diff --git a/nixos/modules/tasks/filesystems.nix b/nixos/modules/tasks/filesystems.nix
index 9dd250f140ce..5f21e668f7ed 100644
--- a/nixos/modules/tasks/filesystems.nix
+++ b/nixos/modules/tasks/filesystems.nix
@@ -58,6 +58,15 @@ let
         '';
       };
 
+      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;
@@ -81,6 +90,9 @@ let
       mountPoint = mkDefault name;
       device = mkIf (config.fsType == "tmpfs") (mkDefault config.fsType);
       options = mkIf config.autoResize "x-nixos.autoresize";
+
+      # -F needed to allow bare block device without partitions
+      formatOptions = mkIf ((builtins.substring 0 3 config.fsType) == "ext") (mkDefault "-F");
     };
 
   };
@@ -192,8 +204,6 @@ in
           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" ];
@@ -208,7 +218,7 @@ in
                 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}" ];