Move CIFS support into a separate module

nixos/modules/module-list.nix

@@ -316,11 +316,12 @@
   ./system/upstart/upstart.nix
   ./tasks/cpu-freq.nix
   ./tasks/encrypted-devices.nix
+  ./tasks/filesystems.nix
   ./tasks/filesystems/btrfs.nix
+  ./tasks/filesystems/cifs.nix
   ./tasks/filesystems/ext.nix
   ./tasks/filesystems/f2fs.nix
   ./tasks/filesystems/nfs.nix
-  ./tasks/filesystems.nix
   ./tasks/filesystems/reiserfs.nix
   ./tasks/filesystems/unionfs-fuse.nix
   ./tasks/filesystems/vfat.nix

nixos/modules/system/boot/stage-1.nix

@@ -23,22 +23,6 @@ let
   };
 
 
-  needsCifsUtils = kernelPackages.kernel ? features
-                && kernelPackages.kernel.features ? needsCifsUtils
-                && kernelPackages.kernel.features.needsCifsUtils
-                && any (fs: fs.fsType == "cifs") fileSystems;
-
-  busybox =
-    if needsCifsUtils
-    then pkgs.busybox.override {
-           extraConfig = ''
-             CONFIG_FEATURE_MOUNT_CIFS n
-             CONFIG_FEATURE_MOUNT_HELPERS y
-           '';
-         }
-    else pkgs.busybox;
-
-
   # Some additional utilities needed in stage 1, like mount, lvm, fsck
   # etc.  We don't want to bring in all of those packages, so we just
   # copy what we need.  Instead of using statically linked binaries,
@@ -62,7 +46,7 @@ let
       cp -pv ${pkgs.gcc.gcc}/lib*/libgcc_s.so.* $out/lib
 
       # Copy BusyBox.
-      cp -rvd ${busybox}/{bin,sbin} $out/
+      cp -rvd ${pkgs.busybox}/{bin,sbin} $out/
       chmod -R u+w $out
 
       # Copy some utillinux stuff.
@@ -91,11 +75,6 @@ let
       cp -v ${pkgs.kmod}/bin/kmod $out/bin/
       ln -s kmod $out/bin/modprobe
 
-      # Maybe copy cifs utils
-      ${optionalString needsCifsUtils ''
-        cp -v ${pkgs.cifs_utils}/sbin/mount.cifs $out/bin
-      ''}
-
       ${config.boot.initrd.extraUtilsCommands}
 
       # Strip binaries further than normal.

nixos/modules/tasks/filesystems.nix

@@ -137,7 +137,7 @@ in
     system.fsPackages = [ pkgs.dosfstools ];
 
     environment.systemPackages =
-      [ pkgs.ntfs3g pkgs.cifs_utils pkgs.fuse ]
+      [ pkgs.ntfs3g pkgs.fuse ]
       ++ config.system.fsPackages;
 
     environment.etc.fstab.text =

nixos/modules/tasks/filesystems/cifs.nix

@@ -0,0 +1,25 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  inInitrd = any (fs: fs == "cifs") config.boot.initrd.supportedFilesystems;
+
+in
+
+{
+  config = {
+
+    system.fsPackages = [ pkgs.cifs_utils ];
+
+    boot.initrd.availableKernelModules = mkIf inInitrd
+      [ "cifs" "nls_utf8" "hmac" "md4" "ecb" "des_generic" "sha256" ];
+
+    boot.initrd.extraUtilsCommands = mkIf inInitrd
+      ''
+        cp -v ${pkgs.cifs_utils}/sbin/mount.cifs $out/bin
+      '';
+
+  };
+}

pkgs/os-specific/linux/busybox/default.nix

@@ -28,6 +28,10 @@ let
   nixConfig = ''
     CONFIG_PREFIX "$out"
     CONFIG_INSTALL_NO_USR y
+
+    # Use the external mount.cifs program.
+    CONFIG_FEATURE_MOUNT_CIFS n
+    CONFIG_FEATURE_MOUNT_HELPERS y
   '';
 
   staticConfig = stdenv.lib.optionalString enableStatic ''
@@ -49,8 +53,8 @@ stdenv.mkDerivation rec {
     ${configParser}
     cat << EOF | parseconfig
     ${staticConfig}
-    ${extraConfig}
     ${nixConfig}
+    ${extraConfig}
     $extraCrossConfig
     EOF
     make oldconfig