ * The caller must have previously called ext3cow_reserve_inode_write().
++ * Give this, we know that the caller already has write access to iloc->bh.
++ */
++int ext3cow_mark_iloc_dirty(handle_t *handle,
++		struct inode *inode, struct ext3cow_iloc *iloc)
++{
++	int err = 0;
++
++	/* the do_update_inode consumes one bh->b_count */
++	get_bh(iloc->bh);
++
++	/* ext3cow_do_update_inode() does journal_dirty_metadata */
++	err = ext3cow_do_update_inode(handle, inode, iloc);
++	put_bh(iloc->bh);
++	return err;
++}
++
++/*
++ * On success, We end up with an outstanding reference count against
++ * iloc->bh.  This _must_ be cleaned up later.
++ */
++
++int
++ext3cow_reserve_inode_write(handle_t *handle, struct inode *inode,
++			 struct ext3cow_iloc *iloc)
++{
++	int err = 0;
++	if (handle) {
++		err = ext3cow_get_inode_loc(inode, iloc);
++		if (!err) {
++			BUFFER_TRACE(iloc->bh, "get_write_access");
++			err = ext3cow_journal_get_write_access(handle, iloc->bh);
++			if (err) {
++				brelse(iloc->bh);
++				iloc->bh = NULL;
++			}
++		}
++	}
++	ext3cow_std_error(inode->i_sb, err);
++	return err;
++}
++
++/*
++ * What we do here is to mark the in-core inode as clean with respect to inode
++ * dirtiness (it may still be data-dirty).
++ * This means that the in-core inode may be reaped by prune_icache
++ * without having to perform any I/O.  This is a very good thing,
++ * because *any* task may call prune_icache - even ones which
++ * have a transaction open against a different journal.
++ *
++ * Is this cheating?  Not really.  Sure, we haven't written the
++ * inode out, but prune_icache isn't a user-visible syncing function.
++ * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
++ * we start and wait on commits.
++ *
++ * Is this efficient/effective?  Well, we're being nice to the system
++ * by cleaning up our inodes proactively so they can be reaped
++ * without I/O.  But we are potentially leaving up to five seconds'
++ * worth of inodes floating about which prune_icache wants us to
++ * write out.  One way to fix that would be to get prune_icache()
++ * to do a write_super() to free up some memory.  It has the desired
++ * effect.
++ */
++int ext3cow_mark_inode_dirty(handle_t *handle, struct inode *inode)
++{
++	struct ext3cow_iloc iloc;
++	int err;
++
++  if(EXT3COW_IS_FAKEINODE(inode))
++    return 0;
++
++	might_sleep();
++	err = ext3cow_reserve_inode_write(handle, inode, &iloc);
++	if (!err)
++		err = ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++	return err;
++}
++
++/*
++ * ext3cow_dirty_inode() is called from __mark_inode_dirty()
++ *
++ * We're really interested in the case where a file is being extended.
++ * i_size has been changed by generic_commit_write() and we thus need
++ * to include the updated inode in the current transaction.
++ *
++ * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
++ * are allocated to the file.
++ *
++ * If the inode is marked synchronous, we don't honour that here - doing
++ * so would cause a commit on atime updates, which we don't bother doing.
++ * We handle synchronous inodes at the highest possible level.
++ */
++void ext3cow_dirty_inode(struct inode *inode)
++{
++	handle_t *current_handle = ext3cow_journal_current_handle();
++	handle_t *handle;
++
++	handle = ext3cow_journal_start(inode, 2);
++	if (IS_ERR(handle))
++		goto out;
++	if (current_handle &&
++		current_handle->h_transaction != handle->h_transaction) {
++		/* This task has a transaction open against a different fs */
++		printk(KERN_EMERG "%s: transactions do not match!\n",
++		       __FUNCTION__);
++	} else {
++		jbd_debug(5, "marking dirty.  outer handle=%p\n",
++				current_handle);
++		ext3cow_mark_inode_dirty(handle, inode);
++	}
++	ext3cow_journal_stop(handle);
++out:
++	return;
++}
++
++#if 0
++/*
++ * Bind an inode's backing buffer_head into this transaction, to prevent
++ * it from being flushed to disk early.  Unlike
++ * ext3cow_reserve_inode_write, this leaves behind no bh reference and
++ * returns no iloc structure, so the caller needs to repeat the iloc
++ * lookup to mark the inode dirty later.
++ */
++static int ext3cow_pin_inode(handle_t *handle, struct inode *inode)
++{
++	struct ext3cow_iloc iloc;
++
++	int err = 0;
++	if (handle) {
++		err = ext3cow_get_inode_loc(inode, &iloc);
++		if (!err) {
++			BUFFER_TRACE(iloc.bh, "get_write_access");
++			err = journal_get_write_access(handle, iloc.bh);
++			if (!err)
++				err = ext3cow_journal_dirty_metadata(handle,
++								  iloc.bh);
++			brelse(iloc.bh);
++		}
++	}
++	ext3cow_std_error(inode->i_sb, err);
++	return err;
++}
++#endif
++
++int ext3cow_change_inode_journal_flag(struct inode *inode, int val)
++{
++	journal_t *journal;
++	handle_t *handle;
++	int err;
++
++	/*
++	 * We have to be very careful here: changing a data block's
++	 * journaling status dynamically is dangerous.  If we write a
++	 * data block to the journal, change the status and then delete
++	 * that block, we risk forgetting to revoke the old log record
++	 * from the journal and so a subsequent replay can corrupt data.
++	 * So, first we make sure that the journal is empty and that
++	 * nobody is changing anything.
++	 */
++
++	journal = EXT3COW_JOURNAL(inode);
++	if (is_journal_aborted(journal) || IS_RDONLY(inode))
++		return -EROFS;
++
++	journal_lock_updates(journal);
++	journal_flush(journal);
++
++	/*
++	 * OK, there are no updates running now, and all cached data is
++	 * synced to disk.  We are now in a completely consistent state
++	 * which doesn't have anything in the journal, and we know that
++	 * no filesystem updates are running, so it is safe to modify
++	 * the inode's in-core data-journaling state flag now.
++	 */
++
++	if (val)
++		EXT3COW_I(inode)->i_flags |= EXT3COW_JOURNAL_DATA_FL;
++	else
++		EXT3COW_I(inode)->i_flags &= ~EXT3COW_JOURNAL_DATA_FL;
++	ext3cow_set_aops(inode);
++
++	journal_unlock_updates(journal);
++
++	/* Finally we can mark the inode as dirty. */
++
++	handle = ext3cow_journal_start(inode, 1);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	err = ext3cow_mark_inode_dirty(handle, inode);
++	handle->h_sync = 1;
++	ext3cow_journal_stop(handle);
++	ext3cow_std_error(inode->i_sb, err);
++
++	return err;
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/ioctl.c linux-2.6.20.3-ext3cow/fs/ext3cow/ioctl.c
+--- linux-2.6.20.3/fs/ext3cow/ioctl.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/ioctl.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,312 @@
++/*
++ * linux/fs/ext3cow/ioctl.c
++ *
++ * Copyright (C) 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ */
++
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/capability.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/time.h>
++#include <linux/compat.h>
++#include <linux/smp_lock.h>
++#include <asm/uaccess.h>
++
++int ext3cow_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
++		unsigned long arg)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	unsigned int flags;
++	unsigned short rsv_window_size;
++
++	ext3cow_debug ("cmd = %u, arg = %lu\n", cmd, arg);
++
++	switch (cmd) {
++    /* Some IOCTLs for version */
++   case EXT3COW_IOC_TAKESNAPSHOT:
++    return (unsigned int)ext3cow_take_snapshot(inode->i_sb);
++   case EXT3COW_IOC_GETEPOCH:
++    return (unsigned int)EXT3COW_S_EPOCHNUMBER(inode->i_sb);
++	case EXT3COW_IOC_GETFLAGS:
++		flags = ei->i_flags & EXT3COW_FL_USER_VISIBLE;
++		return put_user(flags, (int __user *) arg);
++	case EXT3COW_IOC_SETFLAGS: {
++		handle_t *handle = NULL;
++		int err;
++		struct ext3cow_iloc iloc;
++		unsigned int oldflags;
++		unsigned int jflag;
++
++		if (IS_RDONLY(inode))
++			return -EROFS;
++
++		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
++			return -EACCES;
++
++		if (get_user(flags, (int __user *) arg))
++			return -EFAULT;
++
++		if (!S_ISDIR(inode->i_mode))
++			flags &= ~EXT3COW_DIRSYNC_FL;
++
++		mutex_lock(&inode->i_mutex);
++		oldflags = ei->i_flags;
++
++		/* The JOURNAL_DATA flag is modifiable only by root */
++		jflag = flags & EXT3COW_JOURNAL_DATA_FL;
++
++		/*
++		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
++		 * the relevant capability.
++		 *
++		 * This test looks nicer. Thanks to Pauline Middelink
++		 */
++		if ((flags ^ oldflags) & (EXT3COW_APPEND_FL | EXT3COW_IMMUTABLE_FL)) {
++			if (!capable(CAP_LINUX_IMMUTABLE)) {
++				mutex_unlock(&inode->i_mutex);
++				return -EPERM;
++			}
++		}
++
++		/*
++		 * The JOURNAL_DATA flag can only be changed by
++		 * the relevant capability.
++		 */
++		if ((jflag ^ oldflags) & (EXT3COW_JOURNAL_DATA_FL)) {
++			if (!capable(CAP_SYS_RESOURCE)) {
++				mutex_unlock(&inode->i_mutex);
++				return -EPERM;
++			}
++		}
++
++
++		handle = ext3cow_journal_start(inode, 1);
++		if (IS_ERR(handle)) {
++			mutex_unlock(&inode->i_mutex);
++			return PTR_ERR(handle);
++		}
++		if (IS_SYNC(inode))
++			handle->h_sync = 1;
++		err = ext3cow_reserve_inode_write(handle, inode, &iloc);
++		if (err)
++			goto flags_err;
++
++		flags = flags & EXT3COW_FL_USER_MODIFIABLE;
++		flags |= oldflags & ~EXT3COW_FL_USER_MODIFIABLE;
++		ei->i_flags = flags;
++
++		ext3cow_set_inode_flags(inode);
++		inode->i_ctime = CURRENT_TIME_SEC;
++
++		err = ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++flags_err:
++		ext3cow_journal_stop(handle);
++		if (err) {
++			mutex_unlock(&inode->i_mutex);
++			return err;
++		}
++
++		if ((jflag ^ oldflags) & (EXT3COW_JOURNAL_DATA_FL))
++			err = ext3cow_change_inode_journal_flag(inode, jflag);
++		mutex_unlock(&inode->i_mutex);
++		return err;
++	}
++	case EXT3COW_IOC_GETVERSION:
++	case EXT3COW_IOC_GETVERSION_OLD:
++		return put_user(inode->i_generation, (int __user *) arg);
++	case EXT3COW_IOC_SETVERSION:
++	case EXT3COW_IOC_SETVERSION_OLD: {
++		handle_t *handle;
++		struct ext3cow_iloc iloc;
++		__u32 generation;
++		int err;
++
++		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
++			return -EPERM;
++		if (IS_RDONLY(inode))
++			return -EROFS;
++		if (get_user(generation, (int __user *) arg))
++			return -EFAULT;
++
++		handle = ext3cow_journal_start(inode, 1);
++		if (IS_ERR(handle))
++			return PTR_ERR(handle);
++		err = ext3cow_reserve_inode_write(handle, inode, &iloc);
++		if (err == 0) {
++			inode->i_ctime = CURRENT_TIME_SEC;
++			inode->i_generation = generation;
++			err = ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++		}
++		ext3cow_journal_stop(handle);
++		return err;
++	}
++#ifdef CONFIG_JBD_DEBUG
++	case EXT3COW_IOC_WAIT_FOR_READONLY:
++		/*
++		 * This is racy - by the time we're woken up and running,
++		 * the superblock could be released.  And the module could
++		 * have been unloaded.  So sue me.
++		 *
++		 * Returns 1 if it slept, else zero.
++		 */
++		{
++			struct super_block *sb = inode->i_sb;
++			DECLARE_WAITQUEUE(wait, current);
++			int ret = 0;
++
++			set_current_state(TASK_INTERRUPTIBLE);
++			add_wait_queue(&EXT3COW_SB(sb)->ro_wait_queue, &wait);
++			if (timer_pending(&EXT3COW_SB(sb)->turn_ro_timer)) {
++				schedule();
++				ret = 1;
++			}
++			remove_wait_queue(&EXT3COW_SB(sb)->ro_wait_queue, &wait);
++			return ret;
++		}
++#endif
++	case EXT3COW_IOC_GETRSVSZ:
++		if (test_opt(inode->i_sb, RESERVATION)
++			&& S_ISREG(inode->i_mode)
++			&& ei->i_block_alloc_info) {
++			rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
++			return put_user(rsv_window_size, (int __user *)arg);
++		}
++		return -ENOTTY;
++	case EXT3COW_IOC_SETRSVSZ: {
++
++		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
++			return -ENOTTY;
++
++		if (IS_RDONLY(inode))
++			return -EROFS;
++
++		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
++			return -EACCES;
++
++		if (get_user(rsv_window_size, (int __user *)arg))
++			return -EFAULT;
++
++		if (rsv_window_size > EXT3COW_MAX_RESERVE_BLOCKS)
++			rsv_window_size = EXT3COW_MAX_RESERVE_BLOCKS;
++
++		/*
++		 * need to allocate reservation structure for this inode
++		 * before set the window size
++		 */
++		mutex_lock(&ei->truncate_mutex);
++		if (!ei->i_block_alloc_info)
++			ext3cow_init_block_alloc_info(inode);
++
++		if (ei->i_block_alloc_info){
++			struct ext3cow_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
++			rsv->rsv_goal_size = rsv_window_size;
++		}
++		mutex_unlock(&ei->truncate_mutex);
++		return 0;
++	}
++	case EXT3COW_IOC_GROUP_EXTEND: {
++		ext3cow_fsblk_t n_blocks_count;
++		struct super_block *sb = inode->i_sb;
++		int err;
++
++		if (!capable(CAP_SYS_RESOURCE))
++			return -EPERM;
++
++		if (IS_RDONLY(inode))
++			return -EROFS;
++
++		if (get_user(n_blocks_count, (__u32 __user *)arg))
++			return -EFAULT;
++
++		err = ext3cow_group_extend(sb, EXT3COW_SB(sb)->s_es, n_blocks_count);
++		journal_lock_updates(EXT3COW_SB(sb)->s_journal);
++		journal_flush(EXT3COW_SB(sb)->s_journal);
++		journal_unlock_updates(EXT3COW_SB(sb)->s_journal);
++
++		return err;
++	}
++	case EXT3COW_IOC_GROUP_ADD: {
++		struct ext3cow_new_group_data input;
++		struct super_block *sb = inode->i_sb;
++		int err;
++
++		if (!capable(CAP_SYS_RESOURCE))
++			return -EPERM;
++
++		if (IS_RDONLY(inode))
++			return -EROFS;
++
++		if (copy_from_user(&input, (struct ext3cow_new_group_input __user *)arg,
++				sizeof(input)))
++			return -EFAULT;
++
++		err = ext3cow_group_add(sb, &input);
++		journal_lock_updates(EXT3COW_SB(sb)->s_journal);
++		journal_flush(EXT3COW_SB(sb)->s_journal);
++		journal_unlock_updates(EXT3COW_SB(sb)->s_journal);
++
++		return err;
++	}
++
++
++	default:
++		return -ENOTTY;
++	}
++}
++
++#ifdef CONFIG_COMPAT
++long ext3cow_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
++{
++	struct inode *inode = file->f_path.dentry->d_inode;
++	int ret;
++
++	/* These are just misnamed, they actually get/put from/to user an int */
++	switch (cmd) {
++	case EXT3COW_IOC32_GETFLAGS:
++		cmd = EXT3COW_IOC_GETFLAGS;
++		break;
++	case EXT3COW_IOC32_SETFLAGS:
++		cmd = EXT3COW_IOC_SETFLAGS;
++		break;
++	case EXT3COW_IOC32_GETVERSION:
++		cmd = EXT3COW_IOC_GETVERSION;
++		break;
++	case EXT3COW_IOC32_SETVERSION:
++		cmd = EXT3COW_IOC_SETVERSION;
++		break;
++	case EXT3COW_IOC32_GROUP_EXTEND:
++		cmd = EXT3COW_IOC_GROUP_EXTEND;
++		break;
++	case EXT3COW_IOC32_GETVERSION_OLD:
++		cmd = EXT3COW_IOC_GETVERSION_OLD;
++		break;
++	case EXT3COW_IOC32_SETVERSION_OLD:
++		cmd = EXT3COW_IOC_SETVERSION_OLD;
++		break;
++#ifdef CONFIG_JBD_DEBUG
++	case EXT3COW_IOC32_WAIT_FOR_READONLY:
++		cmd = EXT3COW_IOC_WAIT_FOR_READONLY;
++		break;
++#endif
++	case EXT3COW_IOC32_GETRSVSZ:
++		cmd = EXT3COW_IOC_GETRSVSZ;
++		break;
++	case EXT3COW_IOC32_SETRSVSZ:
++		cmd = EXT3COW_IOC_SETRSVSZ;
++		break;
++	case EXT3COW_IOC_GROUP_ADD:
++		break;
++	default:
++		return -ENOIOCTLCMD;
++	}
++	lock_kernel();
++	ret = ext3cow_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
++	unlock_kernel();
++	return ret;
++}
++#endif
+diff -ruN linux-2.6.20.3/fs/ext3cow/namei.c linux-2.6.20.3-ext3cow/fs/ext3cow/namei.c
+--- linux-2.6.20.3/fs/ext3cow/namei.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/namei.c	2007-04-16 22:44:05.000000000 -0400
+@@ -0,0 +1,2960 @@
++/*
++ *  linux/fs/ext3cow/namei.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/namei.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ *  Directory entry file type support and forward compatibility hooks
++ *	for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
++ *  Hash Tree Directory indexing (c)
++ *	Daniel Phillips, 2001
++ *  Hash Tree Directory indexing porting
++ *	Christopher Li, 2002
++ *  Hash Tree Directory indexing cleanup
++ *	Theodore Ts'o, 2002
++ */
++
++#include <linux/fs.h>
++#include <linux/pagemap.h>
++#include <linux/jbd.h>
++#include <linux/time.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/fcntl.h>
++#include <linux/stat.h>
++#include <linux/string.h>
++#include <linux/quotaops.h>
++#include <linux/buffer_head.h>
++#include <linux/bio.h>
++#include <linux/smp_lock.h>
++
++#include "namei.h"
++#include "xattr.h"
++#include "acl.h"
++
++/*
++ * define how far ahead to read directories while searching them.
++ */
++#define NAMEI_RA_CHUNKS  2
++#define NAMEI_RA_BLOCKS  4
++#define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
++#define NAMEI_RA_INDEX(c,b)  (((c) * NAMEI_RA_BLOCKS) + (b))
++
++/* is the inode marked unchangeable or does the name
++   contain an epoch less than the current system epoch -znjp */
++int is_unchangeable(struct inode *inode, struct dentry *dentry){
++  
++  char *at = NULL;
++
++  if (inode && (EXT3COW_IS_UNCHANGEABLE(inode) || IS_IMMUTABLE(inode)))
++    return 1;
++  if(dentry)
++    at = strrchr(dentry->d_name.name, EXT3COW_FLUX_TOKEN);
++  if(at && (simple_strtol(&at[1], (char **)NULL, 10) > 0))
++    return 1;
++
++  return 0;
++}
++
++static struct buffer_head *ext3cow_append(handle_t *handle,
++					struct inode *inode,
++					u32 *block, int *err)
++{
++	struct buffer_head *bh;
++
++	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;
++
++	if ((bh = ext3cow_bread(handle, inode, *block, 1, err))) {
++		inode->i_size += inode->i_sb->s_blocksize;
++		EXT3COW_I(inode)->i_disksize = inode->i_size;
++		ext3cow_journal_get_write_access(handle,bh);
++	}
++	return bh;
++}
++
++#ifndef assert
++#define assert(test) J_ASSERT(test)
++#endif
++
++#ifndef swap
++#define swap(x, y) do { typeof(x) z = x; x = y; y = z; } while (0)
++#endif
++
++#ifdef DX_DEBUG
++#define dxtrace(command) command
++#else
++#define dxtrace(command)
++#endif
++
++struct fake_dirent
++{
++	__le32 inode;
++	__le16 rec_len;
++	u8 name_len;
++	u8 file_type;
++};
++
++struct dx_countlimit
++{
++	__le16 limit;
++	__le16 count;
++};
++
++struct dx_entry
++{
++	__le32 hash;
++	__le32 block;
++};
++
++/*
++ * dx_root_info is laid out so that if it should somehow get overlaid by a
++ * dirent the two low bits of the hash version will be zero.  Therefore, the
++ * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
++ */
++
++struct dx_root
++{
++	struct fake_dirent dot;
++	char dot_name[4];
++	struct fake_dirent dotdot;
++	char dotdot_name[4];
++	struct dx_root_info
++	{
++		__le32 reserved_zero;
++		u8 hash_version;
++		u8 info_length; /* 8 */
++		u8 indirect_levels;
++		u8 unused_flags;
++	}
++	info;
++	struct dx_entry	entries[0];
++};
++
++struct dx_node
++{
++	struct fake_dirent fake;
++	struct dx_entry	entries[0];
++};
++
++
++struct dx_frame
++{
++	struct buffer_head *bh;
++	struct dx_entry *entries;
++	struct dx_entry *at;
++};
++
++struct dx_map_entry
++{
++	u32 hash;
++	u32 offs;
++};
++
++#ifdef CONFIG_EXT3COW_INDEX
++static inline unsigned dx_get_block (struct dx_entry *entry);
++static void dx_set_block (struct dx_entry *entry, unsigned value);
++static inline unsigned dx_get_hash (struct dx_entry *entry);
++static void dx_set_hash (struct dx_entry *entry, unsigned value);
++static unsigned dx_get_count (struct dx_entry *entries);
++static unsigned dx_get_limit (struct dx_entry *entries);
++static void dx_set_count (struct dx_entry *entries, unsigned value);
++static void dx_set_limit (struct dx_entry *entries, unsigned value);
++static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
++static unsigned dx_node_limit (struct inode *dir);
++static struct dx_frame *dx_probe(struct dentry *dentry,
++				 struct inode *dir,
++				 struct dx_hash_info *hinfo,
++				 struct dx_frame *frame,
++				 int *err);
++static void dx_release (struct dx_frame *frames);
++static int dx_make_map (struct ext3cow_dir_entry_2 *de, int size,
++			struct dx_hash_info *hinfo, struct dx_map_entry map[]);
++static void dx_sort_map(struct dx_map_entry *map, unsigned count);
++static struct ext3cow_dir_entry_2 *dx_move_dirents (char *from, char *to,
++		struct dx_map_entry *offsets, int count);
++static struct ext3cow_dir_entry_2* dx_pack_dirents (char *base, int size);
++static void dx_insert_block (struct dx_frame *frame, u32 hash, u32 block);
++static int ext3cow_htree_next_block(struct inode *dir, __u32 hash,
++				 struct dx_frame *frame,
++				 struct dx_frame *frames,
++				 __u32 *start_hash);
++static struct buffer_head * ext3cow_dx_find_entry(struct dentry *dentry,
++		       struct ext3cow_dir_entry_2 **res_dir, int *err);
++static int ext3cow_dx_add_entry(handle_t *handle, struct dentry *dentry,
++			     struct inode *inode);
++
++/*
++ * Future: use high four bits of block for coalesce-on-delete flags
++ * Mask them off for now.
++ */
++
++static inline unsigned dx_get_block (struct dx_entry *entry)
++{
++	return le32_to_cpu(entry->block) & 0x00ffffff;
++}
++
++static inline void dx_set_block (struct dx_entry *entry, unsigned value)
++{
++	entry->block = cpu_to_le32(value);
++}
++
++static inline unsigned dx_get_hash (struct dx_entry *entry)
++{
++	return le32_to_cpu(entry->hash);
++}
++
++static inline void dx_set_hash (struct dx_entry *entry, unsigned value)
++{
++	entry->hash = cpu_to_le32(value);
++}
++
++static inline unsigned dx_get_count (struct dx_entry *entries)
++{
++	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
++}
++
++static inline unsigned dx_get_limit (struct dx_entry *entries)
++{
++	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
++}
++
++static inline void dx_set_count (struct dx_entry *entries, unsigned value)
++{
++	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
++}
++
++static inline void dx_set_limit (struct dx_entry *entries, unsigned value)
++{
++	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
++}
++
++static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
++{
++	unsigned entry_space = dir->i_sb->s_blocksize - EXT3COW_DIR_REC_LEN(1) -
++		EXT3COW_DIR_REC_LEN(2) - infosize;
++	return 0? 20: entry_space / sizeof(struct dx_entry);
++}
++
++static inline unsigned dx_node_limit (struct inode *dir)
++{
++	unsigned entry_space = dir->i_sb->s_blocksize - EXT3COW_DIR_REC_LEN(0);
++	return 0? 22: entry_space / sizeof(struct dx_entry);
++}
++
++/*
++ * Debug
++ */
++#ifdef DX_DEBUG
++static void dx_show_index (char * label, struct dx_entry *entries)
++{
++        int i, n = dx_get_count (entries);
++        printk("%s index ", label);
++        for (i = 0; i < n; i++)
++        {
++                printk("%x->%u ", i? dx_get_hash(entries + i): 0, dx_get_block(entries + i));
++        }
++        printk("\n");
++}
++
++struct stats
++{
++	unsigned names;
++	unsigned space;
++	unsigned bcount;
++};
++
++static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext3cow_dir_entry_2 *de,
++				 int size, int show_names)
++{
++	unsigned names = 0, space = 0;
++	char *base = (char *) de;
++	struct dx_hash_info h = *hinfo;
++
++	printk("names: ");
++	while ((char *) de < base + size)
++	{
++		if (de->inode)
++		{
++			if (show_names)
++			{
++				int len = de->name_len;
++				char *name = de->name;
++				while (len--) printk("%c", *name++);
++				ext3cowfs_dirhash(de->name, de->name_len, &h);
++				printk(":%x.%u ", h.hash,
++				       ((char *) de - base));
++			}
++			space += EXT3COW_DIR_REC_LEN(de->name_len);
++			names++;
++		}
++		de = (struct ext3cow_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
++	}
++	printk("(%i)\n", names);
++	return (struct stats) { names, space, 1 };
++}
++
++struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
++			     struct dx_entry *entries, int levels)
++{
++	unsigned blocksize = dir->i_sb->s_blocksize;
++	unsigned count = dx_get_count (entries), names = 0, space = 0, i;
++	unsigned bcount = 0;
++	struct buffer_head *bh;
++	int err;
++	printk("%i indexed blocks...\n", count);
++	for (i = 0; i < count; i++, entries++)
++	{
++		u32 block = dx_get_block(entries), hash = i? dx_get_hash(entries): 0;
++		u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
++		struct stats stats;
++		printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
++		if (!(bh = ext3cow_bread (NULL,dir, block, 0,&err))) continue;
++		stats = levels?
++		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
++		   dx_show_leaf(hinfo, (struct ext3cow_dir_entry_2 *) bh->b_data, blocksize, 0);
++		names += stats.names;
++		space += stats.space;
++		bcount += stats.bcount;
++		brelse (bh);
++	}
++	if (bcount)
++		printk("%snames %u, fullness %u (%u%%)\n", levels?"":"   ",
++			names, space/bcount,(space/bcount)*100/blocksize);
++	return (struct stats) { names, space, bcount};
++}
++#endif /* DX_DEBUG */
++
++/*
++ * Probe for a directory leaf block to search.
++ *
++ * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
++ * error in the directory index, and the caller should fall back to
++ * searching the directory normally.  The callers of dx_probe **MUST**
++ * check for this error code, and make sure it never gets reflected
++ * back to userspace.
++ */
++static struct dx_frame *
++dx_probe(struct dentry *dentry, struct inode *dir,
++	 struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
++{
++	unsigned count, indirect;
++	struct dx_entry *at, *entries, *p, *q, *m;
++	struct dx_root *root;
++	struct buffer_head *bh;
++	struct dx_frame *frame = frame_in;
++	u32 hash;
++
++	frame->bh = NULL;
++	if (dentry)
++		dir = dentry->d_parent->d_inode;
++	if (!(bh = ext3cow_bread (NULL,dir, 0, 0, err)))
++		goto fail;
++	root = (struct dx_root *) bh->b_data;
++	if (root->info.hash_version != DX_HASH_TEA &&
++	    root->info.hash_version != DX_HASH_HALF_MD4 &&
++	    root->info.hash_version != DX_HASH_LEGACY) {
++		ext3cow_warning(dir->i_sb, __FUNCTION__,
++			     "Unrecognised inode hash code %d",
++			     root->info.hash_version);
++		brelse(bh);
++		*err = ERR_BAD_DX_DIR;
++		goto fail;
++	}
++	hinfo->hash_version = root->info.hash_version;
++	hinfo->seed = EXT3COW_SB(dir->i_sb)->s_hash_seed;
++	if (dentry)
++		ext3cowfs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo);
++	hash = hinfo->hash;
++
++	if (root->info.unused_flags & 1) {
++		ext3cow_warning(dir->i_sb, __FUNCTION__,
++			     "Unimplemented inode hash flags: %#06x",
++			     root->info.unused_flags);
++		brelse(bh);
++		*err = ERR_BAD_DX_DIR;
++		goto fail;
++	}
++
++	if ((indirect = root->info.indirect_levels) > 1) {
++		ext3cow_warning(dir->i_sb, __FUNCTION__,
++			     "Unimplemented inode hash depth: %#06x",
++			     root->info.indirect_levels);
++		brelse(bh);
++		*err = ERR_BAD_DX_DIR;
++		goto fail;
++	}
++
++	entries = (struct dx_entry *) (((char *)&root->info) +
++				       root->info.info_length);
++	assert(dx_get_limit(entries) == dx_root_limit(dir,
++						      root->info.info_length));
++	dxtrace (printk("Look up %x", hash));
++	while (1)
++	{
++		count = dx_get_count(entries);
++		assert (count && count <= dx_get_limit(entries));
++		p = entries + 1;
++		q = entries + count - 1;
++		while (p <= q)
++		{
++			m = p + (q - p)/2;
++			dxtrace(printk("."));
++			if (dx_get_hash(m) > hash)
++				q = m - 1;
++			else
++				p = m + 1;
++		}
++
++		if (0) // linear search cross check
++		{
++			unsigned n = count - 1;
++			at = entries;
++			while (n--)
++			{
++				dxtrace(printk(","));
++				if (dx_get_hash(++at) > hash)
++				{
++					at--;
++					break;
++				}
++			}
++			assert (at == p - 1);
++		}
++
++		at = p - 1;
++		dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
++		frame->bh = bh;
++		frame->entries = entries;
++		frame->at = at;
++		if (!indirect--) return frame;
++		if (!(bh = ext3cow_bread (NULL,dir, dx_get_block(at), 0, err)))
++			goto fail2;
++		at = entries = ((struct dx_node *) bh->b_data)->entries;
++		assert (dx_get_limit(entries) == dx_node_limit (dir));
++		frame++;
++	}
++fail2:
++	while (frame >= frame_in) {
++		brelse(frame->bh);
++		frame--;
++	}
++fail:
++	return NULL;
++}
++
++static void dx_release (struct dx_frame *frames)
++{
++	if (frames[0].bh == NULL)
++		return;
++
++	if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
++		brelse(frames[1].bh);
++	brelse(frames[0].bh);
++}
++
++/*
++ * This function increments the frame pointer to search the next leaf
++ * block, and reads in the necessary intervening nodes if the search
++ * should be necessary.  Whether or not the search is necessary is
++ * controlled by the hash parameter.  If the hash value is even, then
++ * the search is only continued if the next block starts with that
++ * hash value.  This is used if we are searching for a specific file.
++ *
++ * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
++ *
++ * This function returns 1 if the caller should continue to search,
++ * or 0 if it should not.  If there is an error reading one of the
++ * index blocks, it will a negative error code.
++ *
++ * If start_hash is non-null, it will be filled in with the starting
++ * hash of the next page.
++ */
++static int ext3cow_htree_next_block(struct inode *dir, __u32 hash,
++				 struct dx_frame *frame,
++				 struct dx_frame *frames,
++				 __u32 *start_hash)
++{
++	struct dx_frame *p;
++	struct buffer_head *bh;
++	int err, num_frames = 0;
++	__u32 bhash;
++
++	p = frame;
++	/*
++	 * Find the next leaf page by incrementing the frame pointer.
++	 * If we run out of entries in the interior node, loop around and
++	 * increment pointer in the parent node.  When we break out of
++	 * this loop, num_frames indicates the number of interior
++	 * nodes need to be read.
++	 */
++	while (1) {
++		if (++(p->at) < p->entries + dx_get_count(p->entries))
++			break;
++		if (p == frames)
++			return 0;
++		num_frames++;
++		p--;
++	}
++
++	/*
++	 * If the hash is 1, then continue only if the next page has a
++	 * continuation hash of any value.  This is used for readdir
++	 * handling.  Otherwise, check to see if the hash matches the
++	 * desired contiuation hash.  If it doesn't, return since
++	 * there's no point to read in the successive index pages.
++	 */
++	bhash = dx_get_hash(p->at);
++	if (start_hash)
++		*start_hash = bhash;
++	if ((hash & 1) == 0) {
++		if ((bhash & ~1) != hash)
++			return 0;
++	}
++	/*
++	 * If the hash is HASH_NB_ALWAYS, we always go to the next
++	 * block so no check is necessary
++	 */
++	while (num_frames--) {
++		if (!(bh = ext3cow_bread(NULL, dir, dx_get_block(p->at),
++				      0, &err)))
++			return err; /* Failure */
++		p++;
++		brelse (p->bh);
++		p->bh = bh;
++		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
++	}
++	return 1;
++}
++
++
++/*
++ * p is at least 6 bytes before the end of page
++ */
++static inline struct ext3cow_dir_entry_2 *ext3cow_next_entry(struct ext3cow_dir_entry_2 *p)
++{
++	return (struct ext3cow_dir_entry_2 *)((char*)p + le16_to_cpu(p->rec_len));
++}
++
++/*
++ * This function fills a red-black tree with information from a
++ * directory block.  It returns the number directory entries loaded
++ * into the tree.  If there is an error it is returned in err.
++ */
++static int htree_dirblock_to_tree(struct file *dir_file,
++				  struct inode *dir, int block,
++				  struct dx_hash_info *hinfo,
++				  __u32 start_hash, __u32 start_minor_hash)
++{
++	struct buffer_head *bh;
++	struct ext3cow_dir_entry_2 *de, *top;
++	int err, count = 0;
++
++	dxtrace(printk("In htree dirblock_to_tree: block %d\n", block));
++	if (!(bh = ext3cow_bread (NULL, dir, block, 0, &err)))
++		return err;
++
++	de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++	top = (struct ext3cow_dir_entry_2 *) ((char *) de +
++					   dir->i_sb->s_blocksize -
++					   EXT3COW_DIR_REC_LEN(0));
++	for (; de < top; de = ext3cow_next_entry(de)) {
++		if (!ext3cow_check_dir_entry("htree_dirblock_to_tree", dir, de, bh,
++					(block<<EXT3COW_BLOCK_SIZE_BITS(dir->i_sb))
++						+((char *)de - bh->b_data))) {
++			/* On error, skip the f_pos to the next block. */
++			dir_file->f_pos = (dir_file->f_pos |
++					(dir->i_sb->s_blocksize - 1)) + 1;
++			brelse (bh);
++			return count;
++		}
++		ext3cowfs_dirhash(de->name, de->name_len, hinfo);
++		if ((hinfo->hash < start_hash) ||
++		    ((hinfo->hash == start_hash) &&
++		     (hinfo->minor_hash < start_minor_hash)))
++			continue;
++		if (de->inode == 0)
++			continue;
++		if ((err = ext3cow_htree_store_dirent(dir_file,
++				   hinfo->hash, hinfo->minor_hash, de)) != 0) {
++			brelse(bh);
++			return err;
++		}
++		count++;
++	}
++	brelse(bh);
++	return count;
++}
++
++
++/*
++ * This function fills a red-black tree with information from a
++ * directory.  We start scanning the directory in hash order, starting
++ * at start_hash and start_minor_hash.
++ *
++ * This function returns the number of entries inserted into the tree,
++ * or a negative error code.
++ */
++int ext3cow_htree_fill_tree(struct file *dir_file, __u32 start_hash,
++			 __u32 start_minor_hash, __u32 *next_hash)
++{
++	struct dx_hash_info hinfo;
++	struct ext3cow_dir_entry_2 *de;
++	struct dx_frame frames[2], *frame;
++	struct inode *dir;
++	int block, err;
++	int count = 0;
++	int ret;
++	__u32 hashval;
++
++	dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash,
++		       start_minor_hash));
++	dir = dir_file->f_path.dentry->d_inode;
++	if (!(EXT3COW_I(dir)->i_flags & EXT3COW_INDEX_FL)) {
++		hinfo.hash_version = EXT3COW_SB(dir->i_sb)->s_def_hash_version;
++		hinfo.seed = EXT3COW_SB(dir->i_sb)->s_hash_seed;
++		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
++					       start_hash, start_minor_hash);
++		*next_hash = ~0;
++		return count;
++	}
++	hinfo.hash = start_hash;
++	hinfo.minor_hash = 0;
++	frame = dx_probe(NULL, dir_file->f_path.dentry->d_inode, &hinfo, frames, &err);
++	if (!frame)
++		return err;
++
++	/* Add '.' and '..' from the htree header */
++	if (!start_hash && !start_minor_hash) {
++		de = (struct ext3cow_dir_entry_2 *) frames[0].bh->b_data;
++		if ((err = ext3cow_htree_store_dirent(dir_file, 0, 0, de)) != 0)
++			goto errout;
++		count++;
++	}
++	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
++		de = (struct ext3cow_dir_entry_2 *) frames[0].bh->b_data;
++		de = ext3cow_next_entry(de);
++		if ((err = ext3cow_htree_store_dirent(dir_file, 2, 0, de)) != 0)
++			goto errout;
++		count++;
++	}
++
++	while (1) {
++		block = dx_get_block(frame->at);
++		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
++					     start_hash, start_minor_hash);
++		if (ret < 0) {
++			err = ret;
++			goto errout;
++		}
++		count += ret;
++		hashval = ~0;
++		ret = ext3cow_htree_next_block(dir, HASH_NB_ALWAYS,
++					    frame, frames, &hashval);
++		*next_hash = hashval;
++		if (ret < 0) {
++			err = ret;
++			goto errout;
++		}
++		/*
++		 * Stop if:  (a) there are no more entries, or
++		 * (b) we have inserted at least one entry and the
++		 * next hash value is not a continuation
++		 */
++		if ((ret == 0) ||
++		    (count && ((hashval & 1) == 0)))
++			break;
++	}
++	dx_release(frames);
++	dxtrace(printk("Fill tree: returned %d entries, next hash: %x\n",
++		       count, *next_hash));
++	return count;
++errout:
++	dx_release(frames);
++	return (err);
++}
++
++
++/*
++ * Directory block splitting, compacting
++ */
++
++static int dx_make_map (struct ext3cow_dir_entry_2 *de, int size,
++			struct dx_hash_info *hinfo, struct dx_map_entry *map_tail)
++{
++	int count = 0;
++	char *base = (char *) de;
++	struct dx_hash_info h = *hinfo;
++
++	while ((char *) de < base + size)
++	{
++		if (de->name_len && de->inode) {
++			ext3cowfs_dirhash(de->name, de->name_len, &h);
++			map_tail--;
++			map_tail->hash = h.hash;
++			map_tail->offs = (u32) ((char *) de - base);
++			count++;
++			cond_resched();
++		}
++		/* XXX: do we need to check rec_len == 0 case? -Chris */
++		de = (struct ext3cow_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
++	}
++	return count;
++}
++
++static void dx_sort_map (struct dx_map_entry *map, unsigned count)
++{
++        struct dx_map_entry *p, *q, *top = map + count - 1;
++        int more;
++        /* Combsort until bubble sort doesn't suck */
++        while (count > 2)
++	{
++                count = count*10/13;
++                if (count - 9 < 2) /* 9, 10 -> 11 */
++                        count = 11;
++                for (p = top, q = p - count; q >= map; p--, q--)
++                        if (p->hash < q->hash)
++                                swap(*p, *q);
++        }
++        /* Garden variety bubble sort */
++        do {
++                more = 0;
++                q = top;
++                while (q-- > map)
++		{
++                        if (q[1].hash >= q[0].hash)
++				continue;
++                        swap(*(q+1), *q);
++                        more = 1;
++		}
++	} while(more);
++}
++
++static void dx_insert_block(struct dx_frame *frame, u32 hash, u32 block)
++{
++	struct dx_entry *entries = frame->entries;
++	struct dx_entry *old = frame->at, *new = old + 1;
++	int count = dx_get_count(entries);
++
++	assert(count < dx_get_limit(entries));
++	assert(old < entries + count);
++	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
++	dx_set_hash(new, hash);
++	dx_set_block(new, block);
++	dx_set_count(entries, count + 1);
++}
++#endif
++
++
++static void ext3cow_update_dx_flag(struct inode *inode)
++{
++	if (!EXT3COW_HAS_COMPAT_FEATURE(inode->i_sb,
++				     EXT3COW_FEATURE_COMPAT_DIR_INDEX))
++		EXT3COW_I(inode)->i_flags &= ~EXT3COW_INDEX_FL;
++}
++
++/*
++ * NOTE! unlike strncmp, ext3cow_match returns 1 for success, 0 for failure.
++ *
++ * `len <= EXT3COW_NAME_LEN' is guaranteed by caller.
++ * `de != NULL' is guaranteed by caller.
++ */
++static inline int ext3cow_match (int len, const char * const name,
++			      struct ext3cow_dir_entry_2 * de)
++{
++	if (len != de->name_len)
++		return 0;
++	if (!de->inode)
++		return 0;
++	return !memcmp(name, de->name, len);
++}
++
++/*
++ * Returns 0 if not found, -1 on failure, and 1 on success
++ */
++/* For versioning - this is the function used when looking for
++ * names.  We now handle names which include the flux token,
++ * strip it off and continue looking -znjp */
++static inline int search_dirblock(struct buffer_head * bh,
++				  struct inode *dir,
++				  struct dentry *dentry,
++				  unsigned long offset,
++				  struct ext3cow_dir_entry_2 ** res_dir)
++{
++	struct ext3cow_dir_entry_2 * de;
++	char * dlimit, * flux = NULL;
++	int de_len;
++	char name[EXT3COW_NAME_LEN];
++	int namelen = dentry->d_name.len;
++  unsigned int epoch_number = EXT3COW_I_EPOCHNUMBER(dir);
++
++  /* Get the name for the dentry */
++  memcpy(name, dentry->d_name.name, namelen);
++  name[namelen] = '\0';
++
++  /* Check to see if the flux token is in the name */
++  flux = strrchr(dentry->d_name.name, EXT3COW_FLUX_TOKEN);
++  if(NULL != flux){
++    /* If we're here, the name we want is in the past. */
++    int new_namelen = strlen(dentry->d_name.name) - strlen(flux);
++    /* Get the epoch number */
++    epoch_number = simple_strtol(&flux[1], (char **)NULL, 10) - 1;
++    /* If there's a valid epoch number or if we're version listing
++     * we need the name seperately, otherwise the FLUX_TOKEN exists
++     * in the file name */
++    if(epoch_number + 1 == 0 && (strlen(flux) > 1)){ 
++      /* EXT3COW_FLUX_TOKEN exists in the file name */
++      epoch_number = EXT3COW_S_EPOCHNUMBER(dir->i_sb);
++    }else{
++      /* Grab the correct name and length */
++      memcpy(name, dentry->d_name.name, new_namelen);
++      name[new_namelen] = '\0';
++      namelen = strlen(name);
++    }
++  }
++
++
++	de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++	dlimit = bh->b_data + dir->i_sb->s_blocksize;
++	while ((char *) de < dlimit) {
++		/* this code is executed quadratically often */
++		/* do minimal checking `by hand' */
++
++    /* Can't just return first entry of something;
++     * may exist twice if died and same name appears again. - znjp
++     */
++		if ((char *) de + namelen <= dlimit &&
++		    ext3cow_match (namelen, name, de) && 
++        EXT3COW_IS_DIRENT_SCOPED(de, epoch_number)) {
++			/* found a match - just to be sure, do a full check */
++			if (!ext3cow_check_dir_entry("ext3cow_find_entry",
++						  dir, de, bh, offset))
++				return -1;
++			*res_dir = de;
++			return 1;
++		}
++		/* prevent looping on a bad block */
++		de_len = le16_to_cpu(de->rec_len);
++		if (de_len <= 0)
++			return -1;
++		offset += de_len;
++		de = (struct ext3cow_dir_entry_2 *) ((char *) de + de_len);
++	}
++	return 0;
++}
++
++
++/*
++ *	ext3cow_find_entry()
++ *
++ * finds an entry in the specified directory with the wanted name. It
++ * returns the cache buffer in which the entry was found, and the entry
++ * itself (as a parameter - res_dir). It does NOT read the inode of the
++ * entry - you'll have to do that yourself if you want to.
++ *
++ * The returned buffer_head has ->b_count elevated.  The caller is expected
++ * to brelse() it when appropriate.
++ */
++static struct buffer_head * ext3cow_find_entry (struct dentry *dentry,
++					struct ext3cow_dir_entry_2 ** res_dir)
++{
++	struct super_block * sb;
++	struct buffer_head * bh_use[NAMEI_RA_SIZE];
++	struct buffer_head * bh, *ret = NULL;
++	unsigned long start, block, b;
++	int ra_max = 0;		/* Number of bh's in the readahead
++				   buffer, bh_use[] */
++	int ra_ptr = 0;		/* Current index into readahead
++				   buffer */
++	int num = 0;
++	int nblocks, i, err;
++	struct inode *dir = dentry->d_parent->d_inode;
++	int namelen;
++	const u8 *name;
++	unsigned blocksize;
++
++	*res_dir = NULL;
++	sb = dir->i_sb;
++	blocksize = sb->s_blocksize;
++	namelen = dentry->d_name.len;
++	name = dentry->d_name.name;
++	if (namelen > EXT3COW_NAME_LEN)
++		return NULL;
++#ifdef CONFIG_EXT3COW_INDEX
++	if (is_dx(dir)) {
++		bh = ext3cow_dx_find_entry(dentry, res_dir, &err);
++		/*
++		 * On success, or if the error was file not found,
++		 * return.  Otherwise, fall back to doing a search the
++		 * old fashioned way.
++		 */
++		if (bh || (err != ERR_BAD_DX_DIR))
++			return bh;
++		dxtrace(printk("ext3cow_find_entry: dx failed, falling back\n"));
++	}
++#endif
++	nblocks = dir->i_size >> EXT3COW_BLOCK_SIZE_BITS(sb);
++	start = EXT3COW_I(dir)->i_dir_start_lookup;
++	if (start >= nblocks)
++		start = 0;
++	block = start;
++restart:
++	do {
++		/*
++		 * We deal with the read-ahead logic here.
++		 */
++		if (ra_ptr >= ra_max) {
++			/* Refill the readahead buffer */
++			ra_ptr = 0;
++			b = block;
++			for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
++				/*
++				 * Terminate if we reach the end of the
++				 * directory and must wrap, or if our
++				 * search has finished at this block.
++				 */
++				if (b >= nblocks || (num && block == start)) {
++					bh_use[ra_max] = NULL;
++					break;
++				}
++				num++;
++				bh = ext3cow_getblk(NULL, dir, b++, 0, &err);
++				bh_use[ra_max] = bh;
++				if (bh)
++					ll_rw_block(READ_META, 1, &bh);
++			}
++		}
++		if ((bh = bh_use[ra_ptr++]) == NULL)
++			goto next;
++		wait_on_buffer(bh);
++		if (!buffer_uptodate(bh)) {
++			/* read error, skip block & hope for the best */
++			ext3cow_error(sb, __FUNCTION__, "reading directory #%lu "
++				   "offset %lu", dir->i_ino, block);
++			brelse(bh);
++			goto next;
++		}
++		i = search_dirblock(bh, dir, dentry,
++			    block << EXT3COW_BLOCK_SIZE_BITS(sb), res_dir);
++		if (i == 1) {
++			EXT3COW_I(dir)->i_dir_start_lookup = block;
++			ret = bh;
++			goto cleanup_and_exit;
++		} else {
++			brelse(bh);
++			if (i < 0)
++				goto cleanup_and_exit;
++		}
++	next:
++		if (++block >= nblocks)
++			block = 0;
++	} while (block != start);
++
++	/*
++	 * If the directory has grown while we were searching, then
++	 * search the last part of the directory before giving up.
