Turn fileSystems into an attribute set

So now you can write

  fileSystems =
    [ { mountPoint = "/";
        device = "/dev/sda1";
      }
    ];

as

  fileSystems."/".device = "/dev/sda1";

doc/manual/installation.xml

@@ -230,11 +230,7 @@ $ reboot</screen>
 {
   boot.loader.grub.device = "/dev/sda";
 
-  fileSystems =
+  fileSystems."/".device = "/dev/disk/by-label/nixos";
-    [ { mountPoint = "/";
-        device = "/dev/disk/by-label/nixos";
-      }
-    ];
 
   swapDevices =
     [ { device = "/dev/disk/by-label/swap"; } ];

modules/installer/cd-dvd/iso-image.nix

@@ -184,17 +184,13 @@ in
   # Note that /dev/root is a symlink to the actual root device
   # specified on the kernel command line, created in the stage 1 init
   # script.
-  fileSystems =
+  fileSystems."/".device = "/dev/root";
-    [ { mountPoint = "/";
+
-        device = "/dev/root";
+  fileSystems."/nix/store" =
-      }
+    { fsType = "squashfs";
-      { mountPoint = "/nix/store";
+      device = "/nix-store.squashfs";
-        fsType = "squashfs";
+      options = "loop";
-        device = "/nix-store.squashfs";
+    };
-        options = "loop";
-        neededForBoot = true;
-      }
-    ];
 
   # We need squashfs in the initrd to mount the compressed Nix store,
   # and aufs to make the root filesystem appear writable.

modules/installer/tools/nixos-option.sh

@@ -239,17 +239,14 @@ if $generate; then
   # Add filesystem entries for each partition that you want to see
   # mounted at boot time.  This should include at least the root
   # filesystem.
-  fileSystems =
-    [ # { mountPoint = "/";
-      #   device = "/dev/disk/by-label/nixos";
-      # }
 
-      # { mountPoint = "/data"; # where you want to mount the device
+  # fileSystems."/".device = "/dev/disk/by-label/nixos";
-      #   device = "/dev/sdb";  # the device
+
-      #   fsType = "ext3";      # the type of the partition
+  # fileSystems."/data" =     # where you want to mount the device
-      #   options = "data=journal";
+  #   { device = "/dev/sdb";  # the device
-      # }
+  #     fsType = "ext3";      # the type of the partition
-    ];
+  #     options = "data=journal";
+  #   };
 
   # List swap partitions activated at boot time.
   swapDevices =

modules/system/boot/stage-1.nix

@@ -99,9 +99,12 @@ let
       options.neededForBoot = mkOption {
         default = false;
         type = types.bool;
-        description = "
+        description = ''
-          Mount this file system to boot on NixOS.
+          If set, this file system will be mounted in the initial
-        ";
+          ramdisk.  By default, this applies to the root file system
+          and to the file system containing
+          <filename>/nix/store</filename>.
+        '';
       };
     };
 
@@ -236,8 +239,8 @@ let
   # booting (such as the FS containing /nix/store, or an FS needed for
   # mounting /, like / on a loopback).
   fileSystems = filter
-    (fs: fs.mountPoint == "/" || fs.neededForBoot)
+    (fs: fs.mountPoint == "/" || fs.mountPoint == "/nix" || fs.mountPoint == "/nix/store" || fs.neededForBoot)
-    config.fileSystems;
+    (attrValues config.fileSystems);
 
 
   udevRules = pkgs.stdenv.mkDerivation {

modules/tasks/filesystems.nix

@@ -5,12 +5,14 @@ with utils;
 
 let
 
+  fileSystems = attrValues config.fileSystems;
+
   fstab = pkgs.writeText "fstab"
     ''
       # This is a generated file.  Do not edit!
 
