{ config, lib, pkgs, utils, ... }:
with lib;
with utils;
let
addCheckDesc = desc: elemType: check: types.addCheck elemType check
// { description = "${elemType.description} (with check: ${desc})"; };
isNonEmpty = s: (builtins.match "[ \t\n]*" s) == null;
nonEmptyStr = addCheckDesc "non-empty" types.str isNonEmpty;
fileSystems' = toposort fsBefore (attrValues config.fileSystems);
fileSystems = if fileSystems' ? result
then # use topologically sorted fileSystems everywhere
fileSystems'.result
else # the assertion below will catch this,
# but we fall back to the original order
# anyway so that other modules could check
# their assertions too
(attrValues config.fileSystems);
specialFSTypes = [ "proc" "sysfs" "tmpfs" "ramfs" "devtmpfs" "devpts" ];
nonEmptyWithoutTrailingSlash = addCheckDesc "non-empty without trailing slash" types.str
(s: isNonEmpty s && (builtins.match ".+/" s) == null);
coreFileSystemOpts = { name, config, ... }: {
options = {
mountPoint = mkOption {
example = "/mnt/usb";
type = nonEmptyWithoutTrailingSlash;
description = "Location of the mounted the file system.";
};
device = mkOption {
default = null;
example = "/dev/sda";
type = types.nullOr nonEmptyStr;
description = "Location of the device.";
};
fsType = mkOption {
default = "auto";
example = "ext3";
type = nonEmptyStr;
description = "Type of the file system.";
};
options = mkOption {
default = [ "defaults" ];
example = [ "data=journal" ];
description = "Options used to mount the file system.";
type = types.listOf nonEmptyStr;
};
depends = mkOption {
default = [ ];
example = [ "/persist" ];
type = types.listOf nonEmptyWithoutTrailingSlash;
description = ''
List of paths that should be mounted before this one. This filesystem's
<option>device</option> and <option>mountPoint</option> are always
checked and do not need to be included explicitly. If a path is added
to this list, any other filesystem whose mount point is a parent of
the path will be mounted before this filesystem. The paths do not need
to actually be the <option>mountPoint</option> of some other filesystem.
'';
};
};
config = {
mountPoint = mkDefault name;
device = mkIf (elem config.fsType specialFSTypes) (mkDefault config.fsType);
};
};
fileSystemOpts = { config, ... }: {
options = {
label = mkOption {
default = null;
example = "root-partition";
type = types.nullOr nonEmptyStr;
description = "Label of the device (if any).";
};
autoFormat = mkOption {
default = false;
type = types.bool;
description = ''
If the device does not currently contain a filesystem (as
determined by <command>blkid</command>, then automatically
format it with the filesystem type specified in
<option>fsType</option>. Use with caution.
'';
};
formatOptions = mkOption {
default = "";
type = types.str;
description = ''
If <option>autoFormat</option> option is set specifies
extra options passed to mkfs.
'';
};
autoResize = mkOption {
default = false;
type = types.bool;
description = ''
If set, the filesystem is grown to its maximum size before
being mounted. (This is typically the size of the containing
partition.) This is currently only supported for ext2/3/4
filesystems that are mounted during early boot.
'';
};
noCheck = mkOption {
default = false;
type = types.bool;
description = "Disable running fsck on this filesystem.";
};
};
config = let
defaultFormatOptions =
# -F needed to allow bare block device without partitions
if (builtins.substring 0 3 config.fsType) == "ext" then "-F"
# -q needed for non-interactive operations
else if config.fsType == "jfs" then "-q"
# (same here)
else if config.fsType == "reiserfs" then "-q"
else null;
in {
options = mkIf config.autoResize [ "x-nixos.autoresize" ];
formatOptions = mkIf (defaultFormatOptions != null) (mkDefault defaultFormatOptions);
};
};
# Makes sequence of `specialMount device mountPoint options fsType` commands.
# `systemMount` should be defined in the sourcing script.
makeSpecialMounts = mounts:
pkgs.writeText "mounts.sh" (concatMapStringsSep "\n" (mount: ''
specialMount "${mount.device}" "${mount.mountPoint}" "${concatStringsSep "," mount.options}" "${mount.fsType}"
'') mounts);
in
{
###### interface
options = {
fileSystems = mkOption {
default = {};
example = literalExpression ''
{
"/".device = "/dev/hda1";
"/data" = {
device = "/dev/hda2";
fsType = "ext3";
options = [ "data=journal" ];
};
"/bigdisk".label = "bigdisk";
}
'';
type = types.attrsOf (types.submodule [coreFileSystemOpts fileSystemOpts]);
description = ''
The file systems to be mounted. It must include an entry for
the root directory (<literal>mountPoint = "/"</literal>). Each
entry in the list is an attribute set with the following fields:
<literal>mountPoint</literal>, <literal>device</literal>,
<literal>fsType</literal> (a file system type recognised by
<command>mount</command>; defaults to
<literal>"auto"</literal>), and <literal>options</literal>
(the mount options passed to <command>mount</command> using the
<option>-o</option> flag; defaults to <literal>[ "defaults" ]</literal>).