++	 */
++	block = nblocks;
++	nblocks = dir->i_size >> EXT3COW_BLOCK_SIZE_BITS(sb);
++	if (block < nblocks) {
++		start = 0;
++		goto restart;
++	}
++
++cleanup_and_exit:
++	/* Clean up the read-ahead blocks */
++	for (; ra_ptr < ra_max; ra_ptr++)
++		brelse (bh_use[ra_ptr]);
++	return ret;
++}
++
++#ifdef CONFIG_EXT3COW_INDEX
++static struct buffer_head * ext3cow_dx_find_entry(struct dentry *dentry,
++		       struct ext3cow_dir_entry_2 **res_dir, int *err)
++{
++	struct super_block * sb;
++	struct dx_hash_info	hinfo;
++	u32 hash;
++	struct dx_frame frames[2], *frame;
++	struct ext3cow_dir_entry_2 *de, *top;
++	struct buffer_head *bh;
++	unsigned long block;
++	int retval;
++	int namelen = dentry->d_name.len;
++	const u8 *name = dentry->d_name.name;
++	struct inode *dir = dentry->d_parent->d_inode;
++
++	sb = dir->i_sb;
++	/* NFS may look up ".." - look at dx_root directory block */
++	if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
++		if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err)))
++			return NULL;
++	} else {
++		frame = frames;
++		frame->bh = NULL;			/* for dx_release() */
++		frame->at = (struct dx_entry *)frames;	/* hack for zero entry*/
++		dx_set_block(frame->at, 0);		/* dx_root block is 0 */
++	}
++	hash = hinfo.hash;
++	do {
++		block = dx_get_block(frame->at);
++		if (!(bh = ext3cow_bread (NULL,dir, block, 0, err)))
++			goto errout;
++		de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++		top = (struct ext3cow_dir_entry_2 *) ((char *) de + sb->s_blocksize -
++				       EXT3COW_DIR_REC_LEN(0));
++		for (; de < top; de = ext3cow_next_entry(de))
++		if (ext3cow_match (namelen, name, de)) {
++			if (!ext3cow_check_dir_entry("ext3cow_find_entry",
++						  dir, de, bh,
++				  (block<<EXT3COW_BLOCK_SIZE_BITS(sb))
++					  +((char *)de - bh->b_data))) {
++				brelse (bh);
++				goto errout;
++			}
++			*res_dir = de;
++			dx_release (frames);
++			return bh;
++		}
++		brelse (bh);
++		/* Check to see if we should continue to search */
++		retval = ext3cow_htree_next_block(dir, hash, frame,
++					       frames, NULL);
++		if (retval < 0) {
++			ext3cow_warning(sb, __FUNCTION__,
++			     "error reading index page in directory #%lu",
++			     dir->i_ino);
++			*err = retval;
++			goto errout;
++		}
++	} while (retval == 1);
++
++	*err = -ENOENT;
++errout:
++	dxtrace(printk("%s not found\n", name));
++	dx_release (frames);
++	return NULL;
++}
++#endif
++
++/* ext3cow_lookup: One the key functions of this versioning file sytem,
++ * allowing people to return to the past.
++ *
++ * Two policies for inode chains:
++ * 1) If it's the head of the list, it's the most current inode
++ *    and always changable.  The inode number is static.
++ * 2) If it's any inode in the chain that's not the head,
++ *    than it's an inode in the past and unchangeable.  The inode
++ *    number may change.
++ */
++static struct dentry *ext3cow_lookup(struct inode * dir, struct dentry *dentry,
++                                     struct nameidata *nd)
++{
++	struct inode * inode = NULL;
++	struct ext3cow_dir_entry_2 * de = NULL;
++	struct buffer_head * bh = NULL;
++  unsigned int epoch_number = 0;
++  char * flux = NULL;
++  
++	if (dentry->d_name.len > EXT3COW_NAME_LEN)
++		return ERR_PTR(-ENAMETOOLONG);
++
++  /* Find the epoch number to scope with -znjp 
++   * if the parent is unchangeable, so is the inode 
++   */
++  if(EXT3COW_IS_UNCHANGEABLE(dir))     
++    epoch_number = EXT3COW_I_EPOCHNUMBER(dir);
++  else
++    epoch_number = EXT3COW_S_EPOCHNUMBER(dir->i_sb);
++
++	bh = ext3cow_find_entry(dentry, &de);
++	if (bh) {
++		unsigned long ino = le32_to_cpu(de->inode);
++		brelse (bh);
++		if (!ext3cow_valid_inum(dir->i_sb, ino)) {
++			ext3cow_error(dir->i_sb, "ext3cow_lookup",
++				   "bad inode number: %lu", ino);
++			inode = NULL;
++		} else
++			inode = iget(dir->i_sb, ino);
++
++		if (!inode)
++			return ERR_PTR(-EACCES);
++
++    /* Is this a version listing ? */
++    if ((char)dentry->d_name.name[dentry->d_name.len - 1] == 
++        EXT3COW_FLUX_TOKEN) {
++      /* prevent going round in circles */
++      if (dentry->d_parent && 
++          dentry->d_parent->d_name.name[dentry->d_parent->d_name.len - 1] ==
++          EXT3COW_FLUX_TOKEN) {
++        return NULL;
++      }
++      /* we fake a directory using the directory inode instead of
++       * the file one and subsequently force a call to ext3cow_readdir */
++      iput(inode);
++      inode = ext3cow_fake_inode(dir, EXT3COW_S_EPOCHNUMBER(dir->i_sb));
++      EXT3COW_I(inode)->i_next_inode = EXT3COW_I(dir)->i_next_inode;
++      d_splice_alias(inode, dentry);
++      
++      return NULL;
++    }
++
++    /* Is the user time-shifting to the past? */
++    flux = strrchr(dentry->d_name.name, EXT3COW_FLUX_TOKEN);
++    if(NULL != flux){
++
++      if(strnicmp(&flux[1], "onehour", 8) == 0){
++        epoch_number = get_seconds() - ONEHOUR;
++        printk(KERN_INFO "ONEHOUR!\n");
++      }else if(strnicmp(&flux[1], "yesterday", 10) == 0 ||
++               strnicmp(&flux[1], "oneday", 7) == 0){
++        epoch_number = get_seconds() - YESTERDAY;
++      }else if(strnicmp(&flux[1], "oneweek", 8) == 0){
++        epoch_number = get_seconds() - ONEWEEK;
++      }else if(strnicmp(&flux[1], "onemonth", 9) == 0){
++        epoch_number = get_seconds() - ONEMONTH;
++      }else if(strnicmp(&flux[1], "oneyear", 8) == 0){
++        epoch_number = get_seconds() - ONEYEAR;
++      }else
++        epoch_number = simple_strtol(&flux[1], (char **)NULL, 10) - 1;
++
++      /* No future epochs */
++      if(epoch_number + 1 > EXT3COW_S_EPOCHNUMBER(dir->i_sb))                
++        return ERR_PTR(-ENOENT); 
++
++      /* Move to present 
++      if(epoch_number + 1 == 0)
++        epoch_number = EXT3COW_S_EPOCHNUMBER(dir->i_sb);       
++      */
++    }
++     
++    /* Find correct inode in chain */
++    while(EXT3COW_I_EPOCHNUMBER(inode) > epoch_number){
++
++      printk(KERN_INFO "Looking for %u with epoch %u\n", epoch_number, 
++             EXT3COW_I_EPOCHNUMBER(inode));
++
++      ino = EXT3COW_I(inode)->i_next_inode;
++      if(ino == 0){
++        ext3cow_warning(dir->i_sb, "ext3cow_lookup",
++                        "Next inode is 0 in lookup.");
++        iput(inode);
++        return ERR_PTR(-ENOENT);
++      }
++      iput(inode); /* for correct usage count (i_count) */
++      inode = iget(dir->i_sb, ino);
++      
++      if (!inode){
++        ext3cow_warning(dir->i_sb, "ext3cow_lookup",
++                        "Could not access inode number %lu",
++                        ino);
++        return ERR_PTR(-EACCES);
++      }
++    }
++
++    /* If we're in the past, fake the inode for scoping and "unchangability" */
++    if(flux || (epoch_number != EXT3COW_S_EPOCHNUMBER(dir->i_sb))){
++      printk(KERN_INFO "Faking %s\n", dentry->d_name.name);
++      inode = ext3cow_fake_inode(inode, epoch_number);
++    }
++
++    if (!inode)
++      return ERR_PTR(-EACCES);
++	}
++	return d_splice_alias(inode, dentry);
++}
++
++
++struct dentry *ext3cow_get_parent(struct dentry *child)
++{
++	unsigned long ino;
++	struct dentry *parent;
++	struct inode *inode;
++	struct dentry dotdot;
++	struct ext3cow_dir_entry_2 * de;
++	struct buffer_head *bh;
++
++	dotdot.d_name.name = "..";
++	dotdot.d_name.len = 2;
++	dotdot.d_parent = child; /* confusing, isn't it! */
++
++	bh = ext3cow_find_entry(&dotdot, &de);
++	inode = NULL;
++	if (!bh)
++		return ERR_PTR(-ENOENT);
++	ino = le32_to_cpu(de->inode);
++	brelse(bh);
++
++	if (!ext3cow_valid_inum(child->d_inode->i_sb, ino)) {
++		ext3cow_error(child->d_inode->i_sb, "ext3cow_get_parent",
++			   "bad inode number: %lu", ino);
++		inode = NULL;
++	} else
++		inode = iget(child->d_inode->i_sb, ino);
++
++	if (!inode)
++		return ERR_PTR(-EACCES);
++
++	parent = d_alloc_anon(inode);
++	if (!parent) {
++		iput(inode);
++		parent = ERR_PTR(-ENOMEM);
++	}
++	return parent;
++}
++
++#define S_SHIFT 12
++static unsigned char ext3cow_type_by_mode[S_IFMT >> S_SHIFT] = {
++	[S_IFREG >> S_SHIFT]	= EXT3COW_FT_REG_FILE,
++	[S_IFDIR >> S_SHIFT]	= EXT3COW_FT_DIR,
++	[S_IFCHR >> S_SHIFT]	= EXT3COW_FT_CHRDEV,
++	[S_IFBLK >> S_SHIFT]	= EXT3COW_FT_BLKDEV,
++	[S_IFIFO >> S_SHIFT]	= EXT3COW_FT_FIFO,
++	[S_IFSOCK >> S_SHIFT]	= EXT3COW_FT_SOCK,
++	[S_IFLNK >> S_SHIFT]	= EXT3COW_FT_SYMLINK,
++};
++
++static inline void ext3cow_set_de_type(struct super_block *sb,
++				struct ext3cow_dir_entry_2 *de,
++				umode_t mode) {
++	if (EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_FILETYPE))
++		de->file_type = ext3cow_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
++}
++
++#ifdef CONFIG_EXT3COW_INDEX
++static struct ext3cow_dir_entry_2 *
++dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count)
++{
++	unsigned rec_len = 0;
++
++	while (count--) {
++		struct ext3cow_dir_entry_2 *de = (struct ext3cow_dir_entry_2 *) (from + map->offs);
++		rec_len = EXT3COW_DIR_REC_LEN(de->name_len);
++		memcpy (to, de, rec_len);
++		((struct ext3cow_dir_entry_2 *) to)->rec_len =
++				cpu_to_le16(rec_len);
++		de->inode = 0;
++		map++;
++		to += rec_len;
++	}
++	return (struct ext3cow_dir_entry_2 *) (to - rec_len);
++}
++
++static struct ext3cow_dir_entry_2* dx_pack_dirents(char *base, int size)
++{
++	struct ext3cow_dir_entry_2 *next, *to, *prev, *de = (struct ext3cow_dir_entry_2 *) base;
++	unsigned rec_len = 0;
++
++	prev = to = de;
++	while ((char*)de < base + size) {
++		next = (struct ext3cow_dir_entry_2 *) ((char *) de +
++						    le16_to_cpu(de->rec_len));
++		if (de->inode && de->name_len) {
++			rec_len = EXT3COW_DIR_REC_LEN(de->name_len);
++			if (de > to)
++				memmove(to, de, rec_len);
++			to->rec_len = cpu_to_le16(rec_len);
++			prev = to;
++			to = (struct ext3cow_dir_entry_2 *) (((char *) to) + rec_len);
++		}
++		de = next;
++	}
++	return prev;
++}
++
++static struct ext3cow_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
++			struct buffer_head **bh,struct dx_frame *frame,
++			struct dx_hash_info *hinfo, int *error)
++{
++	unsigned blocksize = dir->i_sb->s_blocksize;
++	unsigned count, continued;
++	struct buffer_head *bh2;
++	u32 newblock;
++	u32 hash2;
++	struct dx_map_entry *map;
++	char *data1 = (*bh)->b_data, *data2;
++	unsigned split;
++	struct ext3cow_dir_entry_2 *de = NULL, *de2;
++	int	err;
++
++	bh2 = ext3cow_append (handle, dir, &newblock, error);
++	if (!(bh2)) {
++		brelse(*bh);
++		*bh = NULL;
++		goto errout;
++	}
++
++	BUFFER_TRACE(*bh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, *bh);
++	if (err) {
++	journal_error:
++		brelse(*bh);
++		brelse(bh2);
++		*bh = NULL;
++		ext3cow_std_error(dir->i_sb, err);
++		goto errout;
++	}
++	BUFFER_TRACE(frame->bh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, frame->bh);
++	if (err)
++		goto journal_error;
++
++	data2 = bh2->b_data;
++
++	/* create map in the end of data2 block */
++	map = (struct dx_map_entry *) (data2 + blocksize);
++	count = dx_make_map ((struct ext3cow_dir_entry_2 *) data1,
++			     blocksize, hinfo, map);
++	map -= count;
++	split = count/2; // need to adjust to actual middle
++	dx_sort_map (map, count);
++	hash2 = map[split].hash;
++	continued = hash2 == map[split - 1].hash;
++	dxtrace(printk("Split block %i at %x, %i/%i\n",
++		dx_get_block(frame->at), hash2, split, count-split));
++
++	/* Fancy dance to stay within two buffers */
++	de2 = dx_move_dirents(data1, data2, map + split, count - split);
++	de = dx_pack_dirents(data1,blocksize);
++	de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
++	de2->rec_len = cpu_to_le16(data2 + blocksize - (char *) de2);
++	dxtrace(dx_show_leaf (hinfo, (struct ext3cow_dir_entry_2 *) data1, blocksize, 1));
++	dxtrace(dx_show_leaf (hinfo, (struct ext3cow_dir_entry_2 *) data2, blocksize, 1));
++
++	/* Which block gets the new entry? */
++	if (hinfo->hash >= hash2)
++	{
++		swap(*bh, bh2);
++		de = de2;
++	}
++	dx_insert_block (frame, hash2 + continued, newblock);
++	err = ext3cow_journal_dirty_metadata (handle, bh2);
++	if (err)
++		goto journal_error;
++	err = ext3cow_journal_dirty_metadata (handle, frame->bh);
++	if (err)
++		goto journal_error;
++	brelse (bh2);
++	dxtrace(dx_show_index ("frame", frame->entries));
++errout:
++	return de;
++}
++#endif
++
++
++/*
++ * Add a new entry into a directory (leaf) block.  If de is non-NULL,
++ * it points to a directory entry which is guaranteed to be large
++ * enough for new directory entry.  If de is NULL, then
++ * add_dirent_to_buf will attempt search the directory block for
++ * space.  It will return -ENOSPC if no space is available, and -EIO
++ * and -EEXIST if directory entry already exists.
++ *
++ * NOTE!  bh is NOT released in the case where ENOSPC is returned.  In
++ * all other cases bh is released.
++ */
++static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
++			     struct inode *inode, struct ext3cow_dir_entry_2 *de,
++			     struct buffer_head * bh)
++{
++	struct inode	*dir = dentry->d_parent->d_inode;
++	const char	*name = dentry->d_name.name;
++	int		namelen = dentry->d_name.len;
++	unsigned long	offset = 0;
++	unsigned short	reclen;
++	int		nlen, rlen, err;
++	char		*top;
++
++	reclen = EXT3COW_DIR_REC_LEN(namelen);
++	if (!de) {
++		de = (struct ext3cow_dir_entry_2 *)bh->b_data;
++		top = bh->b_data + dir->i_sb->s_blocksize - reclen;
++		while ((char *) de <= top) {
++			if (!ext3cow_check_dir_entry("ext3cow_add_entry", dir, de,
++						  bh, offset)) {
++				brelse (bh);
++        ext3cow_reclaim_dup_inode(dentry->d_parent->d_parent->d_inode, dir);
++				return -EIO;
++			}
++      /* If name exists and it's still alive, no add. But if it's a new
++       * name in this scope, ok to add. -znjp */
++			if (ext3cow_match (namelen, name, de) && EXT3COW_IS_DIRENT_ALIVE(de)) {
++				brelse (bh);
++				return -EEXIST;
++			}
++			nlen = EXT3COW_DIR_REC_LEN(de->name_len);
++			rlen = le16_to_cpu(de->rec_len);
++			if ((de->inode? rlen - nlen: rlen) >= reclen)
++				break;
++			de = (struct ext3cow_dir_entry_2 *)((char *)de + rlen);
++			offset += rlen;
++		}
++		if ((char *) de > top)
++			return -ENOSPC;
++	}
++	BUFFER_TRACE(bh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, bh);
++	if (err) {
++		ext3cow_std_error(dir->i_sb, err);
++		brelse(bh);
++		return err;
++	}
++
++	/* By now the buffer is marked for journaling */
++	nlen = EXT3COW_DIR_REC_LEN(de->name_len);
++	rlen = le16_to_cpu(de->rec_len);
++	if (de->inode) {
++		struct ext3cow_dir_entry_2 *de1 = (struct ext3cow_dir_entry_2 *)((char *)de + nlen);
++		de1->rec_len = cpu_to_le16(rlen - nlen);
++		de->rec_len = cpu_to_le16(nlen);
++		de = de1;
++	}
++	de->file_type = EXT3COW_FT_UNKNOWN;
++	if (inode) {
++		de->inode = cpu_to_le32(inode->i_ino);
++		ext3cow_set_de_type(dir->i_sb, de, inode->i_mode);
++	} else
++		de->inode = 0;
++  /* For versioning -znjp */
++  de->birth_epoch = cpu_to_le32(EXT3COW_S_EPOCHNUMBER(dir->i_sb));
++  de->death_epoch = cpu_to_le32(EXT3COW_DIRENT_ALIVE);
++	de->name_len = namelen;
++	memcpy (de->name, name, namelen);
++	/*
++	 * XXX shouldn't update any times until successful
++	 * completion of syscall, but too many callers depend
++	 * on this.
++	 *
++	 * XXX similarly, too many callers depend on
++	 * ext3cow_new_inode() setting the times, but error
++	 * recovery deletes the inode, so the worst that can
++	 * happen is that the times are slightly out of date
++	 * and/or different from the directory change time.
++	 */
++	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
++	ext3cow_update_dx_flag(dir);
++	dir->i_version++;
++	ext3cow_mark_inode_dirty(handle, dir);
++	BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++	err = ext3cow_journal_dirty_metadata(handle, bh);
++	if (err)
++		ext3cow_std_error(dir->i_sb, err);
++	brelse(bh);
++	return 0;
++}
++
++#ifdef CONFIG_EXT3COW_INDEX
++/*
++ * This converts a one block unindexed directory to a 3 block indexed
++ * directory, and adds the dentry to the indexed directory.
++ */
++static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
++			    struct inode *inode, struct buffer_head *bh)
++{
++	struct inode	*dir = dentry->d_parent->d_inode;
++	const char	*name = dentry->d_name.name;
++	int		namelen = dentry->d_name.len;
++	struct buffer_head *bh2;
++	struct dx_root	*root;
++	struct dx_frame	frames[2], *frame;
++	struct dx_entry *entries;
++	struct ext3cow_dir_entry_2	*de, *de2;
++	char		*data1, *top;
++	unsigned	len;
++	int		retval;
++	unsigned	blocksize;
++	struct dx_hash_info hinfo;
++	u32		block;
++	struct fake_dirent *fde;
++
++	blocksize =  dir->i_sb->s_blocksize;
++	dxtrace(printk("Creating index\n"));
++	retval = ext3cow_journal_get_write_access(handle, bh);
++	if (retval) {
++		ext3cow_std_error(dir->i_sb, retval);
++		brelse(bh);
++		return retval;
++	}
++	root = (struct dx_root *) bh->b_data;
++
++	bh2 = ext3cow_append (handle, dir, &block, &retval);
++	if (!(bh2)) {
++		brelse(bh);
++		return retval;
++	}
++	EXT3COW_I(dir)->i_flags |= EXT3COW_INDEX_FL;
++	data1 = bh2->b_data;
++
++	/* The 0th block becomes the root, move the dirents out */
++	fde = &root->dotdot;
++	de = (struct ext3cow_dir_entry_2 *)((char *)fde + le16_to_cpu(fde->rec_len));
++	len = ((char *) root) + blocksize - (char *) de;
++	memcpy (data1, de, len);
++	de = (struct ext3cow_dir_entry_2 *) data1;
++	top = data1 + len;
++	while ((char *)(de2=(void*)de+le16_to_cpu(de->rec_len)) < top)
++		de = de2;
++	de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
++	/* Initialize the root; the dot dirents already exist */
++	de = (struct ext3cow_dir_entry_2 *) (&root->dotdot);
++	de->rec_len = cpu_to_le16(blocksize - EXT3COW_DIR_REC_LEN(2));
++	memset (&root->info, 0, sizeof(root->info));
++	root->info.info_length = sizeof(root->info);
++	root->info.hash_version = EXT3COW_SB(dir->i_sb)->s_def_hash_version;
++	entries = root->entries;
++	dx_set_block (entries, 1);
++	dx_set_count (entries, 1);
++	dx_set_limit (entries, dx_root_limit(dir, sizeof(root->info)));
++
++	/* Initialize as for dx_probe */
++	hinfo.hash_version = root->info.hash_version;
++	hinfo.seed = EXT3COW_SB(dir->i_sb)->s_hash_seed;
++	ext3cowfs_dirhash(name, namelen, &hinfo);
++	frame = frames;
++	frame->entries = entries;
++	frame->at = entries;
++	frame->bh = bh;
++	bh = bh2;
++	de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
++	dx_release (frames);
++	if (!(de))
++		return retval;
++
++	return add_dirent_to_buf(handle, dentry, inode, de, bh);
++}
++#endif
++
++/*
++ *	ext3cow_add_entry()
++ *
++ * adds a file entry to the specified directory, using the same
++ * semantics as ext3cow_find_entry(). It returns NULL if it failed.
++ *
++ * NOTE!! The inode part of 'de' is left at 0 - which means you
++ * may not sleep between calling this and putting something into
++ * the entry, as someone else might have used it while you slept.
++ */
++static int ext3cow_add_entry (handle_t *handle, struct dentry *dentry,
++	struct inode *inode)
++{
++	struct inode *dir = dentry->d_parent->d_inode;
++	unsigned long offset;
++	struct buffer_head * bh;
++	struct ext3cow_dir_entry_2 *de;
++	struct super_block * sb;
++	int	retval;
++#ifdef CONFIG_EXT3COW_INDEX
++	int	dx_fallback=0;
++#endif
++	unsigned blocksize;
++	u32 block, blocks;
++
++	sb = dir->i_sb;
++	blocksize = sb->s_blocksize;
++	if (!dentry->d_name.len)
++		return -EINVAL;
++  /* No additions in the past -znjp */
++  if(is_unchangeable(dir, dentry))
++    return -EROFS;
++
++  if(EXT3COW_S_EPOCHNUMBER(sb) > EXT3COW_I_EPOCHNUMBER(dir)){   
++    if(ext3cow_dup_inode(dentry->d_parent->d_parent->d_inode, dir))
++      //if(ext3cow_dup_inode(NULL, dir))
++      return -1;
++  }
++
++#ifdef CONFIG_EXT3COW_INDEX
++	if (is_dx(dir)) {
++		retval = ext3cow_dx_add_entry(handle, dentry, inode);
++		if (!retval || (retval != ERR_BAD_DX_DIR)){
++      ext3cow_reclaim_dup_inode(dentry->d_parent->d_parent->d_inode, dir);
++			return retval;
++    }
++		EXT3COW_I(dir)->i_flags &= ~EXT3COW_INDEX_FL;
++		dx_fallback++;
++		ext3cow_mark_inode_dirty(handle, dir);
++	}
++#endif
++	blocks = dir->i_size >> sb->s_blocksize_bits;
++	for (block = 0, offset = 0; block < blocks; block++) {
++		bh = ext3cow_bread(handle, dir, block, 0, &retval);
++		if(!bh){
++      ext3cow_reclaim_dup_inode(dentry->d_parent->d_parent->d_inode, dir);
++			return retval;
++    }
++		retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
++		if (retval != -ENOSPC)
++			return retval;
++
++#ifdef CONFIG_EXT3COW_INDEX
++		if (blocks == 1 && !dx_fallback &&
++		    EXT3COW_HAS_COMPAT_FEATURE(sb, EXT3COW_FEATURE_COMPAT_DIR_INDEX))
++			return make_indexed_dir(handle, dentry, inode, bh);
++#endif
++		brelse(bh);
++	}
++
++	bh = ext3cow_append(handle, dir, &block, &retval);
++	if (!bh){
++    ext3cow_reclaim_dup_inode(dentry->d_parent->d_parent->d_inode, dir);
++		return retval;
++  }
++	de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++	de->inode = 0;
++	de->rec_len = cpu_to_le16(blocksize);
++	return add_dirent_to_buf(handle, dentry, inode, de, bh);
++}
++
++#ifdef CONFIG_EXT3COW_INDEX
++/*
++ * Returns 0 for success, or a negative error value
++ */
++static int ext3cow_dx_add_entry(handle_t *handle, struct dentry *dentry,
++			     struct inode *inode)
++{
++	struct dx_frame frames[2], *frame;
++	struct dx_entry *entries, *at;
++	struct dx_hash_info hinfo;
++	struct buffer_head * bh;
++	struct inode *dir = dentry->d_parent->d_inode;
++	struct super_block * sb = dir->i_sb;
++	struct ext3cow_dir_entry_2 *de;
++	int err;
++
++	frame = dx_probe(dentry, NULL, &hinfo, frames, &err);
++	if (!frame)
++		return err;
++	entries = frame->entries;
++	at = frame->at;
++
++	if (!(bh = ext3cow_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
++		goto cleanup;
++
++	BUFFER_TRACE(bh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, bh);
++	if (err)
++		goto journal_error;
++
++	err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
++	if (err != -ENOSPC) {
++		bh = NULL;
++		goto cleanup;
++	}
++
++	/* Block full, should compress but for now just split */
++	dxtrace(printk("using %u of %u node entries\n",
++		       dx_get_count(entries), dx_get_limit(entries)));
++	/* Need to split index? */
++	if (dx_get_count(entries) == dx_get_limit(entries)) {
++		u32 newblock;
++		unsigned icount = dx_get_count(entries);
++		int levels = frame - frames;
++		struct dx_entry *entries2;
++		struct dx_node *node2;
++		struct buffer_head *bh2;
++
++		if (levels && (dx_get_count(frames->entries) ==
++			       dx_get_limit(frames->entries))) {
++			ext3cow_warning(sb, __FUNCTION__,
++				     "Directory index full!");
++			err = -ENOSPC;
++			goto cleanup;
++		}
++		bh2 = ext3cow_append (handle, dir, &newblock, &err);
++		if (!(bh2))
++			goto cleanup;
++		node2 = (struct dx_node *)(bh2->b_data);
++		entries2 = node2->entries;
++		node2->fake.rec_len = cpu_to_le16(sb->s_blocksize);
++		node2->fake.inode = 0;
++		BUFFER_TRACE(frame->bh, "get_write_access");
++		err = ext3cow_journal_get_write_access(handle, frame->bh);
++		if (err)
++			goto journal_error;
++		if (levels) {
++			unsigned icount1 = icount/2, icount2 = icount - icount1;
++			unsigned hash2 = dx_get_hash(entries + icount1);
++			dxtrace(printk("Split index %i/%i\n", icount1, icount2));
++
++			BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
++			err = ext3cow_journal_get_write_access(handle,
++							     frames[0].bh);
++			if (err)
++				goto journal_error;
++
++			memcpy ((char *) entries2, (char *) (entries + icount1),
++				icount2 * sizeof(struct dx_entry));
++			dx_set_count (entries, icount1);
++			dx_set_count (entries2, icount2);
++			dx_set_limit (entries2, dx_node_limit(dir));
++
++			/* Which index block gets the new entry? */
++			if (at - entries >= icount1) {
++				frame->at = at = at - entries - icount1 + entries2;
++				frame->entries = entries = entries2;
++				swap(frame->bh, bh2);
++			}
++			dx_insert_block (frames + 0, hash2, newblock);
++			dxtrace(dx_show_index ("node", frames[1].entries));
++			dxtrace(dx_show_index ("node",
++			       ((struct dx_node *) bh2->b_data)->entries));
++			err = ext3cow_journal_dirty_metadata(handle, bh2);
++			if (err)
++				goto journal_error;
++			brelse (bh2);
++		} else {
++			dxtrace(printk("Creating second level index...\n"));
++			memcpy((char *) entries2, (char *) entries,
++			       icount * sizeof(struct dx_entry));
++			dx_set_limit(entries2, dx_node_limit(dir));
++
++			/* Set up root */
++			dx_set_count(entries, 1);
++			dx_set_block(entries + 0, newblock);
++			((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
++
++			/* Add new access path frame */
++			frame = frames + 1;
++			frame->at = at = at - entries + entries2;
++			frame->entries = entries = entries2;
++			frame->bh = bh2;
++			err = ext3cow_journal_get_write_access(handle,
++							     frame->bh);
++			if (err)
++				goto journal_error;
++		}
++		ext3cow_journal_dirty_metadata(handle, frames[0].bh);
++	}
++	de = do_split(handle, dir, &bh, frame, &hinfo, &err);
++	if (!de)
++		goto cleanup;
++	err = add_dirent_to_buf(handle, dentry, inode, de, bh);
++	bh = NULL;
++	goto cleanup;
++
++journal_error:
++	ext3cow_std_error(dir->i_sb, err);
++cleanup:
++	if (bh)
++		brelse(bh);
++	dx_release(frames);
++	return err;
++}
++#endif
++
++/*
++ * ext3cow_delete_entry deletes a directory entry by merging it with the
++ * previous entry
++ */
++static int ext3cow_delete_entry (handle_t *handle,
++                                 struct inode * dir,
++                                 struct ext3cow_dir_entry_2 * de_del,
++                                 struct buffer_head * bh,
++                                 struct dentry *dentry)
++{
++	struct ext3cow_dir_entry_2 * de, * pde;
++	int i;
++
++	i = 0;
++	pde = NULL;
++	de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++	while (i < bh->b_size) {
++		if (!ext3cow_check_dir_entry("ext3cow_delete_entry", dir, de, bh, i))
++			return -EIO;
++		if (de == de_del)  {
++      /* Can't delete an already dead entry - znjp */
++      if(!EXT3COW_IS_DIRENT_ALIVE(de))
++        return 0;
++      
++      if(EXT3COW_S_EPOCHNUMBER(dir->i_sb) > EXT3COW_I_EPOCHNUMBER(dir)){
++        if(ext3cow_dup_inode(dentry->d_parent->d_parent->d_inode, dir))
++          //if(ext3cow_dup_inode(NULL, dir))
++          return -1;
++      }
++
++			BUFFER_TRACE(bh, "get_write_access");
++			ext3cow_journal_get_write_access(handle, bh);
++      /* There used to be code here to adjust the rec_len
++       * but since names really never go away, the code was deleted 
++			if (pde)
++				pde->rec_len =
++					cpu_to_le16(le16_to_cpu(pde->rec_len) +
++						    le16_to_cpu(de->rec_len));
++			else
++				de->inode = 0;
++      */
++      /* Mark it dead - znjp */
++      de->death_epoch = cpu_to_le32(EXT3COW_I_EPOCHNUMBER(dir));
++			dir->i_version++;
++			BUFFER_TRACE(bh, "call ext3cow_journal_dirty_metadata");
++			ext3cow_journal_dirty_metadata(handle, bh);
++			return 0;
++		}
++		i += le16_to_cpu(de->rec_len);
++		pde = de;
++		de = (struct ext3cow_dir_entry_2 *)
++			((char *) de + le16_to_cpu(de->rec_len));
++	}
++	return -ENOENT;
++}
++
++/*
++ * ext3cow_mark_inode_dirty is somewhat expensive, so unlike ext2 we
++ * do not perform it in these functions.  We perform it at the call site,
++ * if it is needed.
++ */
++static inline void ext3cow_inc_count(handle_t *handle, struct inode *inode)
++{
++	inc_nlink(inode);
++}
++
++static inline void ext3cow_dec_count(handle_t *handle, struct inode *inode)
++{
++	drop_nlink(inode);
++}
++
++static int ext3cow_add_nondir(handle_t *handle,
++		struct dentry *dentry, struct inode *inode)
++{
++	int err = ext3cow_add_entry(handle, dentry, inode);
++	if (!err) {
++		ext3cow_mark_inode_dirty(handle, inode);
++		d_instantiate(dentry, inode);
++		return 0;
++	}
++	ext3cow_dec_count(handle, inode);
++	iput(inode);
++	return err;
++}
++
++/*
++ * By the time this is called, we already have created
++ * the directory cache entry for the new file, but it
++ * is so far negative - it has no inode.
++ *
++ * If the create succeeds, we fill in the inode information
++ * with d_instantiate().
++ */
++static int ext3cow_create (struct inode * dir, struct dentry * dentry, int mode,
++		struct nameidata *nd)
++{
++	handle_t *handle;
++	struct inode * inode;
++	int err, retries = 0;
++
++  /* Can't create in the past -znjp */
++  if(is_unchangeable(dir, dentry))
++    return -EROFS;
++
++retry:
++	handle = ext3cow_journal_start(dir, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 3 +
++					2*EXT3COW_QUOTA_INIT_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode = ext3cow_new_inode (handle, dir, mode);
++	err = PTR_ERR(inode);
++	if (!IS_ERR(inode)) {
++		inode->i_op = &ext3cow_file_inode_operations;
++		inode->i_fop = &ext3cow_file_operations;
++		ext3cow_set_aops(inode);
++		err = ext3cow_add_nondir(handle, dentry, inode);
++	}
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++}
++
++static int ext3cow_mknod (struct inode * dir, struct dentry *dentry,
++			int mode, dev_t rdev)
++{
++	handle_t *handle;
++	struct inode *inode;
++	int err, retries = 0;
++
++	if (!new_valid_dev(rdev))
++		return -EINVAL;
++
++retry:
++	handle = ext3cow_journal_start(dir, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 3 +
++					2*EXT3COW_QUOTA_INIT_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode = ext3cow_new_inode (handle, dir, mode);
++	err = PTR_ERR(inode);
++	if (!IS_ERR(inode)) {
++		init_special_inode(inode, inode->i_mode, rdev);
++#ifdef CONFIG_EXT3COW_FS_XATTR
++		inode->i_op = &ext3cow_special_inode_operations;
++#endif
++		err = ext3cow_add_nondir(handle, dentry, inode);
++	}
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++}
++
++static int ext3cow_mkdir(struct inode * dir, struct dentry * dentry, int mode)
++{
++	handle_t *handle;
++	struct inode * inode;
++	struct buffer_head * dir_block;
++	struct ext3cow_dir_entry_2 * de;
++	int err, retries = 0;
++
++	if (dir->i_nlink >= EXT3COW_LINK_MAX)
++		return -EMLINK;
++  /* No mkdirs in the past -znjp */
++  if(is_unchangeable(dir, dentry))
++    return -EROFS;
++
++
++retry:
++	handle = ext3cow_journal_start(dir, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 3 +
++					2*EXT3COW_QUOTA_INIT_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode = ext3cow_new_inode (handle, dir, S_IFDIR | mode);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out_stop;
++
++	inode->i_op = &ext3cow_dir_inode_operations;
++	inode->i_fop = &ext3cow_dir_operations;
++	inode->i_size = EXT3COW_I(inode)->i_disksize = inode->i_sb->s_blocksize;
++	dir_block = ext3cow_bread (handle, inode, 0, 1, &err);
++	if (!dir_block) {
++		drop_nlink(inode); /* is this nlink == 0? */
++		ext3cow_mark_inode_dirty(handle, inode);
++		iput (inode);
++		goto out_stop;
++	}
++	BUFFER_TRACE(dir_block, "get_write_access");
++	ext3cow_journal_get_write_access(handle, dir_block);
++	de = (struct ext3cow_dir_entry_2 *) dir_block->b_data;
++	de->inode = cpu_to_le32(inode->i_ino);
++	de->name_len = 1;
++	de->rec_len = cpu_to_le16(EXT3COW_DIR_REC_LEN(de->name_len));
++  /* For versioning -znjp */
++  de->birth_epoch = cpu_to_le32(EXT3COW_S_EPOCHNUMBER(dir->i_sb));
++  de->death_epoch = cpu_to_le32(EXT3COW_DIRENT_ALIVE);
++	strcpy (de->name, ".");
++	ext3cow_set_de_type(dir->i_sb, de, S_IFDIR);
++	de = (struct ext3cow_dir_entry_2 *)
++			((char *) de + le16_to_cpu(de->rec_len));
++	de->inode = cpu_to_le32(dir->i_ino);
++	de->rec_len = cpu_to_le16(inode->i_sb->s_blocksize-EXT3COW_DIR_REC_LEN(1));
++	de->name_len = 2;
++	strcpy (de->name, "..");
++	ext3cow_set_de_type(dir->i_sb, de, S_IFDIR);
++	inode->i_nlink = 2;
++  /* For versioning -znjp */
++  de->birth_epoch = cpu_to_le32(EXT3COW_I_EPOCHNUMBER(dir)); 
++  de->death_epoch = cpu_to_le32(EXT3COW_DIRENT_ALIVE);
++	BUFFER_TRACE(dir_block, "call ext3cow_journal_dirty_metadata");
++	ext3cow_journal_dirty_metadata(handle, dir_block);
++	brelse (dir_block);
++	ext3cow_mark_inode_dirty(handle, inode);
++	err = ext3cow_add_entry (handle, dentry, inode);
++	if (err) {
++		inode->i_nlink = 0;
++		ext3cow_mark_inode_dirty(handle, inode);
++		iput (inode);
++		goto out_stop;
++	}
++	inc_nlink(dir);
++	ext3cow_update_dx_flag(dir);
++	ext3cow_mark_inode_dirty(handle, dir);
++	d_instantiate(dentry, inode);
++out_stop:
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++}
++
++/*
++ * routine to check that the specified directory is empty (for rmdir)
++ */
++static int empty_dir (struct inode * inode)
++{
++	unsigned long offset;
++	struct buffer_head * bh;
++	struct ext3cow_dir_entry_2 * de, * de1;
++	struct super_block * sb;
++	int err = 0;
++
++	sb = inode->i_sb;
++	if (inode->i_size < EXT3COW_DIR_REC_LEN(1) + EXT3COW_DIR_REC_LEN(2) ||
++	    !(bh = ext3cow_bread (NULL, inode, 0, 0, &err))) {
++		if (err)
++			ext3cow_error(inode->i_sb, __FUNCTION__,
++				   "error %d reading directory #%lu offset 0",
++				   err, inode->i_ino);
++		else
++			ext3cow_warning(inode->i_sb, __FUNCTION__,
++				     "bad directory (dir #%lu) - no data block",
++				     inode->i_ino);
++		return 1;
++	}
++	de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++	de1 = (struct ext3cow_dir_entry_2 *)
++			((char *) de + le16_to_cpu(de->rec_len));
++	if (le32_to_cpu(de->inode) != inode->i_ino ||
++			!le32_to_cpu(de1->inode) ||
++			strcmp (".", de->name) ||
++			strcmp ("..", de1->name)) {
++		ext3cow_warning (inode->i_sb, "empty_dir",
++			      "bad directory (dir #%lu) - no `.' or `..'",
++			      inode->i_ino);
++		brelse (bh);
++		return 1;
++	}
++	offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
++	de = (struct ext3cow_dir_entry_2 *)
++			((char *) de1 + le16_to_cpu(de1->rec_len));
++	while (offset < inode->i_size ) {
++		if (!bh ||
++			(void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
++			err = 0;
++			brelse (bh);
++			bh = ext3cow_bread (NULL, inode,
++				offset >> EXT3COW_BLOCK_SIZE_BITS(sb), 0, &err);
++			if (!bh) {
++				if (err)
++					ext3cow_error(sb, __FUNCTION__,
++						   "error %d reading directory"
++						   " #%lu offset %lu",
++						   err, inode->i_ino, offset);
++				offset += sb->s_blocksize;
++				continue;
++			}
++			de = (struct ext3cow_dir_entry_2 *) bh->b_data;
++		}
++		if (!ext3cow_check_dir_entry("empty_dir", inode, de, bh, offset)) {
++			de = (struct ext3cow_dir_entry_2 *)(bh->b_data +
++							 sb->s_blocksize);
++			offset = (offset | (sb->s_blocksize - 1)) + 1;
++			continue;
++		}
++    /* Can remove a dir only if all dirents are out of scope -znjp */
++		if (le32_to_cpu(de->inode) &&
++        EXT3COW_IS_DIRENT_SCOPED(de, EXT3COW_I_EPOCHNUMBER(inode))) {
++			brelse (bh);
++			return 0;
++		}
++		offset += le16_to_cpu(de->rec_len);
++		de = (struct ext3cow_dir_entry_2 *)
++				((char *) de + le16_to_cpu(de->rec_len));
++	}
++	brelse (bh);
++	return 1;
++}
++
++/* ext3cow_orphan_add() links an unlinked or truncated inode into a list of
++ * such inodes, starting at the superblock, in case we crash before the
++ * file is closed/deleted, or in case the inode truncate spans multiple
++ * transactions and the last transaction is not recovered after a crash.
++ *
++ * At filesystem recovery time, we walk this list deleting unlinked
++ * inodes and truncating linked inodes in ext3cow_orphan_cleanup().
++ */
++int ext3cow_orphan_add(handle_t *handle, struct inode *inode)
++{
++	struct super_block *sb = inode->i_sb;
++	struct ext3cow_iloc iloc;
++	int err = 0, rc;
++
++	lock_super(sb);
++	if (!list_empty(&EXT3COW_I(inode)->i_orphan))
++		goto out_unlock;
++
++	/* Orphan handling is only valid for files with data blocks
++	 * being truncated, or files being unlinked. */
++
++	/* @@@ FIXME: Observation from aviro:
++	 * I think I can trigger J_ASSERT in ext3cow_orphan_add().  We block
++	 * here (on lock_super()), so race with ext3cow_link() which might bump
++	 * ->i_nlink. For, say it, character device. Not a regular file,
++	 * not a directory, not a symlink and ->i_nlink > 0.
++	 */
++	J_ASSERT ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
++		S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
++
++	BUFFER_TRACE(EXT3COW_SB(sb)->s_sbh, "get_write_access");
++	err = ext3cow_journal_get_write_access(handle, EXT3COW_SB(sb)->s_sbh);
++	if (err)
++		goto out_unlock;
++
++	err = ext3cow_reserve_inode_write(handle, inode, &iloc);
++	if (err)
++		goto out_unlock;
++
++	/* Insert this inode at the head of the on-disk orphan list... */
++	NEXT_ORPHAN(inode) = le32_to_cpu(EXT3COW_SB(sb)->s_es->s_last_orphan);
++	EXT3COW_SB(sb)->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
++	err = ext3cow_journal_dirty_metadata(handle, EXT3COW_SB(sb)->s_sbh);
++	rc = ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++	if (!err)
++		err = rc;
++
++	/* Only add to the head of the in-memory list if all the
++	 * previous operations succeeded.  If the orphan_add is going to
++	 * fail (possibly taking the journal offline), we can't risk
++	 * leaving the inode on the orphan list: stray orphan-list
++	 * entries can cause panics at unmount time.
++	 *
++	 * This is safe: on error we're going to ignore the orphan list
++	 * anyway on the next recovery. */
++	if (!err)
++		list_add(&EXT3COW_I(inode)->i_orphan, &EXT3COW_SB(sb)->s_orphan);
++
++	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
++	jbd_debug(4, "orphan inode %lu will point to %d\n",
++			inode->i_ino, NEXT_ORPHAN(inode));
++out_unlock:
++	unlock_super(sb);
++	ext3cow_std_error(inode->i_sb, err);
++	return err;
++}
++
++/*
++ * ext3cow_orphan_del() removes an unlinked or truncated inode from the list
++ * of such inodes stored on disk, because it is finally being cleaned up.
