Added support for btrfs filesystem and made it possible to set arbitary options on FS creation.

Author: makuru-org

lib/default.nix

@@ -32,14 +32,15 @@ rec {
     { image
     , label
     , size ? throw "Specify a size for volume ${image} or use autoCreate = false"
+    , mkfsExtraArgs
     , fsType ? defaultFsType
     , autoCreate ? true
     , ...
     }: pkgs.lib.warnIf
       (label != null && !autoCreate) "Volume is not automatically labeled unless autoCreate is true. Volume has to be labeled manually, otherwise it will not be identified"
       (let labelOption =
              if autoCreate then
-               (if builtins.elem fsType ["ext2" "ext3" "ext4" "xfs"] then "-L"
+               (if builtins.elem fsType ["ext2" "ext3" "ext4" "xfs" "btrfs"] then "-L"
                 else if fsType == "vfat" then "-n"
                 else (pkgs.lib.warnIf (label != null)
                   "Will not label volume ${label} with filesystem type ${fsType}. Open an issue on the microvm.nix project to request a fix."
@@ -48,15 +49,19 @@ rec {
            labelArgument =
              if (labelOption != null && label != null) then "${labelOption} '${label}'"
              else "";
+             mkfsExtraArgsString =
+              if mkfsExtraArgs != null
+              then nixpkgs-lib.escapeShellArgs mkfsExtraArgs
+              else " ";
       in (nixpkgs-lib.optionalString autoCreate ''
-      PATH=$PATH:${with pkgs.buildPackages; lib.makeBinPath [ coreutils util-linux e2fsprogs xfsprogs dosfstools ]}
+      PATH=$PATH:${with pkgs.buildPackages; lib.makeBinPath [ coreutils util-linux e2fsprogs xfsprogs dosfstools btrfs-progs ]}
 
       if [ ! -e '${image}' ]; then
         touch '${image}'
         # Mark NOCOW
         chattr +C '${image}' || true
         truncate -s ${toString size}M '${image}'
-        mkfs.${fsType} ${labelArgument} '${image}'
+        mkfs.${fsType} ${labelArgument} ${mkfsExtraArgsString} '${image}'
       fi
     '')));
 

nixos-modules/microvm/options.nix

@@ -198,10 +198,15 @@ in
             default = true;
             description = "Created image on host automatically before start?";
           };
+          mkfsExtraArgs = mkOption {
+            type = listOf str;
+            default = [];
+            description = "Set extra Filesystem creation parameters";
+          };
           fsType = mkOption {
             type = str;
             default = "ext4";
-            description = "File system for automatic creation and mounting";
+            description = "Filesystem for automatic creation and mounting";
           };
         };
       });