       # Filesystems.
-      ${flip concatMapStrings config.fileSystems (fs:
+      ${flip concatMapStrings fileSystems (fs:
           (if fs.device != null then fs.device else "/dev/disk/by-label/${fs.label}")
           + " " + fs.mountPoint
           + " " + fs.fsType
@@ -27,6 +29,70 @@ let
       )}
     '';
 
+  fileSystemOpts = { name, ... }: {
+
+    options = {
+
+      mountPoint = mkOption {
+        example = "/mnt/usb";
+        type = types.uniq types.string;
+        description = "Location of the mounted the file system.";
+      };
+
+      device = mkOption {
+        default = null;
+        example = "/dev/sda";
+        type = types.uniq (types.nullOr types.string);
+        description = "Location of the device.";
+      };
+
+      label = mkOption {
+        default = null;
+        example = "root-partition";
+        type = types.uniq (types.nullOr types.string);
+        description = "Label of the device (if any).";
+      };
+
+      fsType = mkOption {
+        default = "auto";
+        example = "ext3";
+        type = types.uniq types.string;
+        description = "Type of the file system.";
+      };
+
+      options = mkOption {
+        default = "defaults,relatime";
+        example = "data=journal";
+        type = types.string;
+        merge = pkgs.lib.concatStringsSep ",";
+        description = "Options used to mount the file system.";
+      };
+
+      autoFormat = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          If the device does not currently contain a filesystem (as
+          determined by <command>blkid</command>, then automatically
+          format it with the filesystem type specified in
+          <option>fsType</option>.  Use with caution.
+        '';
+      };
+
+      noCheck = mkOption {
+        default = false;
+        type = types.bool;
+        description = "Disable running fsck on this filesystem.";
+      };
+
+    };
+
+    config = {
+      mountPoint = mkDefault name;
+    };
+
+  };
+
 in
 
 {
@@ -36,20 +102,17 @@ in
   options = {
 
     fileSystems = mkOption {
-      example = [
+      example = {
-        { mountPoint = "/";
+        "/".device = "/dev/hda1";
-          device = "/dev/hda1";
+        "/data" = {
-        }
-        { mountPoint = "/data";
           device = "/dev/hda2";
           fsType = "ext3";
           options = "data=journal";
-        }
+        };
-        { mountPoint = "/bigdisk";
+        "/bigdisk".label = "bigdisk";
-          label = "bigdisk";
+      };
-        }
+      type = types.loaOf types.optionSet;
-      ];
+      options = [ fileSystemOpts ];
-
       description = ''
         The file systems to be mounted.  It must include an entry for
         the root directory (<literal>mountPoint = \"/\"</literal>).  Each
@@ -66,63 +129,6 @@ in
         systems that support it, such as ext2/ext3 (see <command>mke2fs
         -L</command>).
       '';
-
-      type = types.list types.optionSet;
-
-      options = {
-
-        mountPoint = mkOption {
-          example = "/mnt/usb";
-          type = types.uniq types.string;
-          description = "Location of the mounted the file system.";
-        };
-
-        device = mkOption {
-          default = null;
-          example = "/dev/sda";
-          type = types.uniq (types.nullOr types.string);
-          description = "Location of the device.";
-        };
-
-        label = mkOption {
-          default = null;
-          example = "root-partition";
-          type = types.uniq (types.nullOr types.string);
-          description = "Label of the device (if any).";
-        };
-
-        fsType = mkOption {
-          default = "auto";
-          example = "ext3";
-          type = types.uniq types.string;
-          description = "Type of the file system.";
-        };
-
-        options = mkOption {
-          default = "defaults,relatime";
-          example = "data=journal";
-          type = types.string;
-          merge = pkgs.lib.concatStringsSep ",";
-          description = "Options used to mount the file system.";
-        };
-
-        autoFormat = mkOption {
-          default = false;
-          type = types.bool;
-          description = ''
-            If the device does not currently contain a filesystem (as
-            determined by <command>blkid</command>, then automatically
-            format it with the filesystem type specified in
-            <option>fsType</option>.  Use with caution.
-          '';
-        };
-
-        noCheck = mkOption {
-          default = false;
-          type = types.bool;
-          description = "Disable running fsck on this filesystem.";
-        };
-      };
     };
 
     system.fsPackages = mkOption {
@@ -152,12 +158,11 @@ in
 
   config = {
 
-    boot.supportedFilesystems =
+    boot.supportedFilesystems = map (fs: fs.fsType) fileSystems;
-      map (fs: fs.fsType) config.fileSystems;
 
     boot.initrd.supportedFilesystems =
       map (fs: fs.fsType)
-        (filter (fs: fs.mountPoint == "/" || fs.neededForBoot) config.fileSystems);
+        (filter (fs: fs.mountPoint == "/" || fs.neededForBoot) fileSystems);
 