++ */
++int ext3cow_orphan_del(handle_t *handle, struct inode *inode)
++{
++	struct list_head *prev;
++	struct ext3cow_inode_info *ei = EXT3COW_I(inode);
++	struct ext3cow_sb_info *sbi;
++	unsigned long ino_next;
++	struct ext3cow_iloc iloc;
++	int err = 0;
++
++	lock_super(inode->i_sb);
++	if (list_empty(&ei->i_orphan)) {
++		unlock_super(inode->i_sb);
++		return 0;
++	}
++
++	ino_next = NEXT_ORPHAN(inode);
++	prev = ei->i_orphan.prev;
++	sbi = EXT3COW_SB(inode->i_sb);
++
++	jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
++
++	list_del_init(&ei->i_orphan);
++
++	/* If we're on an error path, we may not have a valid
++	 * transaction handle with which to update the orphan list on
++	 * disk, but we still need to remove the inode from the linked
++	 * list in memory. */
++	if (!handle)
++		goto out;
++
++	err = ext3cow_reserve_inode_write(handle, inode, &iloc);
++	if (err)
++		goto out_err;
++
++	if (prev == &sbi->s_orphan) {
++		jbd_debug(4, "superblock will point to %lu\n", ino_next);
++		BUFFER_TRACE(sbi->s_sbh, "get_write_access");
++		err = ext3cow_journal_get_write_access(handle, sbi->s_sbh);
++		if (err)
++			goto out_brelse;
++		sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
++		err = ext3cow_journal_dirty_metadata(handle, sbi->s_sbh);
++	} else {
++		struct ext3cow_iloc iloc2;
++		struct inode *i_prev =
++			&list_entry(prev, struct ext3cow_inode_info, i_orphan)->vfs_inode;
++
++		jbd_debug(4, "orphan inode %lu will point to %lu\n",
++			  i_prev->i_ino, ino_next);
++		err = ext3cow_reserve_inode_write(handle, i_prev, &iloc2);
++		if (err)
++			goto out_brelse;
++		NEXT_ORPHAN(i_prev) = ino_next;
++		err = ext3cow_mark_iloc_dirty(handle, i_prev, &iloc2);
++	}
++	if (err)
++		goto out_brelse;
++	NEXT_ORPHAN(inode) = 0;
++	err = ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++
++out_err:
++	ext3cow_std_error(inode->i_sb, err);
++out:
++	unlock_super(inode->i_sb);
++	return err;
++
++out_brelse:
++	brelse(iloc.bh);
++	goto out_err;
++}
++
++static int ext3cow_rmdir (struct inode * dir, struct dentry *dentry)
++{
++	int retval;
++	struct inode * inode;
++	struct buffer_head * bh;
++	struct ext3cow_dir_entry_2 * de;
++	handle_t *handle;
++
++	/* Initialize quotas before so that eventual writes go in
++	 * separate transaction */
++	DQUOT_INIT(dentry->d_inode);
++	handle = ext3cow_journal_start(dir, EXT3COW_DELETE_TRANS_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	retval = -ENOENT;
++	bh = ext3cow_find_entry (dentry, &de);
++	if (!bh)
++		goto end_rmdir;
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode = dentry->d_inode;
++
++  /* Can't rmdir in the past -znjp */
++  retval = -EROFS;
++  if(is_unchangeable(inode, dentry))
++    goto end_rmdir;
++
++	retval = -EIO;
++	if (le32_to_cpu(de->inode) != inode->i_ino)
++		goto end_rmdir;
++
++	retval = -ENOTEMPTY;
++	if (!empty_dir (inode))
++		goto end_rmdir;
++
++	retval = ext3cow_delete_entry(handle, dir, de, bh, dentry);
++	if (retval)
++		goto end_rmdir;
++	if (inode->i_nlink != 2)
++		ext3cow_warning (inode->i_sb, "ext3cow_rmdir",
++			      "empty directory has nlink!=2 (%d)",
++			      inode->i_nlink);
++	inode->i_version++;
++
++  /* We only delete things that were created in the same epoch -znjp */
++  if(de->birth_epoch == de->death_epoch){
++    clear_nlink(inode);
++    /* There's no need to set i_disksize: the fact that i_nlink is
++     * zero will ensure that the right thing happens during any
++     * recovery. */
++    inode->i_size = 0;
++    ext3cow_orphan_add(handle, inode);
++    drop_nlink(dir);
++  }
++  EXT3COW_I(inode)->i_flags |= EXT3COW_UNCHANGEABLE_FL;
++  inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
++  ext3cow_mark_inode_dirty(handle, inode);
++  ext3cow_update_dx_flag(dir);
++	ext3cow_mark_inode_dirty(handle, dir);
++
++end_rmdir:
++	ext3cow_journal_stop(handle);
++	brelse (bh);
++	return retval;
++}
++
++static int ext3cow_unlink(struct inode * dir, struct dentry *dentry)
++{
++	int retval;
++	struct inode * inode;
++	struct buffer_head * bh;
++	struct ext3cow_dir_entry_2 * de;
++	handle_t *handle;
++
++	/* Initialize quotas before so that eventual writes go
++	 * in separate transaction */
++	DQUOT_INIT(dentry->d_inode);
++	handle = ext3cow_journal_start(dir, EXT3COW_DELETE_TRANS_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	retval = -ENOENT;
++	bh = ext3cow_find_entry (dentry, &de);
++	if (!bh)
++		goto end_unlink;
++
++	inode = dentry->d_inode;
++
++  /* Can't unlink in the past -znjp */
++  retval = -EROFS;
++  if(is_unchangeable(inode, dentry))
++    goto end_unlink;  
++  
++	retval = -EIO;
++	if (le32_to_cpu(de->inode) != inode->i_ino)
++		goto end_unlink;
++
++	if (!inode->i_nlink) {
++		ext3cow_warning (inode->i_sb, "ext3cow_unlink",
++			      "Deleting nonexistent file (%lu), %d",
++			      inode->i_ino, inode->i_nlink);
++		inode->i_nlink = 1;
++	}
++	retval = ext3cow_delete_entry(handle, dir, de, bh, dentry);
++	if (retval)
++		goto end_unlink;
++	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
++	ext3cow_update_dx_flag(dir);
++	ext3cow_mark_inode_dirty(handle, dir);
++
++  /* If the file should be deleted here, don't actually delete it
++   * but mark it unchangeable, i.e. it's now in the past. -znjp */
++
++  /* If file was created in this epoch, then we actually unlink it,
++   * if not, then it belongs to the past, so mark it unchangeable -znjp */
++  if(de->birth_epoch == de->death_epoch){
++  	drop_nlink(inode);
++    if (!inode->i_nlink){
++      ext3cow_orphan_add(handle, inode);
++    }
++  }else{
++    if(!(inode->i_nlink - 1))
++      EXT3COW_I(inode)->i_flags |= EXT3COW_UNCHANGEABLE_FL; 
++  }
++	inode->i_ctime = dir->i_ctime;
++	ext3cow_mark_inode_dirty(handle, inode);
++	retval = 0;
++
++end_unlink:
++	ext3cow_journal_stop(handle);
++	brelse (bh);
++	return retval;
++}
++
++static int ext3cow_symlink (struct inode * dir,
++		struct dentry *dentry, const char * symname)
++{
++	handle_t *handle;
++	struct inode * inode;
++	int l, err, retries = 0;
++
++	l = strlen(symname)+1;
++	if (l > dir->i_sb->s_blocksize)
++		return -ENAMETOOLONG;
++
++retry:
++	handle = ext3cow_journal_start(dir, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 5 +
++					2*EXT3COW_QUOTA_INIT_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode = ext3cow_new_inode (handle, dir, S_IFLNK|S_IRWXUGO);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out_stop;
++
++	if (l > sizeof (EXT3COW_I(inode)->i_data)) {
++		inode->i_op = &ext3cow_symlink_inode_operations;
++		ext3cow_set_aops(inode);
++		/*
++		 * page_symlink() calls into ext3cow_prepare/commit_write.
++		 * We have a transaction open.  All is sweetness.  It also sets
++		 * i_size in generic_commit_write().
++		 */
++		err = __page_symlink(inode, symname, l,
++				mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
++		if (err) {
++			ext3cow_dec_count(handle, inode);
++			ext3cow_mark_inode_dirty(handle, inode);
++			iput (inode);
++			goto out_stop;
++		}
++	} else {
++		inode->i_op = &ext3cow_fast_symlink_inode_operations;
++		memcpy((char*)&EXT3COW_I(inode)->i_data,symname,l);
++		inode->i_size = l-1;
++	}
++	EXT3COW_I(inode)->i_disksize = inode->i_size;
++	err = ext3cow_add_nondir(handle, dentry, inode);
++out_stop:
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++}
++
++static int ext3cow_link (struct dentry * old_dentry,
++		struct inode * dir, struct dentry *dentry)
++{
++	handle_t *handle;
++	struct inode *inode = old_dentry->d_inode;
++	int err, retries = 0;
++
++	if (inode->i_nlink >= EXT3COW_LINK_MAX)
++		return -EMLINK;
++
++retry:
++	handle = ext3cow_journal_start(dir, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(dir))
++		handle->h_sync = 1;
++
++	inode->i_ctime = CURRENT_TIME_SEC;
++	ext3cow_inc_count(handle, inode);
++	atomic_inc(&inode->i_count);
++
++	err = ext3cow_add_nondir(handle, dentry, inode);
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++}
++
++#define PARENT_INO(buffer) \
++	((struct ext3cow_dir_entry_2 *) ((char *) buffer + \
++	le16_to_cpu(((struct ext3cow_dir_entry_2 *) buffer)->rec_len)))->inode
++
++/*
++ * Anybody can rename anything with this: the permission checks are left to the
++ * higher-level routines.
++ */
++static int ext3cow_rename (struct inode * old_dir, struct dentry *old_dentry,
++			   struct inode * new_dir,struct dentry *new_dentry)
++{
++	handle_t *handle;
++	struct inode * old_inode, * new_inode;
++	struct buffer_head * old_bh, * new_bh, * dir_bh;
++	struct ext3cow_dir_entry_2 * old_de, * new_de;
++	int retval;
++
++	old_bh = new_bh = dir_bh = NULL;
++
++	/* Initialize quotas before so that eventual writes go
++	 * in separate transaction */
++	if (new_dentry->d_inode)
++		DQUOT_INIT(new_dentry->d_inode);
++	handle = ext3cow_journal_start(old_dir, 2 *
++                                 EXT3COW_DATA_TRANS_BLOCKS(old_dir->i_sb) +
++                                 EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 2);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
++		handle->h_sync = 1;
++
++	old_bh = ext3cow_find_entry (old_dentry, &old_de);
++	/*
++	 *  Check for inode number is _not_ due to possible IO errors.
++	 *  We might rmdir the source, keep it as pwd of some process
++	 *  and merrily kill the link to whatever was created under the
++	 *  same name. Goodbye sticky bit ;-<
++	 */
++	old_inode = old_dentry->d_inode;
++	retval = -ENOENT;
++	if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
++		goto end_rename;
++
++	new_inode = new_dentry->d_inode;
++	new_bh = ext3cow_find_entry (new_dentry, &new_de);
++	if (new_bh) {
++		if (!new_inode) {
++			brelse (new_bh);
++			new_bh = NULL;
++		}
++	}
++
++  /* can't move something into the past -znjp */
++  retval = -EROFS;
++  if(is_unchangeable(new_inode, new_dentry)) 
++    goto end_rename;
++  /* can't some move from the past -znjp */
++  if(is_unchangeable(old_inode, old_dentry))
++    goto end_rename;
++
++	if (S_ISDIR(old_inode->i_mode)) {
++		if (new_inode) {
++			retval = -ENOTEMPTY;
++			if (!empty_dir (new_inode))
++				goto end_rename;
++		}
++		retval = -EIO;
++		dir_bh = ext3cow_bread (handle, old_inode, 0, 0, &retval);
++		if (!dir_bh)
++			goto end_rename;
++		if (le32_to_cpu(PARENT_INO(dir_bh->b_data)) != old_dir->i_ino)
++			goto end_rename;
++		retval = -EMLINK;
++		if (!new_inode && new_dir!=old_dir &&
++				new_dir->i_nlink >= EXT3COW_LINK_MAX)
++			goto end_rename;
++	}
++	if (!new_bh) {
++		retval = ext3cow_add_entry (handle, new_dentry, old_inode);
++		if (retval)
++			goto end_rename;
++	} else {
++		BUFFER_TRACE(new_bh, "get write access");
++		ext3cow_journal_get_write_access(handle, new_bh);
++		new_de->inode = cpu_to_le32(old_inode->i_ino);
++		if (EXT3COW_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
++					      EXT3COW_FEATURE_INCOMPAT_FILETYPE))
++			new_de->file_type = old_de->file_type;
++		new_dir->i_version++;
++		BUFFER_TRACE(new_bh, "call ext3cow_journal_dirty_metadata");
++		ext3cow_journal_dirty_metadata(handle, new_bh);
++		brelse(new_bh);
++		new_bh = NULL;
++	}
++
++	/*
++	 * Like most other Unix systems, set the ctime for inodes on a
++	 * rename.
++	 */
++	old_inode->i_ctime = CURRENT_TIME_SEC;
++	ext3cow_mark_inode_dirty(handle, old_inode);
++
++	/*
++	 * ok, that's it
++	 */
++	if (le32_to_cpu(old_de->inode) != old_inode->i_ino ||
++	    old_de->name_len != old_dentry->d_name.len ||
++	    strncmp(old_de->name, old_dentry->d_name.name, old_de->name_len) ||
++	    (retval = ext3cow_delete_entry(handle, old_dir,
++                                     old_de, old_bh, new_dentry)) == -ENOENT) {
++		/* old_de could have moved from under us during htree split, so
++		 * make sure that we are deleting the right entry.  We might
++		 * also be pointing to a stale entry in the unused part of
++		 * old_bh so just checking inum and the name isn't enough. */
++		struct buffer_head *old_bh2;
++		struct ext3cow_dir_entry_2 *old_de2;
++
++		old_bh2 = ext3cow_find_entry(old_dentry, &old_de2);
++		if (old_bh2) {
++			retval = ext3cow_delete_entry(handle, old_dir,
++                                    old_de2, old_bh2, new_dentry);
++			brelse(old_bh2);
++		}
++	}
++	if (retval) {
++		ext3cow_warning(old_dir->i_sb, "ext3cow_rename",
++				"Deleting old file (%lu), %d, error=%d",
++				old_dir->i_ino, old_dir->i_nlink, retval);
++	}
++
++	if (new_inode) {
++		new_inode->i_ctime = CURRENT_TIME_SEC;
++	}
++  if(!is_unchangeable(old_inode, old_dentry))
++    old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
++	ext3cow_update_dx_flag(old_dir);
++	if (dir_bh) {
++		BUFFER_TRACE(dir_bh, "get_write_access");
++		ext3cow_journal_get_write_access(handle, dir_bh);
++		PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
++		BUFFER_TRACE(dir_bh, "call ext3cow_journal_dirty_metadata");
++		ext3cow_journal_dirty_metadata(handle, dir_bh);
++		if (!new_inode) {
++			inc_nlink(new_dir);
++			ext3cow_update_dx_flag(new_dir);
++			ext3cow_mark_inode_dirty(handle, new_dir);
++		}
++	}
++	ext3cow_mark_inode_dirty(handle, old_dir);
++	if (new_inode) {
++		ext3cow_mark_inode_dirty(handle, new_inode);
++		if (!new_inode->i_nlink)
++			ext3cow_orphan_add(handle, new_inode);
++	}
++	retval = 0;
++
++end_rename:
++	brelse (dir_bh);
++	brelse (old_bh);
++	brelse (new_bh);
++	ext3cow_journal_stop(handle);
++	return retval;
++}
++
++/* ext3cow_fake_inode: This function creates a VFS-only inode
++ * used for properly scoping views into the past file system - znjp
++ */
++struct inode *ext3cow_fake_inode(struct inode *inode,
++                                 unsigned int epoch_number)
++{
++  struct inode * fake_inode = NULL;
++  struct ext3cow_inode_info * ini = NULL;
++  struct ext3cow_inode_info * fake_ini = NULL;
++  static unsigned int last_ino = UINT_MAX;
++  int err = 0;
++  int block = -1;
++
++  if(NULL == inode){
++    printk(KERN_ERR "Trying to duplicate a NULL inode.\n");
++    return NULL;
++  }
++
++  if(EXT3COW_IS_FAKEINODE(inode)){
++    printk(KERN_ERR "Trying to fake a fake inode.\n");
++    return inode;
++  }
++
++  printk(KERN_INFO "** faking inode %lu\n", inode->i_ino);
++
++  ini = EXT3COW_I(inode);
++  
++  /* Create a new VFS-only inode */
++  fake_inode = new_inode(inode->i_sb);   
++  err = PTR_ERR(fake_inode);
++  if(!IS_ERR(fake_inode)){
++
++    fake_ini = EXT3COW_I(fake_inode);
++
++    printk(KERN_INFO "** got inode %lu setting with %u\n", fake_inode->i_ino,
++           last_ino);
++
++    /* When inode is a directory, we can fake the inode number */
++    //if(S_ISDIR(inode->i_mode))
++    fake_inode->i_ino  = --last_ino;
++
++    fake_inode->i_mode = inode->i_mode;
++    fake_inode->i_uid  = inode->i_uid;
++    fake_inode->i_gid  = inode->i_gid;
++
++    /* uid_high and gid_high code would go here -znjp 
++       fake_inode->i_uid_high = inode->i_uid_high;
++       fake_inode->i_gid_high = inode->i_gid_high;
++    */
++
++    atomic_set(&fake_inode->i_count, 1);
++
++    fake_inode->i_nlink         = inode->i_nlink;
++    fake_inode->i_size          = inode->i_size;
++    fake_inode->i_atime.tv_sec  = inode->i_atime.tv_sec;
++    fake_inode->i_ctime.tv_sec  = inode->i_ctime.tv_sec;
++    fake_inode->i_mtime.tv_sec  = inode->i_mtime.tv_sec;
++    fake_inode->i_atime.tv_nsec = inode->i_atime.tv_nsec;
++    fake_inode->i_ctime.tv_nsec = inode->i_ctime.tv_nsec;
++    fake_inode->i_mtime.tv_nsec = inode->i_mtime.tv_nsec;
++
++    fake_ini->i_state = ini->i_state;
++    fake_ini->i_dir_start_lookup = ini->i_dir_start_lookup;
++    fake_ini->i_dtime = ini->i_dtime;
++
++    fake_inode->i_blocks  = inode->i_blocks;
++    fake_ini->i_flags     = ini->i_flags;
++#ifdef EXT3COW_FRAGMENTS
++    fake_ini->i_faddr     = ini->i_faddr;
++    fake_ini->i_frag_no   = ini->i_frag_no;
++    fake_ini->i_frag_size = ini->i_frag_size;
++#endif
++    fake_ini->i_file_acl = ini->i_file_acl;
++    if (!S_ISREG(fake_inode->i_mode)) {
++      fake_ini->i_dir_acl = ini->i_dir_acl;
++    } 
++    fake_ini->i_disksize = inode->i_size;
++    fake_inode->i_generation = inode->i_generation;
++    //TODO: This could be wrong.
++    //fake_ini->i_block_group = ini->i_block_group; //iloc.block_group;
++
++    for (block = 0; block < EXT3COW_N_BLOCKS; block++)
++      fake_ini->i_data[block] = ini->i_data[block];
++
++    fake_ini->i_extra_isize = ini->i_extra_isize;
++
++    /* set copy-on-write bitmap to 0 */
++    fake_ini->i_cow_bitmap = 0x0000;
++    
++    /* Mark fake inode unchangeable, etc. */
++    fake_ini->i_flags |= EXT3COW_UNCHANGEABLE_FL;
++    fake_ini->i_flags |= EXT3COW_UNVERSIONABLE_FL;
++    fake_ini->i_flags |= EXT3COW_FAKEINODE_FL;
++    fake_ini->i_flags |= EXT3COW_IMMUTABLE_FL;
++
++    /* Make sure we get the right operations */
++    if (S_ISREG(fake_inode->i_mode)) {
++      fake_inode->i_op = &ext3cow_file_inode_operations;
++      fake_inode->i_fop = &ext3cow_file_operations;
++      ext3cow_set_aops(fake_inode);
++    } else if (S_ISDIR(fake_inode->i_mode)) {
++      fake_inode->i_op = &ext3cow_dir_inode_operations;
++      fake_inode->i_fop = &ext3cow_dir_operations;
++    } else if (S_ISLNK(fake_inode->i_mode)) {
++      //if (ext3cow_inode_is_fast_symlink(cow_inode))
++      if((S_ISLNK(fake_inode->i_mode) && fake_inode->i_blocks - 
++          (EXT3COW_I(fake_inode)->i_file_acl ? 
++           (fake_inode->i_sb->s_blocksize >> 9) : 0)))
++        fake_inode->i_op = &ext3cow_fast_symlink_inode_operations;
++      else {
++        fake_inode->i_op = &ext3cow_symlink_inode_operations;
++        ext3cow_set_aops(fake_inode);
++      }
++    } else {
++      fake_inode->i_op = &ext3cow_special_inode_operations;
++    }
++
++    fake_ini->i_epoch_number = epoch_number;
++    fake_ini->i_next_inode = 0;
++    
++    iput(inode); /* dec i_count */
++
++    return fake_inode;
++  }else
++    ext3cow_warning(inode->i_sb, "ext3cow_fake_inode",
++                    "Could not create fake inode.");
++   
++ 	return NULL;
++}
++
++/* 
++ * ext3cow_dup_inode: This function creates a new inode, 
++ * copies all the metadata from the passed in inode,  
++ * and adds it to the version chain, creating a new version.  
++ * The head of the chain never changes; it is always the most current version.
++ * Similar in nature to ext3cow_creat and ext3cow_read_inode. -znjp
++ */
++int ext3cow_dup_inode(struct inode *dir, struct inode *inode){
++
++  struct inode *cow_inode = NULL;
++  struct inode *parent = NULL;
++  struct ext3cow_inode_info *ini = NULL;
++  struct ext3cow_inode_info *cow_ini = NULL;
++  handle_t *handle = NULL;
++  int err = 0;
++  int block = -1;
++  unsigned int epoch_number_temp = 0;
++  int retries = 0;
++
++  printk(KERN_INFO "** duping inode %lu\n", inode->i_ino);
++
++  if(EXT3COW_IS_UNVERSIONABLE(inode))
++    return 0;
++
++  if(NULL == inode){
++    printk(KERN_ERR "Trying to duplicate a NULL inode.\n");
++    return -1;
++  }
++
++	if (inode->i_nlink == 0) {
++		if (inode->i_mode == 0 ||
++		    !(EXT3COW_SB(inode->i_sb)->s_mount_state & EXT3COW_ORPHAN_FS)) {
++			/* this inode is deleted */
++      return -1;
++		}
++		/* The only unlinked inodes we let through here have
++		 * valid i_mode and are being read by the orphan
++		 * recovery code: that's fine, we're about to complete
++		 * the process of deleting those. */
++	}
++
++  ini = EXT3COW_I(inode);
++
++  /* This is for truncate, which can't pass in a parent */
++  if(NULL == dir)
++    parent = inode;
++  else
++    parent = dir;
++
++ retry:
++	handle = ext3cow_journal_start(parent, EXT3COW_DATA_TRANS_BLOCKS(dir->i_sb) +
++					EXT3COW_INDEX_EXTRA_TRANS_BLOCKS + 3 +
++					2*EXT3COW_QUOTA_INIT_BLOCKS(dir->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	if (IS_DIRSYNC(parent))
++		handle->h_sync = 1;
++
++	cow_inode = ext3cow_new_inode (handle, parent, inode->i_mode);
++	err = PTR_ERR(cow_inode);
++	if (!IS_ERR(cow_inode)) {
++
++    printk(KERN_INFO "  ** Allocated new inode %lu\n", cow_inode->i_ino);
++
++    cow_ini = EXT3COW_I(cow_inode);
++    
++    cow_inode->i_mode = inode->i_mode;
++    cow_inode->i_uid  = inode->i_uid;
++    cow_inode->i_gid  = inode->i_gid;
++    
++    /* uid_high and gid_high code would go here -znjp 
++       cow_inode->i_uid_high = inode->i_uid_high;
++       cow_inode->i_gid_high = inode->i_gid_high;
++    */
++
++    cow_inode->i_nlink         = inode->i_nlink;
++    cow_inode->i_size          = inode->i_size;
++    cow_inode->i_atime.tv_sec  = inode->i_atime.tv_sec;
++    cow_inode->i_ctime.tv_sec  = inode->i_ctime.tv_sec;
++    cow_inode->i_mtime.tv_sec  = inode->i_mtime.tv_sec;
++    cow_inode->i_atime.tv_nsec = inode->i_atime.tv_nsec;
++    cow_inode->i_ctime.tv_nsec = inode->i_ctime.tv_nsec;
++    cow_inode->i_mtime.tv_nsec = inode->i_mtime.tv_nsec;
++
++    cow_ini->i_state = ini->i_state;
++    cow_ini->i_dir_start_lookup = ini->i_dir_start_lookup;
++    cow_ini->i_dtime = ini->i_dtime;
++
++    cow_inode->i_blocks  = inode->i_blocks;
++    cow_ini->i_flags     = ini->i_flags;
++#ifdef EXT3COW_FRAGMENTS
++    cow_ini->i_faddr     = ini->i_faddr;
++    cow_ini->i_frag_no   = ini->i_frag_no;
++    cow_ini->i_frag_size = ini->i_frag_size;
++#endif
++    cow_ini->i_file_acl = ini->i_file_acl;
++    if (!S_ISREG(cow_inode->i_mode)) {
++      cow_ini->i_dir_acl = ini->i_dir_acl;
++    } 
++    cow_ini->i_disksize = inode->i_size;
++    cow_inode->i_generation = inode->i_generation;
++    //TODO: This could be wrong.
++    cow_ini->i_block_group = ini->i_block_group; //iloc.block_group;
++
++    for (block = 0; block < EXT3COW_N_BLOCKS; block++)
++      cow_ini->i_data[block] = ini->i_data[block];
++
++    //TODO: This could be wrong
++    //cow_ini->i_orphan = NULL; //INIT_LIST_HEAD(&ei->i_orphan);
++   
++    cow_ini->i_extra_isize = ini->i_extra_isize;
++
++    /* Make sure we get the right operations */
++    if (S_ISREG(cow_inode->i_mode)) {
++      cow_inode->i_op = &ext3cow_file_inode_operations;
++      cow_inode->i_fop = &ext3cow_file_operations;
++      ext3cow_set_aops(cow_inode);
++    } else if (S_ISDIR(cow_inode->i_mode)) {
++      cow_inode->i_op = &ext3cow_dir_inode_operations;
++      cow_inode->i_fop = &ext3cow_dir_operations;
++    } else if (S_ISLNK(cow_inode->i_mode)) {
++      //if (ext3cow_inode_is_fast_symlink(cow_inode))
++      if((S_ISLNK(cow_inode->i_mode) && cow_inode->i_blocks - 
++          (EXT3COW_I(cow_inode)->i_file_acl ? 
++           (cow_inode->i_sb->s_blocksize >> 9) : 0)))
++        cow_inode->i_op = &ext3cow_fast_symlink_inode_operations;
++      else {
++        cow_inode->i_op = &ext3cow_symlink_inode_operations;
++        ext3cow_set_aops(cow_inode);
++      }
++    } else {
++      cow_inode->i_op = &ext3cow_special_inode_operations;
++      /*
++      if (raw_inode->i_block[0])
++        init_special_inode(inode, inode->i_mode,
++                           old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
++      else
++        init_special_inode(inode, inode->i_mode,
++                           new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
++      */
++    }
++    
++    /* Dup in the direct cow bitmap */
++    cow_ini->i_cow_bitmap = ini->i_cow_bitmap;
++    ini->i_cow_bitmap     = 0x0000;
++    /* Mark new inode unchangeable */
++    cow_ini->i_flags |= EXT3COW_UNCHANGEABLE_FL;
++    /* Switch epoch numbers */
++    epoch_number_temp = ini->i_epoch_number;
++    ini->i_epoch_number = cow_ini->i_epoch_number;
++    cow_ini->i_epoch_number = epoch_number_temp;
++    /* Chain Inodes together */
++    cow_ini->i_next_inode = ini->i_next_inode;
++    ini->i_next_inode = cow_inode->i_ino;
++
++    ext3cow_mark_inode_dirty(handle, cow_inode);
++    ext3cow_mark_inode_dirty(handle, inode);
++    
++    iput(cow_inode); /* dec i_count */
++
++    err = 0;
++	}
++	ext3cow_journal_stop(handle);
++	if (err == -ENOSPC && ext3cow_should_retry_alloc(dir->i_sb, &retries))
++		goto retry;
++	return err;
++
++}
++
++/* ext3cow_reclaim_dup_inode: rolls back a recently dup'd inode
++ * on error, including epoch number and bitmaps.  Should not
++ * be used for removing versions.  */
++int ext3cow_reclaim_dup_inode(struct inode *dir, struct inode *inode)
++{
++  //  handle_t *handle = NULL;
++
++  if(is_bad_inode(inode))
++    goto no_delete;
++
++  return 0;
++ no_delete:
++  return -1;
++}
++
++/*
++ * directories can handle most operations...
++ */
++struct inode_operations ext3cow_dir_inode_operations = {
++	.create		= ext3cow_create,
++	.lookup		= ext3cow_lookup,
++	.link		= ext3cow_link,
++	.unlink		= ext3cow_unlink,
++	.symlink	= ext3cow_symlink,
++	.mkdir		= ext3cow_mkdir,
++	.rmdir		= ext3cow_rmdir,
++	.mknod		= ext3cow_mknod,
++	.rename		= ext3cow_rename,
++	.setattr	= ext3cow_setattr,
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	.setxattr	= generic_setxattr,
++	.getxattr	= generic_getxattr,
++	.listxattr	= ext3cow_listxattr,
++	.removexattr	= generic_removexattr,
++#endif
++	.permission	= ext3cow_permission,
++};
++
++struct inode_operations ext3cow_special_inode_operations = {
++	.setattr	= ext3cow_setattr,
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	.setxattr	= generic_setxattr,
++	.getxattr	= generic_getxattr,
++	.listxattr	= ext3cow_listxattr,
++	.removexattr	= generic_removexattr,
++#endif
++	.permission	= ext3cow_permission,
++};
+diff -ruN linux-2.6.20.3/fs/ext3cow/namei.h linux-2.6.20.3-ext3cow/fs/ext3cow/namei.h
+--- linux-2.6.20.3/fs/ext3cow/namei.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/namei.h	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,8 @@
++/*  linux/fs/ext3cow/namei.h
++ *
++ * Copyright (C) 2005 Simtec Electronics
++ *	Ben Dooks <ben@simtec.co.uk>
++ *
++*/
++
++extern struct dentry *ext3cow_get_parent(struct dentry *child);
+diff -ruN linux-2.6.20.3/fs/ext3cow/resize.c linux-2.6.20.3-ext3cow/fs/ext3cow/resize.c
+--- linux-2.6.20.3/fs/ext3cow/resize.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/resize.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,1042 @@
++/*
++ *  linux/fs/ext3cow/resize.c
++ *
++ * Support for resizing an ext3cow filesystem while it is mounted.
++ *
++ * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
++ *
++ * This could probably be made into a module, because it is not often in use.
++ */
++
++
++#define EXT3COWFS_DEBUG
++
++#include <linux/sched.h>
++#include <linux/smp_lock.h>
++#include <linux/ext3cow_jbd.h>
++
++#include <linux/errno.h>
++#include <linux/slab.h>
++
++
++#define outside(b, first, last)	((b) < (first) || (b) >= (last))
++#define inside(b, first, last)	((b) >= (first) && (b) < (last))
++
++static int verify_group_input(struct super_block *sb,
++			      struct ext3cow_new_group_data *input)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	struct ext3cow_super_block *es = sbi->s_es;
++	ext3cow_fsblk_t start = le32_to_cpu(es->s_blocks_count);
++	ext3cow_fsblk_t end = start + input->blocks_count;
++	unsigned group = input->group;
++	ext3cow_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
++	unsigned overhead = ext3cow_bg_has_super(sb, group) ?
++		(1 + ext3cow_bg_num_gdb(sb, group) +
++		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
++	ext3cow_fsblk_t metaend = start + overhead;
++	struct buffer_head *bh = NULL;
++	ext3cow_grpblk_t free_blocks_count;
++	int err = -EINVAL;
++
++	input->free_blocks_count = free_blocks_count =
++		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
++
++	if (test_opt(sb, DEBUG))
++		printk(KERN_DEBUG "EXT3COW-fs: adding %s group %u: %u blocks "
++		       "(%d free, %u reserved)\n",
++		       ext3cow_bg_has_super(sb, input->group) ? "normal" :
++		       "no-super", input->group, input->blocks_count,
++		       free_blocks_count, input->reserved_blocks);
++
++	if (group != sbi->s_groups_count)
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Cannot add at group %u (only %lu groups)",
++			     input->group, sbi->s_groups_count);
++	else if ((start - le32_to_cpu(es->s_first_data_block)) %
++		 EXT3COW_BLOCKS_PER_GROUP(sb))
++		ext3cow_warning(sb, __FUNCTION__, "Last group not full");
++	else if (input->reserved_blocks > input->blocks_count / 5)
++		ext3cow_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
++			     input->reserved_blocks);
++	else if (free_blocks_count < 0)
++		ext3cow_warning(sb, __FUNCTION__, "Bad blocks count %u",
++			     input->blocks_count);
++	else if (!(bh = sb_bread(sb, end - 1)))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Cannot read last block ("E3FSBLK")",
++			     end - 1);
++	else if (outside(input->block_bitmap, start, end))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Block bitmap not in group (block %u)",
++			     input->block_bitmap);
++	else if (outside(input->inode_bitmap, start, end))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Inode bitmap not in group (block %u)",
++			     input->inode_bitmap);
++	else if (outside(input->inode_table, start, end) ||
++	         outside(itend - 1, start, end))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Inode table not in group (blocks %u-"E3FSBLK")",
++			     input->inode_table, itend - 1);
++	else if (input->inode_bitmap == input->block_bitmap)
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Block bitmap same as inode bitmap (%u)",
++			     input->block_bitmap);
++	else if (inside(input->block_bitmap, input->inode_table, itend))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
++			     input->block_bitmap, input->inode_table, itend-1);
++	else if (inside(input->inode_bitmap, input->inode_table, itend))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
++			     input->inode_bitmap, input->inode_table, itend-1);
++	else if (inside(input->block_bitmap, start, metaend))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Block bitmap (%u) in GDT table"
++			     " ("E3FSBLK"-"E3FSBLK")",
++			     input->block_bitmap, start, metaend - 1);
++	else if (inside(input->inode_bitmap, start, metaend))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Inode bitmap (%u) in GDT table"
++			     " ("E3FSBLK"-"E3FSBLK")",
++			     input->inode_bitmap, start, metaend - 1);
++	else if (inside(input->inode_table, start, metaend) ||
++	         inside(itend - 1, start, metaend))
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Inode table (%u-"E3FSBLK") overlaps"
++			     "GDT table ("E3FSBLK"-"E3FSBLK")",
++			     input->inode_table, itend - 1, start, metaend - 1);
++	else
++		err = 0;
++	brelse(bh);
++
++	return err;
++}
++
++static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
++				  ext3cow_fsblk_t blk)
++{
++	struct buffer_head *bh;
++	int err;
++
++	bh = sb_getblk(sb, blk);
++	if (!bh)
++		return ERR_PTR(-EIO);
++	if ((err = ext3cow_journal_get_write_access(handle, bh))) {
++		brelse(bh);
++		bh = ERR_PTR(err);
++	} else {
++		lock_buffer(bh);
++		memset(bh->b_data, 0, sb->s_blocksize);
++		set_buffer_uptodate(bh);
++		unlock_buffer(bh);
++	}
++
++	return bh;
++}
++
++/*
++ * To avoid calling the atomic setbit hundreds or thousands of times, we only
++ * need to use it within a single byte (to ensure we get endianness right).
++ * We can use memset for the rest of the bitmap as there are no other users.
++ */
++static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
++{
++	int i;
++
++	if (start_bit >= end_bit)
++		return;
++
++	ext3cow_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
++	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
++		ext3cow_set_bit(i, bitmap);
++	if (i < end_bit)
++		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
++}
++
++/*
++ * Set up the block and inode bitmaps, and the inode table for the new group.
++ * This doesn't need to be part of the main transaction, since we are only
++ * changing blocks outside the actual filesystem.  We still do journaling to
++ * ensure the recovery is correct in case of a failure just after resize.
++ * If any part of this fails, we simply abort the resize.
++ */
++static int setup_new_group_blocks(struct super_block *sb,
++				  struct ext3cow_new_group_data *input)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	ext3cow_fsblk_t start = ext3cow_group_first_block_no(sb, input->group);
++	int reserved_gdb = ext3cow_bg_has_super(sb, input->group) ?
++		le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
++	unsigned long gdblocks = ext3cow_bg_num_gdb(sb, input->group);
++	struct buffer_head *bh;
++	handle_t *handle;
++	ext3cow_fsblk_t block;
++	ext3cow_grpblk_t bit;
++	int i;
++	int err = 0, err2;
++
++	handle = ext3cow_journal_start_sb(sb, reserved_gdb + gdblocks +
++				       2 + sbi->s_itb_per_group);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++
++	lock_super(sb);
++	if (input->group != sbi->s_groups_count) {
++		err = -EBUSY;
++		goto exit_journal;
++	}
++
++	if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
++		err = PTR_ERR(bh);
++		goto exit_journal;
++	}
++
++	if (ext3cow_bg_has_super(sb, input->group)) {
++		ext3cow_debug("mark backup superblock %#04lx (+0)\n", start);
++		ext3cow_set_bit(0, bh->b_data);
++	}
++
++	/* Copy all of the GDT blocks into the backup in this group */
++	for (i = 0, bit = 1, block = start + 1;
++	     i < gdblocks; i++, block++, bit++) {
++		struct buffer_head *gdb;
++
++		ext3cow_debug("update backup group %#04lx (+%d)\n", block, bit);
++
++		gdb = sb_getblk(sb, block);
++		if (!gdb) {
++			err = -EIO;
++			goto exit_bh;
++		}
++		if ((err = ext3cow_journal_get_write_access(handle, gdb))) {
++			brelse(gdb);
++			goto exit_bh;
++		}
++		lock_buffer(bh);
++		memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
++		set_buffer_uptodate(gdb);
++		unlock_buffer(bh);
++		ext3cow_journal_dirty_metadata(handle, gdb);
++		ext3cow_set_bit(bit, bh->b_data);
++		brelse(gdb);
++	}
++
++	/* Zero out all of the reserved backup group descriptor table blocks */
++	for (i = 0, bit = gdblocks + 1, block = start + bit;
++	     i < reserved_gdb; i++, block++, bit++) {
++		struct buffer_head *gdb;
++
++		ext3cow_debug("clear reserved block %#04lx (+%d)\n", block, bit);
++
++		if (IS_ERR(gdb = bclean(handle, sb, block))) {
++			err = PTR_ERR(bh);
++			goto exit_bh;
++		}
++		ext3cow_journal_dirty_metadata(handle, gdb);
++		ext3cow_set_bit(bit, bh->b_data);
++		brelse(gdb);
++	}
++	ext3cow_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
++		   input->block_bitmap - start);
++	ext3cow_set_bit(input->block_bitmap - start, bh->b_data);
++	ext3cow_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
++		   input->inode_bitmap - start);
++	ext3cow_set_bit(input->inode_bitmap - start, bh->b_data);
++
++	/* Zero out all of the inode table blocks */
++	for (i = 0, block = input->inode_table, bit = block - start;
++	     i < sbi->s_itb_per_group; i++, bit++, block++) {
++		struct buffer_head *it;
++
++		ext3cow_debug("clear inode block %#04lx (+%d)\n", block, bit);
++		if (IS_ERR(it = bclean(handle, sb, block))) {
++			err = PTR_ERR(it);
++			goto exit_bh;
++		}
++		ext3cow_journal_dirty_metadata(handle, it);
++		brelse(it);
++		ext3cow_set_bit(bit, bh->b_data);
++	}
++	mark_bitmap_end(input->blocks_count, EXT3COW_BLOCKS_PER_GROUP(sb),
++			bh->b_data);
++	ext3cow_journal_dirty_metadata(handle, bh);
++	brelse(bh);
++
++	/* Mark unused entries in inode bitmap used */
++	ext3cow_debug("clear inode bitmap %#04x (+%ld)\n",
++		   input->inode_bitmap, input->inode_bitmap - start);
++	if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
++		err = PTR_ERR(bh);
++		goto exit_journal;
++	}
++
++	mark_bitmap_end(EXT3COW_INODES_PER_GROUP(sb), EXT3COW_BLOCKS_PER_GROUP(sb),
++			bh->b_data);
++	ext3cow_journal_dirty_metadata(handle, bh);
++exit_bh:
++	brelse(bh);
++
++exit_journal:
++	unlock_super(sb);
++	if ((err2 = ext3cow_journal_stop(handle)) && !err)
++		err = err2;
++
++	return err;
++}
++
++/*
++ * Iterate through the groups which hold BACKUP superblock/GDT copies in an
++ * ext3cow filesystem.  The counters should be initialized to 1, 5, and 7 before
++ * calling this for the first time.  In a sparse filesystem it will be the
++ * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
++ * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
++ */
++static unsigned ext3cow_list_backups(struct super_block *sb, unsigned *three,
++				  unsigned *five, unsigned *seven)
++{
++	unsigned *min = three;
++	int mult = 3;
++	unsigned ret;
++
++	if (!EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++					EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
++		ret = *min;
++		*min += 1;
++		return ret;
++	}
++
++	if (*five < *min) {
++		min = five;
++		mult = 5;
++	}
++	if (*seven < *min) {
++		min = seven;
++		mult = 7;
++	}
++
++	ret = *min;
++	*min *= mult;
++
++	return ret;
++}
++
++/*
++ * Check that all of the backup GDT blocks are held in the primary GDT block.
++ * It is assumed that they are stored in group order.  Returns the number of
++ * groups in current filesystem that have BACKUPS, or -ve error code.
++ */
++static int verify_reserved_gdb(struct super_block *sb,
++			       struct buffer_head *primary)
++{
++	const ext3cow_fsblk_t blk = primary->b_blocknr;
++	const unsigned long end = EXT3COW_SB(sb)->s_groups_count;
++	unsigned three = 1;
++	unsigned five = 5;
++	unsigned seven = 7;
++	unsigned grp;
++	__le32 *p = (__le32 *)primary->b_data;
++	int gdbackups = 0;
++
++	while ((grp = ext3cow_list_backups(sb, &three, &five, &seven)) < end) {
++		if (le32_to_cpu(*p++) != grp * EXT3COW_BLOCKS_PER_GROUP(sb) + blk){
++			ext3cow_warning(sb, __FUNCTION__,
++				     "reserved GDT "E3FSBLK
++				     " missing grp %d ("E3FSBLK")",
++				     blk, grp,
++				     grp * EXT3COW_BLOCKS_PER_GROUP(sb) + blk);
++			return -EINVAL;
++		}
++		if (++gdbackups > EXT3COW_ADDR_PER_BLOCK(sb))
++			return -EFBIG;
++	}
++
++	return gdbackups;
++}
++
++/*
++ * Called when we need to bring a reserved group descriptor table block into
++ * use from the resize inode.  The primary copy of the new GDT block currently
++ * is an indirect block (under the double indirect block in the resize inode).
++ * The new backup GDT blocks will be stored as leaf blocks in this indirect
++ * block, in group order.  Even though we know all the block numbers we need,
++ * we check to ensure that the resize inode has actually reserved these blocks.
++ *
++ * Don't need to update the block bitmaps because the blocks are still in use.
++ *
++ * We get all of the error cases out of the way, so that we are sure to not
++ * fail once we start modifying the data on disk, because JBD has no rollback.
++ */
++static int add_new_gdb(handle_t *handle, struct inode *inode,
++		       struct ext3cow_new_group_data *input,
++		       struct buffer_head **primary)
++{
++	struct super_block *sb = inode->i_sb;
++	struct ext3cow_super_block *es = EXT3COW_SB(sb)->s_es;
++	unsigned long gdb_num = input->group / EXT3COW_DESC_PER_BLOCK(sb);
++	ext3cow_fsblk_t gdblock = EXT3COW_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
++	struct buffer_head **o_group_desc, **n_group_desc;
++	struct buffer_head *dind;
++	int gdbackups;
++	struct ext3cow_iloc iloc;
++	__le32 *data;
++	int err;
++
++	if (test_opt(sb, DEBUG))
++		printk(KERN_DEBUG
++		       "EXT3COW-fs: ext3cow_add_new_gdb: adding group block %lu\n",
++		       gdb_num);
++
++	/*
++	 * If we are not using the primary superblock/GDT copy don't resize,
++	 * because the user tools have no way of handling this.  Probably a
++	 * bad time to do it anyways.
++	 */
++	if (EXT3COW_SB(sb)->s_sbh->b_blocknr !=
++	    le32_to_cpu(EXT3COW_SB(sb)->s_es->s_first_data_block)) {
++		ext3cow_warning(sb, __FUNCTION__,
++			"won't resize using backup superblock at %llu",
++			(unsigned long long)EXT3COW_SB(sb)->s_sbh->b_blocknr);
++		return -EPERM;
++	}
++
++	*primary = sb_bread(sb, gdblock);
++	if (!*primary)
++		return -EIO;
++
++	if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
++		err = gdbackups;
++		goto exit_bh;
++	}
++
++	data = EXT3COW_I(inode)->i_data + EXT3COW_DIND_BLOCK;
++	dind = sb_bread(sb, le32_to_cpu(*data));
++	if (!dind) {
++		err = -EIO;
++		goto exit_bh;
++	}
++
++	data = (__le32 *)dind->b_data;
++	if (le32_to_cpu(data[gdb_num % EXT3COW_ADDR_PER_BLOCK(sb)]) != gdblock) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "new group %u GDT block "E3FSBLK" not reserved",
++			     input->group, gdblock);
++		err = -EINVAL;
++		goto exit_dind;
++	}
++
++	if ((err = ext3cow_journal_get_write_access(handle, EXT3COW_SB(sb)->s_sbh)))
++		goto exit_dind;
++
++	if ((err = ext3cow_journal_get_write_access(handle, *primary)))
++		goto exit_sbh;
++
++	if ((err = ext3cow_journal_get_write_access(handle, dind)))
++		goto exit_primary;
++
++	/* ext3cow_reserve_inode_write() gets a reference on the iloc */
++	if ((err = ext3cow_reserve_inode_write(handle, inode, &iloc)))
++		goto exit_dindj;
++
++	n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
++			GFP_KERNEL);
++	if (!n_group_desc) {
++		err = -ENOMEM;
++		ext3cow_warning (sb, __FUNCTION__,
++			      "not enough memory for %lu groups", gdb_num + 1);
++		goto exit_inode;
++	}
++
++	/*
++	 * Finally, we have all of the possible failures behind us...
++	 *
++	 * Remove new GDT block from inode double-indirect block and clear out
++	 * the new GDT block for use (which also "frees" the backup GDT blocks
++	 * from the reserved inode).  We don't need to change the bitmaps for
++	 * these blocks, because they are marked as in-use from being in the
++	 * reserved inode, and will become GDT blocks (primary and backup).
++	 */
++	data[gdb_num % EXT3COW_ADDR_PER_BLOCK(sb)] = 0;
++	ext3cow_journal_dirty_metadata(handle, dind);
++	brelse(dind);
++	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
++	ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++	memset((*primary)->b_data, 0, sb->s_blocksize);
++	ext3cow_journal_dirty_metadata(handle, *primary);
++
++	o_group_desc = EXT3COW_SB(sb)->s_group_desc;
++	memcpy(n_group_desc, o_group_desc,
++	       EXT3COW_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
++	n_group_desc[gdb_num] = *primary;
++	EXT3COW_SB(sb)->s_group_desc = n_group_desc;
++	EXT3COW_SB(sb)->s_gdb_count++;
++	kfree(o_group_desc);
++
++	es->s_reserved_gdt_blocks =
++		cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
++	ext3cow_journal_dirty_metadata(handle, EXT3COW_SB(sb)->s_sbh);
++
++	return 0;
++
++exit_inode:
++	//ext3cow_journal_release_buffer(handle, iloc.bh);
++	brelse(iloc.bh);
++exit_dindj:
++	//ext3cow_journal_release_buffer(handle, dind);
++exit_primary:
++	//ext3cow_journal_release_buffer(handle, *primary);
++exit_sbh:
++	//ext3cow_journal_release_buffer(handle, *primary);
++exit_dind:
++	brelse(dind);
++exit_bh:
++	brelse(*primary);
++
++	ext3cow_debug("leaving with error %d\n", err);
++	return err;
++}
++
++/*
++ * Called when we are adding a new group which has a backup copy of each of
++ * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
++ * We need to add these reserved backup GDT blocks to the resize inode, so
++ * that they are kept for future resizing and not allocated to files.
++ *
++ * Each reserved backup GDT block will go into a different indirect block.
++ * The indirect blocks are actually the primary reserved GDT blocks,
++ * so we know in advance what their block numbers are.  We only get the
++ * double-indirect block to verify it is pointing to the primary reserved
++ * GDT blocks so we don't overwrite a data block by accident.  The reserved
++ * backup GDT blocks are stored in their reserved primary GDT block.
++ */
++static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
++			      struct ext3cow_new_group_data *input)
++{
++	struct super_block *sb = inode->i_sb;
++	int reserved_gdb =le16_to_cpu(EXT3COW_SB(sb)->s_es->s_reserved_gdt_blocks);
++	struct buffer_head **primary;
++	struct buffer_head *dind;
++	struct ext3cow_iloc iloc;
++	ext3cow_fsblk_t blk;
++	__le32 *data, *end;
++	int gdbackups = 0;
++	int res, i;
++	int err;
++
++	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
++	if (!primary)
++		return -ENOMEM;
++
++	data = EXT3COW_I(inode)->i_data + EXT3COW_DIND_BLOCK;
++	dind = sb_bread(sb, le32_to_cpu(*data));
++	if (!dind) {
++		err = -EIO;
++		goto exit_free;
++	}
++
++	blk = EXT3COW_SB(sb)->s_sbh->b_blocknr + 1 + EXT3COW_SB(sb)->s_gdb_count;
++	data = (__le32 *)dind->b_data + EXT3COW_SB(sb)->s_gdb_count;
++	end = (__le32 *)dind->b_data + EXT3COW_ADDR_PER_BLOCK(sb);
++
++	/* Get each reserved primary GDT block and verify it holds backups */
++	for (res = 0; res < reserved_gdb; res++, blk++) {
++		if (le32_to_cpu(*data) != blk) {
++			ext3cow_warning(sb, __FUNCTION__,
++				     "reserved block "E3FSBLK
++				     " not at offset %ld",
++				     blk,
++				     (long)(data - (__le32 *)dind->b_data));
++			err = -EINVAL;
++			goto exit_bh;
++		}
++		primary[res] = sb_bread(sb, blk);
++		if (!primary[res]) {
++			err = -EIO;
++			goto exit_bh;
++		}
++		if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
++			brelse(primary[res]);
++			err = gdbackups;
++			goto exit_bh;
++		}
++		if (++data >= end)
++			data = (__le32 *)dind->b_data;
++	}
++
++	for (i = 0; i < reserved_gdb; i++) {
++		if ((err = ext3cow_journal_get_write_access(handle, primary[i]))) {
++			/*
++			int j;
++			for (j = 0; j < i; j++)
++				ext3cow_journal_release_buffer(handle, primary[j]);
++			 */
++			goto exit_bh;
++		}
++	}
++
++	if ((err = ext3cow_reserve_inode_write(handle, inode, &iloc)))
++		goto exit_bh;
++
++	/*
++	 * Finally we can add each of the reserved backup GDT blocks from
++	 * the new group to its reserved primary GDT block.