Instead of specifying <literal>device</literal>, you can also
specify a volume label (<literal>label</literal>) for file
systems that support it, such as ext2/ext3 (see <command>mke2fs
-L</command>).
'';
};
system.fsPackages = mkOption {
internal = true;
default = [ ];
description = "Packages supplying file system mounters and checkers.";
};
boot.supportedFilesystems = mkOption {
default = [ ];
example = [ "btrfs" ];
type = types.listOf types.str;
description = "Names of supported filesystem types.";
};
boot.specialFileSystems = mkOption {
default = {};
type = types.attrsOf (types.submodule coreFileSystemOpts);
internal = true;
description = ''
Special filesystems that are mounted very early during boot.
'';
};
};
###### implementation
config = {
assertions = let
ls = sep: concatMapStringsSep sep (x: x.mountPoint);
notAutoResizable = fs: fs.autoResize && !(hasPrefix "ext" fs.fsType || fs.fsType == "f2fs");
in [
{ assertion = ! (fileSystems' ? cycle);
message = "The ‘fileSystems’ option can't be topologically sorted: mountpoint dependency path ${ls " -> " fileSystems'.cycle} loops to ${ls ", " fileSystems'.loops}";
}
{ assertion = ! (any notAutoResizable fileSystems);
message = let
fs = head (filter notAutoResizable fileSystems);
in
"Mountpoint '${fs.mountPoint}': 'autoResize = true' is not supported for 'fsType = \"${fs.fsType}\"':${if fs.fsType == "auto" then " fsType has to be explicitly set and" else ""} only the ext filesystems and f2fs support it.";
}
];
# Export for use in other modules
system.build.fileSystems = fileSystems;
system.build.earlyMountScript = makeSpecialMounts (toposort fsBefore (attrValues config.boot.specialFileSystems)).result;
boot.supportedFilesystems = map (fs: fs.fsType) fileSystems;
# Add the mount helpers to the system path so that `mount' can find them.
system.fsPackages = [ pkgs.dosfstools ];
environment.systemPackages = with pkgs; [ fuse3 fuse ] ++ config.system.fsPackages;
environment.etc.fstab.text =
let
fsToSkipCheck = [ "none" "bindfs" "btrfs" "zfs" "tmpfs" "nfs" "vboxsf" "glusterfs" "apfs" ];
skipCheck = fs: fs.noCheck || fs.device == "none" || builtins.elem fs.fsType fsToSkipCheck;
# https://wiki.archlinux.org/index.php/fstab#Filepath_spaces
escape = string: builtins.replaceStrings [ " " "\t" ] [ "\\040" "\\011" ] string;
swapOptions = sw: concatStringsSep "," (
sw.options
++ optional (sw.priority != null) "pri=${toString sw.priority}"
++ optional (sw.discardPolicy != null) "discard${optionalString (sw.discardPolicy != "both") "=${toString sw.discardPolicy}"}"
);
in ''
# This is a generated file. Do not edit!
#
# To make changes, edit the fileSystems and swapDevices NixOS options
# in your /etc/nixos/configuration.nix file.
#
# <file system> <mount point> <type> <options> <dump> <pass>
# Filesystems.
${concatMapStrings (fs:
(if fs.device != null then escape fs.device
else if fs.label != null then "/dev/disk/by-label/${escape fs.label}"
else throw "No device specified for mount point ‘${fs.mountPoint}’.")