     # Add the mount helpers to the system path so that `mount' can find them.
     system.fsPackages = [ pkgs.dosfstools ];
@@ -207,7 +212,7 @@ in
             serviceConfig.Type = "oneshot";
           };
 
-      in listToAttrs (map formatDevice (filter (fs: fs.autoFormat) config.fileSystems));
+      in listToAttrs (map formatDevice (filter (fs: fs.autoFormat) fileSystems));
 
   };
 

modules/virtualisation/amazon-image.nix

@@ -62,11 +62,7 @@ with pkgs.lib;
         ''
     );
 
-  fileSystems =
+  fileSystems."/".device = "/dev/disk/by-label/nixos";
-    [ { mountPoint = "/";
-        device = "/dev/disk/by-label/nixos";
-      }
-    ];
 
   boot.initrd.kernelModules = [ "xen-blkfront" "aufs" ];
   boot.kernelModules = [ "xen-netfront" ];

modules/virtualisation/nova-image.nix

@@ -68,11 +68,7 @@ with pkgs.lib;
         ''
     );
 
-  fileSystems =
+  fileSystems."/".device = "/dev/disk/by-label/nixos";
-    [ { mountPoint = "/";
-        device = "/dev/disk/by-label/nixos";
-      }
-    ];
 
   boot.kernelParams = [ "console=ttyS0" ];
 

modules/virtualisation/qemu-vm.nix

@@ -320,35 +320,33 @@ in
   # where the regular value for the `fileSystems' attribute should be
   # disregarded for the purpose of building a VM test image (since
   # those filesystems don't exist in the VM).
-  fileSystems = mkOverride 50 (
+  fileSystems =
-    [ { mountPoint = "/";
+    { "/".device = "/dev/vda";
-        device = "/dev/vda";
+      "/nix/store" =
-      }
+        { device = "//10.0.2.4/store";
-      { mountPoint = "/nix/store";
+          fsType = "cifs";
-        device = "//10.0.2.4/store";
+          options = "guest,sec=none,noperm,noacl";
-        fsType = "cifs";
+        };
-        options = "guest,sec=none,noperm,noacl";
+      "/tmp/xchg" =
-        neededForBoot = true;
+        { device = "//10.0.2.4/xchg";
-      }
+          fsType = "cifs";
-      { mountPoint = "/tmp/xchg";
+          options = "guest,sec=none,noperm,noacl";
-        device = "//10.0.2.4/xchg";
+          neededForBoot = true;
-        fsType = "cifs";
+        };
-        options = "guest,sec=none,noperm,noacl";
+      "/tmp/shared" =
-        neededForBoot = true;
+        { device = "//10.0.2.4/shared";
-      }
+          fsType = "cifs";
-      { mountPoint = "/tmp/shared";
+          options = "guest,sec=none,noperm,noacl";
-        device = "//10.0.2.4/shared";
+          neededForBoot = true;
-        fsType = "cifs";
+        };
-        options = "guest,sec=none,noperm,noacl";
+    } // optionalAttrs cfg.useBootLoader
-        neededForBoot = true;
+    { "/boot" =
-      }
+        { device = "/dev/disk/by-label/boot";
-    ] ++ optional cfg.useBootLoader
+          fsType = "ext4";
-      { mountPoint = "/boot";
+          options = "ro";
-        device = "/dev/disk/by-label/boot";
+          noCheck = true; # fsck fails on a r/o filesystem
-        fsType = "ext4";
+        };
-        options = "ro";
+    };
-        noCheck = true; # fsck fails on a r/o filesystem
-      });
 
   swapDevices = mkOverride 50 [ ];
 

modules/virtualisation/virtualbox-image.nix

@@ -71,11 +71,7 @@ with pkgs.lib;
         ''
     );
 
-  fileSystems =
+  fileSystems."/".device = "/dev/disk/by-label/nixos";
-    [ { mountPoint = "/";
-        device = "/dev/disk/by-label/nixos";
-      }
-    ];
 
   boot.loader.grub.version = 2;
   boot.loader.grub.device = "/dev/sda";