++	 */
++	blk = input->group * EXT3COW_BLOCKS_PER_GROUP(sb);
++	for (i = 0; i < reserved_gdb; i++) {
++		int err2;
++		data = (__le32 *)primary[i]->b_data;
++		/* printk("reserving backup %lu[%u] = %lu\n",
++		       primary[i]->b_blocknr, gdbackups,
++		       blk + primary[i]->b_blocknr); */
++		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
++		err2 = ext3cow_journal_dirty_metadata(handle, primary[i]);
++		if (!err)
++			err = err2;
++	}
++	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
++	ext3cow_mark_iloc_dirty(handle, inode, &iloc);
++
++exit_bh:
++	while (--res >= 0)
++		brelse(primary[res]);
++	brelse(dind);
++
++exit_free:
++	kfree(primary);
++
++	return err;
++}
++
++/*
++ * Update the backup copies of the ext3cow metadata.  These don't need to be part
++ * of the main resize transaction, because e2fsck will re-write them if there
++ * is a problem (basically only OOM will cause a problem).  However, we
++ * _should_ update the backups if possible, in case the primary gets trashed
++ * for some reason and we need to run e2fsck from a backup superblock.  The
++ * important part is that the new block and inode counts are in the backup
++ * superblocks, and the location of the new group metadata in the GDT backups.
++ *
++ * We do not need lock_super() for this, because these blocks are not
++ * otherwise touched by the filesystem code when it is mounted.  We don't
++ * need to worry about last changing from sbi->s_groups_count, because the
++ * worst that can happen is that we do not copy the full number of backups
++ * at this time.  The resize which changed s_groups_count will backup again.
++ */
++static void update_backups(struct super_block *sb,
++			   int blk_off, char *data, int size)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	const unsigned long last = sbi->s_groups_count;
++	const int bpg = EXT3COW_BLOCKS_PER_GROUP(sb);
++	unsigned three = 1;
++	unsigned five = 5;
++	unsigned seven = 7;
++	unsigned group;
++	int rest = sb->s_blocksize - size;
++	handle_t *handle;
++	int err = 0, err2;
++
++	handle = ext3cow_journal_start_sb(sb, EXT3COW_MAX_TRANS_DATA);
++	if (IS_ERR(handle)) {
++		group = 1;
++		err = PTR_ERR(handle);
++		goto exit_err;
++	}
++
++	while ((group = ext3cow_list_backups(sb, &three, &five, &seven)) < last) {
++		struct buffer_head *bh;
++
++		/* Out of journal space, and can't get more - abort - so sad */
++		if (handle->h_buffer_credits == 0 &&
++		    ext3cow_journal_extend(handle, EXT3COW_MAX_TRANS_DATA) &&
++		    (err = ext3cow_journal_restart(handle, EXT3COW_MAX_TRANS_DATA)))
++			break;
++
++		bh = sb_getblk(sb, group * bpg + blk_off);
++		if (!bh) {
++			err = -EIO;
++			break;
++		}
++		ext3cow_debug("update metadata backup %#04lx\n",
++			  (unsigned long)bh->b_blocknr);
++		if ((err = ext3cow_journal_get_write_access(handle, bh)))
++			break;
++		lock_buffer(bh);
++		memcpy(bh->b_data, data, size);
++		if (rest)
++			memset(bh->b_data + size, 0, rest);
++		set_buffer_uptodate(bh);
++		unlock_buffer(bh);
++		ext3cow_journal_dirty_metadata(handle, bh);
++		brelse(bh);
++	}
++	if ((err2 = ext3cow_journal_stop(handle)) && !err)
++		err = err2;
++
++	/*
++	 * Ugh! Need to have e2fsck write the backup copies.  It is too
++	 * late to revert the resize, we shouldn't fail just because of
++	 * the backup copies (they are only needed in case of corruption).
++	 *
++	 * However, if we got here we have a journal problem too, so we
++	 * can't really start a transaction to mark the superblock.
++	 * Chicken out and just set the flag on the hope it will be written
++	 * to disk, and if not - we will simply wait until next fsck.
++	 */
++exit_err:
++	if (err) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "can't update backup for group %d (err %d), "
++			     "forcing fsck on next reboot", group, err);
++		sbi->s_mount_state &= ~EXT3COW_VALID_FS;
++		sbi->s_es->s_state &= cpu_to_le16(~EXT3COW_VALID_FS);
++		mark_buffer_dirty(sbi->s_sbh);
++	}
++}
++
++/* Add group descriptor data to an existing or new group descriptor block.
++ * Ensure we handle all possible error conditions _before_ we start modifying
++ * the filesystem, because we cannot abort the transaction and not have it
++ * write the data to disk.
++ *
++ * If we are on a GDT block boundary, we need to get the reserved GDT block.
++ * Otherwise, we may need to add backup GDT blocks for a sparse group.
++ *
++ * We only need to hold the superblock lock while we are actually adding
++ * in the new group's counts to the superblock.  Prior to that we have
++ * not really "added" the group at all.  We re-check that we are still
++ * adding in the last group in case things have changed since verifying.
++ */
++int ext3cow_group_add(struct super_block *sb, struct ext3cow_new_group_data *input)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	struct ext3cow_super_block *es = sbi->s_es;
++	int reserved_gdb = ext3cow_bg_has_super(sb, input->group) ?
++		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
++	struct buffer_head *primary = NULL;
++	struct ext3cow_group_desc *gdp;
++	struct inode *inode = NULL;
++	handle_t *handle;
++	int gdb_off, gdb_num;
++	int err, err2;
++
++	gdb_num = input->group / EXT3COW_DESC_PER_BLOCK(sb);
++	gdb_off = input->group % EXT3COW_DESC_PER_BLOCK(sb);
++
++	if (gdb_off == 0 && !EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++					EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "Can't resize non-sparse filesystem further");
++		return -EPERM;
++	}
++
++	if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
++	    le32_to_cpu(es->s_blocks_count)) {
++		ext3cow_warning(sb, __FUNCTION__, "blocks_count overflow\n");
++		return -EINVAL;
++	}
++
++	if (le32_to_cpu(es->s_inodes_count) + EXT3COW_INODES_PER_GROUP(sb) <
++	    le32_to_cpu(es->s_inodes_count)) {
++		ext3cow_warning(sb, __FUNCTION__, "inodes_count overflow\n");
++		return -EINVAL;
++	}
++
++	if (reserved_gdb || gdb_off == 0) {
++		if (!EXT3COW_HAS_COMPAT_FEATURE(sb,
++					     EXT3COW_FEATURE_COMPAT_RESIZE_INODE)){
++			ext3cow_warning(sb, __FUNCTION__,
++				     "No reserved GDT blocks, can't resize");
++			return -EPERM;
++		}
++		inode = iget(sb, EXT3COW_RESIZE_INO);
++		if (!inode || is_bad_inode(inode)) {
++			ext3cow_warning(sb, __FUNCTION__,
++				     "Error opening resize inode");
++			iput(inode);
++			return -ENOENT;
++		}
++	}
++
++	if ((err = verify_group_input(sb, input)))
++		goto exit_put;
++
++	if ((err = setup_new_group_blocks(sb, input)))
++		goto exit_put;
++
++	/*
++	 * We will always be modifying at least the superblock and a GDT
++	 * block.  If we are adding a group past the last current GDT block,
++	 * we will also modify the inode and the dindirect block.  If we
++	 * are adding a group with superblock/GDT backups  we will also
++	 * modify each of the reserved GDT dindirect blocks.
++	 */
++	handle = ext3cow_journal_start_sb(sb,
++				       ext3cow_bg_has_super(sb, input->group) ?
++				       3 + reserved_gdb : 4);
++	if (IS_ERR(handle)) {
++		err = PTR_ERR(handle);
++		goto exit_put;
++	}
++
++	lock_super(sb);
++	if (input->group != sbi->s_groups_count) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "multiple resizers run on filesystem!");
++		err = -EBUSY;
++		goto exit_journal;
++	}
++
++	if ((err = ext3cow_journal_get_write_access(handle, sbi->s_sbh)))
++		goto exit_journal;
++
++	/*
++	 * We will only either add reserved group blocks to a backup group
++	 * or remove reserved blocks for the first group in a new group block.
++	 * Doing both would be mean more complex code, and sane people don't
++	 * use non-sparse filesystems anymore.  This is already checked above.
++	 */
++	if (gdb_off) {
++		primary = sbi->s_group_desc[gdb_num];
++		if ((err = ext3cow_journal_get_write_access(handle, primary)))
++			goto exit_journal;
++
++		if (reserved_gdb && ext3cow_bg_num_gdb(sb, input->group) &&
++		    (err = reserve_backup_gdb(handle, inode, input)))
++			goto exit_journal;
++	} else if ((err = add_new_gdb(handle, inode, input, &primary)))
++		goto exit_journal;
++
++	/*
++	 * OK, now we've set up the new group.  Time to make it active.
++	 *
++	 * Current kernels don't lock all allocations via lock_super(),
++	 * so we have to be safe wrt. concurrent accesses the group
++	 * data.  So we need to be careful to set all of the relevant
++	 * group descriptor data etc. *before* we enable the group.
++	 *
++	 * The key field here is sbi->s_groups_count: as long as
++	 * that retains its old value, nobody is going to access the new
++	 * group.
++	 *
++	 * So first we update all the descriptor metadata for the new
++	 * group; then we update the total disk blocks count; then we
++	 * update the groups count to enable the group; then finally we
++	 * update the free space counts so that the system can start
++	 * using the new disk blocks.
++	 */
++
++	/* Update group descriptor block for new group */
++	gdp = (struct ext3cow_group_desc *)primary->b_data + gdb_off;
++
++	gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
++	gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
++	gdp->bg_inode_table = cpu_to_le32(input->inode_table);
++	gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
++	gdp->bg_free_inodes_count = cpu_to_le16(EXT3COW_INODES_PER_GROUP(sb));
++
++	/*
++	 * Make the new blocks and inodes valid next.  We do this before
++	 * increasing the group count so that once the group is enabled,
++	 * all of its blocks and inodes are already valid.
++	 *
++	 * We always allocate group-by-group, then block-by-block or
++	 * inode-by-inode within a group, so enabling these
++	 * blocks/inodes before the group is live won't actually let us
++	 * allocate the new space yet.
++	 */
++	es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
++		input->blocks_count);
++	es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
++		EXT3COW_INODES_PER_GROUP(sb));
++
++	/*
++	 * We need to protect s_groups_count against other CPUs seeing
++	 * inconsistent state in the superblock.
++	 *
++	 * The precise rules we use are:
++	 *
++	 * * Writers of s_groups_count *must* hold lock_super
++	 * AND
++	 * * Writers must perform a smp_wmb() after updating all dependent
++	 *   data and before modifying the groups count
++	 *
++	 * * Readers must hold lock_super() over the access
++	 * OR
++	 * * Readers must perform an smp_rmb() after reading the groups count
++	 *   and before reading any dependent data.
++	 *
++	 * NB. These rules can be relaxed when checking the group count
++	 * while freeing data, as we can only allocate from a block
++	 * group after serialising against the group count, and we can
++	 * only then free after serialising in turn against that
++	 * allocation.
++	 */
++	smp_wmb();
++
++	/* Update the global fs size fields */
++	sbi->s_groups_count++;
++
++	ext3cow_journal_dirty_metadata(handle, primary);
++
++	/* Update the reserved block counts only once the new group is
++	 * active. */
++	es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
++		input->reserved_blocks);
++
++	/* Update the free space counts */
++	percpu_counter_mod(&sbi->s_freeblocks_counter,
++			   input->free_blocks_count);
++	percpu_counter_mod(&sbi->s_freeinodes_counter,
++			   EXT3COW_INODES_PER_GROUP(sb));
++
++	ext3cow_journal_dirty_metadata(handle, sbi->s_sbh);
++	sb->s_dirt = 1;
++
++exit_journal:
++	unlock_super(sb);
++	if ((err2 = ext3cow_journal_stop(handle)) && !err)
++		err = err2;
++	if (!err) {
++		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
++			       sizeof(struct ext3cow_super_block));
++		update_backups(sb, primary->b_blocknr, primary->b_data,
++			       primary->b_size);
++	}
++exit_put:
++	iput(inode);
++	return err;
++} /* ext3cow_group_add */
++
++/* Extend the filesystem to the new number of blocks specified.  This entry
++ * point is only used to extend the current filesystem to the end of the last
++ * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
++ * for emergencies (because it has no dependencies on reserved blocks).
++ *
++ * If we _really_ wanted, we could use default values to call ext3cow_group_add()
++ * allow the "remount" trick to work for arbitrary resizing, assuming enough
++ * GDT blocks are reserved to grow to the desired size.
++ */
++int ext3cow_group_extend(struct super_block *sb, struct ext3cow_super_block *es,
++		      ext3cow_fsblk_t n_blocks_count)
++{
++	ext3cow_fsblk_t o_blocks_count;
++	unsigned long o_groups_count;
++	ext3cow_grpblk_t last;
++	ext3cow_grpblk_t add;
++	struct buffer_head * bh;
++	handle_t *handle;
++	int err;
++	unsigned long freed_blocks;
++
++	/* We don't need to worry about locking wrt other resizers just
++	 * yet: we're going to revalidate es->s_blocks_count after
++	 * taking lock_super() below. */
++	o_blocks_count = le32_to_cpu(es->s_blocks_count);
++	o_groups_count = EXT3COW_SB(sb)->s_groups_count;
++
++	if (test_opt(sb, DEBUG))
++		printk(KERN_DEBUG "EXT3COW-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
++		       o_blocks_count, n_blocks_count);
++
++	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
++		return 0;
++
++	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
++		printk(KERN_ERR "EXT3COW-fs: filesystem on %s:"
++			" too large to resize to %lu blocks safely\n",
++			sb->s_id, n_blocks_count);
++		if (sizeof(sector_t) < 8)
++			ext3cow_warning(sb, __FUNCTION__,
++			"CONFIG_LBD not enabled\n");
++		return -EINVAL;
++	}
++
++	if (n_blocks_count < o_blocks_count) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "can't shrink FS - resize aborted");
++		return -EBUSY;
++	}
++
++	/* Handle the remaining blocks in the last group only. */
++	last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
++		EXT3COW_BLOCKS_PER_GROUP(sb);
++
++	if (last == 0) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "need to use ext2online to resize further");
++		return -EPERM;
++	}
++
++	add = EXT3COW_BLOCKS_PER_GROUP(sb) - last;
++
++	if (o_blocks_count + add < o_blocks_count) {
++		ext3cow_warning(sb, __FUNCTION__, "blocks_count overflow");
++		return -EINVAL;
++	}
++
++	if (o_blocks_count + add > n_blocks_count)
++		add = n_blocks_count - o_blocks_count;
++
++	if (o_blocks_count + add < n_blocks_count)
++		ext3cow_warning(sb, __FUNCTION__,
++			     "will only finish group ("E3FSBLK
++			     " blocks, %u new)",
++			     o_blocks_count + add, add);
++
++	/* See if the device is actually as big as what was requested */
++	bh = sb_bread(sb, o_blocks_count + add -1);
++	if (!bh) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "can't read last block, resize aborted");
++		return -ENOSPC;
++	}
++	brelse(bh);
++
++	/* We will update the superblock, one block bitmap, and
++	 * one group descriptor via ext3cow_free_blocks().
++	 */
++	handle = ext3cow_journal_start_sb(sb, 3);
++	if (IS_ERR(handle)) {
++		err = PTR_ERR(handle);
++		ext3cow_warning(sb, __FUNCTION__, "error %d on journal start",err);
++		goto exit_put;
++	}
++
++	lock_super(sb);
++	if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "multiple resizers run on filesystem!");
++		unlock_super(sb);
++		err = -EBUSY;
++		goto exit_put;
++	}
++
++	if ((err = ext3cow_journal_get_write_access(handle,
++						 EXT3COW_SB(sb)->s_sbh))) {
++		ext3cow_warning(sb, __FUNCTION__,
++			     "error %d on journal write access", err);
++		unlock_super(sb);
++		ext3cow_journal_stop(handle);
++		goto exit_put;
++	}
++	es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
++	ext3cow_journal_dirty_metadata(handle, EXT3COW_SB(sb)->s_sbh);
++	sb->s_dirt = 1;
++	unlock_super(sb);
++	ext3cow_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
++		   o_blocks_count + add);
++	ext3cow_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
++	ext3cow_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
++		   o_blocks_count + add);
++	if ((err = ext3cow_journal_stop(handle)))
++		goto exit_put;
++	if (test_opt(sb, DEBUG))
++		printk(KERN_DEBUG "EXT3COW-fs: extended group to %u blocks\n",
++		       le32_to_cpu(es->s_blocks_count));
++	update_backups(sb, EXT3COW_SB(sb)->s_sbh->b_blocknr, (char *)es,
++		       sizeof(struct ext3cow_super_block));
++exit_put:
++	return err;
++} /* ext3cow_group_extend */
+diff -ruN linux-2.6.20.3/fs/ext3cow/super.c linux-2.6.20.3-ext3cow/fs/ext3cow/super.c
+--- linux-2.6.20.3/fs/ext3cow/super.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/super.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,2808 @@
++/*
++ *  linux/fs/ext3cow/super.c
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/inode.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  Big-endian to little-endian byte-swapping/bitmaps by
++ *        David S. Miller (davem@caip.rutgers.edu), 1995
++ */
++
++#include <linux/module.h>
++#include <linux/string.h>
++#include <linux/fs.h>
++#include <linux/time.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/slab.h>
++#include <linux/init.h>
++#include <linux/blkdev.h>
++#include <linux/parser.h>
++#include <linux/smp_lock.h>
++#include <linux/buffer_head.h>
++#include <linux/vfs.h>
++#include <linux/random.h>
++#include <linux/mount.h>
++#include <linux/namei.h>
++#include <linux/quotaops.h>
++#include <linux/seq_file.h>
++
++#include <asm/uaccess.h>
++
++#include "xattr.h"
++#include "acl.h"
++#include "namei.h"
++
++static int ext3cow_load_journal(struct super_block *, struct ext3cow_super_block *,
++			     unsigned long journal_devnum);
++static int ext3cow_create_journal(struct super_block *, struct ext3cow_super_block *,
++			       unsigned int);
++static void ext3cow_commit_super (struct super_block * sb,
++			       struct ext3cow_super_block * es,
++			       int sync);
++static void ext3cow_mark_recovery_complete(struct super_block * sb,
++					struct ext3cow_super_block * es);
++static void ext3cow_clear_journal_err(struct super_block * sb,
++				   struct ext3cow_super_block * es);
++static int ext3cow_sync_fs(struct super_block *sb, int wait);
++static const char *ext3cow_decode_error(struct super_block * sb, int errno,
++				     char nbuf[16]);
++static int ext3cow_remount (struct super_block * sb, int * flags, char * data);
++static int ext3cow_statfs (struct dentry * dentry, struct kstatfs * buf);
++static void ext3cow_unlockfs(struct super_block *sb);
++static void ext3cow_write_super (struct super_block * sb);
++static void ext3cow_write_super_lockfs(struct super_block *sb);
++
++/*
++ * Wrappers for journal_start/end.
++ *
++ * The only special thing we need to do here is to make sure that all
++ * journal_end calls result in the superblock being marked dirty, so
++ * that sync() will call the filesystem's write_super callback if
++ * appropriate.
++ */
++handle_t *ext3cow_journal_start_sb(struct super_block *sb, int nblocks)
++{
++	journal_t *journal;
++
++	if (sb->s_flags & MS_RDONLY)
++		return ERR_PTR(-EROFS);
++
++	/* Special case here: if the journal has aborted behind our
++	 * backs (eg. EIO in the commit thread), then we still need to
++	 * take the FS itself readonly cleanly. */
++	journal = EXT3COW_SB(sb)->s_journal;
++	if (is_journal_aborted(journal)) {
++		ext3cow_abort(sb, __FUNCTION__,
++			   "Detected aborted journal");
++		return ERR_PTR(-EROFS);
++	}
++
++	return journal_start(journal, nblocks);
++}
++
++/*
++ * The only special thing we need to do here is to make sure that all
++ * journal_stop calls result in the superblock being marked dirty, so
++ * that sync() will call the filesystem's write_super callback if
++ * appropriate.
++ */
++int __ext3cow_journal_stop(const char *where, handle_t *handle)
++{
++	struct super_block *sb;
++	int err;
++	int rc;
++
++	sb = handle->h_transaction->t_journal->j_private;
++	err = handle->h_err;
++	rc = journal_stop(handle);
++
++	if (!err)
++		err = rc;
++	if (err)
++		__ext3cow_std_error(sb, where, err);
++	return err;
++}
++
++void ext3cow_journal_abort_handle(const char *caller, const char *err_fn,
++		struct buffer_head *bh, handle_t *handle, int err)
++{
++	char nbuf[16];
++	const char *errstr = ext3cow_decode_error(NULL, err, nbuf);
++
++	if (bh)
++		BUFFER_TRACE(bh, "abort");
++
++	if (!handle->h_err)
++		handle->h_err = err;
++
++	if (is_handle_aborted(handle))
++		return;
++
++	printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
++	       caller, errstr, err_fn);
++
++	journal_abort_handle(handle);
++}
++
++/* Deal with the reporting of failure conditions on a filesystem such as
++ * inconsistencies detected or read IO failures.
++ *
++ * On ext2, we can store the error state of the filesystem in the
++ * superblock.  That is not possible on ext3cow, because we may have other
++ * write ordering constraints on the superblock which prevent us from
++ * writing it out straight away; and given that the journal is about to
++ * be aborted, we can't rely on the current, or future, transactions to
++ * write out the superblock safely.
++ *
++ * We'll just use the journal_abort() error code to record an error in
++ * the journal instead.  On recovery, the journal will compain about
++ * that error until we've noted it down and cleared it.
++ */
++
++static void ext3cow_handle_error(struct super_block *sb)
++{
++	struct ext3cow_super_block *es = EXT3COW_SB(sb)->s_es;
++
++	EXT3COW_SB(sb)->s_mount_state |= EXT3COW_ERROR_FS;
++	es->s_state |= cpu_to_le16(EXT3COW_ERROR_FS);
++
++	if (sb->s_flags & MS_RDONLY)
++		return;
++
++	if (!test_opt (sb, ERRORS_CONT)) {
++		journal_t *journal = EXT3COW_SB(sb)->s_journal;
++
++		EXT3COW_SB(sb)->s_mount_opt |= EXT3COW_MOUNT_ABORT;
++		if (journal)
++			journal_abort(journal, -EIO);
++	}
++	if (test_opt (sb, ERRORS_RO)) {
++		printk (KERN_CRIT "Remounting filesystem read-only\n");
++		sb->s_flags |= MS_RDONLY;
++	}
++	ext3cow_commit_super(sb, es, 1);
++	if (test_opt(sb, ERRORS_PANIC))
++		panic("EXT3COW-fs (device %s): panic forced after error\n",
++			sb->s_id);
++}
++
++void ext3cow_error (struct super_block * sb, const char * function,
++		 const char * fmt, ...)
++{
++	va_list args;
++
++	va_start(args, fmt);
++	printk(KERN_CRIT "EXT3COW-fs error (device %s): %s: ",sb->s_id, function);
++	vprintk(fmt, args);
++	printk("\n");
++	va_end(args);
++
++	ext3cow_handle_error(sb);
++}
++
++static const char *ext3cow_decode_error(struct super_block * sb, int errno,
++				     char nbuf[16])
++{
++	char *errstr = NULL;
++
++	switch (errno) {
++	case -EIO:
++		errstr = "IO failure";
++		break;
++	case -ENOMEM:
++		errstr = "Out of memory";
++		break;
++	case -EROFS:
++		if (!sb || EXT3COW_SB(sb)->s_journal->j_flags & JFS_ABORT)
++			errstr = "Journal has aborted";
++		else
++			errstr = "Readonly filesystem";
++		break;
++	default:
++		/* If the caller passed in an extra buffer for unknown
++		 * errors, textualise them now.  Else we just return
++		 * NULL. */
++		if (nbuf) {
++			/* Check for truncated error codes... */
++			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
++				errstr = nbuf;
++		}
++		break;
++	}
++
++	return errstr;
++}
++
++/* __ext3cow_std_error decodes expected errors from journaling functions
++ * automatically and invokes the appropriate error response.  */
++
++void __ext3cow_std_error (struct super_block * sb, const char * function,
++		       int errno)
++{
++	char nbuf[16];
++	const char *errstr;
++
++	/* Special case: if the error is EROFS, and we're not already
++	 * inside a transaction, then there's really no point in logging
++	 * an error. */
++	if (errno == -EROFS && journal_current_handle() == NULL &&
++	    (sb->s_flags & MS_RDONLY))
++		return;
++
++	errstr = ext3cow_decode_error(sb, errno, nbuf);
++	printk (KERN_CRIT "EXT3COW-fs error (device %s) in %s: %s\n",
++		sb->s_id, function, errstr);
++
++	ext3cow_handle_error(sb);
++}
++
++/*
++ * ext3cow_abort is a much stronger failure handler than ext3cow_error.  The
++ * abort function may be used to deal with unrecoverable failures such
++ * as journal IO errors or ENOMEM at a critical moment in log management.
++ *
++ * We unconditionally force the filesystem into an ABORT|READONLY state,
++ * unless the error response on the fs has been set to panic in which
++ * case we take the easy way out and panic immediately.
++ */
++
++void ext3cow_abort (struct super_block * sb, const char * function,
++		 const char * fmt, ...)
++{
++	va_list args;
++
++	printk (KERN_CRIT "ext3cow_abort called.\n");
++
++	va_start(args, fmt);
++	printk(KERN_CRIT "EXT3COW-fs error (device %s): %s: ",sb->s_id, function);
++	vprintk(fmt, args);
++	printk("\n");
++	va_end(args);
++
++	if (test_opt(sb, ERRORS_PANIC))
++		panic("EXT3COW-fs panic from previous error\n");
++
++	if (sb->s_flags & MS_RDONLY)
++		return;
++
++	printk(KERN_CRIT "Remounting filesystem read-only\n");
++	EXT3COW_SB(sb)->s_mount_state |= EXT3COW_ERROR_FS;
++	sb->s_flags |= MS_RDONLY;
++	EXT3COW_SB(sb)->s_mount_opt |= EXT3COW_MOUNT_ABORT;
++	journal_abort(EXT3COW_SB(sb)->s_journal, -EIO);
++}
++
++void ext3cow_warning (struct super_block * sb, const char * function,
++		   const char * fmt, ...)
++{
++	va_list args;
++
++	va_start(args, fmt);
++	printk(KERN_WARNING "EXT3COW-fs warning (device %s): %s: ",
++	       sb->s_id, function);
++	vprintk(fmt, args);
++	printk("\n");
++	va_end(args);
++}
++
++void ext3cow_update_dynamic_rev(struct super_block *sb)
++{
++	struct ext3cow_super_block *es = EXT3COW_SB(sb)->s_es;
++
++	if (le32_to_cpu(es->s_rev_level) > EXT3COW_GOOD_OLD_REV)
++		return;
++
++	ext3cow_warning(sb, __FUNCTION__,
++		     "updating to rev %d because of new feature flag, "
++		     "running e2fsck is recommended",
++		     EXT3COW_DYNAMIC_REV);
++
++	es->s_first_ino = cpu_to_le32(EXT3COW_GOOD_OLD_FIRST_INO);
++	es->s_inode_size = cpu_to_le16(EXT3COW_GOOD_OLD_INODE_SIZE);
++	es->s_rev_level = cpu_to_le32(EXT3COW_DYNAMIC_REV);
++	/* leave es->s_feature_*compat flags alone */
++	/* es->s_uuid will be set by e2fsck if empty */
++
++	/*
++	 * The rest of the superblock fields should be zero, and if not it
++	 * means they are likely already in use, so leave them alone.  We
++	 * can leave it up to e2fsck to clean up any inconsistencies there.
++	 */
++}
++
++/*
++ * Open the external journal device
++ */
++static struct block_device *ext3cow_blkdev_get(dev_t dev)
++{
++	struct block_device *bdev;
++	char b[BDEVNAME_SIZE];
++
++	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
++	if (IS_ERR(bdev))
++		goto fail;
++	return bdev;
++
++fail:
++	printk(KERN_ERR "EXT3COW: failed to open journal device %s: %ld\n",
++			__bdevname(dev, b), PTR_ERR(bdev));
++	return NULL;
++}
++
++/*
++ * Release the journal device
++ */
++static int ext3cow_blkdev_put(struct block_device *bdev)
++{
++	bd_release(bdev);
++	return blkdev_put(bdev);
++}
++
++static int ext3cow_blkdev_remove(struct ext3cow_sb_info *sbi)
++{
++	struct block_device *bdev;
++	int ret = -ENODEV;
++
++	bdev = sbi->journal_bdev;
++	if (bdev) {
++		ret = ext3cow_blkdev_put(bdev);
++		sbi->journal_bdev = NULL;
++	}
++	return ret;
++}
++
++static inline struct inode *orphan_list_entry(struct list_head *l)
++{
++	return &list_entry(l, struct ext3cow_inode_info, i_orphan)->vfs_inode;
++}
++
++static void dump_orphan_list(struct super_block *sb, struct ext3cow_sb_info *sbi)
++{
++	struct list_head *l;
++
++	printk(KERN_ERR "sb orphan head is %d\n",
++	       le32_to_cpu(sbi->s_es->s_last_orphan));
++
++	printk(KERN_ERR "sb_info orphan list:\n");
++	list_for_each(l, &sbi->s_orphan) {
++		struct inode *inode = orphan_list_entry(l);
++		printk(KERN_ERR "  "
++		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
++		       inode->i_sb->s_id, inode->i_ino, inode,
++		       inode->i_mode, inode->i_nlink,
++		       NEXT_ORPHAN(inode));
++	}
++}
++
++static void ext3cow_put_super (struct super_block * sb)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	struct ext3cow_super_block *es = sbi->s_es;
++	int i;
++
++	ext3cow_xattr_put_super(sb);
++	journal_destroy(sbi->s_journal);
++	if (!(sb->s_flags & MS_RDONLY)) {
++		EXT3COW_CLEAR_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++		es->s_state = cpu_to_le16(sbi->s_mount_state);
++		BUFFER_TRACE(sbi->s_sbh, "marking dirty");
++		mark_buffer_dirty(sbi->s_sbh);
++		ext3cow_commit_super(sb, es, 1);
++	}
++
++	for (i = 0; i < sbi->s_gdb_count; i++)
++		brelse(sbi->s_group_desc[i]);
++	kfree(sbi->s_group_desc);
++	percpu_counter_destroy(&sbi->s_freeblocks_counter);
++	percpu_counter_destroy(&sbi->s_freeinodes_counter);
++	percpu_counter_destroy(&sbi->s_dirs_counter);
++	brelse(sbi->s_sbh);
++#ifdef CONFIG_QUOTA
++	for (i = 0; i < MAXQUOTAS; i++)
++		kfree(sbi->s_qf_names[i]);
++#endif
++
++	/* Debugging code just in case the in-memory inode orphan list
++	 * isn't empty.  The on-disk one can be non-empty if we've
++	 * detected an error and taken the fs readonly, but the
++	 * in-memory list had better be clean by this point. */
++	if (!list_empty(&sbi->s_orphan))
++		dump_orphan_list(sb, sbi);
++	J_ASSERT(list_empty(&sbi->s_orphan));
++
++	invalidate_bdev(sb->s_bdev, 0);
++	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
++		/*
++		 * Invalidate the journal device's buffers.  We don't want them
++		 * floating about in memory - the physical journal device may
++		 * hotswapped, and it breaks the `ro-after' testing code.
++		 */
++		sync_blockdev(sbi->journal_bdev);
++		invalidate_bdev(sbi->journal_bdev, 0);
++		ext3cow_blkdev_remove(sbi);
++	}
++	sb->s_fs_info = NULL;
++	kfree(sbi);
++	return;
++}
++
++static struct kmem_cache *ext3cow_inode_cachep;
++
++/*
++ * Called inside transaction, so use GFP_NOFS
++ */
++static struct inode *ext3cow_alloc_inode(struct super_block *sb)
++{
++	struct ext3cow_inode_info *ei;
++
++	ei = kmem_cache_alloc(ext3cow_inode_cachep, GFP_NOFS);
++	if (!ei)
++		return NULL;
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	ei->i_acl = EXT3COW_ACL_NOT_CACHED;
++	ei->i_default_acl = EXT3COW_ACL_NOT_CACHED;
++#endif
++	ei->i_block_alloc_info = NULL;
++	ei->vfs_inode.i_version = 1;
++	return &ei->vfs_inode;
++}
++
++static void ext3cow_destroy_inode(struct inode *inode)
++{
++	kmem_cache_free(ext3cow_inode_cachep, EXT3COW_I(inode));
++}
++
++static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
++{
++	struct ext3cow_inode_info *ei = (struct ext3cow_inode_info *) foo;
++
++	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
++	    SLAB_CTOR_CONSTRUCTOR) {
++		INIT_LIST_HEAD(&ei->i_orphan);
++#ifdef CONFIG_EXT3COW_FS_XATTR
++		init_rwsem(&ei->xattr_sem);
++#endif
++		mutex_init(&ei->truncate_mutex);
++		inode_init_once(&ei->vfs_inode);
++	}
++}
++
++static int init_inodecache(void)
++{
++	ext3cow_inode_cachep = kmem_cache_create("ext3cow_inode_cache",
++					     sizeof(struct ext3cow_inode_info),
++					     0, (SLAB_RECLAIM_ACCOUNT|
++						SLAB_MEM_SPREAD),
++					     init_once, NULL);
++	if (ext3cow_inode_cachep == NULL)
++		return -ENOMEM;
++	return 0;
++}
++
++static void destroy_inodecache(void)
++{
++	kmem_cache_destroy(ext3cow_inode_cachep);
++}
++
++static void ext3cow_clear_inode(struct inode *inode)
++{
++	struct ext3cow_block_alloc_info *rsv = EXT3COW_I(inode)->i_block_alloc_info;
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	if (EXT3COW_I(inode)->i_acl &&
++			EXT3COW_I(inode)->i_acl != EXT3COW_ACL_NOT_CACHED) {
++		posix_acl_release(EXT3COW_I(inode)->i_acl);
++		EXT3COW_I(inode)->i_acl = EXT3COW_ACL_NOT_CACHED;
++	}
++	if (EXT3COW_I(inode)->i_default_acl &&
++			EXT3COW_I(inode)->i_default_acl != EXT3COW_ACL_NOT_CACHED) {
++		posix_acl_release(EXT3COW_I(inode)->i_default_acl);
++		EXT3COW_I(inode)->i_default_acl = EXT3COW_ACL_NOT_CACHED;
++	}
++#endif
++	ext3cow_discard_reservation(inode);
++	EXT3COW_I(inode)->i_block_alloc_info = NULL;
++	if (unlikely(rsv))
++		kfree(rsv);
++}
++
++static inline void ext3cow_show_quota_options(struct seq_file *seq, struct super_block *sb)
++{
++#if defined(CONFIG_QUOTA)
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++
++	if (sbi->s_jquota_fmt)
++		seq_printf(seq, ",jqfmt=%s",
++		(sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");
++
++	if (sbi->s_qf_names[USRQUOTA])
++		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
++
++	if (sbi->s_qf_names[GRPQUOTA])
++		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
++
++	if (sbi->s_mount_opt & EXT3COW_MOUNT_USRQUOTA)
++		seq_puts(seq, ",usrquota");
++
++	if (sbi->s_mount_opt & EXT3COW_MOUNT_GRPQUOTA)
++		seq_puts(seq, ",grpquota");
++#endif
++}
++
++static int ext3cow_show_options(struct seq_file *seq, struct vfsmount *vfs)
++{
++	struct super_block *sb = vfs->mnt_sb;
++
++	if (test_opt(sb, DATA_FLAGS) == EXT3COW_MOUNT_JOURNAL_DATA)
++		seq_puts(seq, ",data=journal");
++	else if (test_opt(sb, DATA_FLAGS) == EXT3COW_MOUNT_ORDERED_DATA)
++		seq_puts(seq, ",data=ordered");
++	else if (test_opt(sb, DATA_FLAGS) == EXT3COW_MOUNT_WRITEBACK_DATA)
++		seq_puts(seq, ",data=writeback");
++
++	ext3cow_show_quota_options(seq, sb);
++
++	return 0;
++}
++
++
++static struct dentry *ext3cow_get_dentry(struct super_block *sb, void *vobjp)
++{
++	__u32 *objp = vobjp;
++	unsigned long ino = objp[0];
++	__u32 generation = objp[1];
++	struct inode *inode;
++	struct dentry *result;
++
++	if (ino < EXT3COW_FIRST_INO(sb) && ino != EXT3COW_ROOT_INO)
++		return ERR_PTR(-ESTALE);
++	if (ino > le32_to_cpu(EXT3COW_SB(sb)->s_es->s_inodes_count))
++		return ERR_PTR(-ESTALE);
++
++	/* iget isn't really right if the inode is currently unallocated!!
++	 *
++	 * ext3cow_read_inode will return a bad_inode if the inode had been
++	 * deleted, so we should be safe.
++	 *
++	 * Currently we don't know the generation for parent directory, so
++	 * a generation of 0 means "accept any"
++	 */
++	inode = iget(sb, ino);
++	if (inode == NULL)
++		return ERR_PTR(-ENOMEM);
++	if (is_bad_inode(inode) ||
++	    (generation && inode->i_generation != generation)) {
++		iput(inode);
++		return ERR_PTR(-ESTALE);
++	}
++	/* now to find a dentry.
