nixos/grow-partition: Resize partition online instead of in initrd

There's no reason to do this in initrd. Partitions can be resized online.
We just have to make sure it happens before we resize the file system.

This also makes grow-partition work with systemd-initrd

1 files changed, 25 insertions, 29 deletions

diff --git a/nixos/modules/system/boot/grow-partition.nix b/nixos/modules/system/boot/grow-partition.nix
index a2764187a53..1ce4d5e5623 100644
--- a/nixos/modules/system/boot/grow-partition.nix
+++ b/nixos/modules/system/boot/grow-partition.nix
@@ -16,29 +16,28 @@ with lib;
   };
 
   config = mkIf config.boot.growPartition {
-
-    assertions = [{
-      assertion = !config.boot.initrd.systemd.enable;
-      message = "systemd stage 1 does not support 'boot.growPartition' yet.";
-    }];
-
-    boot.initrd.extraUtilsCommands = ''
-      copy_bin_and_libs ${pkgs.gawk}/bin/gawk
-      copy_bin_and_libs ${pkgs.gnused}/bin/sed
-      copy_bin_and_libs ${pkgs.util-linux}/sbin/sfdisk
-      copy_bin_and_libs ${pkgs.util-linux}/sbin/lsblk
-
-      substitute "${pkgs.cloud-utils.guest}/bin/.growpart-wrapped" "$out/bin/growpart" \
-        --replace "${pkgs.bash}/bin/sh" "/bin/sh" \
-        --replace "awk" "gawk" \
-        --replace "sed" "gnused"
-
-      ln -s sed $out/bin/gnused
-    '';
-
-    boot.initrd.postDeviceCommands = ''
-      rootDevice="${config.fileSystems."/".device}"
-      if waitDevice "$rootDevice"; then
+    assertions = [
+      {
+        assertion = !config.boot.initrd.systemd.repart.enable && !config.systemd.repart.enable;
+        message = "systemd-repart already grows the root partition and thus you should not use boot.growPartition";
+      }
+    ];
+    systemd.services.growpart = {
+      wantedBy = [ "-.mount" ];
+      after = [ "-.mount" ];
+      before = [ "systemd-growfs-root.service" ];
+      conflicts = [ "shutdown.target" ];
+      unitConfig.DefaultDependencies = false;
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+        TimeoutSec = "infinity";
+        # growpart returns 1 if the partition is already grown
+        SuccessExitStatus = "0 1";
+      };
+
+      script = ''
+        rootDevice="${config.fileSystems."/".device}"
         rootDevice="$(readlink -f "$rootDevice")"
         parentDevice="$rootDevice"
         while [ "''${parentDevice%[0-9]}" != "''${parentDevice}" ]; do
@@ -48,11 +47,8 @@ with lib;
         if [ "''${parentDevice%[0-9]p}" != "''${parentDevice}" ] && [ -b "''${parentDevice%p}" ]; then
           parentDevice="''${parentDevice%p}"
         fi
-        TMPDIR=/run sh $(type -P growpart) "$parentDevice" "$partNum"
-        udevadm settle
-      fi
-    '';
-
+        "${pkgs.cloud-utils.guest}/bin/growpart" "$parentDevice" "$partNum"
+      '';
+    };
   };
-
 }