+ " " + escape fs.mountPoint
+ " " + fs.fsType
+ " " + builtins.concatStringsSep "," fs.options
+ " 0"
+ " " + (if skipCheck fs then "0" else
if fs.mountPoint == "/" then "1" else "2")
+ "\n"
) fileSystems}
# Swap devices.
${flip concatMapStrings config.swapDevices (sw:
"${sw.realDevice} none swap ${swapOptions sw}\n"
)}
'';
# Provide a target that pulls in all filesystems.
systemd.targets.fs =
{ description = "All File Systems";
wants = [ "local-fs.target" "remote-fs.target" ];
};
systemd.services =
# Emit systemd services to format requested filesystems.
let
formatDevice = fs:
let
mountPoint' = "${escapeSystemdPath fs.mountPoint}.mount";
device' = escapeSystemdPath fs.device;
device'' = "${device'}.device";
in nameValuePair "mkfs-${device'}"
{ description = "Initialisation of Filesystem ${fs.device}";
wantedBy = [ mountPoint' ];
before = [ mountPoint' "systemd-fsck@${device'}.service" ];
requires = [ device'' ];
after = [ device'' ];
path = [ pkgs.util-linux ] ++ config.system.fsPackages;
script =
''
if ! [ -e "${fs.device}" ]; then exit 1; fi
# FIXME: this is scary. The test could be more robust.
type=$(blkid -p -s TYPE -o value "${fs.device}" || true)
if [ -z "$type" ]; then
echo "creating ${fs.fsType} filesystem on ${fs.device}..."
mkfs.${fs.fsType} ${fs.formatOptions} "${fs.device}"
fi
'';
unitConfig.RequiresMountsFor = [ "${dirOf fs.device}" ];
unitConfig.DefaultDependencies = false; # needed to prevent a cycle
serviceConfig.Type = "oneshot";
};
in listToAttrs (map formatDevice (filter (fs: fs.autoFormat) fileSystems)) // {
# Mount /sys/fs/pstore for evacuating panic logs and crashdumps from persistent storage onto the disk using systemd-pstore.
# This cannot be done with the other special filesystems because the pstore module (which creates the mount point) is not loaded then.
"mount-pstore" = {
serviceConfig = {
Type = "oneshot";
# skip on kernels without the pstore module
ExecCondition = "${pkgs.kmod}/bin/modprobe -b pstore";
ExecStart = pkgs.writeShellScript "mount-pstore.sh" ''
set -eu
# if the pstore module is builtin it will have mounted the persistent store automatically. it may also be already mounted for other reasons.
${pkgs.util-linux}/bin/mountpoint -q /sys/fs/pstore || ${pkgs.util-linux}/bin/mount -t pstore -o nosuid,noexec,nodev pstore /sys/fs/pstore
# wait up to 1.5 seconds for the backend to be registered and the files to appear. a systemd path unit cannot detect this happening; and succeeding after a restart would not start dependent units.
TRIES=15
while [ "$(cat /sys/module/pstore/parameters/backend)" = "(null)" ]; do
if (( $TRIES )); then
sleep 0.1
TRIES=$((TRIES-1))
else
echo "Persistent Storage backend was not registered in time." >&2
break
fi
done
'';
RemainAfterExit = true;
};
unitConfig = {
ConditionVirtualization = "!container";
DefaultDependencies = false; # needed to prevent a cycle
};
before = [ "systemd-pstore.service" ];
wantedBy = [ "systemd-pstore.service" ];
};
};
systemd.tmpfiles.rules = [
"d /run/keys 0750 root ${toString config.ids.gids.keys}"
"z /run/keys 0750 root ${toString config.ids.gids.keys}"
];
# Sync mount options with systemd's src/core/mount-setup.c: mount_table.
boot.specialFileSystems = {
"/proc" = { fsType = "proc"; options = [ "nosuid" "noexec" "nodev" ]; };
"/run" = { fsType = "tmpfs"; options = [ "nosuid" "nodev" "strictatime" "mode=755" "size=${config.boot.runSize}" ]; };
"/dev" = { fsType = "devtmpfs"; options = [ "nosuid" "strictatime" "mode=755" "size=${config.boot.devSize}" ]; };
"/dev/shm" = { fsType = "tmpfs"; options = [ "nosuid" "nodev" "strictatime" "mode=1777" "size=${config.boot.devShmSize}" ]; };
"/dev/pts" = { fsType = "devpts"; options = [ "nosuid" "noexec" "mode=620" "ptmxmode=0666" "gid=${toString config.ids.gids.tty}" ]; };
# To hold secrets that shouldn't be written to disk
"/run/keys" = { fsType = "ramfs"; options = [ "nosuid" "nodev" "mode=750" ]; };
} // optionalAttrs (!config.boot.isContainer) {
# systemd-nspawn populates /sys by itself, and remounting it causes all
# kinds of weird issues (most noticeably, waiting for host disk device
# nodes).
"/sys" = { fsType = "sysfs"; options = [ "nosuid" "noexec" "nodev" ]; };
};
};
}