++	 * If possible, get a well-connected one
++	 */
++	result = d_alloc_anon(inode);
++	if (!result) {
++		iput(inode);
++		return ERR_PTR(-ENOMEM);
++	}
++	return result;
++}
++
++#ifdef CONFIG_QUOTA
++#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
++#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
++
++static int ext3cow_dquot_initialize(struct inode *inode, int type);
++static int ext3cow_dquot_drop(struct inode *inode);
++static int ext3cow_write_dquot(struct dquot *dquot);
++static int ext3cow_acquire_dquot(struct dquot *dquot);
++static int ext3cow_release_dquot(struct dquot *dquot);
++static int ext3cow_mark_dquot_dirty(struct dquot *dquot);
++static int ext3cow_write_info(struct super_block *sb, int type);
++static int ext3cow_quota_on(struct super_block *sb, int type, int format_id, char *path);
++static int ext3cow_quota_on_mount(struct super_block *sb, int type);
++static ssize_t ext3cow_quota_read(struct super_block *sb, int type, char *data,
++			       size_t len, loff_t off);
++static ssize_t ext3cow_quota_write(struct super_block *sb, int type,
++				const char *data, size_t len, loff_t off);
++
++static struct dquot_operations ext3cow_quota_operations = {
++	.initialize	= ext3cow_dquot_initialize,
++	.drop		= ext3cow_dquot_drop,
++	.alloc_space	= dquot_alloc_space,
++	.alloc_inode	= dquot_alloc_inode,
++	.free_space	= dquot_free_space,
++	.free_inode	= dquot_free_inode,
++	.transfer	= dquot_transfer,
++	.write_dquot	= ext3cow_write_dquot,
++	.acquire_dquot	= ext3cow_acquire_dquot,
++	.release_dquot	= ext3cow_release_dquot,
++	.mark_dirty	= ext3cow_mark_dquot_dirty,
++	.write_info	= ext3cow_write_info
++};
++
++static struct quotactl_ops ext3cow_qctl_operations = {
++	.quota_on	= ext3cow_quota_on,
++	.quota_off	= vfs_quota_off,
++	.quota_sync	= vfs_quota_sync,
++	.get_info	= vfs_get_dqinfo,
++	.set_info	= vfs_set_dqinfo,
++	.get_dqblk	= vfs_get_dqblk,
++	.set_dqblk	= vfs_set_dqblk
++};
++#endif
++
++static struct super_operations ext3cow_sops = {
++	.alloc_inode	= ext3cow_alloc_inode,
++	.destroy_inode	= ext3cow_destroy_inode,
++	.read_inode	= ext3cow_read_inode,
++	.write_inode	= ext3cow_write_inode,
++	.dirty_inode	= ext3cow_dirty_inode,
++	.delete_inode	= ext3cow_delete_inode,
++	.put_super	= ext3cow_put_super,
++	.write_super	= ext3cow_write_super,
++	.sync_fs	= ext3cow_sync_fs,
++	.write_super_lockfs = ext3cow_write_super_lockfs,
++	.unlockfs	= ext3cow_unlockfs,
++	.statfs		= ext3cow_statfs,
++	.remount_fs	= ext3cow_remount,
++	.clear_inode	= ext3cow_clear_inode,
++	.show_options	= ext3cow_show_options,
++#ifdef CONFIG_QUOTA
++	.quota_read	= ext3cow_quota_read,
++	.quota_write	= ext3cow_quota_write,
++#endif
++};
++
++static struct export_operations ext3cow_export_ops = {
++	.get_parent = ext3cow_get_parent,
++	.get_dentry = ext3cow_get_dentry,
++};
++
++enum {
++	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
++	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
++	Opt_nouid32, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
++	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
++	Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
++	Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
++	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
++	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
++	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
++	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
++	Opt_grpquota
++};
++
++static match_table_t tokens = {
++	{Opt_bsd_df, "bsddf"},
++	{Opt_minix_df, "minixdf"},
++	{Opt_grpid, "grpid"},
++	{Opt_grpid, "bsdgroups"},
++	{Opt_nogrpid, "nogrpid"},
++	{Opt_nogrpid, "sysvgroups"},
++	{Opt_resgid, "resgid=%u"},
++	{Opt_resuid, "resuid=%u"},
++	{Opt_sb, "sb=%u"},
++	{Opt_err_cont, "errors=continue"},
++	{Opt_err_panic, "errors=panic"},
++	{Opt_err_ro, "errors=remount-ro"},
++	{Opt_nouid32, "nouid32"},
++	{Opt_nocheck, "nocheck"},
++	{Opt_nocheck, "check=none"},
++	{Opt_debug, "debug"},
++	{Opt_oldalloc, "oldalloc"},
++	{Opt_orlov, "orlov"},
++	{Opt_user_xattr, "user_xattr"},
++	{Opt_nouser_xattr, "nouser_xattr"},
++	{Opt_acl, "acl"},
++	{Opt_noacl, "noacl"},
++	{Opt_reservation, "reservation"},
++	{Opt_noreservation, "noreservation"},
++	{Opt_noload, "noload"},
++	{Opt_nobh, "nobh"},
++	{Opt_bh, "bh"},
++	{Opt_commit, "commit=%u"},
++	{Opt_journal_update, "journal=update"},
++	{Opt_journal_inum, "journal=%u"},
++	{Opt_journal_dev, "journal_dev=%u"},
++	{Opt_abort, "abort"},
++	{Opt_data_journal, "data=journal"},
++	{Opt_data_ordered, "data=ordered"},
++	{Opt_data_writeback, "data=writeback"},
++	{Opt_offusrjquota, "usrjquota="},
++	{Opt_usrjquota, "usrjquota=%s"},
++	{Opt_offgrpjquota, "grpjquota="},
++	{Opt_grpjquota, "grpjquota=%s"},
++	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
++	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
++	{Opt_grpquota, "grpquota"},
++	{Opt_noquota, "noquota"},
++	{Opt_quota, "quota"},
++	{Opt_usrquota, "usrquota"},
++	{Opt_barrier, "barrier=%u"},
++	{Opt_err, NULL},
++	{Opt_resize, "resize"},
++};
++
++static ext3cow_fsblk_t get_sb_block(void **data)
++{
++	ext3cow_fsblk_t	sb_block;
++	char		*options = (char *) *data;
++
++	if (!options || strncmp(options, "sb=", 3) != 0)
++		return 1;	/* Default location */
++	options += 3;
++	/*todo: use simple_strtoll with >32bit ext3cow */
++	sb_block = simple_strtoul(options, &options, 0);
++	if (*options && *options != ',') {
++		printk("EXT3COW-fs: Invalid sb specification: %s\n",
++		       (char *) *data);
++		return 1;
++	}
++	if (*options == ',')
++		options++;
++	*data = (void *) options;
++	return sb_block;
++}
++
++static int parse_options (char *options, struct super_block *sb,
++			  unsigned int *inum, unsigned long *journal_devnum,
++			  ext3cow_fsblk_t *n_blocks_count, int is_remount)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	char * p;
++	substring_t args[MAX_OPT_ARGS];
++	int data_opt = 0;
++	int option;
++#ifdef CONFIG_QUOTA
++	int qtype;
++	char *qname;
++#endif
++
++	if (!options)
++		return 1;
++
++	while ((p = strsep (&options, ",")) != NULL) {
++		int token;
++		if (!*p)
++			continue;
++
++		token = match_token(p, tokens, args);
++		switch (token) {
++		case Opt_bsd_df:
++			clear_opt (sbi->s_mount_opt, MINIX_DF);
++			break;
++		case Opt_minix_df:
++			set_opt (sbi->s_mount_opt, MINIX_DF);
++			break;
++		case Opt_grpid:
++			set_opt (sbi->s_mount_opt, GRPID);
++			break;
++		case Opt_nogrpid:
++			clear_opt (sbi->s_mount_opt, GRPID);
++			break;
++		case Opt_resuid:
++			if (match_int(&args[0], &option))
++				return 0;
++			sbi->s_resuid = option;
++			break;
++		case Opt_resgid:
++			if (match_int(&args[0], &option))
++				return 0;
++			sbi->s_resgid = option;
++			break;
++		case Opt_sb:
++			/* handled by get_sb_block() instead of here */
++			/* *sb_block = match_int(&args[0]); */
++			break;
++		case Opt_err_panic:
++			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
++			clear_opt (sbi->s_mount_opt, ERRORS_RO);
++			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
++			break;
++		case Opt_err_ro:
++			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
++			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
++			set_opt (sbi->s_mount_opt, ERRORS_RO);
++			break;
++		case Opt_err_cont:
++			clear_opt (sbi->s_mount_opt, ERRORS_RO);
++			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
++			set_opt (sbi->s_mount_opt, ERRORS_CONT);
++			break;
++		case Opt_nouid32:
++			set_opt (sbi->s_mount_opt, NO_UID32);
++			break;
++		case Opt_nocheck:
++			clear_opt (sbi->s_mount_opt, CHECK);
++			break;
++		case Opt_debug:
++			set_opt (sbi->s_mount_opt, DEBUG);
++			break;
++		case Opt_oldalloc:
++			set_opt (sbi->s_mount_opt, OLDALLOC);
++			break;
++		case Opt_orlov:
++			clear_opt (sbi->s_mount_opt, OLDALLOC);
++			break;
++#ifdef CONFIG_EXT3COW_FS_XATTR
++		case Opt_user_xattr:
++			set_opt (sbi->s_mount_opt, XATTR_USER);
++			break;
++		case Opt_nouser_xattr:
++			clear_opt (sbi->s_mount_opt, XATTR_USER);
++			break;
++#else
++		case Opt_user_xattr:
++		case Opt_nouser_xattr:
++			printk("EXT3COW (no)user_xattr options not supported\n");
++			break;
++#endif
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++		case Opt_acl:
++			set_opt(sbi->s_mount_opt, POSIX_ACL);
++			break;
++		case Opt_noacl:
++			clear_opt(sbi->s_mount_opt, POSIX_ACL);
++			break;
++#else
++		case Opt_acl:
++		case Opt_noacl:
++			printk("EXT3COW (no)acl options not supported\n");
++			break;
++#endif
++		case Opt_reservation:
++			set_opt(sbi->s_mount_opt, RESERVATION);
++			break;
++		case Opt_noreservation:
++			clear_opt(sbi->s_mount_opt, RESERVATION);
++			break;
++		case Opt_journal_update:
++			/* @@@ FIXME */
++			/* Eventually we will want to be able to create
++			   a journal file here.  For now, only allow the
++			   user to specify an existing inode to be the
++			   journal file. */
++			if (is_remount) {
++				printk(KERN_ERR "EXT3COW-fs: cannot specify "
++				       "journal on remount\n");
++				return 0;
++			}
++			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
++			break;
++		case Opt_journal_inum:
++			if (is_remount) {
++				printk(KERN_ERR "EXT3COW-fs: cannot specify "
++				       "journal on remount\n");
++				return 0;
++			}
++			if (match_int(&args[0], &option))
++				return 0;
++			*inum = option;
++			break;
++		case Opt_journal_dev:
++			if (is_remount) {
++				printk(KERN_ERR "EXT3COW-fs: cannot specify "
++				       "journal on remount\n");
++				return 0;
++			}
++			if (match_int(&args[0], &option))
++				return 0;
++			*journal_devnum = option;
++			break;
++		case Opt_noload:
++			set_opt (sbi->s_mount_opt, NOLOAD);
++			break;
++		case Opt_commit:
++			if (match_int(&args[0], &option))
++				return 0;
++			if (option < 0)
++				return 0;
++			if (option == 0)
++				option = JBD_DEFAULT_MAX_COMMIT_AGE;
++			sbi->s_commit_interval = HZ * option;
++			break;
++		case Opt_data_journal:
++			data_opt = EXT3COW_MOUNT_JOURNAL_DATA;
++			goto datacheck;
++		case Opt_data_ordered:
++			data_opt = EXT3COW_MOUNT_ORDERED_DATA;
++			goto datacheck;
++		case Opt_data_writeback:
++			data_opt = EXT3COW_MOUNT_WRITEBACK_DATA;
++		datacheck:
++			if (is_remount) {
++				if ((sbi->s_mount_opt & EXT3COW_MOUNT_DATA_FLAGS)
++						!= data_opt) {
++					printk(KERN_ERR
++						"EXT3COW-fs: cannot change data "
++						"mode on remount\n");
++					return 0;
++				}
++			} else {
++				sbi->s_mount_opt &= ~EXT3COW_MOUNT_DATA_FLAGS;
++				sbi->s_mount_opt |= data_opt;
++			}
++			break;
++#ifdef CONFIG_QUOTA
++		case Opt_usrjquota:
++			qtype = USRQUOTA;
++			goto set_qf_name;
++		case Opt_grpjquota:
++			qtype = GRPQUOTA;
++set_qf_name:
++			if (sb_any_quota_enabled(sb)) {
++				printk(KERN_ERR
++					"EXT3COW-fs: Cannot change journalled "
++					"quota options when quota turned on.\n");
++				return 0;
++			}
++			qname = match_strdup(&args[0]);
++			if (!qname) {
++				printk(KERN_ERR
++					"EXT3COW-fs: not enough memory for "
++					"storing quotafile name.\n");
++				return 0;
++			}
++			if (sbi->s_qf_names[qtype] &&
++			    strcmp(sbi->s_qf_names[qtype], qname)) {
++				printk(KERN_ERR
++					"EXT3COW-fs: %s quota file already "
++					"specified.\n", QTYPE2NAME(qtype));
++				kfree(qname);
++				return 0;
++			}
++			sbi->s_qf_names[qtype] = qname;
++			if (strchr(sbi->s_qf_names[qtype], '/')) {
++				printk(KERN_ERR
++					"EXT3COW-fs: quotafile must be on "
++					"filesystem root.\n");
++				kfree(sbi->s_qf_names[qtype]);
++				sbi->s_qf_names[qtype] = NULL;
++				return 0;
++			}
++			set_opt(sbi->s_mount_opt, QUOTA);
++			break;
++		case Opt_offusrjquota:
++			qtype = USRQUOTA;
++			goto clear_qf_name;
++		case Opt_offgrpjquota:
++			qtype = GRPQUOTA;
++clear_qf_name:
++			if (sb_any_quota_enabled(sb)) {
++				printk(KERN_ERR "EXT3COW-fs: Cannot change "
++					"journalled quota options when "
++					"quota turned on.\n");
++				return 0;
++			}
++			/*
++			 * The space will be released later when all options
++			 * are confirmed to be correct
++			 */
++			sbi->s_qf_names[qtype] = NULL;
++			break;
++		case Opt_jqfmt_vfsold:
++			sbi->s_jquota_fmt = QFMT_VFS_OLD;
++			break;
++		case Opt_jqfmt_vfsv0:
++			sbi->s_jquota_fmt = QFMT_VFS_V0;
++			break;
++		case Opt_quota:
++		case Opt_usrquota:
++			set_opt(sbi->s_mount_opt, QUOTA);
++			set_opt(sbi->s_mount_opt, USRQUOTA);
++			break;
++		case Opt_grpquota:
++			set_opt(sbi->s_mount_opt, QUOTA);
++			set_opt(sbi->s_mount_opt, GRPQUOTA);
++			break;
++		case Opt_noquota:
++			if (sb_any_quota_enabled(sb)) {
++				printk(KERN_ERR "EXT3COW-fs: Cannot change quota "
++					"options when quota turned on.\n");
++				return 0;
++			}
++			clear_opt(sbi->s_mount_opt, QUOTA);
++			clear_opt(sbi->s_mount_opt, USRQUOTA);
++			clear_opt(sbi->s_mount_opt, GRPQUOTA);
++			break;
++#else
++		case Opt_quota:
++		case Opt_usrquota:
++		case Opt_grpquota:
++		case Opt_usrjquota:
++		case Opt_grpjquota:
++		case Opt_offusrjquota:
++		case Opt_offgrpjquota:
++		case Opt_jqfmt_vfsold:
++		case Opt_jqfmt_vfsv0:
++			printk(KERN_ERR
++				"EXT3COW-fs: journalled quota options not "
++				"supported.\n");
++			break;
++		case Opt_noquota:
++			break;
++#endif
++		case Opt_abort:
++			set_opt(sbi->s_mount_opt, ABORT);
++			break;
++		case Opt_barrier:
++			if (match_int(&args[0], &option))
++				return 0;
++			if (option)
++				set_opt(sbi->s_mount_opt, BARRIER);
++			else
++				clear_opt(sbi->s_mount_opt, BARRIER);
++			break;
++		case Opt_ignore:
++			break;
++		case Opt_resize:
++			if (!is_remount) {
++				printk("EXT3COW-fs: resize option only available "
++					"for remount\n");
++				return 0;
++			}
++			if (match_int(&args[0], &option) != 0)
++				return 0;
++			*n_blocks_count = option;
++			break;
++		case Opt_nobh:
++			set_opt(sbi->s_mount_opt, NOBH);
++			break;
++		case Opt_bh:
++			clear_opt(sbi->s_mount_opt, NOBH);
++			break;
++		default:
++			printk (KERN_ERR
++				"EXT3COW-fs: Unrecognized mount option \"%s\" "
++				"or missing value\n", p);
++			return 0;
++		}
++	}
++#ifdef CONFIG_QUOTA
++	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
++		if ((sbi->s_mount_opt & EXT3COW_MOUNT_USRQUOTA) &&
++		     sbi->s_qf_names[USRQUOTA])
++			clear_opt(sbi->s_mount_opt, USRQUOTA);
++
++		if ((sbi->s_mount_opt & EXT3COW_MOUNT_GRPQUOTA) &&
++		     sbi->s_qf_names[GRPQUOTA])
++			clear_opt(sbi->s_mount_opt, GRPQUOTA);
++
++		if ((sbi->s_qf_names[USRQUOTA] &&
++				(sbi->s_mount_opt & EXT3COW_MOUNT_GRPQUOTA)) ||
++		    (sbi->s_qf_names[GRPQUOTA] &&
++				(sbi->s_mount_opt & EXT3COW_MOUNT_USRQUOTA))) {
++			printk(KERN_ERR "EXT3COW-fs: old and new quota "
++					"format mixing.\n");
++			return 0;
++		}
++
++		if (!sbi->s_jquota_fmt) {
++			printk(KERN_ERR "EXT3COW-fs: journalled quota format "
++					"not specified.\n");
++			return 0;
++		}
++	} else {
++		if (sbi->s_jquota_fmt) {
++			printk(KERN_ERR "EXT3COW-fs: journalled quota format "
++					"specified with no journalling "
++					"enabled.\n");
++			return 0;
++		}
++	}
++#endif
++	return 1;
++}
++
++static int ext3cow_setup_super(struct super_block *sb, struct ext3cow_super_block *es,
++			    int read_only)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	int res = 0;
++
++	if (le32_to_cpu(es->s_rev_level) > EXT3COW_MAX_SUPP_REV) {
++		printk (KERN_ERR "EXT3COW-fs warning: revision level too high, "
++			"forcing read-only mode\n");
++		res = MS_RDONLY;
++	}
++	if (read_only)
++		return res;
++	if (!(sbi->s_mount_state & EXT3COW_VALID_FS))
++		printk (KERN_WARNING "EXT3COW-fs warning: mounting unchecked fs, "
++			"running e2fsck is recommended\n");
++	else if ((sbi->s_mount_state & EXT3COW_ERROR_FS))
++		printk (KERN_WARNING
++			"EXT3COW-fs warning: mounting fs with errors, "
++			"running e2fsck is recommended\n");
++	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
++		 le16_to_cpu(es->s_mnt_count) >=
++		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
++		printk (KERN_WARNING
++			"EXT3COW-fs warning: maximal mount count reached, "
++			"running e2fsck is recommended\n");
++	else if (le32_to_cpu(es->s_checkinterval) &&
++		(le32_to_cpu(es->s_lastcheck) +
++			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
++		printk (KERN_WARNING
++			"EXT3COW-fs warning: checktime reached, "
++			"running e2fsck is recommended\n");
++#if 0
++		/* @@@ We _will_ want to clear the valid bit if we find
++                   inconsistencies, to force a fsck at reboot.  But for
++                   a plain journaled filesystem we can keep it set as
++                   valid forever! :) */
++	es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT3COW_VALID_FS);
++#endif
++	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
++		es->s_max_mnt_count = cpu_to_le16(EXT3COW_DFL_MAX_MNT_COUNT);
++	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
++	es->s_mtime = cpu_to_le32(get_seconds());
++	ext3cow_update_dynamic_rev(sb);
++	EXT3COW_SET_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++
++	ext3cow_commit_super(sb, es, 1);
++	if (test_opt(sb, DEBUG))
++		printk(KERN_INFO "[EXT3COW FS bs=%lu, gc=%lu, "
++				"bpg=%lu, ipg=%lu, mo=%04lx]\n",
++			sb->s_blocksize,
++			sbi->s_groups_count,
++			EXT3COW_BLOCKS_PER_GROUP(sb),
++			EXT3COW_INODES_PER_GROUP(sb),
++			sbi->s_mount_opt);
++
++	printk(KERN_INFO "EXT3COW FS on %s, ", sb->s_id);
++	if (EXT3COW_SB(sb)->s_journal->j_inode == NULL) {
++		char b[BDEVNAME_SIZE];
++
++		printk("external journal on %s\n",
++			bdevname(EXT3COW_SB(sb)->s_journal->j_dev, b));
++	} else {
++		printk("internal journal\n");
++	}
++	return res;
++}
++
++/* Called at mount-time, super-block is locked */
++static int ext3cow_check_descriptors (struct super_block * sb)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	ext3cow_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
++	ext3cow_fsblk_t last_block;
++	struct ext3cow_group_desc * gdp = NULL;
++	int desc_block = 0;
++	int i;
++
++	ext3cow_debug ("Checking group descriptors");
++
++	for (i = 0; i < sbi->s_groups_count; i++)
++	{
++		if (i == sbi->s_groups_count - 1)
++			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
++		else
++			last_block = first_block +
++				(EXT3COW_BLOCKS_PER_GROUP(sb) - 1);
++
++		if ((i % EXT3COW_DESC_PER_BLOCK(sb)) == 0)
++			gdp = (struct ext3cow_group_desc *)
++					sbi->s_group_desc[desc_block++]->b_data;
++		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
++		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
++		{
++			ext3cow_error (sb, "ext3cow_check_descriptors",
++				    "Block bitmap for group %d"
++				    " not in group (block %lu)!",
++				    i, (unsigned long)
++					le32_to_cpu(gdp->bg_block_bitmap));
++			return 0;
++		}
++		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
++		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
++		{
++			ext3cow_error (sb, "ext3cow_check_descriptors",
++				    "Inode bitmap for group %d"
++				    " not in group (block %lu)!",
++				    i, (unsigned long)
++					le32_to_cpu(gdp->bg_inode_bitmap));
++			return 0;
++		}
++		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
++		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
++		    last_block)
++		{
++			ext3cow_error (sb, "ext3cow_check_descriptors",
++				    "Inode table for group %d"
++				    " not in group (block %lu)!",
++				    i, (unsigned long)
++					le32_to_cpu(gdp->bg_inode_table));
++			return 0;
++		}
++		first_block += EXT3COW_BLOCKS_PER_GROUP(sb);
++		gdp++;
++	}
++
++	sbi->s_es->s_free_blocks_count=cpu_to_le32(ext3cow_count_free_blocks(sb));
++	sbi->s_es->s_free_inodes_count=cpu_to_le32(ext3cow_count_free_inodes(sb));
++	return 1;
++}
++
++
++/* ext3cow_orphan_cleanup() walks a singly-linked list of inodes (starting at
++ * the superblock) which were deleted from all directories, but held open by
++ * a process at the time of a crash.  We walk the list and try to delete these
++ * inodes at recovery time (only with a read-write filesystem).
++ *
++ * In order to keep the orphan inode chain consistent during traversal (in
++ * case of crash during recovery), we link each inode into the superblock
++ * orphan list_head and handle it the same way as an inode deletion during
++ * normal operation (which journals the operations for us).
++ *
++ * We only do an iget() and an iput() on each inode, which is very safe if we
++ * accidentally point at an in-use or already deleted inode.  The worst that
++ * can happen in this case is that we get a "bit already cleared" message from
++ * ext3cow_free_inode().  The only reason we would point at a wrong inode is if
++ * e2fsck was run on this filesystem, and it must have already done the orphan
++ * inode cleanup for us, so we can safely abort without any further action.
++ */
++static void ext3cow_orphan_cleanup (struct super_block * sb,
++				 struct ext3cow_super_block * es)
++{
++	unsigned int s_flags = sb->s_flags;
++	int nr_orphans = 0, nr_truncates = 0;
++#ifdef CONFIG_QUOTA
++	int i;
++#endif
++	if (!es->s_last_orphan) {
++		jbd_debug(4, "no orphan inodes to clean up\n");
++		return;
++	}
++
++	if (bdev_read_only(sb->s_bdev)) {
++		printk(KERN_ERR "EXT3COW-fs: write access "
++			"unavailable, skipping orphan cleanup.\n");
++		return;
++	}
++
++	if (EXT3COW_SB(sb)->s_mount_state & EXT3COW_ERROR_FS) {
++		if (es->s_last_orphan)
++			jbd_debug(1, "Errors on filesystem, "
++				  "clearing orphan list.\n");
++		es->s_last_orphan = 0;
++		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
++		return;
++	}
++
++	if (s_flags & MS_RDONLY) {
++		printk(KERN_INFO "EXT3COW-fs: %s: orphan cleanup on readonly fs\n",
++		       sb->s_id);
++		sb->s_flags &= ~MS_RDONLY;
++	}
++#ifdef CONFIG_QUOTA
++	/* Needed for iput() to work correctly and not trash data */
++	sb->s_flags |= MS_ACTIVE;
++	/* Turn on quotas so that they are updated correctly */
++	for (i = 0; i < MAXQUOTAS; i++) {
++		if (EXT3COW_SB(sb)->s_qf_names[i]) {
++			int ret = ext3cow_quota_on_mount(sb, i);
++			if (ret < 0)
++				printk(KERN_ERR
++					"EXT3COW-fs: Cannot turn on journalled "
++					"quota: error %d\n", ret);
++		}
++	}
++#endif
++
++	while (es->s_last_orphan) {
++		struct inode *inode;
++
++		if (!(inode =
++		      ext3cow_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
++			es->s_last_orphan = 0;
++			break;
++		}
++
++		list_add(&EXT3COW_I(inode)->i_orphan, &EXT3COW_SB(sb)->s_orphan);
++		DQUOT_INIT(inode);
++		if (inode->i_nlink) {
++			printk(KERN_DEBUG
++				"%s: truncating inode %lu to %Ld bytes\n",
++				__FUNCTION__, inode->i_ino, inode->i_size);
++			jbd_debug(2, "truncating inode %lu to %Ld bytes\n",
++				  inode->i_ino, inode->i_size);
++			ext3cow_truncate(inode);
++			nr_truncates++;
++		} else {
++			printk(KERN_DEBUG
++				"%s: deleting unreferenced inode %lu\n",
++				__FUNCTION__, inode->i_ino);
++			jbd_debug(2, "deleting unreferenced inode %lu\n",
++				  inode->i_ino);
++			nr_orphans++;
++		}
++		iput(inode);  /* The delete magic happens here! */
++	}
++
++#define PLURAL(x) (x), ((x)==1) ? "" : "s"
++
++	if (nr_orphans)
++		printk(KERN_INFO "EXT3COW-fs: %s: %d orphan inode%s deleted\n",
++		       sb->s_id, PLURAL(nr_orphans));
++	if (nr_truncates)
++		printk(KERN_INFO "EXT3COW-fs: %s: %d truncate%s cleaned up\n",
++		       sb->s_id, PLURAL(nr_truncates));
++#ifdef CONFIG_QUOTA
++	/* Turn quotas off */
++	for (i = 0; i < MAXQUOTAS; i++) {
++		if (sb_dqopt(sb)->files[i])
++			vfs_quota_off(sb, i);
++	}
++#endif
++	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
++}
++
++/*
++ * Maximal file size.  There is a direct, and {,double-,triple-}indirect
++ * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
++ * We need to be 1 filesystem block less than the 2^32 sector limit.
++ */
++static loff_t ext3cow_max_size(int bits)
++{
++	loff_t res = EXT3COW_NDIR_BLOCKS;
++	/* This constant is calculated to be the largest file size for a
++	 * dense, 4k-blocksize file such that the total number of
++	 * sectors in the file, including data and all indirect blocks,
++	 * does not exceed 2^32. */
++	const loff_t upper_limit = 0x1ff7fffd000LL;
++
++	res += 1LL << (bits-2);
++	res += 1LL << (2*(bits-2));
++	res += 1LL << (3*(bits-2));
++	res <<= bits;
++	if (res > upper_limit)
++		res = upper_limit;
++	return res;
++}
++
++static ext3cow_fsblk_t descriptor_loc(struct super_block *sb,
++				    ext3cow_fsblk_t logic_sb_block,
++				    int nr)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	unsigned long bg, first_meta_bg;
++	int has_super = 0;
++
++	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
++
++	if (!EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_META_BG) ||
++	    nr < first_meta_bg)
++		return (logic_sb_block + nr + 1);
++	bg = sbi->s_desc_per_block * nr;
++	if (ext3cow_bg_has_super(sb, bg))
++		has_super = 1;
++	return (has_super + ext3cow_group_first_block_no(sb, bg));
++}
++
++
++static int ext3cow_fill_super (struct super_block *sb, void *data, int silent)
++{
++	struct buffer_head * bh;
++	struct ext3cow_super_block *es = NULL;
++	struct ext3cow_sb_info *sbi;
++	ext3cow_fsblk_t block;
++	ext3cow_fsblk_t sb_block = get_sb_block(&data);
++	ext3cow_fsblk_t logic_sb_block;
++	unsigned long offset = 0;
++	unsigned int journal_inum = 0;
++	unsigned long journal_devnum = 0;
++	unsigned long def_mount_opts;
++	struct inode *root;
++	int blocksize;
++	int hblock;
++	int db_count;
++	int i;
++	int needs_recovery;
++	__le32 features;
++
++	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
++	if (!sbi)
++		return -ENOMEM;
++	sb->s_fs_info = sbi;
++	sbi->s_mount_opt = 0;
++	sbi->s_resuid = EXT3COW_DEF_RESUID;
++	sbi->s_resgid = EXT3COW_DEF_RESGID;
++
++	unlock_kernel();
++
++	blocksize = sb_min_blocksize(sb, EXT3COW_MIN_BLOCK_SIZE);
++	if (!blocksize) {
++		printk(KERN_ERR "EXT3COW-fs: unable to set blocksize\n");
++		goto out_fail;
++	}
++
++	/*
++	 * The ext3cow superblock will not be buffer aligned for other than 1kB
++	 * block sizes.  We need to calculate the offset from buffer start.
++	 */
++	if (blocksize != EXT3COW_MIN_BLOCK_SIZE) {
++		logic_sb_block = (sb_block * EXT3COW_MIN_BLOCK_SIZE) / blocksize;
++		offset = (sb_block * EXT3COW_MIN_BLOCK_SIZE) % blocksize;
++	} else {
++		logic_sb_block = sb_block;
++	}
++
++	if (!(bh = sb_bread(sb, logic_sb_block))) {
++		printk (KERN_ERR "EXT3COW-fs: unable to read superblock\n");
++		goto out_fail;
++	}
++	/*
++	 * Note: s_es must be initialized as soon as possible because
++	 *       some ext3cow macro-instructions depend on its value
++	 */
++	es = (struct ext3cow_super_block *) (((char *)bh->b_data) + offset);
++	sbi->s_es = es;
++	sb->s_magic = le16_to_cpu(es->s_magic);
++	if (sb->s_magic != EXT3COW_SUPER_MAGIC)
++		goto cantfind_ext3cow;
++
++	/* Set defaults before we parse the mount options */
++	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
++	if (def_mount_opts & EXT3COW_DEFM_DEBUG)
++		set_opt(sbi->s_mount_opt, DEBUG);
++	if (def_mount_opts & EXT3COW_DEFM_BSDGROUPS)
++		set_opt(sbi->s_mount_opt, GRPID);
++	if (def_mount_opts & EXT3COW_DEFM_UID16)
++		set_opt(sbi->s_mount_opt, NO_UID32);
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	if (def_mount_opts & EXT3COW_DEFM_XATTR_USER)
++		set_opt(sbi->s_mount_opt, XATTR_USER);
++#endif
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	if (def_mount_opts & EXT3COW_DEFM_ACL)
++		set_opt(sbi->s_mount_opt, POSIX_ACL);
++#endif
++	if ((def_mount_opts & EXT3COW_DEFM_JMODE) == EXT3COW_DEFM_JMODE_DATA)
++		sbi->s_mount_opt |= EXT3COW_MOUNT_JOURNAL_DATA;
++	else if ((def_mount_opts & EXT3COW_DEFM_JMODE) == EXT3COW_DEFM_JMODE_ORDERED)
++		sbi->s_mount_opt |= EXT3COW_MOUNT_ORDERED_DATA;
++	else if ((def_mount_opts & EXT3COW_DEFM_JMODE) == EXT3COW_DEFM_JMODE_WBACK)
++		sbi->s_mount_opt |= EXT3COW_MOUNT_WRITEBACK_DATA;
++
++	if (le16_to_cpu(sbi->s_es->s_errors) == EXT3COW_ERRORS_PANIC)
++		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
++	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT3COW_ERRORS_RO)
++		set_opt(sbi->s_mount_opt, ERRORS_RO);
++	else
++		set_opt(sbi->s_mount_opt, ERRORS_CONT);
++
++	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
++	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
++
++	set_opt(sbi->s_mount_opt, RESERVATION);
++
++	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
++			    NULL, 0))
++		goto failed_mount;
++
++	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
++		((sbi->s_mount_opt & EXT3COW_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
++
++	if (le32_to_cpu(es->s_rev_level) == EXT3COW_GOOD_OLD_REV &&
++	    (EXT3COW_HAS_COMPAT_FEATURE(sb, ~0U) ||
++	     EXT3COW_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
++	     EXT3COW_HAS_INCOMPAT_FEATURE(sb, ~0U)))
++		printk(KERN_WARNING
++		       "EXT3COW-fs warning: feature flags set on rev 0 fs, "
++		       "running e2fsck is recommended\n");
++	/*
++	 * Check feature flags regardless of the revision level, since we
++	 * previously didn't change the revision level when setting the flags,
++	 * so there is a chance incompat flags are set on a rev 0 filesystem.
++	 */
++	features = EXT3COW_HAS_INCOMPAT_FEATURE(sb, ~EXT3COW_FEATURE_INCOMPAT_SUPP);
++	if (features) {
++		printk(KERN_ERR "EXT3COW-fs: %s: couldn't mount because of "
++		       "unsupported optional features (%x).\n",
++		       sb->s_id, le32_to_cpu(features));
++		goto failed_mount;
++	}
++	features = EXT3COW_HAS_RO_COMPAT_FEATURE(sb, ~EXT3COW_FEATURE_RO_COMPAT_SUPP);
++	if (!(sb->s_flags & MS_RDONLY) && features) {
++		printk(KERN_ERR "EXT3COW-fs: %s: couldn't mount RDWR because of "
++		       "unsupported optional features (%x).\n",
++		       sb->s_id, le32_to_cpu(features));
++		goto failed_mount;
++	}
++	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
++
++	if (blocksize < EXT3COW_MIN_BLOCK_SIZE ||
++	    blocksize > EXT3COW_MAX_BLOCK_SIZE) {
++		printk(KERN_ERR
++		       "EXT3COW-fs: Unsupported filesystem blocksize %d on %s.\n",
++		       blocksize, sb->s_id);
++		goto failed_mount;
++	}
++
++	hblock = bdev_hardsect_size(sb->s_bdev);
++	if (sb->s_blocksize != blocksize) {
++		/*
++		 * Make sure the blocksize for the filesystem is larger
++		 * than the hardware sectorsize for the machine.
++		 */
++		if (blocksize < hblock) {
++			printk(KERN_ERR "EXT3COW-fs: blocksize %d too small for "
++			       "device blocksize %d.\n", blocksize, hblock);
++			goto failed_mount;
++		}
++
++		brelse (bh);
++		sb_set_blocksize(sb, blocksize);
++		logic_sb_block = (sb_block * EXT3COW_MIN_BLOCK_SIZE) / blocksize;
++		offset = (sb_block * EXT3COW_MIN_BLOCK_SIZE) % blocksize;
++		bh = sb_bread(sb, logic_sb_block);
++		if (!bh) {
++			printk(KERN_ERR
++			       "EXT3COW-fs: Can't read superblock on 2nd try.\n");
++			goto failed_mount;
++		}
++		es = (struct ext3cow_super_block *)(((char *)bh->b_data) + offset);
++		sbi->s_es = es;
++		if (es->s_magic != cpu_to_le16(EXT3COW_SUPER_MAGIC)) {
++			printk (KERN_ERR
++				"EXT3COW-fs: Magic mismatch, very weird !\n");
++			goto failed_mount;
++		}
++	}
++
++	sb->s_maxbytes = ext3cow_max_size(sb->s_blocksize_bits);
++
++	if (le32_to_cpu(es->s_rev_level) == EXT3COW_GOOD_OLD_REV) {
++		sbi->s_inode_size = EXT3COW_GOOD_OLD_INODE_SIZE;
++		sbi->s_first_ino = EXT3COW_GOOD_OLD_FIRST_INO;
++	} else {
++		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
++		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
++		if ((sbi->s_inode_size < EXT3COW_GOOD_OLD_INODE_SIZE) ||
++		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
++		    (sbi->s_inode_size > blocksize)) {
++			printk (KERN_ERR
++				"EXT3COW-fs: unsupported inode size: %d\n",
++				sbi->s_inode_size);
++			goto failed_mount;
++		}
++	}
++	sbi->s_frag_size = EXT3COW_MIN_FRAG_SIZE <<
++				   le32_to_cpu(es->s_log_frag_size);
++	if (blocksize != sbi->s_frag_size) {
++		printk(KERN_ERR
++		       "EXT3COW-fs: fragsize %lu != blocksize %u (unsupported)\n",
++		       sbi->s_frag_size, blocksize);
++		goto failed_mount;
++	}
++	sbi->s_frags_per_block = 1;
++	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
++	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
++	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
++	if (EXT3COW_INODE_SIZE(sb) == 0)
++		goto cantfind_ext3cow;
++	sbi->s_inodes_per_block = blocksize / EXT3COW_INODE_SIZE(sb);
++	if (sbi->s_inodes_per_block == 0)
++		goto cantfind_ext3cow;
++	sbi->s_itb_per_group = sbi->s_inodes_per_group /
++					sbi->s_inodes_per_block;
++	sbi->s_desc_per_block = blocksize / sizeof(struct ext3cow_group_desc);
++	sbi->s_sbh = bh;
++	sbi->s_mount_state = le16_to_cpu(es->s_state);
++	sbi->s_addr_per_block_bits = ilog2(EXT3COW_ADDR_PER_BLOCK(sb));
++	sbi->s_desc_per_block_bits = ilog2(EXT3COW_DESC_PER_BLOCK(sb));
++	for (i=0; i < 4; i++)
++		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
++	sbi->s_def_hash_version = es->s_def_hash_version;
++
++  /* Epoch number for versioning -znjp */
++  sbi->s_epoch_number = le32_to_cpu(es->s_epoch_number);
++  printk(KERN_INFO "EXT3COW-fs: System epoch number: %u\n",
++         sbi->s_epoch_number);
++
++	if (sbi->s_blocks_per_group > blocksize * 8) {
++		printk (KERN_ERR
++			"EXT3COW-fs: #blocks per group too big: %lu\n",
++			sbi->s_blocks_per_group);
++		goto failed_mount;
++	}
++	if (sbi->s_frags_per_group > blocksize * 8) {
++		printk (KERN_ERR
++			"EXT3COW-fs: #fragments per group too big: %lu\n",
++			sbi->s_frags_per_group);
++		goto failed_mount;
++	}
++	if (sbi->s_inodes_per_group > blocksize * 8) {
++		printk (KERN_ERR
++			"EXT3COW-fs: #inodes per group too big: %lu\n",
++			sbi->s_inodes_per_group);
++		goto failed_mount;
++	}
++
++	if (le32_to_cpu(es->s_blocks_count) >
++		    (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
++		printk(KERN_ERR "EXT3COW-fs: filesystem on %s:"
++			" too large to mount safely\n", sb->s_id);
++		if (sizeof(sector_t) < 8)
++			printk(KERN_WARNING "EXT3COW-fs: CONFIG_LBD not "
++					"enabled\n");
++		goto failed_mount;
++	}
++
++	if (EXT3COW_BLOCKS_PER_GROUP(sb) == 0)
++		goto cantfind_ext3cow;
++	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
++			       le32_to_cpu(es->s_first_data_block) - 1)
++				       / EXT3COW_BLOCKS_PER_GROUP(sb)) + 1;
++	db_count = (sbi->s_groups_count + EXT3COW_DESC_PER_BLOCK(sb) - 1) /
++		   EXT3COW_DESC_PER_BLOCK(sb);
++	sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
++				    GFP_KERNEL);
++	if (sbi->s_group_desc == NULL) {
++		printk (KERN_ERR "EXT3COW-fs: not enough memory\n");
++		goto failed_mount;
++	}
++
++	bgl_lock_init(&sbi->s_blockgroup_lock);
++
++	for (i = 0; i < db_count; i++) {
++		block = descriptor_loc(sb, logic_sb_block, i);
++		sbi->s_group_desc[i] = sb_bread(sb, block);
++		if (!sbi->s_group_desc[i]) {
++			printk (KERN_ERR "EXT3COW-fs: "
++				"can't read group descriptor %d\n", i);
++			db_count = i;
++			goto failed_mount2;
++		}
++	}
++	if (!ext3cow_check_descriptors (sb)) {
++		printk(KERN_ERR "EXT3COW-fs: group descriptors corrupted!\n");
++		goto failed_mount2;
++	}
++	sbi->s_gdb_count = db_count;
++	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
++	spin_lock_init(&sbi->s_next_gen_lock);
++
++	percpu_counter_init(&sbi->s_freeblocks_counter,
++		ext3cow_count_free_blocks(sb));
++	percpu_counter_init(&sbi->s_freeinodes_counter,
++		ext3cow_count_free_inodes(sb));
++	percpu_counter_init(&sbi->s_dirs_counter,
++		ext3cow_count_dirs(sb));
++
++	/* per fileystem reservation list head & lock */
++	spin_lock_init(&sbi->s_rsv_window_lock);
++	sbi->s_rsv_window_root = RB_ROOT;
++	/* Add a single, static dummy reservation to the start of the
++	 * reservation window list --- it gives us a placeholder for
++	 * append-at-start-of-list which makes the allocation logic
++	 * _much_ simpler. */
++	sbi->s_rsv_window_head.rsv_start = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++	sbi->s_rsv_window_head.rsv_end = EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED;
++	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
++	sbi->s_rsv_window_head.rsv_goal_size = 0;
++	ext3cow_rsv_window_add(sb, &sbi->s_rsv_window_head);
++
++	/*
++	 * set up enough so that it can read an inode
++	 */
++	sb->s_op = &ext3cow_sops;
++	sb->s_export_op = &ext3cow_export_ops;
++	sb->s_xattr = ext3cow_xattr_handlers;
++#ifdef CONFIG_QUOTA
++	sb->s_qcop = &ext3cow_qctl_operations;
++	sb->dq_op = &ext3cow_quota_operations;
++#endif
++	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
++
++	sb->s_root = NULL;
++
++	needs_recovery = (es->s_last_orphan != 0 ||
++			  EXT3COW_HAS_INCOMPAT_FEATURE(sb,
++				    EXT3COW_FEATURE_INCOMPAT_RECOVER));
++
++	/*
++	 * The first inode we look at is the journal inode.  Don't try
++	 * root first: it may be modified in the journal!
++	 */
++	if (!test_opt(sb, NOLOAD) &&
++	    EXT3COW_HAS_COMPAT_FEATURE(sb, EXT3COW_FEATURE_COMPAT_HAS_JOURNAL)) {
++		if (ext3cow_load_journal(sb, es, journal_devnum))
++			goto failed_mount3;
++	} else if (journal_inum) {
++		if (ext3cow_create_journal(sb, es, journal_inum))
++			goto failed_mount3;
++	} else {
++		if (!silent)
++			printk (KERN_ERR
++				"ext3cow: No journal on filesystem on %s\n",
++				sb->s_id);
++		goto failed_mount3;
++	}
++
++	/* We have now updated the journal if required, so we can
++	 * validate the data journaling mode. */
++	switch (test_opt(sb, DATA_FLAGS)) {
++	case 0:
++		/* No mode set, assume a default based on the journal
++                   capabilities: ORDERED_DATA if the journal can
++                   cope, else JOURNAL_DATA */
++		if (journal_check_available_features
++		    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE))
++			set_opt(sbi->s_mount_opt, ORDERED_DATA);
++		else
++			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
++		break;
++
++	case EXT3COW_MOUNT_ORDERED_DATA:
++	case EXT3COW_MOUNT_WRITEBACK_DATA:
++		if (!journal_check_available_features
++		    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)) {
++			printk(KERN_ERR "EXT3COW-fs: Journal does not support "
++			       "requested data journaling mode\n");
++			goto failed_mount4;
++		}
++	default:
++		break;
++	}
++
++	if (test_opt(sb, NOBH)) {
++		if (!(test_opt(sb, DATA_FLAGS) == EXT3COW_MOUNT_WRITEBACK_DATA)) {
++			printk(KERN_WARNING "EXT3COW-fs: Ignoring nobh option - "
++				"its supported only with writeback mode\n");
++			clear_opt(sbi->s_mount_opt, NOBH);
++		}
++	}
++	/*
++	 * The journal_load will have done any necessary log recovery,
++	 * so we can safely mount the rest of the filesystem now.
++	 */
++
++	root = iget(sb, EXT3COW_ROOT_INO);
++	sb->s_root = d_alloc_root(root);
++	if (!sb->s_root) {
++		printk(KERN_ERR "EXT3COW-fs: get root inode failed\n");
++		iput(root);
++		goto failed_mount4;
++	}
++	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
++		dput(sb->s_root);
++		sb->s_root = NULL;
++		printk(KERN_ERR "EXT3COW-fs: corrupt root inode, run e2fsck\n");
++		goto failed_mount4;
++	}
++
++	ext3cow_setup_super (sb, es, sb->s_flags & MS_RDONLY);
++	/*
++	 * akpm: core read_super() calls in here with the superblock locked.
++	 * That deadlocks, because orphan cleanup needs to lock the superblock
++	 * in numerous places.  Here we just pop the lock - it's relatively
++	 * harmless, because we are now ready to accept write_super() requests,
++	 * and aviro says that's the only reason for hanging onto the
++	 * superblock lock.
++	 */
++	EXT3COW_SB(sb)->s_mount_state |= EXT3COW_ORPHAN_FS;
++	ext3cow_orphan_cleanup(sb, es);
++	EXT3COW_SB(sb)->s_mount_state &= ~EXT3COW_ORPHAN_FS;
++	if (needs_recovery)
++		printk (KERN_INFO "EXT3COW-fs: recovery complete.\n");
++	ext3cow_mark_recovery_complete(sb, es);
++	printk (KERN_INFO "EXT3COW-fs: mounted filesystem with %s data mode.\n",
++		test_opt(sb,DATA_FLAGS) == EXT3COW_MOUNT_JOURNAL_DATA ? "journal":
++		test_opt(sb,DATA_FLAGS) == EXT3COW_MOUNT_ORDERED_DATA ? "ordered":
++		"writeback");
++
++	lock_kernel();
++	return 0;
++
++cantfind_ext3cow:
++	if (!silent)
++		printk(KERN_ERR "VFS: Can't find ext3cow filesystem on dev %s.\n",
++		       sb->s_id);
++	goto failed_mount;
++
++failed_mount4:
++	journal_destroy(sbi->s_journal);
++failed_mount3:
++	percpu_counter_destroy(&sbi->s_freeblocks_counter);
++	percpu_counter_destroy(&sbi->s_freeinodes_counter);
++	percpu_counter_destroy(&sbi->s_dirs_counter);
++failed_mount2:
++	for (i = 0; i < db_count; i++)
++		brelse(sbi->s_group_desc[i]);
++	kfree(sbi->s_group_desc);
++failed_mount:
++#ifdef CONFIG_QUOTA
++	for (i = 0; i < MAXQUOTAS; i++)
++		kfree(sbi->s_qf_names[i]);
++#endif
++	ext3cow_blkdev_remove(sbi);
++	brelse(bh);
++out_fail:
++	sb->s_fs_info = NULL;
++	kfree(sbi);
++	lock_kernel();
++	return -EINVAL;
++}
++
++/*
++ * Setup any per-fs journal parameters now.  We'll do this both on
++ * initial mount, once the journal has been initialised but before we've
++ * done any recovery; and again on any subsequent remount.
++ */
++static void ext3cow_init_journal_params(struct super_block *sb, journal_t *journal)
++{
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++
++	if (sbi->s_commit_interval)
++		journal->j_commit_interval = sbi->s_commit_interval;
++	/* We could also set up an ext3cow-specific default for the commit
++	 * interval here, but for now we'll just fall back to the jbd
++	 * default. */
++
++	spin_lock(&journal->j_state_lock);
++	if (test_opt(sb, BARRIER))
++		journal->j_flags |= JFS_BARRIER;
++	else
++		journal->j_flags &= ~JFS_BARRIER;
++	spin_unlock(&journal->j_state_lock);
++}
++
++static journal_t *ext3cow_get_journal(struct super_block *sb,
++				   unsigned int journal_inum)
++{
++	struct inode *journal_inode;
++	journal_t *journal;
++
++	/* First, test for the existence of a valid inode on disk.  Bad
++	 * things happen if we iget() an unused inode, as the subsequent
++	 * iput() will try to delete it. */
++
++	journal_inode = iget(sb, journal_inum);
++	if (!journal_inode) {
++		printk(KERN_ERR "EXT3COW-fs: no journal found.\n");
++		return NULL;
++	}
++	if (!journal_inode->i_nlink) {
++		make_bad_inode(journal_inode);
++		iput(journal_inode);
++		printk(KERN_ERR "EXT3COW-fs: journal inode is deleted.\n");
++		return NULL;
++	}
++
++	jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
++		  journal_inode, journal_inode->i_size);
++	if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
++		printk(KERN_ERR "EXT3COW-fs: invalid journal inode.\n");
++		iput(journal_inode);
++		return NULL;
++	}
++
++	journal = journal_init_inode(journal_inode);
++	if (!journal) {
++		printk(KERN_ERR "EXT3COW-fs: Could not load journal inode\n");
++		iput(journal_inode);
++		return NULL;
++	}
++  /* Make sure the journal never gets versioned -znjp */
++  EXT3COW_I(journal_inode)->i_flags |= EXT3COW_UNVERSIONABLE_FL;
++	journal->j_private = sb;
++	ext3cow_init_journal_params(sb, journal);
++	return journal;
++}
++
++static journal_t *ext3cow_get_dev_journal(struct super_block *sb,
++				       dev_t j_dev)
++{
++	struct buffer_head * bh;
++	journal_t *journal;
++	ext3cow_fsblk_t start;
++	ext3cow_fsblk_t len;
++	int hblock, blocksize;
++	ext3cow_fsblk_t sb_block;
++	unsigned long offset;
++	struct ext3cow_super_block * es;
++	struct block_device *bdev;
++
++	bdev = ext3cow_blkdev_get(j_dev);
++	if (bdev == NULL)
++		return NULL;
++
++	if (bd_claim(bdev, sb)) {
++		printk(KERN_ERR
++		        "EXT3COW: failed to claim external journal device.\n");
++		blkdev_put(bdev);
++		return NULL;
++	}
++
++	blocksize = sb->s_blocksize;
++	hblock = bdev_hardsect_size(bdev);
++	if (blocksize < hblock) {
++		printk(KERN_ERR
++			"EXT3COW-fs: blocksize too small for journal device.\n");
++		goto out_bdev;
++	}
++
++	sb_block = EXT3COW_MIN_BLOCK_SIZE / blocksize;
++	offset = EXT3COW_MIN_BLOCK_SIZE % blocksize;
++	set_blocksize(bdev, blocksize);
++	if (!(bh = __bread(bdev, sb_block, blocksize))) {
++		printk(KERN_ERR "EXT3COW-fs: couldn't read superblock of "
++		       "external journal\n");
++		goto out_bdev;
++	}
++
++	es = (struct ext3cow_super_block *) (((char *)bh->b_data) + offset);
++	if ((le16_to_cpu(es->s_magic) != EXT3COW_SUPER_MAGIC) ||
++	    !(le32_to_cpu(es->s_feature_incompat) &
++	      EXT3COW_FEATURE_INCOMPAT_JOURNAL_DEV)) {
++		printk(KERN_ERR "EXT3COW-fs: external journal has "
++					"bad superblock\n");
++		brelse(bh);
++		goto out_bdev;
++	}
++
++	if (memcmp(EXT3COW_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
++		printk(KERN_ERR "EXT3COW-fs: journal UUID does not match\n");
++		brelse(bh);
++		goto out_bdev;
++	}
++
++	len = le32_to_cpu(es->s_blocks_count);
++	start = sb_block + 1;
++	brelse(bh);	/* we're done with the superblock */
++
++	journal = journal_init_dev(bdev, sb->s_bdev,
++					start, len, blocksize);
++	if (!journal) {
++		printk(KERN_ERR "EXT3COW-fs: failed to create device journal\n");
++		goto out_bdev;
++	}
++	journal->j_private = sb;
++	ll_rw_block(READ, 1, &journal->j_sb_buffer);
++	wait_on_buffer(journal->j_sb_buffer);
++	if (!buffer_uptodate(journal->j_sb_buffer)) {
++		printk(KERN_ERR "EXT3COW-fs: I/O error on journal device\n");
++		goto out_journal;
++	}
++	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
++		printk(KERN_ERR "EXT3COW-fs: External journal has more than one "
++					"user (unsupported) - %d\n",
++			be32_to_cpu(journal->j_superblock->s_nr_users));
++		goto out_journal;
++	}
++	EXT3COW_SB(sb)->journal_bdev = bdev;
++	ext3cow_init_journal_params(sb, journal);
++	return journal;
++out_journal:
++	journal_destroy(journal);
++out_bdev:
++	ext3cow_blkdev_put(bdev);
++	return NULL;
++}
++
++static int ext3cow_load_journal(struct super_block *sb,
++			     struct ext3cow_super_block *es,
++			     unsigned long journal_devnum)
++{
++	journal_t *journal;
++	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
++	dev_t journal_dev;
++	int err = 0;
++	int really_read_only;
++
++	if (journal_devnum &&
++	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
++		printk(KERN_INFO "EXT3COW-fs: external journal device major/minor "
++			"numbers have changed\n");
++		journal_dev = new_decode_dev(journal_devnum);
++	} else
++		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
++
++	really_read_only = bdev_read_only(sb->s_bdev);
++
++	/*
++	 * Are we loading a blank journal or performing recovery after a
++	 * crash?  For recovery, we need to check in advance whether we
++	 * can get read-write access to the device.
++	 */
++
++	if (EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER)) {
++		if (sb->s_flags & MS_RDONLY) {
++			printk(KERN_INFO "EXT3COW-fs: INFO: recovery "
++					"required on readonly filesystem.\n");
++			if (really_read_only) {
++				printk(KERN_ERR "EXT3COW-fs: write access "
++					"unavailable, cannot proceed.\n");
++				return -EROFS;
++			}
++			printk (KERN_INFO "EXT3COW-fs: write access will "
++					"be enabled during recovery.\n");
++		}
++	}
++
++	if (journal_inum && journal_dev) {
++		printk(KERN_ERR "EXT3COW-fs: filesystem has both journal "
++		       "and inode journals!\n");
++		return -EINVAL;
++	}
++
++	if (journal_inum) {
++		if (!(journal = ext3cow_get_journal(sb, journal_inum)))
++			return -EINVAL;
++	} else {
++		if (!(journal = ext3cow_get_dev_journal(sb, journal_dev)))
++			return -EINVAL;
++	}
++
++	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
++		err = journal_update_format(journal);
++		if (err)  {
++			printk(KERN_ERR "EXT3COW-fs: error updating journal.\n");
++			journal_destroy(journal);
++			return err;
++		}
++	}
++
++	if (!EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER))
++		err = journal_wipe(journal, !really_read_only);
++	if (!err)
++		err = journal_load(journal);
++
++	if (err) {
++		printk(KERN_ERR "EXT3COW-fs: error loading journal.\n");
++		journal_destroy(journal);
++		return err;
++	}
++
++	EXT3COW_SB(sb)->s_journal = journal;
++	ext3cow_clear_journal_err(sb, es);
++
++	if (journal_devnum &&
++	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
++		es->s_journal_dev = cpu_to_le32(journal_devnum);
++		sb->s_dirt = 1;
++
++		/* Make sure we flush the recovery flag to disk. */
++		ext3cow_commit_super(sb, es, 1);
++	}
++
++	return 0;
++}
++
++static int ext3cow_create_journal(struct super_block * sb,
++			       struct ext3cow_super_block * es,
++			       unsigned int journal_inum)
++{
++	journal_t *journal;
++
++	if (sb->s_flags & MS_RDONLY) {
++		printk(KERN_ERR "EXT3COW-fs: readonly filesystem when trying to "
++				"create journal.\n");
++		return -EROFS;
++	}
++
++	if (!(journal = ext3cow_get_journal(sb, journal_inum)))
++		return -EINVAL;
++
++	printk(KERN_INFO "EXT3COW-fs: creating new journal on inode %u\n",
++	       journal_inum);
++
++	if (journal_create(journal)) {
++		printk(KERN_ERR "EXT3COW-fs: error creating journal.\n");
++		journal_destroy(journal);
++		return -EIO;
++	}
++
++	EXT3COW_SB(sb)->s_journal = journal;
++
++	ext3cow_update_dynamic_rev(sb);
++	EXT3COW_SET_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++	EXT3COW_SET_COMPAT_FEATURE(sb, EXT3COW_FEATURE_COMPAT_HAS_JOURNAL);
++
++	es->s_journal_inum = cpu_to_le32(journal_inum);
++	sb->s_dirt = 1;
++
++	/* Make sure we flush the recovery flag to disk. */
++	ext3cow_commit_super(sb, es, 1);
++
++	return 0;
++}
++
++static void ext3cow_commit_super (struct super_block * sb,
++			       struct ext3cow_super_block * es,
++			       int sync)
++{
++	struct buffer_head *sbh = EXT3COW_SB(sb)->s_sbh;
++
++	if (!sbh)
++		return;
++	es->s_wtime = cpu_to_le32(get_seconds());
++	es->s_free_blocks_count = cpu_to_le32(ext3cow_count_free_blocks(sb));
++	es->s_free_inodes_count = cpu_to_le32(ext3cow_count_free_inodes(sb));
++	BUFFER_TRACE(sbh, "marking dirty");
++	mark_buffer_dirty(sbh);
++	if (sync)
++		sync_dirty_buffer(sbh);
++}
++
++
++/*
++ * Have we just finished recovery?  If so, and if we are mounting (or
++ * remounting) the filesystem readonly, then we will end up with a
++ * consistent fs on disk.  Record that fact.
