nixos/filesystems: Make most simple filesystems compatible with systemd

This includes disabling some features in the initrd by default, this is
only done when the new initrd is used. Namely, ext and bcache are
disabled by default. bcache gets an own enable option while ext is
detected like any other filesystem.

nixos/modules/installer/cd-dvd/system-tarball-sheevaplug.nix

···
   boot.initrd.availableKernelModules =
     [ "mvsdio" "reiserfs" "ext3" "ums-cypress" "rtc_mv" "ext4" ];
 
-  boot.postBootCommands =
+  boot.postBootCommands = lib.mkIf (!boot.initrd.systemd.enable)
     ''
       mkdir -p /mnt
 
       cp ${dummyConfiguration} /etc/nixos/configuration.nix
     '';
 
-  boot.initrd.extraUtilsCommands =
+  boot.initrd.extraUtilsCommands = lib.mkIf (!boot.initrd.systemd.enable)
     ''
       copy_bin_and_libs ${pkgs.util-linux}/sbin/hwclock
     '';
 
-  boot.initrd.postDeviceCommands =
+  boot.initrd.postDeviceCommands = lib.mkIf (!boot.initrd.systemd.enable)
     ''
       hwclock -s
     '';

nixos/modules/tasks/bcache.nix

···
-{ pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
+  options.boot.initrd.services.bcache.enable = (lib.mkEnableOption "bcache support in the initrd") // {
+    visible = false; # only works with systemd stage 1
+  };
 
-  environment.systemPackages = [ pkgs.bcache-tools ];
+  config = {
 
-  services.udev.packages = [ pkgs.bcache-tools ];
+    environment.systemPackages = [ pkgs.bcache-tools ];
 
-  boot.initrd.extraUdevRulesCommands = ''
-    cp -v ${pkgs.bcache-tools}/lib/udev/rules.d/*.rules $out/
-  '';
+    services.udev.packages = [ pkgs.bcache-tools ];
+
+    boot.initrd.extraUdevRulesCommands = lib.mkIf (!config.boot.initrd.systemd.enable) ''
+      cp -v ${pkgs.bcache-tools}/lib/udev/rules.d/*.rules $out/
+    '';
 
+    boot.initrd.services.udev = lib.mkIf config.boot.initrd.services.bcache.enable {
+      packages = [ pkgs.bcache-tools ];
+      binPackages = [ pkgs.bcache-tools ];
+    };
+  };
 }

nixos/modules/tasks/filesystems/btrfs.nix

···
         ]
       );
 
-      boot.initrd.extraUtilsCommands = mkIf inInitrd
+      boot.initrd.extraUtilsCommands = mkIf (inInitrd && !config.boot.initrd.systemd.enable)
       ''
         copy_bin_and_libs ${pkgs.btrfs-progs}/bin/btrfs
         ln -sv btrfs $out/bin/btrfsck
         ln -sv btrfsck $out/bin/fsck.btrfs
       '';
 
-      boot.initrd.extraUtilsCommandsTest = mkIf inInitrd
+      boot.initrd.extraUtilsCommandsTest = mkIf (inInitrd && !config.boot.initrd.systemd.enable)
       ''
         $out/bin/btrfs --version
       '';

nixos/modules/tasks/filesystems/cifs.nix

···
     boot.initrd.availableKernelModules = mkIf inInitrd
       [ "cifs" "nls_utf8" "hmac" "md4" "ecb" "des_generic" "sha256" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !config.boot.initrd.systemd.enable)
       ''
         copy_bin_and_libs ${pkgs.cifs-utils}/sbin/mount.cifs
       '';

nixos/modules/tasks/filesystems/ext.nix

···
-{ pkgs, ... }:
+{ config, lib, pkgs, ... }:
+
+let
+
+  inInitrd = lib.any (fs: fs == "ext2" || fs == "ext3" || fs == "ext4") config.boot.initrd.supportedFilesystems;
+
+in
 
 {
   config = {
 
-    system.fsPackages = [ pkgs.e2fsprogs ];
+    system.fsPackages = lib.mkIf (config.boot.initrd.systemd.enable -> inInitrd) [ pkgs.e2fsprogs ];
 
     # As of kernel 4.3, there is no separate ext3 driver (they're also handled by ext4.ko)
-    boot.initrd.availableKernelModules = [ "ext2" "ext4" ];
+    boot.initrd.availableKernelModules = lib.mkIf (config.boot.initrd.systemd.enable -> inInitrd) [ "ext2" "ext4" ];
 
