anchor.diff:                  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} ${concatStringsSep " " mkfsOpts} "${fs.device}"
  +                  mkfs.${fs.fsType} ${fs.formatOptions} "${fs.device}"
                   fi
                 '';
               unitConfig.RequiresMountsFor = [ "${dirOf fs.device}" ];
  
positive.code:           let
              mountPoint' = escapeSystemdPath fs.mountPoint;
              device' = escapeSystemdPath fs.device;
              # -F needed to allow bare block device without partitions
              mkfsOpts = optional ((builtins.substring 0 3 fs.fsType) == "ext") "-F";
            in nameValuePair "mkfs-${device'}"
            { description = "Initialisation of Filesystem ${fs.device}";
              wantedBy = [ "${mountPoint'}.mount" ];
  
negative.code:         '';
        };
  
        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;
  