++ */
++static void ext3cow_mark_recovery_complete(struct super_block * sb,
++					struct ext3cow_super_block * es)
++{
++	journal_t *journal = EXT3COW_SB(sb)->s_journal;
++
++	journal_lock_updates(journal);
++	journal_flush(journal);
++	if (EXT3COW_HAS_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER) &&
++	    sb->s_flags & MS_RDONLY) {
++		EXT3COW_CLEAR_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++		sb->s_dirt = 0;
++		ext3cow_commit_super(sb, es, 1);
++	}
++	journal_unlock_updates(journal);
++}
++
++/*
++ * If we are mounting (or read-write remounting) a filesystem whose journal
++ * has recorded an error from a previous lifetime, move that error to the
++ * main filesystem now.
++ */
++static void ext3cow_clear_journal_err(struct super_block * sb,
++				   struct ext3cow_super_block * es)
++{
++	journal_t *journal;
++	int j_errno;
++	const char *errstr;
++
++	journal = EXT3COW_SB(sb)->s_journal;
++
++	/*
++	 * Now check for any error status which may have been recorded in the
++	 * journal by a prior ext3cow_error() or ext3cow_abort()
++	 */
++
++	j_errno = journal_errno(journal);
++	if (j_errno) {
++		char nbuf[16];
++
++		errstr = ext3cow_decode_error(sb, j_errno, nbuf);
++		ext3cow_warning(sb, __FUNCTION__, "Filesystem error recorded "
++			     "from previous mount: %s", errstr);
++		ext3cow_warning(sb, __FUNCTION__, "Marking fs in need of "
++			     "filesystem check.");
++
++		EXT3COW_SB(sb)->s_mount_state |= EXT3COW_ERROR_FS;
++		es->s_state |= cpu_to_le16(EXT3COW_ERROR_FS);
++		ext3cow_commit_super (sb, es, 1);
++
++		journal_clear_err(journal);
++	}
++}
++
++/*
++ * Force the running and committing transactions to commit,
++ * and wait on the commit.
++ */
++int ext3cow_force_commit(struct super_block *sb)
++{
++	journal_t *journal;
++	int ret;
++
++	if (sb->s_flags & MS_RDONLY)
++		return 0;
++
++	journal = EXT3COW_SB(sb)->s_journal;
++	sb->s_dirt = 0;
++	ret = ext3cow_journal_force_commit(journal);
++	return ret;
++}
++
++/*
++ * Ext3 always journals updates to the superblock itself, so we don't
++ * have to propagate any other updates to the superblock on disk at this
++ * point.  Just start an async writeback to get the buffers on their way
++ * to the disk.
++ *
++ * This implicitly triggers the writebehind on sync().
++ */
++
++static void ext3cow_write_super (struct super_block * sb)
++{
++	if (mutex_trylock(&sb->s_lock) != 0)
++		BUG();
++	sb->s_dirt = 0;
++}
++
++static int ext3cow_sync_fs(struct super_block *sb, int wait)
++{
++	tid_t target;
++
++	sb->s_dirt = 0;
++	if (journal_start_commit(EXT3COW_SB(sb)->s_journal, &target)) {
++		if (wait)
++			log_wait_commit(EXT3COW_SB(sb)->s_journal, target);
++	}
++	return 0;
++}
++
++/*
++ * LVM calls this function before a (read-only) snapshot is created.  This
++ * gives us a chance to flush the journal completely and mark the fs clean.
++ */
++static void ext3cow_write_super_lockfs(struct super_block *sb)
++{
++	sb->s_dirt = 0;
++
++	if (!(sb->s_flags & MS_RDONLY)) {
++		journal_t *journal = EXT3COW_SB(sb)->s_journal;
++
++		/* Now we set up the journal barrier. */
++		journal_lock_updates(journal);
++		journal_flush(journal);
++
++		/* Journal blocked and flushed, clear needs_recovery flag. */
++		EXT3COW_CLEAR_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++		ext3cow_commit_super(sb, EXT3COW_SB(sb)->s_es, 1);
++	}
++}
++
++/*
++ * Called by LVM after the snapshot is done.  We need to reset the RECOVER
++ * flag here, even though the filesystem is not technically dirty yet.
++ */
++static void ext3cow_unlockfs(struct super_block *sb)
++{
++	if (!(sb->s_flags & MS_RDONLY)) {
++		lock_super(sb);
++		/* Reser the needs_recovery flag before the fs is unlocked. */
++		EXT3COW_SET_INCOMPAT_FEATURE(sb, EXT3COW_FEATURE_INCOMPAT_RECOVER);
++		ext3cow_commit_super(sb, EXT3COW_SB(sb)->s_es, 1);
++		unlock_super(sb);
++		journal_unlock_updates(EXT3COW_SB(sb)->s_journal);
++	}
++}
++
++static int ext3cow_remount (struct super_block * sb, int * flags, char * data)
++{
++	struct ext3cow_super_block * es;
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	ext3cow_fsblk_t n_blocks_count = 0;
++	unsigned long old_sb_flags;
++	struct ext3cow_mount_options old_opts;
++	int err;
++#ifdef CONFIG_QUOTA
++	int i;
++#endif
++
++	/* Store the original options */
++	old_sb_flags = sb->s_flags;
++	old_opts.s_mount_opt = sbi->s_mount_opt;
++	old_opts.s_resuid = sbi->s_resuid;
++	old_opts.s_resgid = sbi->s_resgid;
++	old_opts.s_commit_interval = sbi->s_commit_interval;
++#ifdef CONFIG_QUOTA
++	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
++	for (i = 0; i < MAXQUOTAS; i++)
++		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
++#endif
++
++	/*
++	 * Allow the "check" option to be passed as a remount option.
++	 */
++	if (!parse_options(data, sb, NULL, NULL, &n_blocks_count, 1)) {
++		err = -EINVAL;
++		goto restore_opts;
++	}
++
++	if (sbi->s_mount_opt & EXT3COW_MOUNT_ABORT)
++		ext3cow_abort(sb, __FUNCTION__, "Abort forced by user");
++
++	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
++		((sbi->s_mount_opt & EXT3COW_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
++
++	es = sbi->s_es;
++
++	ext3cow_init_journal_params(sb, sbi->s_journal);
++
++	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
++		n_blocks_count > le32_to_cpu(es->s_blocks_count)) {
++		if (sbi->s_mount_opt & EXT3COW_MOUNT_ABORT) {
++			err = -EROFS;
++			goto restore_opts;
++		}
++
++		if (*flags & MS_RDONLY) {
++			/*
++			 * First of all, the unconditional stuff we have to do
++			 * to disable replay of the journal when we next remount
++			 */
++			sb->s_flags |= MS_RDONLY;
++
++			/*
++			 * OK, test if we are remounting a valid rw partition
++			 * readonly, and if so set the rdonly flag and then
++			 * mark the partition as valid again.
++			 */
++			if (!(es->s_state & cpu_to_le16(EXT3COW_VALID_FS)) &&
++			    (sbi->s_mount_state & EXT3COW_VALID_FS))
++				es->s_state = cpu_to_le16(sbi->s_mount_state);
++
++			ext3cow_mark_recovery_complete(sb, es);
++		} else {
++			__le32 ret;
++			if ((ret = EXT3COW_HAS_RO_COMPAT_FEATURE(sb,
++					~EXT3COW_FEATURE_RO_COMPAT_SUPP))) {
++				printk(KERN_WARNING "EXT3COW-fs: %s: couldn't "
++				       "remount RDWR because of unsupported "
++				       "optional features (%x).\n",
++				       sb->s_id, le32_to_cpu(ret));
++				err = -EROFS;
++				goto restore_opts;
++			}
++			/*
++			 * Mounting a RDONLY partition read-write, so reread
++			 * and store the current valid flag.  (It may have
++			 * been changed by e2fsck since we originally mounted
++			 * the partition.)
++			 */
++			ext3cow_clear_journal_err(sb, es);
++			sbi->s_mount_state = le16_to_cpu(es->s_state);
++			if ((err = ext3cow_group_extend(sb, es, n_blocks_count)))
++				goto restore_opts;
++			if (!ext3cow_setup_super (sb, es, 0))
++				sb->s_flags &= ~MS_RDONLY;
++		}
++	}
++#ifdef CONFIG_QUOTA
++	/* Release old quota file names */
++	for (i = 0; i < MAXQUOTAS; i++)
++		if (old_opts.s_qf_names[i] &&
++		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
++			kfree(old_opts.s_qf_names[i]);
++#endif
++	return 0;
++restore_opts:
++	sb->s_flags = old_sb_flags;
++	sbi->s_mount_opt = old_opts.s_mount_opt;
++	sbi->s_resuid = old_opts.s_resuid;
++	sbi->s_resgid = old_opts.s_resgid;
++	sbi->s_commit_interval = old_opts.s_commit_interval;
++#ifdef CONFIG_QUOTA
++	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
++	for (i = 0; i < MAXQUOTAS; i++) {
++		if (sbi->s_qf_names[i] &&
++		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
++			kfree(sbi->s_qf_names[i]);
++		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
++	}
++#endif
++	return err;
++}
++
++static int ext3cow_statfs (struct dentry * dentry, struct kstatfs * buf)
++{
++	struct super_block *sb = dentry->d_sb;
++	struct ext3cow_sb_info *sbi = EXT3COW_SB(sb);
++	struct ext3cow_super_block *es = sbi->s_es;
++	ext3cow_fsblk_t overhead;
++	int i;
++	u64 fsid;
++
++	if (test_opt (sb, MINIX_DF))
++		overhead = 0;
++	else {
++		unsigned long ngroups;
++		ngroups = EXT3COW_SB(sb)->s_groups_count;
++		smp_rmb();
++
++		/*
++		 * Compute the overhead (FS structures)
++		 */
++
++		/*
++		 * All of the blocks before first_data_block are
++		 * overhead
++		 */
++		overhead = le32_to_cpu(es->s_first_data_block);
++
++		/*
++		 * Add the overhead attributed to the superblock and
++		 * block group descriptors.  If the sparse superblocks
++		 * feature is turned on, then not all groups have this.
++		 */
++		for (i = 0; i < ngroups; i++) {
++			overhead += ext3cow_bg_has_super(sb, i) +
++				ext3cow_bg_num_gdb(sb, i);
++			cond_resched();
++		}
++
++		/*
++		 * Every block group has an inode bitmap, a block
++		 * bitmap, and an inode table.
++		 */
++		overhead += (ngroups * (2 + EXT3COW_SB(sb)->s_itb_per_group));
++	}
++
++	buf->f_type = EXT3COW_SUPER_MAGIC;
++	buf->f_bsize = sb->s_blocksize;
++	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
++	buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
++	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
++	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
++		buf->f_bavail = 0;
++	buf->f_files = le32_to_cpu(es->s_inodes_count);
++	buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
++	buf->f_namelen = EXT3COW_NAME_LEN;
++	fsid = le64_to_cpup((void *)es->s_uuid) ^
++	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
++	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
++	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
++	return 0;
++}
++
++/* Helper function for writing quotas on sync - we need to start transaction before quota file
++ * is locked for write. Otherwise the are possible deadlocks:
++ * Process 1                         Process 2
++ * ext3cow_create()                     quota_sync()
++ *   journal_start()                   write_dquot()
++ *   DQUOT_INIT()                        down(dqio_mutex)
++ *     down(dqio_mutex)                    journal_start()
++ *
++ */
++
++#ifdef CONFIG_QUOTA
++
++static inline struct inode *dquot_to_inode(struct dquot *dquot)
++{
++	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
++}
++
++static int ext3cow_dquot_initialize(struct inode *inode, int type)
++{
++	handle_t *handle;
++	int ret, err;
++
++	/* We may create quota structure so we need to reserve enough blocks */
++	handle = ext3cow_journal_start(inode, 2*EXT3COW_QUOTA_INIT_BLOCKS(inode->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_initialize(inode, type);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++static int ext3cow_dquot_drop(struct inode *inode)
++{
++	handle_t *handle;
++	int ret, err;
++
++	/* We may delete quota structure so we need to reserve enough blocks */
++	handle = ext3cow_journal_start(inode, 2*EXT3COW_QUOTA_DEL_BLOCKS(inode->i_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_drop(inode);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++static int ext3cow_write_dquot(struct dquot *dquot)
++{
++	int ret, err;
++	handle_t *handle;
++	struct inode *inode;
++
++	inode = dquot_to_inode(dquot);
++	handle = ext3cow_journal_start(inode,
++					EXT3COW_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_commit(dquot);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++static int ext3cow_acquire_dquot(struct dquot *dquot)
++{
++	int ret, err;
++	handle_t *handle;
++
++	handle = ext3cow_journal_start(dquot_to_inode(dquot),
++					EXT3COW_QUOTA_INIT_BLOCKS(dquot->dq_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_acquire(dquot);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++static int ext3cow_release_dquot(struct dquot *dquot)
++{
++	int ret, err;
++	handle_t *handle;
++
++	handle = ext3cow_journal_start(dquot_to_inode(dquot),
++					EXT3COW_QUOTA_DEL_BLOCKS(dquot->dq_sb));
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_release(dquot);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++static int ext3cow_mark_dquot_dirty(struct dquot *dquot)
++{
++	/* Are we journalling quotas? */
++	if (EXT3COW_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
++	    EXT3COW_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
++		dquot_mark_dquot_dirty(dquot);
++		return ext3cow_write_dquot(dquot);
++	} else {
++		return dquot_mark_dquot_dirty(dquot);
++	}
++}
++
++static int ext3cow_write_info(struct super_block *sb, int type)
++{
++	int ret, err;
++	handle_t *handle;
++
++	/* Data block + inode block */
++	handle = ext3cow_journal_start(sb->s_root->d_inode, 2);
++	if (IS_ERR(handle))
++		return PTR_ERR(handle);
++	ret = dquot_commit_info(sb, type);
++	err = ext3cow_journal_stop(handle);
++	if (!ret)
++		ret = err;
++	return ret;
++}
++
++/*
++ * Turn on quotas during mount time - we need to find
++ * the quota file and such...
++ */
++static int ext3cow_quota_on_mount(struct super_block *sb, int type)
++{
++	return vfs_quota_on_mount(sb, EXT3COW_SB(sb)->s_qf_names[type],
++			EXT3COW_SB(sb)->s_jquota_fmt, type);
++}
++
++/*
++ * Standard function to be called on quota_on
++ */
++static int ext3cow_quota_on(struct super_block *sb, int type, int format_id,
++			 char *path)
++{
++	int err;
++	struct nameidata nd;
++
++	if (!test_opt(sb, QUOTA))
++		return -EINVAL;
++	/* Not journalling quota? */
++	if (!EXT3COW_SB(sb)->s_qf_names[USRQUOTA] &&
++	    !EXT3COW_SB(sb)->s_qf_names[GRPQUOTA])
++		return vfs_quota_on(sb, type, format_id, path);
++	err = path_lookup(path, LOOKUP_FOLLOW, &nd);
++	if (err)
++		return err;
++	/* Quotafile not on the same filesystem? */
++	if (nd.mnt->mnt_sb != sb) {
++		path_release(&nd);
++		return -EXDEV;
++	}
++	/* Quotafile not of fs root? */
++	if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
++		printk(KERN_WARNING
++			"EXT3COW-fs: Quota file not on filesystem root. "
++			"Journalled quota will not work.\n");
++	path_release(&nd);
++	return vfs_quota_on(sb, type, format_id, path);
++}
++
++/* Read data from quotafile - avoid pagecache and such because we cannot afford
++ * acquiring the locks... As quota files are never truncated and quota code
++ * itself serializes the operations (and noone else should touch the files)
++ * we don't have to be afraid of races */
++static ssize_t ext3cow_quota_read(struct super_block *sb, int type, char *data,
++			       size_t len, loff_t off)
++{
++	struct inode *inode = sb_dqopt(sb)->files[type];
++	sector_t blk = off >> EXT3COW_BLOCK_SIZE_BITS(sb);
++	int err = 0;
++	int offset = off & (sb->s_blocksize - 1);
++	int tocopy;
++	size_t toread;
++	struct buffer_head *bh;
++	loff_t i_size = i_size_read(inode);
++
++	if (off > i_size)
++		return 0;
++	if (off+len > i_size)
++		len = i_size-off;
++	toread = len;
++	while (toread > 0) {
++		tocopy = sb->s_blocksize - offset < toread ?
++				sb->s_blocksize - offset : toread;
++		bh = ext3cow_bread(NULL, inode, blk, 0, &err);
++		if (err)
++			return err;
++		if (!bh)	/* A hole? */
++			memset(data, 0, tocopy);
++		else
++			memcpy(data, bh->b_data+offset, tocopy);
++		brelse(bh);
++		offset = 0;
++		toread -= tocopy;
++		data += tocopy;
++		blk++;
++	}
++	return len;
++}
++
++/* Write to quotafile (we know the transaction is already started and has
++ * enough credits) */
++static ssize_t ext3cow_quota_write(struct super_block *sb, int type,
++				const char *data, size_t len, loff_t off)
++{
++	struct inode *inode = sb_dqopt(sb)->files[type];
++	sector_t blk = off >> EXT3COW_BLOCK_SIZE_BITS(sb);
++	int err = 0;
++	int offset = off & (sb->s_blocksize - 1);
++	int tocopy;
++	int journal_quota = EXT3COW_SB(sb)->s_qf_names[type] != NULL;
++	size_t towrite = len;
++	struct buffer_head *bh;
++	handle_t *handle = journal_current_handle();
++
++	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
++	while (towrite > 0) {
++		tocopy = sb->s_blocksize - offset < towrite ?
++				sb->s_blocksize - offset : towrite;
++		bh = ext3cow_bread(handle, inode, blk, 1, &err);
++		if (!bh)
++			goto out;
++		if (journal_quota) {
++			err = ext3cow_journal_get_write_access(handle, bh);
++			if (err) {
++				brelse(bh);
++				goto out;
++			}
++		}
++		lock_buffer(bh);
++		memcpy(bh->b_data+offset, data, tocopy);
++		flush_dcache_page(bh->b_page);
++		unlock_buffer(bh);
++		if (journal_quota)
++			err = ext3cow_journal_dirty_metadata(handle, bh);
++		else {
++			/* Always do at least ordered writes for quotas */
++			err = ext3cow_journal_dirty_data(handle, bh);
++			mark_buffer_dirty(bh);
++		}
++		brelse(bh);
++		if (err)
++			goto out;
++		offset = 0;
++		towrite -= tocopy;
++		data += tocopy;
++		blk++;
++	}
++out:
++	if (len == towrite)
++		return err;
++	if (inode->i_size < off+len-towrite) {
++		i_size_write(inode, off+len-towrite);
++		EXT3COW_I(inode)->i_disksize = inode->i_size;
++	}
++	inode->i_version++;
++	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
++	ext3cow_mark_inode_dirty(handle, inode);
++	mutex_unlock(&inode->i_mutex);
++	return len - towrite;
++}
++
++#endif
++
++static int ext3cow_get_sb(struct file_system_type *fs_type,
++	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
++{
++	return get_sb_bdev(fs_type, flags, dev_name, data, ext3cow_fill_super, mnt);
++}
++
++/* Code to update the epoch counter in the super block -znjp */
++unsigned int ext3cow_take_snapshot(struct super_block *sb){
++
++  struct ext3cow_sb_info *sbi = NULL;
++  struct ext3cow_super_block *es = NULL;
++  tid_t target;
++
++  if(NULL == sb){
++    printk("EXT3COW-fs: superblock is NULL when taking snapshot.\n");
++    return -1;
++  }
++
++  sbi = EXT3COW_SB(sb);
++  es = sbi->s_es;
++
++  /* Sync the dirty blocks */
++  if (journal_start_commit(EXT3COW_SB(sb)->s_journal, &target)) {
++    log_wait_commit(EXT3COW_SB(sb)->s_journal, target);
++	}
++  
++
++  sbi->s_epoch_number = cpu_to_le32(get_seconds());
++  es->s_epoch_number = sbi->s_epoch_number;
++  sb->s_dirt = 1;
++
++  BUFFER_TRACE(EXT3COW_SB(sb)->s_sbh, "marking dirty");
++  mark_buffer_dirty(sbi->s_sbh);
++  ext3cow_commit_super (sb, es, 1);
++
++  return (unsigned int)sbi->s_epoch_number;
++}
++
++static struct file_system_type ext3cow_fs_type = {
++	.owner		= THIS_MODULE,
++	.name		= "ext3cow",
++	.get_sb		= ext3cow_get_sb,
++	.kill_sb	= kill_block_super,
++	.fs_flags	= FS_REQUIRES_DEV,
++};
++
++static int __init init_ext3cow_fs(void)
++{
++	int err = init_ext3cow_xattr();
++	if (err)
++		return err;
++	err = init_inodecache();
++	if (err)
++		goto out1;
++        err = register_filesystem(&ext3cow_fs_type);
++	if (err)
++		goto out;
++	return 0;
++out:
++	destroy_inodecache();
++out1:
++	exit_ext3cow_xattr();
++	return err;
++}
++
++static void __exit exit_ext3cow_fs(void)
++{
++	unregister_filesystem(&ext3cow_fs_type);
++	destroy_inodecache();
++	exit_ext3cow_xattr();
++}
++
++MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
++MODULE_DESCRIPTION("Second Extended Filesystem with journaling extensions");
++MODULE_LICENSE("GPL");
++module_init(init_ext3cow_fs)
++module_exit(exit_ext3cow_fs)
+diff -ruN linux-2.6.20.3/fs/ext3cow/symlink.c linux-2.6.20.3-ext3cow/fs/ext3cow/symlink.c
+--- linux-2.6.20.3/fs/ext3cow/symlink.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/symlink.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,54 @@
++/*
++ *  linux/fs/ext3cow/symlink.c
++ *
++ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/fs/minix/symlink.c
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ *
++ *  ext3cow symlink handling code
++ */
++
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/namei.h>
++#include "xattr.h"
++
++static void * ext3cow_follow_link(struct dentry *dentry, struct nameidata *nd)
++{
++	struct ext3cow_inode_info *ei = EXT3COW_I(dentry->d_inode);
++	nd_set_link(nd, (char*)ei->i_data);
++	return NULL;
++}
++
++struct inode_operations ext3cow_symlink_inode_operations = {
++	.readlink	= generic_readlink,
++	.follow_link	= page_follow_link_light,
++	.put_link	= page_put_link,
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	.setxattr	= generic_setxattr,
++	.getxattr	= generic_getxattr,
++	.listxattr	= ext3cow_listxattr,
++	.removexattr	= generic_removexattr,
++#endif
++};
++
++struct inode_operations ext3cow_fast_symlink_inode_operations = {
++	.readlink	= generic_readlink,
++	.follow_link	= ext3cow_follow_link,
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	.setxattr	= generic_setxattr,
++	.getxattr	= generic_getxattr,
++	.listxattr	= ext3cow_listxattr,
++	.removexattr	= generic_removexattr,
++#endif
++};
+diff -ruN linux-2.6.20.3/fs/ext3cow/xattr.c linux-2.6.20.3-ext3cow/fs/ext3cow/xattr.c
+--- linux-2.6.20.3/fs/ext3cow/xattr.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/xattr.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,1314 @@
++/*
++ * linux/fs/ext3cow/xattr.c
++ *
++ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
++ *
++ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
++ * Ext3 code with a lot of help from Eric Jarman <ejarman@acm.org>.
++ * Extended attributes for symlinks and special files added per
++ *  suggestion of Luka Renko <luka.renko@hermes.si>.
++ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
++ *  Red Hat Inc.
++ * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
++ *  and Andreas Gruenbacher <agruen@suse.de>.
++ */
++
++/*
++ * Extended attributes are stored directly in inodes (on file systems with
++ * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
++ * field contains the block number if an inode uses an additional block. All
++ * attributes must fit in the inode and one additional block. Blocks that
++ * contain the identical set of attributes may be shared among several inodes.
++ * Identical blocks are detected by keeping a cache of blocks that have
++ * recently been accessed.
++ *
++ * The attributes in inodes and on blocks have a different header; the entries
++ * are stored in the same format:
++ *
++ *   +------------------+
++ *   | header           |
++ *   | entry 1          | |
++ *   | entry 2          | | growing downwards
++ *   | entry 3          | v
++ *   | four null bytes  |
++ *   | . . .            |
++ *   | value 1          | ^
++ *   | value 3          | | growing upwards
++ *   | value 2          | |
++ *   +------------------+
++ *
++ * The header is followed by multiple entry descriptors. In disk blocks, the
++ * entry descriptors are kept sorted. In inodes, they are unsorted. The
++ * attribute values are aligned to the end of the block in no specific order.
++ *
++ * Locking strategy
++ * ----------------
++ * EXT3COW_I(inode)->i_file_acl is protected by EXT3COW_I(inode)->xattr_sem.
++ * EA blocks are only changed if they are exclusive to an inode, so
++ * holding xattr_sem also means that nothing but the EA block's reference
++ * count can change. Multiple writers to the same block are synchronized
++ * by the buffer lock.
++ */
++
++#include <linux/init.h>
++#include <linux/fs.h>
++#include <linux/slab.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/mbcache.h>
++#include <linux/quotaops.h>
++#include <linux/rwsem.h>
++#include "xattr.h"
++#include "acl.h"
++
++#define BHDR(bh) ((struct ext3cow_xattr_header *)((bh)->b_data))
++#define ENTRY(ptr) ((struct ext3cow_xattr_entry *)(ptr))
++#define BFIRST(bh) ENTRY(BHDR(bh)+1)
++#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
++
++#define IHDR(inode, raw_inode) \
++	((struct ext3cow_xattr_ibody_header *) \
++		((void *)raw_inode + \
++		 EXT3COW_GOOD_OLD_INODE_SIZE + \
++		 EXT3COW_I(inode)->i_extra_isize))
++#define IFIRST(hdr) ((struct ext3cow_xattr_entry *)((hdr)+1))
++
++#ifdef EXT3COW_XATTR_DEBUG
++# define ea_idebug(inode, f...) do { \
++		printk(KERN_DEBUG "inode %s:%lu: ", \
++			inode->i_sb->s_id, inode->i_ino); \
++		printk(f); \
++		printk("\n"); \
++	} while (0)
++# define ea_bdebug(bh, f...) do { \
++		char b[BDEVNAME_SIZE]; \
++		printk(KERN_DEBUG "block %s:%lu: ", \
++			bdevname(bh->b_bdev, b), \
++			(unsigned long) bh->b_blocknr); \
++		printk(f); \
++		printk("\n"); \
++	} while (0)
++#else
++# define ea_idebug(f...)
++# define ea_bdebug(f...)
++#endif
++
++static void ext3cow_xattr_cache_insert(struct buffer_head *);
++static struct buffer_head *ext3cow_xattr_cache_find(struct inode *,
++						 struct ext3cow_xattr_header *,
++						 struct mb_cache_entry **);
++static void ext3cow_xattr_rehash(struct ext3cow_xattr_header *,
++			      struct ext3cow_xattr_entry *);
++
++static struct mb_cache *ext3cow_xattr_cache;
++
++static struct xattr_handler *ext3cow_xattr_handler_map[] = {
++	[EXT3COW_XATTR_INDEX_USER]		     = &ext3cow_xattr_user_handler,
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	[EXT3COW_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext3cow_xattr_acl_access_handler,
++	[EXT3COW_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext3cow_xattr_acl_default_handler,
++#endif
++	[EXT3COW_XATTR_INDEX_TRUSTED]	     = &ext3cow_xattr_trusted_handler,
++#ifdef CONFIG_EXT3COW_FS_SECURITY
++	[EXT3COW_XATTR_INDEX_SECURITY]	     = &ext3cow_xattr_security_handler,
++#endif
++};
++
++struct xattr_handler *ext3cow_xattr_handlers[] = {
++	&ext3cow_xattr_user_handler,
++	&ext3cow_xattr_trusted_handler,
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	&ext3cow_xattr_acl_access_handler,
++	&ext3cow_xattr_acl_default_handler,
++#endif
++#ifdef CONFIG_EXT3COW_FS_SECURITY
++	&ext3cow_xattr_security_handler,
++#endif
++	NULL
++};
++
++static inline struct xattr_handler *
++ext3cow_xattr_handler(int name_index)
++{
++	struct xattr_handler *handler = NULL;
++
++	if (name_index > 0 && name_index < ARRAY_SIZE(ext3cow_xattr_handler_map))
++		handler = ext3cow_xattr_handler_map[name_index];
++	return handler;
++}
++
++/*
++ * Inode operation listxattr()
++ *
++ * dentry->d_inode->i_mutex: don't care
++ */
++ssize_t
++ext3cow_listxattr(struct dentry *dentry, char *buffer, size_t size)
++{
++	return ext3cow_xattr_list(dentry->d_inode, buffer, size);
++}
++
++static int
++ext3cow_xattr_check_names(struct ext3cow_xattr_entry *entry, void *end)
++{
++	while (!IS_LAST_ENTRY(entry)) {
++		struct ext3cow_xattr_entry *next = EXT3COW_XATTR_NEXT(entry);
++		if ((void *)next >= end)
++			return -EIO;
++		entry = next;
++	}
++	return 0;
++}
++
++static inline int
++ext3cow_xattr_check_block(struct buffer_head *bh)
++{
++	int error;
++
++	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3COW_XATTR_MAGIC) ||
++	    BHDR(bh)->h_blocks != cpu_to_le32(1))
++		return -EIO;
++	error = ext3cow_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
++	return error;
++}
++
++static inline int
++ext3cow_xattr_check_entry(struct ext3cow_xattr_entry *entry, size_t size)
++{
++	size_t value_size = le32_to_cpu(entry->e_value_size);
++
++	if (entry->e_value_block != 0 || value_size > size ||
++	    le16_to_cpu(entry->e_value_offs) + value_size > size)
++		return -EIO;
++	return 0;
++}
++
++static int
++ext3cow_xattr_find_entry(struct ext3cow_xattr_entry **pentry, int name_index,
++		      const char *name, size_t size, int sorted)
++{
++	struct ext3cow_xattr_entry *entry;
++	size_t name_len;
++	int cmp = 1;
++
++	if (name == NULL)
++		return -EINVAL;
++	name_len = strlen(name);
++	entry = *pentry;
++	for (; !IS_LAST_ENTRY(entry); entry = EXT3COW_XATTR_NEXT(entry)) {
++		cmp = name_index - entry->e_name_index;
++		if (!cmp)
++			cmp = name_len - entry->e_name_len;
++		if (!cmp)
++			cmp = memcmp(name, entry->e_name, name_len);
++		if (cmp <= 0 && (sorted || cmp == 0))
++			break;
++	}
++	*pentry = entry;
++	if (!cmp && ext3cow_xattr_check_entry(entry, size))
++			return -EIO;
++	return cmp ? -ENODATA : 0;
++}
++
++static int
++ext3cow_xattr_block_get(struct inode *inode, int name_index, const char *name,
++		     void *buffer, size_t buffer_size)
++{
++	struct buffer_head *bh = NULL;
++	struct ext3cow_xattr_entry *entry;
++	size_t size;
++	int error;
++
++	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
++		  name_index, name, buffer, (long)buffer_size);
++
++	error = -ENODATA;
++	if (!EXT3COW_I(inode)->i_file_acl)
++		goto cleanup;
++	ea_idebug(inode, "reading block %u", EXT3COW_I(inode)->i_file_acl);
++	bh = sb_bread(inode->i_sb, EXT3COW_I(inode)->i_file_acl);
++	if (!bh)
++		goto cleanup;
++	ea_bdebug(bh, "b_count=%d, refcount=%d",
++		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
++	if (ext3cow_xattr_check_block(bh)) {
++bad_block:	ext3cow_error(inode->i_sb, __FUNCTION__,
++			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
++			   EXT3COW_I(inode)->i_file_acl);
++		error = -EIO;
++		goto cleanup;
++	}
++	ext3cow_xattr_cache_insert(bh);
++	entry = BFIRST(bh);
++	error = ext3cow_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
++	if (error == -EIO)
++		goto bad_block;
++	if (error)
++		goto cleanup;
++	size = le32_to_cpu(entry->e_value_size);
++	if (buffer) {
++		error = -ERANGE;
++		if (size > buffer_size)
++			goto cleanup;
++		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
++		       size);
++	}
++	error = size;
++
++cleanup:
++	brelse(bh);
++	return error;
++}
++
++static int
++ext3cow_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
++		     void *buffer, size_t buffer_size)
++{
++	struct ext3cow_xattr_ibody_header *header;
++	struct ext3cow_xattr_entry *entry;
++	struct ext3cow_inode *raw_inode;
++	struct ext3cow_iloc iloc;
++	size_t size;
++	void *end;
++	int error;
++
++	if (!(EXT3COW_I(inode)->i_state & EXT3COW_STATE_XATTR))
++		return -ENODATA;
++	error = ext3cow_get_inode_loc(inode, &iloc);
++	if (error)
++		return error;
++	raw_inode = ext3cow_raw_inode(&iloc);
++	header = IHDR(inode, raw_inode);
++	entry = IFIRST(header);
++	end = (void *)raw_inode + EXT3COW_SB(inode->i_sb)->s_inode_size;
++	error = ext3cow_xattr_check_names(entry, end);
++	if (error)
++		goto cleanup;
++	error = ext3cow_xattr_find_entry(&entry, name_index, name,
++				      end - (void *)entry, 0);
++	if (error)
++		goto cleanup;
++	size = le32_to_cpu(entry->e_value_size);
++	if (buffer) {
++		error = -ERANGE;
++		if (size > buffer_size)
++			goto cleanup;
++		memcpy(buffer, (void *)IFIRST(header) +
++		       le16_to_cpu(entry->e_value_offs), size);
++	}
++	error = size;
++
++cleanup:
++	brelse(iloc.bh);
++	return error;
++}
++
++/*
++ * ext3cow_xattr_get()
++ *
++ * Copy an extended attribute into the buffer
++ * provided, or compute the buffer size required.
++ * Buffer is NULL to compute the size of the buffer required.
++ *
++ * Returns a negative error number on failure, or the number of bytes
++ * used / required on success.
++ */
++int
++ext3cow_xattr_get(struct inode *inode, int name_index, const char *name,
++	       void *buffer, size_t buffer_size)
++{
++	int error;
++
++	down_read(&EXT3COW_I(inode)->xattr_sem);
++	error = ext3cow_xattr_ibody_get(inode, name_index, name, buffer,
++				     buffer_size);
++	if (error == -ENODATA)
++		error = ext3cow_xattr_block_get(inode, name_index, name, buffer,
++					     buffer_size);
++	up_read(&EXT3COW_I(inode)->xattr_sem);
++	return error;
++}
++
++static int
++ext3cow_xattr_list_entries(struct inode *inode, struct ext3cow_xattr_entry *entry,
++			char *buffer, size_t buffer_size)
++{
++	size_t rest = buffer_size;
++
++	for (; !IS_LAST_ENTRY(entry); entry = EXT3COW_XATTR_NEXT(entry)) {
++		struct xattr_handler *handler =
++			ext3cow_xattr_handler(entry->e_name_index);
++
++		if (handler) {
++			size_t size = handler->list(inode, buffer, rest,
++						    entry->e_name,
++						    entry->e_name_len);
++			if (buffer) {
++				if (size > rest)
++					return -ERANGE;
++				buffer += size;
++			}
++			rest -= size;
++		}
++	}
++	return buffer_size - rest;
++}
++
++static int
++ext3cow_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
++{
++	struct buffer_head *bh = NULL;
++	int error;
++
++	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
++		  buffer, (long)buffer_size);
++
++	error = 0;
++	if (!EXT3COW_I(inode)->i_file_acl)
++		goto cleanup;
++	ea_idebug(inode, "reading block %u", EXT3COW_I(inode)->i_file_acl);
++	bh = sb_bread(inode->i_sb, EXT3COW_I(inode)->i_file_acl);
++	error = -EIO;
++	if (!bh)
++		goto cleanup;
++	ea_bdebug(bh, "b_count=%d, refcount=%d",
++		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
++	if (ext3cow_xattr_check_block(bh)) {
++		ext3cow_error(inode->i_sb, __FUNCTION__,
++			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
++			   EXT3COW_I(inode)->i_file_acl);
++		error = -EIO;
++		goto cleanup;
++	}
++	ext3cow_xattr_cache_insert(bh);
++	error = ext3cow_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
++
++cleanup:
++	brelse(bh);
++
++	return error;
++}
++
++static int
++ext3cow_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
++{
++	struct ext3cow_xattr_ibody_header *header;
++	struct ext3cow_inode *raw_inode;
++	struct ext3cow_iloc iloc;
++	void *end;
++	int error;
++
++	if (!(EXT3COW_I(inode)->i_state & EXT3COW_STATE_XATTR))
++		return 0;
++	error = ext3cow_get_inode_loc(inode, &iloc);
++	if (error)
++		return error;
++	raw_inode = ext3cow_raw_inode(&iloc);
++	header = IHDR(inode, raw_inode);
++	end = (void *)raw_inode + EXT3COW_SB(inode->i_sb)->s_inode_size;
++	error = ext3cow_xattr_check_names(IFIRST(header), end);
++	if (error)
++		goto cleanup;
++	error = ext3cow_xattr_list_entries(inode, IFIRST(header),
++					buffer, buffer_size);
++
++cleanup:
++	brelse(iloc.bh);
++	return error;
++}
++
++/*
++ * ext3cow_xattr_list()
++ *
++ * Copy a list of attribute names into the buffer
++ * provided, or compute the buffer size required.
++ * Buffer is NULL to compute the size of the buffer required.
++ *
++ * Returns a negative error number on failure, or the number of bytes
++ * used / required on success.
++ */
++int
++ext3cow_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
++{
++	int i_error, b_error;
++
++	down_read(&EXT3COW_I(inode)->xattr_sem);
++	i_error = ext3cow_xattr_ibody_list(inode, buffer, buffer_size);
++	if (i_error < 0) {
++		b_error = 0;
++	} else {
++		if (buffer) {
++			buffer += i_error;
++			buffer_size -= i_error;
++		}
++		b_error = ext3cow_xattr_block_list(inode, buffer, buffer_size);
++		if (b_error < 0)
++			i_error = 0;
++	}
++	up_read(&EXT3COW_I(inode)->xattr_sem);
++	return i_error + b_error;
++}
++
++/*
++ * If the EXT3COW_FEATURE_COMPAT_EXT_ATTR feature of this file system is
++ * not set, set it.
++ */
++static void ext3cow_xattr_update_super_block(handle_t *handle,
++					  struct super_block *sb)
++{
++	if (EXT3COW_HAS_COMPAT_FEATURE(sb, EXT3COW_FEATURE_COMPAT_EXT_ATTR))
++		return;
++
++	if (ext3cow_journal_get_write_access(handle, EXT3COW_SB(sb)->s_sbh) == 0) {
++		EXT3COW_SET_COMPAT_FEATURE(sb, EXT3COW_FEATURE_COMPAT_EXT_ATTR);
++		sb->s_dirt = 1;
++		ext3cow_journal_dirty_metadata(handle, EXT3COW_SB(sb)->s_sbh);
++	}
++}
++
++/*
++ * Release the xattr block BH: If the reference count is > 1, decrement
++ * it; otherwise free the block.
++ */
++static void
++ext3cow_xattr_release_block(handle_t *handle, struct inode *inode,
++			 struct buffer_head *bh)
++{
++	struct mb_cache_entry *ce = NULL;
++
++	ce = mb_cache_entry_get(ext3cow_xattr_cache, bh->b_bdev, bh->b_blocknr);
++	if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
++		ea_bdebug(bh, "refcount now=0; freeing");
++		if (ce)
++			mb_cache_entry_free(ce);
++		ext3cow_free_blocks(handle, inode, bh->b_blocknr, 1);
++		get_bh(bh);
++		ext3cow_forget(handle, 1, inode, bh, bh->b_blocknr);
++	} else {
++		if (ext3cow_journal_get_write_access(handle, bh) == 0) {
++			lock_buffer(bh);
++			BHDR(bh)->h_refcount = cpu_to_le32(
++				le32_to_cpu(BHDR(bh)->h_refcount) - 1);
++			ext3cow_journal_dirty_metadata(handle, bh);
++			if (IS_SYNC(inode))
++				handle->h_sync = 1;
++			DQUOT_FREE_BLOCK(inode, 1);
++			unlock_buffer(bh);
++			ea_bdebug(bh, "refcount now=%d; releasing",
++				  le32_to_cpu(BHDR(bh)->h_refcount));
++		}
++		if (ce)
++			mb_cache_entry_release(ce);
++	}
++}
++
++struct ext3cow_xattr_info {
++	int name_index;
++	const char *name;
++	const void *value;
++	size_t value_len;
++};
++
++struct ext3cow_xattr_search {
++	struct ext3cow_xattr_entry *first;
++	void *base;
++	void *end;
++	struct ext3cow_xattr_entry *here;
++	int not_found;
++};
++
++static int
++ext3cow_xattr_set_entry(struct ext3cow_xattr_info *i, struct ext3cow_xattr_search *s)
++{
++	struct ext3cow_xattr_entry *last;
++	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
++
++	/* Compute min_offs and last. */
++	last = s->first;
++	for (; !IS_LAST_ENTRY(last); last = EXT3COW_XATTR_NEXT(last)) {
++		if (!last->e_value_block && last->e_value_size) {
++			size_t offs = le16_to_cpu(last->e_value_offs);
++			if (offs < min_offs)
++				min_offs = offs;
++		}
++	}
++	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
++	if (!s->not_found) {
++		if (!s->here->e_value_block && s->here->e_value_size) {
++			size_t size = le32_to_cpu(s->here->e_value_size);
++			free += EXT3COW_XATTR_SIZE(size);
++		}
++		free += EXT3COW_XATTR_LEN(name_len);
++	}
++	if (i->value) {
++		if (free < EXT3COW_XATTR_SIZE(i->value_len) ||
++		    free < EXT3COW_XATTR_LEN(name_len) +
++			   EXT3COW_XATTR_SIZE(i->value_len))
++			return -ENOSPC;
++	}
++
++	if (i->value && s->not_found) {
++		/* Insert the new name. */
++		size_t size = EXT3COW_XATTR_LEN(name_len);
++		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
++		memmove((void *)s->here + size, s->here, rest);
++		memset(s->here, 0, size);
++		s->here->e_name_index = i->name_index;
++		s->here->e_name_len = name_len;
++		memcpy(s->here->e_name, i->name, name_len);
++	} else {
++		if (!s->here->e_value_block && s->here->e_value_size) {
++			void *first_val = s->base + min_offs;
++			size_t offs = le16_to_cpu(s->here->e_value_offs);
++			void *val = s->base + offs;
++			size_t size = EXT3COW_XATTR_SIZE(
++				le32_to_cpu(s->here->e_value_size));
++
++			if (i->value && size == EXT3COW_XATTR_SIZE(i->value_len)) {
++				/* The old and the new value have the same
++				   size. Just replace. */
++				s->here->e_value_size =
++					cpu_to_le32(i->value_len);
++				memset(val + size - EXT3COW_XATTR_PAD, 0,
++				       EXT3COW_XATTR_PAD); /* Clear pad bytes. */
++				memcpy(val, i->value, i->value_len);
++				return 0;
++			}
++
++			/* Remove the old value. */
++			memmove(first_val + size, first_val, val - first_val);
++			memset(first_val, 0, size);
++			s->here->e_value_size = 0;
++			s->here->e_value_offs = 0;
++			min_offs += size;
++
++			/* Adjust all value offsets. */
++			last = s->first;
++			while (!IS_LAST_ENTRY(last)) {
++				size_t o = le16_to_cpu(last->e_value_offs);
++				if (!last->e_value_block &&
++				    last->e_value_size && o < offs)
++					last->e_value_offs =
++						cpu_to_le16(o + size);
++				last = EXT3COW_XATTR_NEXT(last);
++			}
++		}
++		if (!i->value) {
++			/* Remove the old name. */
++			size_t size = EXT3COW_XATTR_LEN(name_len);
++			last = ENTRY((void *)last - size);
++			memmove(s->here, (void *)s->here + size,
++				(void *)last - (void *)s->here + sizeof(__u32));
++			memset(last, 0, size);
++		}
++	}
++
++	if (i->value) {
++		/* Insert the new value. */
++		s->here->e_value_size = cpu_to_le32(i->value_len);
++		if (i->value_len) {
++			size_t size = EXT3COW_XATTR_SIZE(i->value_len);
++			void *val = s->base + min_offs - size;
++			s->here->e_value_offs = cpu_to_le16(min_offs - size);
++			memset(val + size - EXT3COW_XATTR_PAD, 0,
++			       EXT3COW_XATTR_PAD); /* Clear the pad bytes. */
++			memcpy(val, i->value, i->value_len);
++		}
++	}
++	return 0;
++}
++
++struct ext3cow_xattr_block_find {
++	struct ext3cow_xattr_search s;
++	struct buffer_head *bh;
++};
++
++static int
++ext3cow_xattr_block_find(struct inode *inode, struct ext3cow_xattr_info *i,
++		      struct ext3cow_xattr_block_find *bs)
++{
++	struct super_block *sb = inode->i_sb;
++	int error;
++
++	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
++		  i->name_index, i->name, i->value, (long)i->value_len);
++
++	if (EXT3COW_I(inode)->i_file_acl) {
++		/* The inode already has an extended attribute block. */
++		bs->bh = sb_bread(sb, EXT3COW_I(inode)->i_file_acl);
++		error = -EIO;
++		if (!bs->bh)
++			goto cleanup;
++		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
++			atomic_read(&(bs->bh->b_count)),
++			le32_to_cpu(BHDR(bs->bh)->h_refcount));
++		if (ext3cow_xattr_check_block(bs->bh)) {
++			ext3cow_error(sb, __FUNCTION__,
++				"inode %lu: bad block "E3FSBLK, inode->i_ino,
++				EXT3COW_I(inode)->i_file_acl);
++			error = -EIO;
++			goto cleanup;
++		}
++		/* Find the named attribute. */
++		bs->s.base = BHDR(bs->bh);
++		bs->s.first = BFIRST(bs->bh);
++		bs->s.end = bs->bh->b_data + bs->bh->b_size;
++		bs->s.here = bs->s.first;
++		error = ext3cow_xattr_find_entry(&bs->s.here, i->name_index,
++					      i->name, bs->bh->b_size, 1);
++		if (error && error != -ENODATA)
++			goto cleanup;
++		bs->s.not_found = error;
++	}
++	error = 0;
++
++cleanup:
++	return error;
++}
++
++static int
++ext3cow_xattr_block_set(handle_t *handle, struct inode *inode,
++		     struct ext3cow_xattr_info *i,
++		     struct ext3cow_xattr_block_find *bs)
++{
++	struct super_block *sb = inode->i_sb;
++	struct buffer_head *new_bh = NULL;
++	struct ext3cow_xattr_search *s = &bs->s;
++	struct mb_cache_entry *ce = NULL;
++	int error;
++
++#define header(x) ((struct ext3cow_xattr_header *)(x))
++
++	if (i->value && i->value_len > sb->s_blocksize)
++		return -ENOSPC;
++	if (s->base) {
++		ce = mb_cache_entry_get(ext3cow_xattr_cache, bs->bh->b_bdev,
++					bs->bh->b_blocknr);
++		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
++			if (ce) {
++				mb_cache_entry_free(ce);
++				ce = NULL;
++			}
++			ea_bdebug(bs->bh, "modifying in-place");
++			error = ext3cow_journal_get_write_access(handle, bs->bh);
++			if (error)
++				goto cleanup;
++			lock_buffer(bs->bh);
++			error = ext3cow_xattr_set_entry(i, s);
++			if (!error) {
++				if (!IS_LAST_ENTRY(s->first))
++					ext3cow_xattr_rehash(header(s->base),
++							  s->here);
++				ext3cow_xattr_cache_insert(bs->bh);
++			}
++			unlock_buffer(bs->bh);
++			if (error == -EIO)
++				goto bad_block;
++			if (!error)
++				error = ext3cow_journal_dirty_metadata(handle,
++								    bs->bh);
++			if (error)
++				goto cleanup;
++			goto inserted;
++		} else {
++			int offset = (char *)s->here - bs->bh->b_data;
++
++			if (ce) {
++				mb_cache_entry_release(ce);
++				ce = NULL;
++			}
++			ea_bdebug(bs->bh, "cloning");
++			s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
++			error = -ENOMEM;
++			if (s->base == NULL)
++				goto cleanup;
++			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
++			s->first = ENTRY(header(s->base)+1);
++			header(s->base)->h_refcount = cpu_to_le32(1);
++			s->here = ENTRY(s->base + offset);
++			s->end = s->base + bs->bh->b_size;
++		}
++	} else {
++		/* Allocate a buffer where we construct the new block. */
++		s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
++		/* assert(header == s->base) */
++		error = -ENOMEM;
++		if (s->base == NULL)
++			goto cleanup;
++		memset(s->base, 0, sb->s_blocksize);
++		header(s->base)->h_magic = cpu_to_le32(EXT3COW_XATTR_MAGIC);
++		header(s->base)->h_blocks = cpu_to_le32(1);
++		header(s->base)->h_refcount = cpu_to_le32(1);
++		s->first = ENTRY(header(s->base)+1);
++		s->here = ENTRY(header(s->base)+1);
++		s->end = s->base + sb->s_blocksize;
++	}
++
++	error = ext3cow_xattr_set_entry(i, s);
++	if (error == -EIO)
++		goto bad_block;
++	if (error)
++		goto cleanup;
++	if (!IS_LAST_ENTRY(s->first))
++		ext3cow_xattr_rehash(header(s->base), s->here);
++
++inserted:
++	if (!IS_LAST_ENTRY(s->first)) {
++		new_bh = ext3cow_xattr_cache_find(inode, header(s->base), &ce);
++		if (new_bh) {
++			/* We found an identical block in the cache. */
++			if (new_bh == bs->bh)
++				ea_bdebug(new_bh, "keeping");
++			else {
++				/* The old block is released after updating
++				   the inode. */
++				error = -EDQUOT;
++				if (DQUOT_ALLOC_BLOCK(inode, 1))
++					goto cleanup;
++				error = ext3cow_journal_get_write_access(handle,
++								      new_bh);
++				if (error)
++					goto cleanup_dquot;
++				lock_buffer(new_bh);
++				BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
++					le32_to_cpu(BHDR(new_bh)->h_refcount));
++				ea_bdebug(new_bh, "reusing; refcount now=%d",
++					le32_to_cpu(BHDR(new_bh)->h_refcount));
++				unlock_buffer(new_bh);
++				error = ext3cow_journal_dirty_metadata(handle,
++								    new_bh);
++				if (error)
++					goto cleanup_dquot;
++			}
++			mb_cache_entry_release(ce);
++			ce = NULL;
++		} else if (bs->bh && s->base == bs->bh->b_data) {
++			/* We were modifying this block in-place. */
++			ea_bdebug(bs->bh, "keeping this block");
++			new_bh = bs->bh;
++			get_bh(new_bh);
++		} else {
++			/* We need to allocate a new block */
++			ext3cow_fsblk_t goal = le32_to_cpu(
++					EXT3COW_SB(sb)->s_es->s_first_data_block) +
++				(ext3cow_fsblk_t)EXT3COW_I(inode)->i_block_group *
++				EXT3COW_BLOCKS_PER_GROUP(sb);
++			ext3cow_fsblk_t block = ext3cow_new_block(handle, inode,
++							goal, &error);
++			if (error)
++				goto cleanup;
++			ea_idebug(inode, "creating block %d", block);
++
++			new_bh = sb_getblk(sb, block);
++			if (!new_bh) {
++getblk_failed:
++				ext3cow_free_blocks(handle, inode, block, 1);
++				error = -EIO;
++				goto cleanup;
++			}
++			lock_buffer(new_bh);
++			error = ext3cow_journal_get_create_access(handle, new_bh);
++			if (error) {
++				unlock_buffer(new_bh);
++				goto getblk_failed;
++			}
++			memcpy(new_bh->b_data, s->base, new_bh->b_size);
++			set_buffer_uptodate(new_bh);
++			unlock_buffer(new_bh);
++			ext3cow_xattr_cache_insert(new_bh);
++			error = ext3cow_journal_dirty_metadata(handle, new_bh);
++			if (error)
++				goto cleanup;
++		}
++	}
++
++	/* Update the inode. */
++	EXT3COW_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
++
++	/* Drop the previous xattr block. */
++	if (bs->bh && bs->bh != new_bh)
++		ext3cow_xattr_release_block(handle, inode, bs->bh);
++	error = 0;
++
++cleanup:
++	if (ce)
++		mb_cache_entry_release(ce);
++	brelse(new_bh);
++	if (!(bs->bh && s->base == bs->bh->b_data))
++		kfree(s->base);
++
++	return error;
++
++cleanup_dquot:
++	DQUOT_FREE_BLOCK(inode, 1);
++	goto cleanup;
++
++bad_block:
++	ext3cow_error(inode->i_sb, __FUNCTION__,
++		   "inode %lu: bad block "E3FSBLK, inode->i_ino,
++		   EXT3COW_I(inode)->i_file_acl);
++	goto cleanup;
++
++#undef header
++}
++
++struct ext3cow_xattr_ibody_find {
++	struct ext3cow_xattr_search s;
++	struct ext3cow_iloc iloc;
++};
++
++static int
++ext3cow_xattr_ibody_find(struct inode *inode, struct ext3cow_xattr_info *i,
++		      struct ext3cow_xattr_ibody_find *is)
++{
++	struct ext3cow_xattr_ibody_header *header;
++	struct ext3cow_inode *raw_inode;
++	int error;
++
++	if (EXT3COW_I(inode)->i_extra_isize == 0)
++		return 0;
++	raw_inode = ext3cow_raw_inode(&is->iloc);
++	header = IHDR(inode, raw_inode);
++	is->s.base = is->s.first = IFIRST(header);
++	is->s.here = is->s.first;
++	is->s.end = (void *)raw_inode + EXT3COW_SB(inode->i_sb)->s_inode_size;
++	if (EXT3COW_I(inode)->i_state & EXT3COW_STATE_XATTR) {
++		error = ext3cow_xattr_check_names(IFIRST(header), is->s.end);
++		if (error)
++			return error;
++		/* Find the named attribute. */
++		error = ext3cow_xattr_find_entry(&is->s.here, i->name_index,
++					      i->name, is->s.end -
++					      (void *)is->s.base, 0);
++		if (error && error != -ENODATA)
++			return error;
++		is->s.not_found = error;
++	}
++	return 0;
++}
++
++static int
++ext3cow_xattr_ibody_set(handle_t *handle, struct inode *inode,
++		     struct ext3cow_xattr_info *i,
++		     struct ext3cow_xattr_ibody_find *is)
++{
++	struct ext3cow_xattr_ibody_header *header;
++	struct ext3cow_xattr_search *s = &is->s;
++	int error;
++
++	if (EXT3COW_I(inode)->i_extra_isize == 0)
++		return -ENOSPC;
++	error = ext3cow_xattr_set_entry(i, s);
++	if (error)
++		return error;
++	header = IHDR(inode, ext3cow_raw_inode(&is->iloc));
++	if (!IS_LAST_ENTRY(s->first)) {
++		header->h_magic = cpu_to_le32(EXT3COW_XATTR_MAGIC);
++		EXT3COW_I(inode)->i_state |= EXT3COW_STATE_XATTR;
++	} else {
++		header->h_magic = cpu_to_le32(0);
++		EXT3COW_I(inode)->i_state &= ~EXT3COW_STATE_XATTR;
++	}
++	return 0;
++}
++
++/*
++ * ext3cow_xattr_set_handle()
++ *
++ * Create, replace or remove an extended attribute for this inode. Buffer
++ * is NULL to remove an existing extended attribute, and non-NULL to
++ * either replace an existing extended attribute, or create a new extended
++ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
++ * specify that an extended attribute must exist and must not exist
++ * previous to the call, respectively.