-    boot.initrd.extraUtilsCommands =
+    boot.initrd.extraUtilsCommands = lib.mkIf (!config.boot.initrd.systemd.enable)
       ''
         # Copy e2fsck and friends.
         copy_bin_and_libs ${pkgs.e2fsprogs}/sbin/e2fsck

nixos/modules/tasks/filesystems/f2fs.nix

···
 
     boot.initrd.availableKernelModules = mkIf inInitrd [ "f2fs" "crc32" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd ''
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !config.boot.initrd.systemd.enable) ''
       copy_bin_and_libs ${pkgs.f2fs-tools}/sbin/fsck.f2fs
       ${optionalString (any (fs: fs.autoResize) fileSystems) ''
         # We need f2fs-tools' tools to resize filesystems

nixos/modules/tasks/filesystems/jfs.nix

···
 
     boot.initrd.kernelModules = mkIf inInitrd [ "jfs" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd ''
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !boot.initrd.systemd.enable) ''
       copy_bin_and_libs ${pkgs.jfsutils}/sbin/fsck.jfs
     '';
   };

nixos/modules/tasks/filesystems/reiserfs.nix

···
 
     boot.initrd.kernelModules = mkIf inInitrd [ "reiserfs" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !config.boot.initrd.systemd.enable)
       ''
         copy_bin_and_libs ${pkgs.reiserfsprogs}/sbin/reiserfsck
         ln -s reiserfsck $out/bin/fsck.reiserfs

nixos/modules/tasks/filesystems/unionfs-fuse.nix

···
     (lib.mkIf (lib.any (fs: fs == "unionfs-fuse") config.boot.initrd.supportedFilesystems) {
       boot.initrd.kernelModules = [ "fuse" ];
 
-      boot.initrd.extraUtilsCommands = ''
+      boot.initrd.extraUtilsCommands = lib.mkIf (!config.boot.initrd.systemd.enable) ''
         copy_bin_and_libs ${pkgs.fuse}/sbin/mount.fuse
         copy_bin_and_libs ${pkgs.unionfs-fuse}/bin/unionfs
         substitute ${pkgs.unionfs-fuse}/sbin/mount.unionfs-fuse $out/bin/mount.unionfs-fuse \
···
         chmod +x $out/bin/mount.unionfs-fuse
       '';
 
-      boot.initrd.postDeviceCommands = ''
+      boot.initrd.postDeviceCommands = lib.mkIf (!config.boot.initrd.systemd.enable) ''
           # Hacky!!! fuse hard-codes the path to mount
           mkdir -p /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.util-linux.name}-bin/bin
           ln -s $(which mount) /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.util-linux.name}-bin/bin
           ln -s $(which umount) /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${pkgs.util-linux.name}-bin/bin
         '';
+
+      boot.initrd.systemd.extraBin = {
+        "mount.fuse" = "${pkgs.fuse}/bin/mount.fuse";
+        "unionfs" = "${pkgs.unionfs-fuse}/bin/unionfs";
+        "mount.unionfs-fuse" = pkgs.runCommand "mount.unionfs-fuse" {} ''
+          substitute ${pkgs.unionfs-fuse}/sbin/mount.unionfs-fuse $out \
+            --replace '${pkgs.bash}/bin/bash' /bin/sh \
+            --replace '${pkgs.fuse}/sbin' /bin \
+            --replace '${pkgs.unionfs-fuse}/bin' /bin
+        '';
+      };
     })
 
     (lib.mkIf (lib.any (fs: fs == "unionfs-fuse") config.boot.supportedFilesystems) {

nixos/modules/tasks/filesystems/vfat.nix

···
 
     boot.initrd.kernelModules = mkIf inInitrd [ "vfat" "nls_cp437" "nls_iso8859-1" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !config.boot.initrd.systemd.enable)
       ''
         copy_bin_and_libs ${pkgs.dosfstools}/sbin/dosfsck
         ln -sv dosfsck $out/bin/fsck.vfat

nixos/modules/tasks/filesystems/xfs.nix

···
 
     boot.initrd.availableKernelModules = mkIf inInitrd [ "xfs" "crc32c" ];
 
-    boot.initrd.extraUtilsCommands = mkIf inInitrd
+    boot.initrd.extraUtilsCommands = mkIf (inInitrd && !boot.initrd.systemd.enable)
       ''
         copy_bin_and_libs ${pkgs.xfsprogs.bin}/bin/fsck.xfs
         copy_bin_and_libs ${pkgs.xfsprogs.bin}/bin/xfs_repair
       '';
 
     # Trick just to set 'sh' after the extraUtils nuke-refs.
-    boot.initrd.extraUtilsCommandsTest = mkIf inInitrd
+    boot.initrd.extraUtilsCommandsTest = mkIf (inInitrd && !boot.initrd.systemd.enable)
       ''
         sed -i -e 's,^#!.*,#!'$out/bin/sh, $out/bin/fsck.xfs
       '';