++ *
++ * Returns 0, or a negative error number on failure.
++ */
++int
++ext3cow_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
++		      const char *name, const void *value, size_t value_len,
++		      int flags)
++{
++	struct ext3cow_xattr_info i = {
++		.name_index = name_index,
++		.name = name,
++		.value = value,
++		.value_len = value_len,
++
++	};
++	struct ext3cow_xattr_ibody_find is = {
++		.s = { .not_found = -ENODATA, },
++	};
++	struct ext3cow_xattr_block_find bs = {
++		.s = { .not_found = -ENODATA, },
++	};
++	int error;
++
++	if (!name)
++		return -EINVAL;
++	if (strlen(name) > 255)
++		return -ERANGE;
++	down_write(&EXT3COW_I(inode)->xattr_sem);
++	error = ext3cow_get_inode_loc(inode, &is.iloc);
++	if (error)
++		goto cleanup;
++
++	if (EXT3COW_I(inode)->i_state & EXT3COW_STATE_NEW) {
++		struct ext3cow_inode *raw_inode = ext3cow_raw_inode(&is.iloc);
++		memset(raw_inode, 0, EXT3COW_SB(inode->i_sb)->s_inode_size);
++		EXT3COW_I(inode)->i_state &= ~EXT3COW_STATE_NEW;
++	}
++
++	error = ext3cow_xattr_ibody_find(inode, &i, &is);
++	if (error)
++		goto cleanup;
++	if (is.s.not_found)
++		error = ext3cow_xattr_block_find(inode, &i, &bs);
++	if (error)
++		goto cleanup;
++	if (is.s.not_found && bs.s.not_found) {
++		error = -ENODATA;
++		if (flags & XATTR_REPLACE)
++			goto cleanup;
++		error = 0;
++		if (!value)
++			goto cleanup;
++	} else {
++		error = -EEXIST;
++		if (flags & XATTR_CREATE)
++			goto cleanup;
++	}
++	error = ext3cow_journal_get_write_access(handle, is.iloc.bh);
++	if (error)
++		goto cleanup;
++	if (!value) {
++		if (!is.s.not_found)
++			error = ext3cow_xattr_ibody_set(handle, inode, &i, &is);
++		else if (!bs.s.not_found)
++			error = ext3cow_xattr_block_set(handle, inode, &i, &bs);
++	} else {
++		error = ext3cow_xattr_ibody_set(handle, inode, &i, &is);
++		if (!error && !bs.s.not_found) {
++			i.value = NULL;
++			error = ext3cow_xattr_block_set(handle, inode, &i, &bs);
++		} else if (error == -ENOSPC) {
++			error = ext3cow_xattr_block_set(handle, inode, &i, &bs);
++			if (error)
++				goto cleanup;
++			if (!is.s.not_found) {
++				i.value = NULL;
++				error = ext3cow_xattr_ibody_set(handle, inode, &i,
++							     &is);
++			}
++		}
++	}
++	if (!error) {
++		ext3cow_xattr_update_super_block(handle, inode->i_sb);
++		inode->i_ctime = CURRENT_TIME_SEC;
++		error = ext3cow_mark_iloc_dirty(handle, inode, &is.iloc);
++		/*
++		 * The bh is consumed by ext3cow_mark_iloc_dirty, even with
++		 * error != 0.
++		 */
++		is.iloc.bh = NULL;
++		if (IS_SYNC(inode))
++			handle->h_sync = 1;
++	}
++
++cleanup:
++	brelse(is.iloc.bh);
++	brelse(bs.bh);
++	up_write(&EXT3COW_I(inode)->xattr_sem);
++	return error;
++}
++
++/*
++ * ext3cow_xattr_set()
++ *
++ * Like ext3cow_xattr_set_handle, but start from an inode. This extended
++ * attribute modification is a filesystem transaction by itself.
++ *
++ * Returns 0, or a negative error number on failure.
++ */
++int
++ext3cow_xattr_set(struct inode *inode, int name_index, const char *name,
++	       const void *value, size_t value_len, int flags)
++{
++	handle_t *handle;
++	int error, retries = 0;
++
++retry:
++	handle = ext3cow_journal_start(inode, EXT3COW_DATA_TRANS_BLOCKS(inode->i_sb));
++	if (IS_ERR(handle)) {
++		error = PTR_ERR(handle);
++	} else {
++		int error2;
++
++		error = ext3cow_xattr_set_handle(handle, inode, name_index, name,
++					      value, value_len, flags);
++		error2 = ext3cow_journal_stop(handle);
++		if (error == -ENOSPC &&
++		    ext3cow_should_retry_alloc(inode->i_sb, &retries))
++			goto retry;
++		if (error == 0)
++			error = error2;
++	}
++
++	return error;
++}
++
++/*
++ * ext3cow_xattr_delete_inode()
++ *
++ * Free extended attribute resources associated with this inode. This
++ * is called immediately before an inode is freed. We have exclusive
++ * access to the inode.
++ */
++void
++ext3cow_xattr_delete_inode(handle_t *handle, struct inode *inode)
++{
++	struct buffer_head *bh = NULL;
++
++	if (!EXT3COW_I(inode)->i_file_acl)
++		goto cleanup;
++	bh = sb_bread(inode->i_sb, EXT3COW_I(inode)->i_file_acl);
++	if (!bh) {
++		ext3cow_error(inode->i_sb, __FUNCTION__,
++			"inode %lu: block "E3FSBLK" read error", inode->i_ino,
++			EXT3COW_I(inode)->i_file_acl);
++		goto cleanup;
++	}
++	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3COW_XATTR_MAGIC) ||
++	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
++		ext3cow_error(inode->i_sb, __FUNCTION__,
++			"inode %lu: bad block "E3FSBLK, inode->i_ino,
++			EXT3COW_I(inode)->i_file_acl);
++		goto cleanup;
++	}
++	ext3cow_xattr_release_block(handle, inode, bh);
++	EXT3COW_I(inode)->i_file_acl = 0;
++
++cleanup:
++	brelse(bh);
++}
++
++/*
++ * ext3cow_xattr_put_super()
++ *
++ * This is called when a file system is unmounted.
++ */
++void
++ext3cow_xattr_put_super(struct super_block *sb)
++{
++	mb_cache_shrink(sb->s_bdev);
++}
++
++/*
++ * ext3cow_xattr_cache_insert()
++ *
++ * Create a new entry in the extended attribute cache, and insert
++ * it unless such an entry is already in the cache.
++ *
++ * Returns 0, or a negative error number on failure.
++ */
++static void
++ext3cow_xattr_cache_insert(struct buffer_head *bh)
++{
++	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
++	struct mb_cache_entry *ce;
++	int error;
++
++	ce = mb_cache_entry_alloc(ext3cow_xattr_cache);
++	if (!ce) {
++		ea_bdebug(bh, "out of memory");
++		return;
++	}
++	error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
++	if (error) {
++		mb_cache_entry_free(ce);
++		if (error == -EBUSY) {
++			ea_bdebug(bh, "already in cache");
++			error = 0;
++		}
++	} else {
++		ea_bdebug(bh, "inserting [%x]", (int)hash);
++		mb_cache_entry_release(ce);
++	}
++}
++
++/*
++ * ext3cow_xattr_cmp()
++ *
++ * Compare two extended attribute blocks for equality.
++ *
++ * Returns 0 if the blocks are equal, 1 if they differ, and
++ * a negative error number on errors.
++ */
++static int
++ext3cow_xattr_cmp(struct ext3cow_xattr_header *header1,
++	       struct ext3cow_xattr_header *header2)
++{
++	struct ext3cow_xattr_entry *entry1, *entry2;
++
++	entry1 = ENTRY(header1+1);
++	entry2 = ENTRY(header2+1);
++	while (!IS_LAST_ENTRY(entry1)) {
++		if (IS_LAST_ENTRY(entry2))
++			return 1;
++		if (entry1->e_hash != entry2->e_hash ||
++		    entry1->e_name_index != entry2->e_name_index ||
++		    entry1->e_name_len != entry2->e_name_len ||
++		    entry1->e_value_size != entry2->e_value_size ||
++		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
++			return 1;
++		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
++			return -EIO;
++		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
++			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
++			   le32_to_cpu(entry1->e_value_size)))
++			return 1;
++
++		entry1 = EXT3COW_XATTR_NEXT(entry1);
++		entry2 = EXT3COW_XATTR_NEXT(entry2);
++	}
++	if (!IS_LAST_ENTRY(entry2))
++		return 1;
++	return 0;
++}
++
++/*
++ * ext3cow_xattr_cache_find()
++ *
++ * Find an identical extended attribute block.
++ *
++ * Returns a pointer to the block found, or NULL if such a block was
++ * not found or an error occurred.
++ */
++static struct buffer_head *
++ext3cow_xattr_cache_find(struct inode *inode, struct ext3cow_xattr_header *header,
++		      struct mb_cache_entry **pce)
++{
++	__u32 hash = le32_to_cpu(header->h_hash);
++	struct mb_cache_entry *ce;
++
++	if (!header->h_hash)
++		return NULL;  /* never share */
++	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
++again:
++	ce = mb_cache_entry_find_first(ext3cow_xattr_cache, 0,
++				       inode->i_sb->s_bdev, hash);
++	while (ce) {
++		struct buffer_head *bh;
++
++		if (IS_ERR(ce)) {
++			if (PTR_ERR(ce) == -EAGAIN)
++				goto again;
++			break;
++		}
++		bh = sb_bread(inode->i_sb, ce->e_block);
++		if (!bh) {
++			ext3cow_error(inode->i_sb, __FUNCTION__,
++				"inode %lu: block %lu read error",
++				inode->i_ino, (unsigned long) ce->e_block);
++		} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
++				EXT3COW_XATTR_REFCOUNT_MAX) {
++			ea_idebug(inode, "block %lu refcount %d>=%d",
++				  (unsigned long) ce->e_block,
++				  le32_to_cpu(BHDR(bh)->h_refcount),
++					  EXT3COW_XATTR_REFCOUNT_MAX);
++		} else if (ext3cow_xattr_cmp(header, BHDR(bh)) == 0) {
++			*pce = ce;
++			return bh;
++		}
++		brelse(bh);
++		ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
++	}
++	return NULL;
++}
++
++#define NAME_HASH_SHIFT 5
++#define VALUE_HASH_SHIFT 16
++
++/*
++ * ext3cow_xattr_hash_entry()
++ *
++ * Compute the hash of an extended attribute.
++ */
++static inline void ext3cow_xattr_hash_entry(struct ext3cow_xattr_header *header,
++					 struct ext3cow_xattr_entry *entry)
++{
++	__u32 hash = 0;
++	char *name = entry->e_name;
++	int n;
++
++	for (n=0; n < entry->e_name_len; n++) {
++		hash = (hash << NAME_HASH_SHIFT) ^
++		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
++		       *name++;
++	}
++
++	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
++		__le32 *value = (__le32 *)((char *)header +
++			le16_to_cpu(entry->e_value_offs));
++		for (n = (le32_to_cpu(entry->e_value_size) +
++		     EXT3COW_XATTR_ROUND) >> EXT3COW_XATTR_PAD_BITS; n; n--) {
++			hash = (hash << VALUE_HASH_SHIFT) ^
++			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
++			       le32_to_cpu(*value++);
++		}
++	}
++	entry->e_hash = cpu_to_le32(hash);
++}
++
++#undef NAME_HASH_SHIFT
++#undef VALUE_HASH_SHIFT
++
++#define BLOCK_HASH_SHIFT 16
++
++/*
++ * ext3cow_xattr_rehash()
++ *
++ * Re-compute the extended attribute hash value after an entry has changed.
++ */
++static void ext3cow_xattr_rehash(struct ext3cow_xattr_header *header,
++			      struct ext3cow_xattr_entry *entry)
++{
++	struct ext3cow_xattr_entry *here;
++	__u32 hash = 0;
++
++	ext3cow_xattr_hash_entry(header, entry);
++	here = ENTRY(header+1);
++	while (!IS_LAST_ENTRY(here)) {
++		if (!here->e_hash) {
++			/* Block is not shared if an entry's hash value == 0 */
++			hash = 0;
++			break;
++		}
++		hash = (hash << BLOCK_HASH_SHIFT) ^
++		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
++		       le32_to_cpu(here->e_hash);
++		here = EXT3COW_XATTR_NEXT(here);
++	}
++	header->h_hash = cpu_to_le32(hash);
++}
++
++#undef BLOCK_HASH_SHIFT
++
++int __init
++init_ext3cow_xattr(void)
++{
++	ext3cow_xattr_cache = mb_cache_create("ext3cow_xattr", NULL,
++		sizeof(struct mb_cache_entry) +
++		sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
++	if (!ext3cow_xattr_cache)
++		return -ENOMEM;
++	return 0;
++}
++
++void
++exit_ext3cow_xattr(void)
++{
++	if (ext3cow_xattr_cache)
++		mb_cache_destroy(ext3cow_xattr_cache);
++	ext3cow_xattr_cache = NULL;
++}
+diff -ruN linux-2.6.20.3/fs/ext3cow/xattr.h linux-2.6.20.3-ext3cow/fs/ext3cow/xattr.h
+--- linux-2.6.20.3/fs/ext3cow/xattr.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/xattr.h	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,145 @@
++/*
++  File: fs/ext3cow/xattr.h
++
++  On-disk format of extended attributes for the ext3cow filesystem.
++
++  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
++*/
++
++#include <linux/xattr.h>
++
++/* Magic value in attribute blocks */
++#define EXT3COW_XATTR_MAGIC		0xEA020000
++
++/* Maximum number of references to one attribute block */
++#define EXT3COW_XATTR_REFCOUNT_MAX		1024
++
++/* Name indexes */
++#define EXT3COW_XATTR_INDEX_USER			1
++#define EXT3COW_XATTR_INDEX_POSIX_ACL_ACCESS	2
++#define EXT3COW_XATTR_INDEX_POSIX_ACL_DEFAULT	3
++#define EXT3COW_XATTR_INDEX_TRUSTED		4
++#define	EXT3COW_XATTR_INDEX_LUSTRE			5
++#define EXT3COW_XATTR_INDEX_SECURITY	        6
++
++struct ext3cow_xattr_header {
++	__le32	h_magic;	/* magic number for identification */
++	__le32	h_refcount;	/* reference count */
++	__le32	h_blocks;	/* number of disk blocks used */
++	__le32	h_hash;		/* hash value of all attributes */
++	__u32	h_reserved[4];	/* zero right now */
++};
++
++struct ext3cow_xattr_ibody_header {
++	__le32	h_magic;	/* magic number for identification */
++};
++
++struct ext3cow_xattr_entry {
++	__u8	e_name_len;	/* length of name */
++	__u8	e_name_index;	/* attribute name index */
++	__le16	e_value_offs;	/* offset in disk block of value */
++	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
++	__le32	e_value_size;	/* size of attribute value */
++	__le32	e_hash;		/* hash value of name and value */
++	char	e_name[0];	/* attribute name */
++};
++
++#define EXT3COW_XATTR_PAD_BITS		2
++#define EXT3COW_XATTR_PAD		(1<<EXT3COW_XATTR_PAD_BITS)
++#define EXT3COW_XATTR_ROUND		(EXT3COW_XATTR_PAD-1)
++#define EXT3COW_XATTR_LEN(name_len) \
++	(((name_len) + EXT3COW_XATTR_ROUND + \
++	sizeof(struct ext3cow_xattr_entry)) & ~EXT3COW_XATTR_ROUND)
++#define EXT3COW_XATTR_NEXT(entry) \
++	( (struct ext3cow_xattr_entry *)( \
++	  (char *)(entry) + EXT3COW_XATTR_LEN((entry)->e_name_len)) )
++#define EXT3COW_XATTR_SIZE(size) \
++	(((size) + EXT3COW_XATTR_ROUND) & ~EXT3COW_XATTR_ROUND)
++
++# ifdef CONFIG_EXT3COW_FS_XATTR
++
++extern struct xattr_handler ext3cow_xattr_user_handler;
++extern struct xattr_handler ext3cow_xattr_trusted_handler;
++extern struct xattr_handler ext3cow_xattr_acl_access_handler;
++extern struct xattr_handler ext3cow_xattr_acl_default_handler;
++extern struct xattr_handler ext3cow_xattr_security_handler;
++
++extern ssize_t ext3cow_listxattr(struct dentry *, char *, size_t);
++
++extern int ext3cow_xattr_get(struct inode *, int, const char *, void *, size_t);
++extern int ext3cow_xattr_list(struct inode *, char *, size_t);
++extern int ext3cow_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
++extern int ext3cow_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
++
++extern void ext3cow_xattr_delete_inode(handle_t *, struct inode *);
++extern void ext3cow_xattr_put_super(struct super_block *);
++
++extern int init_ext3cow_xattr(void);
++extern void exit_ext3cow_xattr(void);
++
++extern struct xattr_handler *ext3cow_xattr_handlers[];
++
++# else  /* CONFIG_EXT3COW_FS_XATTR */
++
++static inline int
++ext3cow_xattr_get(struct inode *inode, int name_index, const char *name,
++	       void *buffer, size_t size, int flags)
++{
++	return -EOPNOTSUPP;
++}
++
++static inline int
++ext3cow_xattr_list(struct inode *inode, void *buffer, size_t size)
++{
++	return -EOPNOTSUPP;
++}
++
++static inline int
++ext3cow_xattr_set(struct inode *inode, int name_index, const char *name,
++	       const void *value, size_t size, int flags)
++{
++	return -EOPNOTSUPP;
++}
++
++static inline int
++ext3cow_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
++	       const char *name, const void *value, size_t size, int flags)
++{
++	return -EOPNOTSUPP;
++}
++
++static inline void
++ext3cow_xattr_delete_inode(handle_t *handle, struct inode *inode)
++{
++}
++
++static inline void
++ext3cow_xattr_put_super(struct super_block *sb)
++{
++}
++
++static inline int
++init_ext3cow_xattr(void)
++{
++	return 0;
++}
++
++static inline void
++exit_ext3cow_xattr(void)
++{
++}
++
++#define ext3cow_xattr_handlers	NULL
++
++# endif  /* CONFIG_EXT3COW_FS_XATTR */
++
++#ifdef CONFIG_EXT3COW_FS_SECURITY
++extern int ext3cow_init_security(handle_t *handle, struct inode *inode,
++				struct inode *dir);
++#else
++static inline int ext3cow_init_security(handle_t *handle, struct inode *inode,
++				struct inode *dir)
++{
++	return 0;
++}
++#endif
+diff -ruN linux-2.6.20.3/fs/ext3cow/xattr_security.c linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_security.c
+--- linux-2.6.20.3/fs/ext3cow/xattr_security.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_security.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,77 @@
++/*
++ * linux/fs/ext3cow/xattr_security.c
++ * Handler for storing security labels as extended attributes.
++ */
++
++#include <linux/module.h>
++#include <linux/string.h>
++#include <linux/fs.h>
++#include <linux/smp_lock.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/ext3cow_fs.h>
++#include <linux/security.h>
++#include "xattr.h"
++
++static size_t
++ext3cow_xattr_security_list(struct inode *inode, char *list, size_t list_size,
++			 const char *name, size_t name_len)
++{
++	const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
++	const size_t total_len = prefix_len + name_len + 1;
++
++
++	if (list && total_len <= list_size) {
++		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
++		memcpy(list+prefix_len, name, name_len);
++		list[prefix_len + name_len] = '\0';
++	}
++	return total_len;
++}
++
++static int
++ext3cow_xattr_security_get(struct inode *inode, const char *name,
++		       void *buffer, size_t size)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	return ext3cow_xattr_get(inode, EXT3COW_XATTR_INDEX_SECURITY, name,
++			      buffer, size);
++}
++
++static int
++ext3cow_xattr_security_set(struct inode *inode, const char *name,
++		       const void *value, size_t size, int flags)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	return ext3cow_xattr_set(inode, EXT3COW_XATTR_INDEX_SECURITY, name,
++			      value, size, flags);
++}
++
++int
++ext3cow_init_security(handle_t *handle, struct inode *inode, struct inode *dir)
++{
++	int err;
++	size_t len;
++	void *value;
++	char *name;
++
++	err = security_inode_init_security(inode, dir, &name, &value, &len);
++	if (err) {
++		if (err == -EOPNOTSUPP)
++			return 0;
++		return err;
++	}
++	err = ext3cow_xattr_set_handle(handle, inode, EXT3COW_XATTR_INDEX_SECURITY,
++				    name, value, len, 0);
++	kfree(name);
++	kfree(value);
++	return err;
++}
++
++struct xattr_handler ext3cow_xattr_security_handler = {
++	.prefix	= XATTR_SECURITY_PREFIX,
++	.list	= ext3cow_xattr_security_list,
++	.get	= ext3cow_xattr_security_get,
++	.set	= ext3cow_xattr_security_set,
++};
+diff -ruN linux-2.6.20.3/fs/ext3cow/xattr_trusted.c linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_trusted.c
+--- linux-2.6.20.3/fs/ext3cow/xattr_trusted.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_trusted.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,62 @@
++/*
++ * linux/fs/ext3cow/xattr_trusted.c
++ * Handler for trusted extended attributes.
++ *
++ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
++ */
++
++#include <linux/module.h>
++#include <linux/string.h>
++#include <linux/capability.h>
++#include <linux/fs.h>
++#include <linux/smp_lock.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/ext3cow_fs.h>
++#include "xattr.h"
++
++#define XATTR_TRUSTED_PREFIX "trusted."
++
++static size_t
++ext3cow_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
++			const char *name, size_t name_len)
++{
++	const size_t prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;
++	const size_t total_len = prefix_len + name_len + 1;
++
++	if (!capable(CAP_SYS_ADMIN))
++		return 0;
++
++	if (list && total_len <= list_size) {
++		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
++		memcpy(list+prefix_len, name, name_len);
++		list[prefix_len + name_len] = '\0';
++	}
++	return total_len;
++}
++
++static int
++ext3cow_xattr_trusted_get(struct inode *inode, const char *name,
++		       void *buffer, size_t size)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	return ext3cow_xattr_get(inode, EXT3COW_XATTR_INDEX_TRUSTED, name,
++			      buffer, size);
++}
++
++static int
++ext3cow_xattr_trusted_set(struct inode *inode, const char *name,
++		       const void *value, size_t size, int flags)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	return ext3cow_xattr_set(inode, EXT3COW_XATTR_INDEX_TRUSTED, name,
++			      value, size, flags);
++}
++
++struct xattr_handler ext3cow_xattr_trusted_handler = {
++	.prefix	= XATTR_TRUSTED_PREFIX,
++	.list	= ext3cow_xattr_trusted_list,
++	.get	= ext3cow_xattr_trusted_get,
++	.set	= ext3cow_xattr_trusted_set,
++};
+diff -ruN linux-2.6.20.3/fs/ext3cow/xattr_user.c linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_user.c
+--- linux-2.6.20.3/fs/ext3cow/xattr_user.c	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/fs/ext3cow/xattr_user.c	2007-04-07 14:23:50.000000000 -0400
+@@ -0,0 +1,64 @@
++/*
++ * linux/fs/ext3cow/xattr_user.c
++ * Handler for extended user attributes.
++ *
++ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
++ */
++
++#include <linux/module.h>
++#include <linux/string.h>
++#include <linux/fs.h>
++#include <linux/smp_lock.h>
++#include <linux/ext3cow_jbd.h>
++#include <linux/ext3cow_fs.h>
++#include "xattr.h"
++
++#define XATTR_USER_PREFIX "user."
++
++static size_t
++ext3cow_xattr_user_list(struct inode *inode, char *list, size_t list_size,
++		     const char *name, size_t name_len)
++{
++	const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
++	const size_t total_len = prefix_len + name_len + 1;
++
++	if (!test_opt(inode->i_sb, XATTR_USER))
++		return 0;
++
++	if (list && total_len <= list_size) {
++		memcpy(list, XATTR_USER_PREFIX, prefix_len);
++		memcpy(list+prefix_len, name, name_len);
++		list[prefix_len + name_len] = '\0';
++	}
++	return total_len;
++}
++
++static int
++ext3cow_xattr_user_get(struct inode *inode, const char *name,
++		    void *buffer, size_t size)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	if (!test_opt(inode->i_sb, XATTR_USER))
++		return -EOPNOTSUPP;
++	return ext3cow_xattr_get(inode, EXT3COW_XATTR_INDEX_USER, name, buffer, size);
++}
++
++static int
++ext3cow_xattr_user_set(struct inode *inode, const char *name,
++		    const void *value, size_t size, int flags)
++{
++	if (strcmp(name, "") == 0)
++		return -EINVAL;
++	if (!test_opt(inode->i_sb, XATTR_USER))
++		return -EOPNOTSUPP;
++	return ext3cow_xattr_set(inode, EXT3COW_XATTR_INDEX_USER, name,
++			      value, size, flags);
++}
++
++struct xattr_handler ext3cow_xattr_user_handler = {
++	.prefix	= XATTR_USER_PREFIX,
++	.list	= ext3cow_xattr_user_list,
++	.get	= ext3cow_xattr_user_get,
++	.set	= ext3cow_xattr_user_set,
++};
+diff -ruN linux-2.6.20.3/include/linux/ext3cow_fs.h linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs.h
+--- linux-2.6.20.3/include/linux/ext3cow_fs.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs.h	2007-04-07 15:30:04.000000000 -0400
+@@ -0,0 +1,947 @@
++/*
++ *  linux/include/linux/ext3cow_fs.h
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/include/linux/minix_fs.h
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ */
++
++#ifndef _LINUX_EXT3COW_FS_H
++#define _LINUX_EXT3COW_FS_H
++
++#include <linux/types.h>
++#include <linux/magic.h>
++
++/*
++ * The second extended filesystem constants/structures
++ */
++
++/*
++ * Define EXT3COWFS_DEBUG to produce debug messages
++ */
++#undef EXT3COWFS_DEBUG
++
++/*
++ * Define EXT3COW_RESERVATION to reserve data blocks for expanding files
++ */
++#define EXT3COW_DEFAULT_RESERVE_BLOCKS     8
++/*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
++#define EXT3COW_MAX_RESERVE_BLOCKS         1027
++#define EXT3COW_RESERVE_WINDOW_NOT_ALLOCATED 0
++/*
++ * Always enable hashed directories
++ */
++//#define CONFIG_EXT3COW_INDEX
++
++/*
++ * Debug code
++ */
++#ifdef EXT3COWFS_DEBUG
++#define ext3cow_debug(f, a...)						\
++	do {								\
++		printk (KERN_DEBUG "EXT3COW-fs DEBUG (%s, %d): %s:",	\
++			__FILE__, __LINE__, __FUNCTION__);		\
++		printk (KERN_DEBUG f, ## a);				\
++	} while (0)
++#else
++#define ext3cow_debug(f, a...)	do {} while (0)
++#endif
++
++/*
++ * Special inodes numbers
++ */
++#define	EXT3COW_BAD_INO		 1	/* Bad blocks inode */
++#define EXT3COW_ROOT_INO		 2	/* Root inode */
++#define EXT3COW_BOOT_LOADER_INO	 5	/* Boot loader inode */
++#define EXT3COW_UNDEL_DIR_INO	 6	/* Undelete directory inode */
++#define EXT3COW_RESIZE_INO		 7	/* Reserved group descriptors inode */
++#define EXT3COW_JOURNAL_INO	 8	/* Journal inode */
++
++/* First non-reserved inode for old ext3cow filesystems */
++#define EXT3COW_GOOD_OLD_FIRST_INO	11
++
++/*
++ * Maximal count of links to a file
++ */
++#define EXT3COW_LINK_MAX		32000
++
++/* For versioning -znjp */
++#define EXT3COW_FLUX_TOKEN '@'
++/* Macros for scoping - in seconds -znjp */
++#define ONEHOUR   3600
++#define YESTERDAY 86400
++#define ONEWEEK   604800
++#define ONEMONTH  2419200
++#define ONEYEAR   31449600
++
++/*
++ * Macro-instructions used to manage several block sizes
++ */
++#define EXT3COW_MIN_BLOCK_SIZE		1024
++#define	EXT3COW_MAX_BLOCK_SIZE		4096
++#define EXT3COW_MIN_BLOCK_LOG_SIZE		  10
++#ifdef __KERNEL__
++# define EXT3COW_BLOCK_SIZE(s)		((s)->s_blocksize)
++#else
++# define EXT3COW_BLOCK_SIZE(s)		(EXT3COW_MIN_BLOCK_SIZE << (s)->s_log_block_size)
++#endif
++//#define	EXT3COW_ADDR_PER_BLOCK(s)		(EXT3COW_BLOCK_SIZE(s) / sizeof (__u32))
++#ifdef __KERNEL__
++# define EXT3COW_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
++#else
++# define EXT3COW_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
++#endif
++#ifdef __KERNEL__
++#define	EXT3COW_ADDR_PER_BLOCK_BITS(s)	(EXT3COW_SB(s)->s_addr_per_block_bits)
++#define EXT3COW_INODE_SIZE(s)		(EXT3COW_SB(s)->s_inode_size)
++#define EXT3COW_FIRST_INO(s)		(EXT3COW_SB(s)->s_first_ino)
++#else
++#define EXT3COW_INODE_SIZE(s)	(((s)->s_rev_level == EXT3COW_GOOD_OLD_REV) ? \
++				 EXT3COW_GOOD_OLD_INODE_SIZE : \
++				 (s)->s_inode_size)
++#define EXT3COW_FIRST_INO(s)	(((s)->s_rev_level == EXT3COW_GOOD_OLD_REV) ? \
++				 EXT3COW_GOOD_OLD_FIRST_INO : \
++				 (s)->s_first_ino)
++#endif
++/*
++ * Macro-instructions for versioning support - znjp
++ */
++#define EXT3COW_COWBITMAP_SIZE (sizeof(__u32) * 8) /* one word */
++#define EXT3COW_COWBITMAPS_PER_IBLOCK(s) \
++  (( (EXT3COW_BLOCK_SIZE(s) / sizeof(__u32)) / (EXT3COW_COWBITMAP_SIZE)))
++/* Accounts for COW bitmaps */
++#define EXT3COW_ADDR_PER_BLOCK(s) ((EXT3COW_BLOCK_SIZE(s) / sizeof(__u32)) - EXT3COW_COWBITMAPS_PER_IBLOCK(s))
++
++/*
++ * Macro-instructions used to manage fragments
++ */
++#define EXT3COW_MIN_FRAG_SIZE		1024
++#define	EXT3COW_MAX_FRAG_SIZE		4096
++#define EXT3COW_MIN_FRAG_LOG_SIZE		  10
++#ifdef __KERNEL__
++# define EXT3COW_FRAG_SIZE(s)		(EXT3COW_SB(s)->s_frag_size)
++# define EXT3COW_FRAGS_PER_BLOCK(s)	(EXT3COW_SB(s)->s_frags_per_block)
++#else
++# define EXT3COW_FRAG_SIZE(s)		(EXT3COW_MIN_FRAG_SIZE << (s)->s_log_frag_size)
++# define EXT3COW_FRAGS_PER_BLOCK(s)	(EXT3COW_BLOCK_SIZE(s) / EXT3COW_FRAG_SIZE(s))
++#endif
++
++/*
++ * Structure of a blocks group descriptor
++ */
++struct ext3cow_group_desc
++{
++	__le32	bg_block_bitmap;		/* Blocks bitmap block */
++	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
++	__le32	bg_inode_table;		/* Inodes table block */
++	__le16	bg_free_blocks_count;	/* Free blocks count */
++	__le16	bg_free_inodes_count;	/* Free inodes count */
++	__le16	bg_used_dirs_count;	/* Directories count */
++	__u16	bg_pad;
++	__le32	bg_reserved[3];
++};
++
++/*
++ * Macro-instructions used to manage group descriptors
++ */
++#ifdef __KERNEL__
++# define EXT3COW_BLOCKS_PER_GROUP(s)	(EXT3COW_SB(s)->s_blocks_per_group)
++# define EXT3COW_DESC_PER_BLOCK(s)		(EXT3COW_SB(s)->s_desc_per_block)
++# define EXT3COW_INODES_PER_GROUP(s)	(EXT3COW_SB(s)->s_inodes_per_group)
++# define EXT3COW_DESC_PER_BLOCK_BITS(s)	(EXT3COW_SB(s)->s_desc_per_block_bits)
++#else
++# define EXT3COW_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)
++# define EXT3COW_DESC_PER_BLOCK(s)		(EXT3COW_BLOCK_SIZE(s) / sizeof (struct ext3cow_group_desc))
++# define EXT3COW_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)
++#endif
++
++/*
++ * Constants relative to the data blocks
++ */
++#define	EXT3COW_NDIR_BLOCKS		12
++#define	EXT3COW_IND_BLOCK			EXT3COW_NDIR_BLOCKS
++#define	EXT3COW_DIND_BLOCK			(EXT3COW_IND_BLOCK + 1)
++#define	EXT3COW_TIND_BLOCK			(EXT3COW_DIND_BLOCK + 1)
++#define	EXT3COW_N_BLOCKS			(EXT3COW_TIND_BLOCK + 1)
++
++/*
++ * Inode flags
++ */
++#define	EXT3COW_SECRM_FL			0x00000001 /* Secure deletion */
++#define	EXT3COW_UNRM_FL			0x00000002 /* Undelete */
++#define	EXT3COW_COMPR_FL			0x00000004 /* Compress file */
++#define EXT3COW_SYNC_FL			0x00000008 /* Synchronous updates */
++#define EXT3COW_IMMUTABLE_FL		0x00000010 /* Immutable file */
++#define EXT3COW_APPEND_FL			0x00000020 /* writes to file may only append */
++#define EXT3COW_NODUMP_FL			0x00000040 /* do not dump file */
++#define EXT3COW_NOATIME_FL			0x00000080 /* do not update atime */
++/* Reserved for compression usage... */
++#define EXT3COW_DIRTY_FL			0x00000100
++#define EXT3COW_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
++#define EXT3COW_NOCOMPR_FL			0x00000400 /* Don't compress */
++#define EXT3COW_ECOMPR_FL			0x00000800 /* Compression error */
++/* End compression flags --- maybe not all used */
++#define EXT3COW_INDEX_FL			0x00001000 /* hash-indexed directory */
++#define EXT3COW_IMAGIC_FL			0x00002000 /* AFS directory */
++#define EXT3COW_JOURNAL_DATA_FL		0x00004000 /* file data should be journaled */
++#define EXT3COW_NOTAIL_FL			0x00008000 /* file tail should not be merged */
++#define EXT3COW_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
++#define EXT3COW_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
++/* Used for Versioning - znjp */
++#define EXT3COW_UNCHANGEABLE_FL 0x00040000
++#define EXT3COW_UNVERSIONABLE_FL 0x00080000
++#define EXT3COW_FAKEINODE_FL    0x00100000
++#define EXT3COW_RESERVED_FL		0x80000000 /* reserved for ext3cow lib */
++
++#define EXT3COW_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
++#define EXT3COW_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
++
++/*
++ * Inode dynamic state flags
++ */
++#define EXT3COW_STATE_JDATA		0x00000001 /* journaled data exists */
++#define EXT3COW_STATE_NEW			0x00000002 /* inode is newly created */
++#define EXT3COW_STATE_XATTR		0x00000004 /* has in-inode xattrs */
++
++/* Used to pass group descriptor data when online resize is done */
++struct ext3cow_new_group_input {
++	__u32 group;            /* Group number for this data */
++	__u32 block_bitmap;     /* Absolute block number of block bitmap */
++	__u32 inode_bitmap;     /* Absolute block number of inode bitmap */
++	__u32 inode_table;      /* Absolute block number of inode table start */
++	__u32 blocks_count;     /* Total number of blocks in this group */
++	__u16 reserved_blocks;  /* Number of reserved blocks in this group */
++	__u16 unused;
++};
++
++/* The struct ext3cow_new_group_input in kernel space, with free_blocks_count */
++struct ext3cow_new_group_data {
++	__u32 group;
++	__u32 block_bitmap;
++	__u32 inode_bitmap;
++	__u32 inode_table;
++	__u32 blocks_count;
++	__u16 reserved_blocks;
++	__u16 unused;
++	__u32 free_blocks_count;
++};
++
++
++/*
++ * ioctl commands
++ */
++#define	EXT3COW_IOC_GETFLAGS		FS_IOC_GETFLAGS
++#define	EXT3COW_IOC_SETFLAGS		FS_IOC_SETFLAGS
++#define	EXT3COW_IOC_GETVERSION		_IOR('f', 3, long)
++#define	EXT3COW_IOC_SETVERSION		_IOW('f', 4, long)
++#define EXT3COW_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
++#define EXT3COW_IOC_GROUP_ADD		_IOW('f', 8,struct ext3cow_new_group_input)
++#define	EXT3COW_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
++#define	EXT3COW_IOC_SETVERSION_OLD		FS_IOC_SETVERSION
++#ifdef CONFIG_JBD_DEBUG
++#define EXT3COW_IOC_WAIT_FOR_READONLY	_IOR('f', 99, long)
++#endif
++#define EXT3COW_IOC_GETRSVSZ		_IOR('f', 5, long)
++#define EXT3COW_IOC_SETRSVSZ		_IOW('f', 6, long)
++/* ioctls for versioning - znjp */
++#define EXT3COW_IOC_TAKESNAPSHOT _IOR('f', 7, long)
++#define EXT3COW_IOC_GETEPOCH _IOR('f', 8, long)
++
++/*
++ * ioctl commands in 32 bit emulation
++ */
++#define EXT3COW_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
++#define EXT3COW_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
++#define EXT3COW_IOC32_GETVERSION		_IOR('f', 3, int)
++#define EXT3COW_IOC32_SETVERSION		_IOW('f', 4, int)
++#define EXT3COW_IOC32_GETRSVSZ		_IOR('f', 5, int)
++#define EXT3COW_IOC32_SETRSVSZ		_IOW('f', 6, int)
++#define EXT3COW_IOC32_GROUP_EXTEND		_IOW('f', 7, unsigned int)
++#ifdef CONFIG_JBD_DEBUG
++#define EXT3COW_IOC32_WAIT_FOR_READONLY	_IOR('f', 99, int)
++#endif
++#define EXT3COW_IOC32_GETVERSION_OLD	FS_IOC32_GETVERSION
++#define EXT3COW_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION
++
++
++/*
++ *  Mount options
++ */
++struct ext3cow_mount_options {
++	unsigned long s_mount_opt;
++	uid_t s_resuid;
++	gid_t s_resgid;
++	unsigned long s_commit_interval;
++#ifdef CONFIG_QUOTA
++	int s_jquota_fmt;
++	char *s_qf_names[MAXQUOTAS];
++#endif
++};
++
++/*
++ * Structure of an inode on the disk
++ */
++struct ext3cow_inode {
++	__le16	i_mode;		/* File mode */
++	__le16	i_uid;		/* Low 16 bits of Owner Uid */
++	__le32	i_size;		/* Size in bytes */
++	__le32	i_atime;	/* Access time */
++	__le32	i_ctime;	/* Creation time */
++	__le32	i_mtime;	/* Modification time */
++	__le32	i_dtime;	/* Deletion Time */
++	__le16	i_gid;		/* Low 16 bits of Group Id */
++	__le16	i_links_count;	/* Links count */
++	__le32	i_blocks;	/* Blocks count */
++	__le32	i_flags;	/* File flags */
++	union {
++		struct {
++			//__u32  l_i_reserved1;
++      /* Direct block COW bitmap -znjp */
++      __u16 l_i_direct_cow_bitmap;
++      __u16 l_i_pad1;
++		} linux1;
++		struct {
++			__u32  h_i_translator;
++		} hurd1;
++		struct {
++			__u32  m_i_reserved1;
++		} masix1;
++	} osd1;				/* OS dependent 1 */
++	__le32	i_block[EXT3COW_N_BLOCKS];/* Pointers to blocks */
++	__le32	i_generation;	/* File version (for NFS) */
++	__le32	i_file_acl;	/* File ACL */
++	__le32	i_dir_acl;	/* Directory ACL */
++	__le32	i_faddr;	/* Fragment address */
++	union {
++		struct {
++			__u8	l_i_frag;	/* Fragment number */
++			__u8	l_i_fsize;	/* Fragment size */
++			__u16	i_pad1;
++			//__le16	l_i_uid_high;	/* these 2 fields    */
++			//__le16	l_i_gid_high;	/* were reserved2[0] */
++			//__u32	l_i_reserved2;
++      /* Epoch number for versioning -znjp */
++      __le32 l_i_epoch_number;
++      __u32 l_i_next_inode;
++		} linux2;
++		struct {
++			__u8	h_i_frag;	/* Fragment number */
++			__u8	h_i_fsize;	/* Fragment size */
++			__u16	h_i_mode_high;
++			__u16	h_i_uid_high;
++			__u16	h_i_gid_high;
++			__u32	h_i_author;
++		} hurd2;
++		struct {
++			__u8	m_i_frag;	/* Fragment number */
++			__u8	m_i_fsize;	/* Fragment size */
++			__u16	m_pad1;
++			__u32	m_i_reserved2[2];
++		} masix2;
++	} osd2;				/* OS dependent 2 */
++	__le16	i_extra_isize;
++	__le16	i_pad1;
++};
++
++#define i_size_high	i_dir_acl
++
++#if defined(__KERNEL__) || defined(__linux__)
++/* For versioning -znjp */
++//#define i_reserved1	osd1.linux1.l_i_reserved1
++#define i_cowbitmap osd1.linux1.l_i_direct_cow_bitmap
++#define i_frag		osd2.linux2.l_i_frag
++#define i_fsize		osd2.linux2.l_i_fsize
++#define i_uid_low	i_uid
++#define i_gid_low	i_gid
++/* For versioning -znjp */
++//#define i_uid_high	osd2.linux2.l_i_uid_high
++//#define i_gid_high	osd2.linux2.l_i_gid_high
++//#define i_reserved2	osd2.linux2.l_i_reserved2
++#define i_epch_number osd2.linux2.l_i_epoch_number
++#define i_nxt_inode osd2.linux2.l_i_next_inode
++
++#elif defined(__GNU__)
++
++#define i_translator	osd1.hurd1.h_i_translator
++#define i_frag		osd2.hurd2.h_i_frag;
++#define i_fsize		osd2.hurd2.h_i_fsize;
++#define i_uid_high	osd2.hurd2.h_i_uid_high
++#define i_gid_high	osd2.hurd2.h_i_gid_high
++#define i_author	osd2.hurd2.h_i_author
++
++#elif defined(__masix__)
++
++#define i_reserved1	osd1.masix1.m_i_reserved1
++#define i_frag		osd2.masix2.m_i_frag
++#define i_fsize		osd2.masix2.m_i_fsize
++#define i_reserved2	osd2.masix2.m_i_reserved2
++
++#endif /* defined(__KERNEL__) || defined(__linux__) */
++
++/*
++ * File system states
++ */
++#define	EXT3COW_VALID_FS			0x0001	/* Unmounted cleanly */
++#define	EXT3COW_ERROR_FS			0x0002	/* Errors detected */
++#define	EXT3COW_ORPHAN_FS			0x0004	/* Orphans being recovered */
++
++/*
++ * Mount flags
++ */
++#define EXT3COW_MOUNT_CHECK		0x00001	/* Do mount-time checks */
++#define EXT3COW_MOUNT_OLDALLOC		0x00002  /* Don't use the new Orlov allocator */
++#define EXT3COW_MOUNT_GRPID		0x00004	/* Create files with directory's group */
++#define EXT3COW_MOUNT_DEBUG		0x00008	/* Some debugging messages */
++#define EXT3COW_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
++#define EXT3COW_MOUNT_ERRORS_RO		0x00020	/* Remount fs ro on errors */
++#define EXT3COW_MOUNT_ERRORS_PANIC		0x00040	/* Panic on errors */
++#define EXT3COW_MOUNT_MINIX_DF		0x00080	/* Mimics the Minix statfs */
++#define EXT3COW_MOUNT_NOLOAD		0x00100	/* Don't use existing journal*/
++#define EXT3COW_MOUNT_ABORT		0x00200	/* Fatal error detected */
++#define EXT3COW_MOUNT_DATA_FLAGS		0x00C00	/* Mode for data writes: */
++#define EXT3COW_MOUNT_JOURNAL_DATA		0x00400	/* Write data to journal */
++#define EXT3COW_MOUNT_ORDERED_DATA		0x00800	/* Flush data before commit */
++#define EXT3COW_MOUNT_WRITEBACK_DATA	0x00C00	/* No data ordering */
++#define EXT3COW_MOUNT_UPDATE_JOURNAL	0x01000	/* Update the journal format */
++#define EXT3COW_MOUNT_NO_UID32		0x02000  /* Disable 32-bit UIDs */
++#define EXT3COW_MOUNT_XATTR_USER		0x04000	/* Extended user attributes */
++#define EXT3COW_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
++#define EXT3COW_MOUNT_RESERVATION		0x10000	/* Preallocation */
++#define EXT3COW_MOUNT_BARRIER		0x20000 /* Use block barriers */
++#define EXT3COW_MOUNT_NOBH			0x40000 /* No bufferheads */
++#define EXT3COW_MOUNT_QUOTA		0x80000 /* Some quota option set */
++#define EXT3COW_MOUNT_USRQUOTA		0x100000 /* "old" user quota */
++#define EXT3COW_MOUNT_GRPQUOTA		0x200000 /* "old" group quota */
++
++/* Compatibility, for having both ext2_fs.h and ext3cow_fs.h included at once */
++#ifndef _LINUX_EXT2_FS_H
++#define clear_opt(o, opt)		o &= ~EXT3COW_MOUNT_##opt
++#define set_opt(o, opt)			o |= EXT3COW_MOUNT_##opt
++#define test_opt(sb, opt)		(EXT3COW_SB(sb)->s_mount_opt & \
++					 EXT3COW_MOUNT_##opt)
++#else
++#define EXT2_MOUNT_NOLOAD		EXT3COW_MOUNT_NOLOAD
++#define EXT2_MOUNT_ABORT		EXT3COW_MOUNT_ABORT
++#define EXT2_MOUNT_DATA_FLAGS		EXT3COW_MOUNT_DATA_FLAGS
++#endif
++
++#define ext3cow_set_bit			ext2_set_bit
++#define ext3cow_set_bit_atomic		ext2_set_bit_atomic
++#define ext3cow_clear_bit			ext2_clear_bit
++#define ext3cow_clear_bit_atomic		ext2_clear_bit_atomic
++#define ext3cow_test_bit			ext2_test_bit
++#define ext3cow_find_first_zero_bit	ext2_find_first_zero_bit
++#define ext3cow_find_next_zero_bit		ext2_find_next_zero_bit
++
++/*
++ * Maximal mount counts between two filesystem checks
++ */
++#define EXT3COW_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
++#define EXT3COW_DFL_CHECKINTERVAL		0	/* Don't use interval check */
++
++/*
++ * Behaviour when detecting errors
++ */
++#define EXT3COW_ERRORS_CONTINUE		1	/* Continue execution */
++#define EXT3COW_ERRORS_RO			2	/* Remount fs read-only */
++#define EXT3COW_ERRORS_PANIC		3	/* Panic */
++#define EXT3COW_ERRORS_DEFAULT		EXT3COW_ERRORS_CONTINUE
++
++/*
++ * Structure of the super block
++ */
++struct ext3cow_super_block {
++/*00*/	__le32	s_inodes_count;		/* Inodes count */
++	__le32	s_blocks_count;		/* Blocks count */
++	__le32	s_r_blocks_count;	/* Reserved blocks count */
++	__le32	s_free_blocks_count;	/* Free blocks count */
++/*10*/	__le32	s_free_inodes_count;	/* Free inodes count */
++	__le32	s_first_data_block;	/* First Data Block */
++	__le32	s_log_block_size;	/* Block size */
++	__le32	s_log_frag_size;	/* Fragment size */
++/*20*/	__le32	s_blocks_per_group;	/* # Blocks per group */
++	__le32	s_frags_per_group;	/* # Fragments per group */
++	__le32	s_inodes_per_group;	/* # Inodes per group */
++	__le32	s_mtime;		/* Mount time */
++/*30*/	__le32	s_wtime;		/* Write time */
++	__le16	s_mnt_count;		/* Mount count */
++	__le16	s_max_mnt_count;	/* Maximal mount count */
++	__le16	s_magic;		/* Magic signature */
++	__le16	s_state;		/* File system state */
++	__le16	s_errors;		/* Behaviour when detecting errors */
++	__le16	s_minor_rev_level;	/* minor revision level */
++/*40*/	__le32	s_lastcheck;		/* time of last check */
++	__le32	s_checkinterval;	/* max. time between checks */
++	__le32	s_creator_os;		/* OS */
++	__le32	s_rev_level;		/* Revision level */
++/*50*/	__le16	s_def_resuid;		/* Default uid for reserved blocks */
++	__le16	s_def_resgid;		/* Default gid for reserved blocks */
++	/*
++	 * These fields are for EXT3COW_DYNAMIC_REV superblocks only.
++	 *
++	 * Note: the difference between the compatible feature set and
++	 * the incompatible feature set is that if there is a bit set
++	 * in the incompatible feature set that the kernel doesn't
++	 * know about, it should refuse to mount the filesystem.
++	 *
++	 * e2fsck's requirements are more strict; if it doesn't know
++	 * about a feature in either the compatible or incompatible
++	 * feature set, it must abort and not try to meddle with
++	 * things it doesn't understand...
++	 */
++	__le32	s_first_ino;		/* First non-reserved inode */
++	__le16   s_inode_size;		/* size of inode structure */
++	__le16	s_block_group_nr;	/* block group # of this superblock */
++	__le32	s_feature_compat;	/* compatible feature set */
++/*60*/	__le32	s_feature_incompat;	/* incompatible feature set */
++	__le32	s_feature_ro_compat;	/* readonly-compatible feature set */
++/*68*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
++/*78*/	char	s_volume_name[16];	/* volume name */
++/*88*/	char	s_last_mounted[64];	/* directory where last mounted */
++/*C8*/	__le32	s_algorithm_usage_bitmap; /* For compression */
++	/*
++	 * Performance hints.  Directory preallocation should only
++	 * happen if the EXT3COW_FEATURE_COMPAT_DIR_PREALLOC flag is on.
++	 */
++	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
++	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
++	__le16	s_reserved_gdt_blocks;	/* Per group desc for online growth */
++	/*
++	 * Journaling support valid if EXT3COW_FEATURE_COMPAT_HAS_JOURNAL set.
++	 */
++/*D0*/	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
++/*E0*/	__le32	s_journal_inum;		/* inode number of journal file */
++	__le32	s_journal_dev;		/* device number of journal file */
++	__le32	s_last_orphan;		/* start of list of inodes to delete */
++	__le32	s_hash_seed[4];		/* HTREE hash seed */
++	__u8	s_def_hash_version;	/* Default hash version to use */
++	__u8	s_reserved_char_pad;
++	__u16	s_reserved_word_pad;
++	__le32	s_default_mount_opts;
++	__le32	s_first_meta_bg;	/* First metablock block group */
++  /* Added for version - znjp */
++  __le32 s_epoch_number;
++	__u32	s_reserved[189];	/* Padding to the end of the block */
++};
++
++#ifdef __KERNEL__
++#include <linux/ext3cow_fs_i.h>
++#include <linux/ext3cow_fs_sb.h>
++static inline struct ext3cow_sb_info * EXT3COW_SB(struct super_block *sb)
++{
++	return sb->s_fs_info;
++}
++static inline struct ext3cow_inode_info *EXT3COW_I(struct inode *inode)
++{
++	return container_of(inode, struct ext3cow_inode_info, vfs_inode);
++}
++
++static inline int ext3cow_valid_inum(struct super_block *sb, unsigned long ino)
++{
++	return ino == EXT3COW_ROOT_INO ||
++		ino == EXT3COW_JOURNAL_INO ||
++		ino == EXT3COW_RESIZE_INO ||
++		(ino >= EXT3COW_FIRST_INO(sb) &&
++		 ino <= le32_to_cpu(EXT3COW_SB(sb)->s_es->s_inodes_count));
++}
++#else
++/* Assume that user mode programs are passing in an ext3cowfs superblock, not
++ * a kernel struct super_block.  This will allow us to call the feature-test
++ * macros from user land. */
++#define EXT3COW_SB(sb)	(sb)
++#endif
++
++#define NEXT_ORPHAN(inode) EXT3COW_I(inode)->i_dtime
++
++/*
++ * Codes for operating systems
++ */
++#define EXT3COW_OS_LINUX		0
++#define EXT3COW_OS_HURD		1
++#define EXT3COW_OS_MASIX		2
++#define EXT3COW_OS_FREEBSD		3
++#define EXT3COW_OS_LITES		4
++
++/*
++ * Revision levels
++ */
++#define EXT3COW_GOOD_OLD_REV	0	/* The good old (original) format */
++#define EXT3COW_DYNAMIC_REV	1	/* V2 format w/ dynamic inode sizes */
++
++#define EXT3COW_CURRENT_REV	EXT3COW_GOOD_OLD_REV
++#define EXT3COW_MAX_SUPP_REV	EXT3COW_DYNAMIC_REV
++
++#define EXT3COW_GOOD_OLD_INODE_SIZE 128
++
++/*
++ * Feature set definitions
++ */
++
++#define EXT3COW_HAS_COMPAT_FEATURE(sb,mask)			\
++	( EXT3COW_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
++#define EXT3COW_HAS_RO_COMPAT_FEATURE(sb,mask)			\
++	( EXT3COW_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
++#define EXT3COW_HAS_INCOMPAT_FEATURE(sb,mask)			\
++	( EXT3COW_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
++#define EXT3COW_SET_COMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
++#define EXT3COW_SET_RO_COMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
++#define EXT3COW_SET_INCOMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
++#define EXT3COW_CLEAR_COMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
++#define EXT3COW_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
++#define EXT3COW_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
++	EXT3COW_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
++
++#define EXT3COW_FEATURE_COMPAT_DIR_PREALLOC	0x0001
++#define EXT3COW_FEATURE_COMPAT_IMAGIC_INODES	0x0002
++#define EXT3COW_FEATURE_COMPAT_HAS_JOURNAL		0x0004
++#define EXT3COW_FEATURE_COMPAT_EXT_ATTR		0x0008
++#define EXT3COW_FEATURE_COMPAT_RESIZE_INODE	0x0010
++#define EXT3COW_FEATURE_COMPAT_DIR_INDEX		0x0020
++
++#define EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
++#define EXT3COW_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
++#define EXT3COW_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
++
++#define EXT3COW_FEATURE_INCOMPAT_COMPRESSION	0x0001
++#define EXT3COW_FEATURE_INCOMPAT_FILETYPE		0x0002
++#define EXT3COW_FEATURE_INCOMPAT_RECOVER		0x0004 /* Needs recovery */
++#define EXT3COW_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008 /* Journal device */
++#define EXT3COW_FEATURE_INCOMPAT_META_BG		0x0010
++
++#define EXT3COW_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
++#define EXT3COW_FEATURE_INCOMPAT_SUPP	(EXT3COW_FEATURE_INCOMPAT_FILETYPE| \
++					 EXT3COW_FEATURE_INCOMPAT_RECOVER| \
++					 EXT3COW_FEATURE_INCOMPAT_META_BG)
++#define EXT3COW_FEATURE_RO_COMPAT_SUPP	(EXT3COW_FEATURE_RO_COMPAT_SPARSE_SUPER| \
++					 EXT3COW_FEATURE_RO_COMPAT_LARGE_FILE| \
++					 EXT3COW_FEATURE_RO_COMPAT_BTREE_DIR)
++
++/*
++ * Default values for user and/or group using reserved blocks
++ */
++#define	EXT3COW_DEF_RESUID		0
++#define	EXT3COW_DEF_RESGID		0
++
++/*
++ * Default mount options
++ */
++#define EXT3COW_DEFM_DEBUG		0x0001
++#define EXT3COW_DEFM_BSDGROUPS	0x0002
++#define EXT3COW_DEFM_XATTR_USER	0x0004
++#define EXT3COW_DEFM_ACL		0x0008
++#define EXT3COW_DEFM_UID16		0x0010
++#define EXT3COW_DEFM_JMODE		0x0060
++#define EXT3COW_DEFM_JMODE_DATA	0x0020
++#define EXT3COW_DEFM_JMODE_ORDERED	0x0040
++#define EXT3COW_DEFM_JMODE_WBACK	0x0060
++
++/*
++ * Structure of a directory entry
++ */
++#define EXT3COW_NAME_LEN 255
++
++struct ext3cow_dir_entry {
++	__le32	inode;			/* Inode number */
++	__le16	rec_len;		/* Directory entry length */
++	__le16	name_len;		/* Name length */
++	char	name[EXT3COW_NAME_LEN];	/* File name */
++};
++
++/*
++ * The new version of the directory entry.  Since EXT3COW structures are
++ * stored in intel byte order, and the name_len field could never be
++ * bigger than 255 chars, it's safe to reclaim the extra byte for the
++ * file_type field.
++ */
++struct ext3cow_dir_entry_2 {
++	__le32	inode;			/* Inode number */
++	__le16	rec_len;		/* Directory entry length */
++	__u8	name_len;		/* Name length */
++	__u8	file_type;
++  /* Added for versioning - znjp */
++  __u32 birth_epoch;
++  __u32 death_epoch;
++	char	name[EXT3COW_NAME_LEN];	/* File name */
++};
++
++/*
++ * Ext3 directory file types.  Only the low 3 bits are used.  The
++ * other bits are reserved for now.
++ */
++#define EXT3COW_FT_UNKNOWN		0
++#define EXT3COW_FT_REG_FILE	1
++#define EXT3COW_FT_DIR		2
++#define EXT3COW_FT_CHRDEV		3
++#define EXT3COW_FT_BLKDEV		4
++#define EXT3COW_FT_FIFO		5
++#define EXT3COW_FT_SOCK		6
++#define EXT3COW_FT_SYMLINK		7
++
++#define EXT3COW_FT_MAX		8
++
++/* Versioning macros - znjp */
++#define EXT3COW_DIRENT_ALIVE 0
++#define EXT3COW_IS_DIRENT_ALIVE(de) ((le32_to_cpu(de->death_epoch) == EXT3COW_DIRENT_ALIVE))
++#define EXT3COW_IS_DIRENT_SCOPED(de, epoch) \
++((le32_to_cpu(de->birth_epoch) <= epoch) && \
++(EXT3COW_IS_DIRENT_ALIVE(de) || (!EXT3COW_IS_DIRENT_ALIVE(de) && \
++le32_to_cpu(de->death_epoch) > epoch)))
++#define EXT3COW_I_EPOCHNUMBER(inode) (((unsigned int)EXT3COW_I(inode)->i_epoch_number))
++#define EXT3COW_S_EPOCHNUMBER(sb) (((unsigned int)EXT3COW_SB(sb)->s_epoch_number))
++#define EXT3COW_I_NEXT_INODE(inode) (((unsigned int)EXT3COW_I(inode)->i_next_inode))
++#define EXT3COW_IS_UNVERSIONABLE(inode) (((unsigned int)EXT3COW_I(inode)->i_flags & EXT3COW_UNVERSIONABLE_FL))
++#define EXT3COW_IS_UNCHANGEABLE(inode) (((unsigned int)EXT3COW_I(inode)->i_flags & EXT3COW_UNCHANGEABLE_FL))
++#define EXT3COW_IS_FAKEINODE(inode) (((unsigned int)EXT3COW_I(inode)->i_flags & EXT3COW_FAKEINODE_FL))
++
++
++/*
++ * EXT3COW_DIR_PAD defines the directory entries boundaries
++ *
++ * NOTE: It must be a multiple of 4
++ */
++#define EXT3COW_DIR_PAD			4
++#define EXT3COW_DIR_ROUND			(EXT3COW_DIR_PAD - 1)
++/* Added 8 to account for birth and death epochs -znjp */
++#define EXT3COW_DIR_REC_LEN(name_len)	(((name_len) + 16 + EXT3COW_DIR_ROUND) & \
++					 ~EXT3COW_DIR_ROUND)
++/*
++ * Hash Tree Directory indexing
++ * (c) Daniel Phillips, 2001
++ */
++
++#ifdef CONFIG_EXT3COW_INDEX
++  #define is_dx(dir) (EXT3COW_HAS_COMPAT_FEATURE(dir->i_sb, \
++					      EXT3COW_FEATURE_COMPAT_DIR_INDEX) && \
++		      (EXT3COW_I(dir)->i_flags & EXT3COW_INDEX_FL))
++#define EXT3COW_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT3COW_LINK_MAX)
++#define EXT3COW_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)
++#else
++  #define is_dx(dir) 0
++#define EXT3COW_DIR_LINK_MAX(dir) ((dir)->i_nlink >= EXT3COW_LINK_MAX)
++#define EXT3COW_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2)
++#endif
++
++/* Legal values for the dx_root hash_version field: */
++
++#define DX_HASH_LEGACY		0
++#define DX_HASH_HALF_MD4	1
++#define DX_HASH_TEA		2
++
++#ifdef __KERNEL__
++
++/* hash info structure used by the directory hash */
++struct dx_hash_info
++{
++	u32		hash;
++	u32		minor_hash;
++	int		hash_version;
++	u32		*seed;
++};
++
++#define EXT3COW_HTREE_EOF	0x7fffffff
++
++/*
++ * Control parameters used by ext3cow_htree_next_block
++ */
++#define HASH_NB_ALWAYS		1
++
++
++/*
++ * Describe an inode's exact location on disk and in memory
++ */
++struct ext3cow_iloc
++{
++	struct buffer_head *bh;
++	unsigned long offset;
++	unsigned long block_group;
++};
++
++static inline struct ext3cow_inode *ext3cow_raw_inode(struct ext3cow_iloc *iloc)
++{
++	return (struct ext3cow_inode *) (iloc->bh->b_data + iloc->offset);
++}
++
++/*
++ * This structure is stuffed into the struct file's private_data field
++ * for directories.  It is where we put information so that we can do
++ * readdir operations in hash tree order.
++ */
++struct dir_private_info {
++	struct rb_root	root;
++	struct rb_node	*curr_node;
++	struct fname	*extra_fname;
++	loff_t		last_pos;
++	__u32		curr_hash;
++	__u32		curr_minor_hash;
++	__u32		next_hash;
++};
++
++/* calculate the first block number of the group */
++static inline ext3cow_fsblk_t
++ext3cow_group_first_block_no(struct super_block *sb, unsigned long group_no)
++{
++	return group_no * (ext3cow_fsblk_t)EXT3COW_BLOCKS_PER_GROUP(sb) +
++		le32_to_cpu(EXT3COW_SB(sb)->s_es->s_first_data_block);
++}
++
++/*
++ * Special error return code only used by dx_probe() and its callers.
++ */
++#define ERR_BAD_DX_DIR	-75000
++
++/*
++ * Function prototypes
++ */
++
++/*
++ * Ok, these declarations are also in <linux/kernel.h> but none of the
++ * ext3cow source programs needs to include it so they are duplicated here.
++ */
++# define NORET_TYPE    /**/
++# define ATTRIB_NORET  __attribute__((noreturn))
++# define NORET_AND     noreturn,
++
++/* balloc.c */
++extern int ext3cow_bg_has_super(struct super_block *sb, int group);
++extern unsigned long ext3cow_bg_num_gdb(struct super_block *sb, int group);
++extern ext3cow_fsblk_t ext3cow_new_block (handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t goal, int *errp);
++extern ext3cow_fsblk_t ext3cow_new_blocks (handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t goal, unsigned long *count, int *errp);
++extern void ext3cow_free_blocks (handle_t *handle, struct inode *inode,
++			ext3cow_fsblk_t block, unsigned long count);
++extern void ext3cow_free_blocks_sb (handle_t *handle, struct super_block *sb,
++				 ext3cow_fsblk_t block, unsigned long count,
++				unsigned long *pdquot_freed_blocks);
++extern ext3cow_fsblk_t ext3cow_count_free_blocks (struct super_block *);
++extern void ext3cow_check_blocks_bitmap (struct super_block *);
++extern struct ext3cow_group_desc * ext3cow_get_group_desc(struct super_block * sb,
++						    unsigned int block_group,
++						    struct buffer_head ** bh);
++extern int ext3cow_should_retry_alloc(struct super_block *sb, int *retries);
++extern void ext3cow_init_block_alloc_info(struct inode *);
++extern void ext3cow_rsv_window_add(struct super_block *sb, struct ext3cow_reserve_window_node *rsv);
++
++
++/* dir.c */
++extern int ext3cow_check_dir_entry(const char *, struct inode *,
++				struct ext3cow_dir_entry_2 *,
++				struct buffer_head *, unsigned long);
++extern int ext3cow_htree_store_dirent(struct file *dir_file, __u32 hash,
++				    __u32 minor_hash,
++				    struct ext3cow_dir_entry_2 *dirent);
++extern void ext3cow_htree_free_dir_info(struct dir_private_info *p);
++
++/* fsync.c */
++extern int ext3cow_sync_file (struct file *, struct dentry *, int);
++
++/* hash.c */
++extern int ext3cowfs_dirhash(const char *name, int len, struct
++			  dx_hash_info *hinfo);
++
++/* ialloc.c */
++extern struct inode * ext3cow_new_inode (handle_t *, struct inode *, int);
++extern void ext3cow_free_inode (handle_t *, struct inode *);
++extern struct inode * ext3cow_orphan_get (struct super_block *, unsigned long);
++extern unsigned long ext3cow_count_free_inodes (struct super_block *);
++extern unsigned long ext3cow_count_dirs (struct super_block *);
++extern void ext3cow_check_inodes_bitmap (struct super_block *);
++extern unsigned long ext3cow_count_free (struct buffer_head *, unsigned);
++
++
++/* inode.c */
++int ext3cow_forget(handle_t *handle, int is_metadata, struct inode *inode,
++		struct buffer_head *bh, ext3cow_fsblk_t blocknr);
++struct buffer_head * ext3cow_getblk (handle_t *, struct inode *, long, int, int *);
++struct buffer_head * ext3cow_bread (handle_t *, struct inode *, int, int, int *);
++int ext3cow_get_blocks_handle(handle_t *handle, struct inode *inode,
++	sector_t iblock, unsigned long maxblocks, struct buffer_head *bh_result,
++	int create, int extend_disksize);
++
++extern void ext3cow_read_inode (struct inode *);
++extern int  ext3cow_write_inode (struct inode *, int);
++extern int  ext3cow_setattr (struct dentry *, struct iattr *);
++extern void ext3cow_delete_inode (struct inode *);
++extern int  ext3cow_sync_inode (handle_t *, struct inode *);
++extern void ext3cow_discard_reservation (struct inode *);
++extern void ext3cow_dirty_inode(struct inode *);
++extern int ext3cow_change_inode_journal_flag(struct inode *, int);
++extern int ext3cow_get_inode_loc(struct inode *, struct ext3cow_iloc *);
++extern void ext3cow_truncate (struct inode *);
++extern void ext3cow_set_inode_flags(struct inode *);
++extern void ext3cow_set_aops(struct inode *inode);
++
++/* ioctl.c */
++extern int ext3cow_ioctl (struct inode *, struct file *, unsigned int,
++		       unsigned long);
++extern long ext3cow_compat_ioctl (struct file *, unsigned int, unsigned long);
++
++/* namei.c */
++extern int is_unchangeable(struct inode *, struct dentry *);
++extern int ext3cow_orphan_add(handle_t *, struct inode *);
++extern int ext3cow_orphan_del(handle_t *, struct inode *);
++extern int ext3cow_htree_fill_tree(struct file *dir_file, __u32 start_hash,
++				__u32 start_minor_hash, __u32 *next_hash);
++extern struct inode *ext3cow_fake_inode(struct inode *, unsigned int);
++extern int ext3cow_dup_inode(struct inode *, struct inode *);
++extern int ext3cow_reclaim_dup_inode(struct inode *, struct inode *);
++
++/* resize.c */
++extern int ext3cow_group_add(struct super_block *sb,
++				struct ext3cow_new_group_data *input);
++extern int ext3cow_group_extend(struct super_block *sb,
++				struct ext3cow_super_block *es,
++				ext3cow_fsblk_t n_blocks_count);
++
++/* super.c */
++extern void ext3cow_error (struct super_block *, const char *, const char *, ...)
++	__attribute__ ((format (printf, 3, 4)));
++extern void __ext3cow_std_error (struct super_block *, const char *, int);
++extern void ext3cow_abort (struct super_block *, const char *, const char *, ...)
++	__attribute__ ((format (printf, 3, 4)));
++extern void ext3cow_warning (struct super_block *, const char *, const char *, ...)
++	__attribute__ ((format (printf, 3, 4)));
++extern void ext3cow_update_dynamic_rev (struct super_block *sb);
++extern unsigned int ext3cow_take_snapshot(struct super_block *sb);
++
++#define ext3cow_std_error(sb, errno)				\
++do {								\
++	if ((errno))						\
++		__ext3cow_std_error((sb), __FUNCTION__, (errno));	\
++} while (0)
++
++/*
++ * Inodes and files operations
++ */
++
++/* dir.c */
++extern const struct file_operations ext3cow_dir_operations;
++
++/* file.c */
++extern struct inode_operations ext3cow_file_inode_operations;
++extern const struct file_operations ext3cow_file_operations;
++
++/* namei.c */
++extern struct inode_operations ext3cow_dir_inode_operations;
++extern struct inode_operations ext3cow_special_inode_operations;
++
++/* symlink.c */
++extern struct inode_operations ext3cow_symlink_inode_operations;
++extern struct inode_operations ext3cow_fast_symlink_inode_operations;
++
++
++#endif	/* __KERNEL__ */
++
++#endif	/* _LINUX_EXT3COW_FS_H */
+diff -ruN linux-2.6.20.3/include/linux/ext3cow_fs_i.h linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs_i.h
+--- linux-2.6.20.3/include/linux/ext3cow_fs_i.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs_i.h	2007-03-24 15:22:06.000000000 -0400
+@@ -0,0 +1,152 @@
++/*
++ *  linux/include/linux/ext3cow_fs_i.h
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/include/linux/minix_fs_i.h
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ */
++
++#ifndef _LINUX_EXT3COW_FS_I
++#define _LINUX_EXT3COW_FS_I
++
++#include <linux/rwsem.h>
++#include <linux/rbtree.h>
++#include <linux/seqlock.h>
++#include <linux/mutex.h>
++
++/* data type for block offset of block group */
++typedef int ext3cow_grpblk_t;
++
++/* data type for filesystem-wide blocks number */
++typedef unsigned long ext3cow_fsblk_t;
++
++#define E3FSBLK "%lu"
++
++struct ext3cow_reserve_window {
++	ext3cow_fsblk_t	_rsv_start;	/* First byte reserved */
++	ext3cow_fsblk_t	_rsv_end;	/* Last byte reserved or 0 */
++};
++
++struct ext3cow_reserve_window_node {
++	struct rb_node		rsv_node;
++	__u32			rsv_goal_size;
++	__u32			rsv_alloc_hit;
++	struct ext3cow_reserve_window	rsv_window;
++};
++
++struct ext3cow_block_alloc_info {
++	/* information about reservation window */
++	struct ext3cow_reserve_window_node	rsv_window_node;
++	/*
++	 * was i_next_alloc_block in ext3cow_inode_info
++	 * is the logical (file-relative) number of the
++	 * most-recently-allocated block in this file.
++	 * We use this for detecting linearly ascending allocation requests.
++	 */
++	__u32                   last_alloc_logical_block;
++	/*
++	 * Was i_next_alloc_goal in ext3cow_inode_info
++	 * is the *physical* companion to i_next_alloc_block.
++	 * it the the physical block number of the block which was most-recentl
++	 * allocated to this file.  This give us the goal (target) for the next
++	 * allocation when we detect linearly ascending requests.
++	 */
++	ext3cow_fsblk_t		last_alloc_physical_block;
++};
++
++#define rsv_start rsv_window._rsv_start
++#define rsv_end rsv_window._rsv_end
++
++/*
++ * third extended file system inode data in memory
++ */
++struct ext3cow_inode_info {
++	__le32	i_data[15];	/* unconverted */
++	__u32	i_flags;
++#ifdef EXT3COW_FRAGMENTS
++	__u32	i_faddr;
++	__u8	i_frag_no;
++	__u8	i_frag_size;
++#endif
++	ext3cow_fsblk_t	i_file_acl;
++	__u32	i_dir_acl;
++	__u32	i_dtime;
++
++	/*
++	 * i_block_group is the number of the block group which contains
++	 * this file's inode.  Constant across the lifetime of the inode,
++	 * it is ued for making block allocation decisions - we try to
++	 * place a file's data blocks near its inode block, and new inodes
++	 * near to their parent directory's inode.
++	 */
++	__u32	i_block_group;
++	__u32	i_state;		/* Dynamic state flags for ext3cow */
++
++	/* block reservation info */
++	struct ext3cow_block_alloc_info *i_block_alloc_info;
++
++	__u32	i_dir_start_lookup;
++
++  /* For versioning -znjp */
++  __u16 i_cow_bitmap;
++  __u32 i_epoch_number;
++  __u32 i_next_inode;
++#ifdef CONFIG_EXT3COW_FS_XATTR
++	/*
++	 * Extended attributes can be read independently of the main file
++	 * data. Taking i_mutex even when reading would cause contention
++	 * between readers of EAs and writers of regular file data, so
++	 * instead we synchronize on xattr_sem when reading or changing
++	 * EAs.
++	 */
++	struct rw_semaphore xattr_sem;
++#endif
++#ifdef CONFIG_EXT3COW_FS_POSIX_ACL
++	struct posix_acl	*i_acl;
++	struct posix_acl	*i_default_acl;
++#endif
++
++	struct list_head i_orphan;	/* unlinked but open inodes */
++
++	/*
++	 * i_disksize keeps track of what the inode size is ON DISK, not
++	 * in memory.  During truncate, i_size is set to the new size by
++	 * the VFS prior to calling ext3cow_truncate(), but the filesystem won't
++	 * set i_disksize to 0 until the truncate is actually under way.
++	 *
++	 * The intent is that i_disksize always represents the blocks which
++	 * are used by this file.  This allows recovery to restart truncate
++	 * on orphans if we crash during truncate.  We actually write i_disksize
++	 * into the on-disk inode when writing inodes out, instead of i_size.
++	 *
++	 * The only time when i_disksize and i_size may be different is when
++	 * a truncate is in progress.  The only things which change i_disksize
++	 * are ext3cow_get_block (growth) and ext3cow_truncate (shrinkth).
++	 */
++	loff_t	i_disksize;
++
++	/* on-disk additional length */
++	__u16 i_extra_isize;
++
++	/*
++	 * truncate_mutex is for serialising ext3cow_truncate() against
++	 * ext3cow_getblock().  In the 2.4 ext2 design, great chunks of inode's
++	 * data tree are chopped off during truncate. We can't do that in
++	 * ext3cow because whenever we perform intermediate commits during
++	 * truncate, the inode and all the metadata blocks *must* be in a
++	 * consistent state which allows truncation of the orphans to restart
++	 * during recovery.  Hence we must fix the get_block-vs-truncate race
++	 * by other means, so we have truncate_mutex.
++	 */
++	struct mutex truncate_mutex;
++	struct inode vfs_inode;
++};
++
++#endif	/* _LINUX_EXT3COW_FS_I */
+diff -ruN linux-2.6.20.3/include/linux/ext3cow_fs_sb.h linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs_sb.h
+--- linux-2.6.20.3/include/linux/ext3cow_fs_sb.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/include/linux/ext3cow_fs_sb.h	2007-03-24 15:22:35.000000000 -0400
+@@ -0,0 +1,86 @@
++/*
++ *  linux/include/linux/ext3cow_fs_sb.h
++ *
++ * Copyright (C) 1992, 1993, 1994, 1995
++ * Remy Card (card@masi.ibp.fr)
++ * Laboratoire MASI - Institut Blaise Pascal
++ * Universite Pierre et Marie Curie (Paris VI)
++ *
++ *  from
++ *
++ *  linux/include/linux/minix_fs_sb.h
++ *
++ *  Copyright (C) 1991, 1992  Linus Torvalds
++ */
++
++#ifndef _LINUX_EXT3COW_FS_SB
++#define _LINUX_EXT3COW_FS_SB
++
++#ifdef __KERNEL__
++#include <linux/timer.h>
++#include <linux/wait.h>
++#include <linux/blockgroup_lock.h>
++#include <linux/percpu_counter.h>
++#endif
++#include <linux/rbtree.h>
++
++/*
++ * third extended-fs super-block data in memory
++ */
++struct ext3cow_sb_info {
++	unsigned long s_frag_size;	/* Size of a fragment in bytes */
++	unsigned long s_frags_per_block;/* Number of fragments per block */
++	unsigned long s_inodes_per_block;/* Number of inodes per block */
++	unsigned long s_frags_per_group;/* Number of fragments in a group */
++	unsigned long s_blocks_per_group;/* Number of blocks in a group */
++	unsigned long s_inodes_per_group;/* Number of inodes in a group */
++	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
++	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
++	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
++	unsigned long s_groups_count;	/* Number of groups in the fs */
++	struct buffer_head * s_sbh;	/* Buffer containing the super block */
++	struct ext3cow_super_block * s_es;	/* Pointer to the super block in the buffer */
++	struct buffer_head ** s_group_desc;
++	unsigned long  s_mount_opt;
++	uid_t s_resuid;
++	gid_t s_resgid;
++	unsigned short s_mount_state;
++	unsigned short s_pad;
++	int s_addr_per_block_bits;
++	int s_desc_per_block_bits;
++	int s_inode_size;
++	int s_first_ino;
++	spinlock_t s_next_gen_lock;
++	u32 s_next_generation;
++	u32 s_hash_seed[4];
++	int s_def_hash_version;
++	struct percpu_counter s_freeblocks_counter;
++	struct percpu_counter s_freeinodes_counter;
++	struct percpu_counter s_dirs_counter;
++	struct blockgroup_lock s_blockgroup_lock;
++
++	/* root of the per fs reservation window tree */
++	spinlock_t s_rsv_window_lock;
++	struct rb_root s_rsv_window_root;
++	struct ext3cow_reserve_window_node s_rsv_window_head;
++
++  /* For versioning -znjp */
++  u32 s_epoch_number;
++
++	/* Journaling */
++	struct inode * s_journal_inode;
++	struct journal_s * s_journal;
++	struct list_head s_orphan;
++	unsigned long s_commit_interval;
++	struct block_device *journal_bdev;
++#ifdef CONFIG_JBD_DEBUG
++	struct timer_list turn_ro_timer;	/* For turning read-only (crash simulation) */
++	wait_queue_head_t ro_wait_queue;	/* For people waiting for the fs to go read-only */
++#endif
++#ifdef CONFIG_QUOTA
++	char *s_qf_names[MAXQUOTAS];		/* Names of quota files with journalled quota */
++	int s_jquota_fmt;			/* Format of quota to use */
++#endif
++};
++
++#endif	/* _LINUX_EXT3COW_FS_SB */
+diff -ruN linux-2.6.20.3/include/linux/ext3cow_jbd.h linux-2.6.20.3-ext3cow/include/linux/ext3cow_jbd.h
+--- linux-2.6.20.3/include/linux/ext3cow_jbd.h	1969-12-31 19:00:00.000000000 -0500
++++ linux-2.6.20.3-ext3cow/include/linux/ext3cow_jbd.h	2007-03-24 13:58:07.000000000 -0400
+@@ -0,0 +1,226 @@
++/*
++ * linux/include/linux/ext3cow_jbd.h
++ *
++ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
++ *
++ * Copyright 1998--1999 Red Hat corp --- All Rights Reserved
++ *
++ * This file is part of the Linux kernel and is made available under
++ * the terms of the GNU General Public License, version 2, or at your
++ * option, any later version, incorporated herein by reference.
++ *
++ * Ext3-specific journaling extensions.
++ */
++
++#ifndef _LINUX_EXT3COW_JBD_H
++#define _LINUX_EXT3COW_JBD_H
++
++#include <linux/fs.h>
++#include <linux/jbd.h>
++#include <linux/ext3cow_fs.h>
++
++#define EXT3COW_JOURNAL(inode)	(EXT3COW_SB((inode)->i_sb)->s_journal)
++
++/* Define the number of blocks we need to account to a transaction to
++ * modify one block of data.
++ *
++ * We may have to touch one inode, one bitmap buffer, up to three
++ * indirection blocks, the group and superblock summaries, and the data
++ * block to complete the transaction.  */
++
++#define EXT3COW_SINGLEDATA_TRANS_BLOCKS	8U
++
++/* Extended attribute operations touch at most two data buffers,
++ * two bitmap buffers, and two group summaries, in addition to the inode
++ * and the superblock, which are already accounted for. */
++
++#define EXT3COW_XATTR_TRANS_BLOCKS		6U
++
++/* Define the minimum size for a transaction which modifies data.  This
++ * needs to take into account the fact that we may end up modifying two
++ * quota files too (one for the group, one for the user quota).  The
++ * superblock only gets updated once, of course, so don't bother
++ * counting that again for the quota updates. */
++
++#define EXT3COW_DATA_TRANS_BLOCKS(sb)	(EXT3COW_SINGLEDATA_TRANS_BLOCKS + \
++					 EXT3COW_XATTR_TRANS_BLOCKS - 2 + \
++					 2*EXT3COW_QUOTA_TRANS_BLOCKS(sb))
++
++/* Delete operations potentially hit one directory's namespace plus an
++ * entire inode, plus arbitrary amounts of bitmap/indirection data.  Be
++ * generous.  We can grow the delete transaction later if necessary. */
++
++#define EXT3COW_DELETE_TRANS_BLOCKS(sb)	(2 * EXT3COW_DATA_TRANS_BLOCKS(sb) + 64)
++
++/* Define an arbitrary limit for the amount of data we will anticipate
++ * writing to any given transaction.  For unbounded transactions such as
++ * write(2) and truncate(2) we can write more than this, but we always
++ * start off at the maximum transaction size and grow the transaction
++ * optimistically as we go. */
++
++#define EXT3COW_MAX_TRANS_DATA		64U
++
++/* We break up a large truncate or write transaction once the handle's
++ * buffer credits gets this low, we need either to extend the
++ * transaction or to start a new one.  Reserve enough space here for
++ * inode, bitmap, superblock, group and indirection updates for at least
++ * one block, plus two quota updates.  Quota allocations are not
++ * needed. */
++
++#define EXT3COW_RESERVE_TRANS_BLOCKS	12U
++
++#define EXT3COW_INDEX_EXTRA_TRANS_BLOCKS	8
++
++#ifdef CONFIG_QUOTA
++/* Amount of blocks needed for quota update - we know that the structure was
++ * allocated so we need to update only inode+data */
++#define EXT3COW_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 0)
++/* Amount of blocks needed for quota insert/delete - we do some block writes
++ * but inode, sb and group updates are done only once */
++#define EXT3COW_QUOTA_INIT_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_INIT_ALLOC*\
++		(EXT3COW_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_INIT_REWRITE) : 0)
++#define EXT3COW_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_DEL_ALLOC*\
++		(EXT3COW_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_DEL_REWRITE) : 0)
++#else
++#define EXT3COW_QUOTA_TRANS_BLOCKS(sb) 0
++#define EXT3COW_QUOTA_INIT_BLOCKS(sb) 0
++#define EXT3COW_QUOTA_DEL_BLOCKS(sb) 0
++#endif
++
++int
++ext3cow_mark_iloc_dirty(handle_t *handle,
++		     struct inode *inode,
++		     struct ext3cow_iloc *iloc);
++
++/*
++ * On success, We end up with an outstanding reference count against
++ * iloc->bh.  This _must_ be cleaned up later.
++ */
++
++int ext3cow_reserve_inode_write(handle_t *handle, struct inode *inode,
++			struct ext3cow_iloc *iloc);
++
++int ext3cow_mark_inode_dirty(handle_t *handle, struct inode *inode);
++
++/*
++ * Wrapper functions with which ext3cow calls into JBD.  The intent here is
++ * to allow these to be turned into appropriate stubs so ext3cow can control
++ * ext2 filesystems, so ext2+ext3cow systems only nee one fs.  This work hasn't
++ * been done yet.
++ */
++
++static inline void ext3cow_journal_release_buffer(handle_t *handle,
++						struct buffer_head *bh)
++{
++	journal_release_buffer(handle, bh);
++}
++
++void ext3cow_journal_abort_handle(const char *caller, const char *err_fn,
++		struct buffer_head *bh, handle_t *handle, int err);
++
++int __ext3cow_journal_get_undo_access(const char *where, handle_t *handle,
++				struct buffer_head *bh);
++
++int __ext3cow_journal_get_write_access(const char *where, handle_t *handle,
++				struct buffer_head *bh);
++
++int __ext3cow_journal_forget(const char *where, handle_t *handle,
++				struct buffer_head *bh);
++
++int __ext3cow_journal_revoke(const char *where, handle_t *handle,
++				unsigned long blocknr, struct buffer_head *bh);
++
++int __ext3cow_journal_get_create_access(const char *where,
++				handle_t *handle, struct buffer_head *bh);
++
++int __ext3cow_journal_dirty_metadata(const char *where,
++				handle_t *handle, struct buffer_head *bh);
++
++#define ext3cow_journal_get_undo_access(handle, bh) \
++	__ext3cow_journal_get_undo_access(__FUNCTION__, (handle), (bh))
++#define ext3cow_journal_get_write_access(handle, bh) \
++	__ext3cow_journal_get_write_access(__FUNCTION__, (handle), (bh))
++#define ext3cow_journal_revoke(handle, blocknr, bh) \
++	__ext3cow_journal_revoke(__FUNCTION__, (handle), (blocknr), (bh))
++#define ext3cow_journal_get_create_access(handle, bh) \
++	__ext3cow_journal_get_create_access(__FUNCTION__, (handle), (bh))
++#define ext3cow_journal_dirty_metadata(handle, bh) \
++	__ext3cow_journal_dirty_metadata(__FUNCTION__, (handle), (bh))
++#define ext3cow_journal_forget(handle, bh) \
++	__ext3cow_journal_forget(__FUNCTION__, (handle), (bh))
++
++int ext3cow_journal_dirty_data(handle_t *handle, struct buffer_head *bh);
++
++handle_t *ext3cow_journal_start_sb(struct super_block *sb, int nblocks);
++int __ext3cow_journal_stop(const char *where, handle_t *handle);
++
++static inline handle_t *ext3cow_journal_start(struct inode *inode, int nblocks)
++{
++	return ext3cow_journal_start_sb(inode->i_sb, nblocks);
++}
++
++#define ext3cow_journal_stop(handle) \
++	__ext3cow_journal_stop(__FUNCTION__, (handle))
++
++static inline handle_t *ext3cow_journal_current_handle(void)
++{
++	return journal_current_handle();
++}
++
++static inline int ext3cow_journal_extend(handle_t *handle, int nblocks)
++{
++	return journal_extend(handle, nblocks);
++}
++
++static inline int ext3cow_journal_restart(handle_t *handle, int nblocks)
++{
++	return journal_restart(handle, nblocks);
++}
++
++static inline int ext3cow_journal_blocks_per_page(struct inode *inode)
++{
++	return journal_blocks_per_page(inode);
++}
++
++static inline int ext3cow_journal_force_commit(journal_t *journal)
++{
++	return journal_force_commit(journal);
++}
++
++/* super.c */
++int ext3cow_force_commit(struct super_block *sb);
++
++static inline int ext3cow_should_journal_data(struct inode *inode)
++{
++	if (!S_ISREG(inode->i_mode))
++		return 1;
++	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3COW_MOUNT_JOURNAL_DATA)
++		return 1;
++	if (EXT3COW_I(inode)->i_flags & EXT3COW_JOURNAL_DATA_FL)
++		return 1;
++	return 0;
++}
++
++static inline int ext3cow_should_order_data(struct inode *inode)
++{
++	if (!S_ISREG(inode->i_mode))
++		return 0;
++	if (EXT3COW_I(inode)->i_flags & EXT3COW_JOURNAL_DATA_FL)
++		return 0;
++	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3COW_MOUNT_ORDERED_DATA)
++		return 1;
++	return 0;
++}
++
++static inline int ext3cow_should_writeback_data(struct inode *inode)
++{
++	if (!S_ISREG(inode->i_mode))
++		return 0;
++	if (EXT3COW_I(inode)->i_flags & EXT3COW_JOURNAL_DATA_FL)
++		return 0;
++	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3COW_MOUNT_WRITEBACK_DATA)
++		return 1;
++	return 0;
++}
++
++#endif	/* _LINUX_EXT3COW_JBD_H */
+diff -ruN linux-2.6.20.3/include/linux/magic.h linux-2.6.20.3-ext3cow/include/linux/magic.h
+--- linux-2.6.20.3/include/linux/magic.h	2007-03-13 14:27:08.000000000 -0400
++++ linux-2.6.20.3-ext3cow/include/linux/magic.h	2007-03-24 14:06:39.000000000 -0400
+@@ -9,6 +9,7 @@
+ #define EFS_SUPER_MAGIC		0x414A53
+ #define EXT2_SUPER_MAGIC	0xEF53
+ #define EXT3_SUPER_MAGIC	0xEF53
++#define EXT3COW_SUPER_MAGIC	0xEF53
+ #define EXT4_SUPER_MAGIC	0xEF53
+ #define HPFS_SUPER_MAGIC	0xf995e849
+ #define ISOFS_SUPER_MAGIC	0x9660
+