* Allow multiple file systems to be mounted in stage 1 (i.e., from the

initrd).  This is useful if /nix (which is necessary for stage 2) is
  on a different file system than /.

svn path=/nixos/trunk/; revision=7862

boot/boot-stage-1-init.sh

@@ -3,6 +3,7 @@
 fail() {
     # If starting stage 2 failed, start an interactive shell.
     echo "Stage 2 failed, starting emergency shell..."
+    echo "(Stage 1 init script is $stage2Init)"
     exec @staticShell@
 }
 
@@ -67,12 +68,55 @@ udevtrigger
 udevsettle
 
 
+# Function for mounting a file system.
+mountFS() {
+    local device="$1"
+    local mountPoint="$2"
+    local options="$3"
+
+    # Check the root device, if .
+    mustCheck=
+    if test -b "$device"; then
+        mustCheck=1
+    else
+        case $device in
+            LABEL=*)
+                mustCheck=1
+                ;;
+        esac
+    fi
+
+    if test -n "$mustCheck"; then
+        fsck -C -a "$device"
+        fsckResult=$?
+
+        if test $(($fsckResult | 2)) = $fsckResult; then
+            echo "fsck finished, rebooting..."
+            sleep 3
+            # reboot -f -d !!! don't have reboot yet
+            fail
+        fi
+
+        if test $(($fsckResult | 4)) = $fsckResult; then
+            echo "$device has unrepaired errors, please fix them manually."
+            fail
+        fi
+
+        if test $fsckResult -ge 8; then
+            echo "fsck on $device failed."
+            fail
+        fi
+    fi
+
+    # Mount read-writable.
+    mount -n -o "$options" "$device" /mnt/root$mountPoint || fail
+}
+
+
 # Try to find and mount the root device.
 mkdir /mnt
 mkdir /mnt/root
 
-echo "mounting the root device..."
-
 if test -n "@autoDetectRootDevice@"; then
 
     # Look for the root device by label.
@@ -109,33 +153,37 @@ if test -n "@autoDetectRootDevice@"; then
 
 else
 
-    # Hard-coded root device.
-    rootDevice="@rootDevice@"
+    # Hard-coded root device(s).
+    mountPoints=(@mountPoints@)
+    devices=(@devices@)
+    fsTypes=(@fsTypes@)
+    optionss=(@optionss@)
 
-    # Check the root device.
-    fsck -C -a "$rootDevice"
-    fsckResult=$?
+    for ((n = 0; n < ${#mountPoints[*]}; n++)); do
+        mountPoint=${mountPoints[$n]}
+        device=${devices[$n]}
+        fsType=${fsTypes[$n]}
+        options=${optionss[$n]}
 
-    if test $(($fsckResult | 2)) = $fsckResult; then
-        echo "fsck finished, rebooting..."
-        sleep 3
-        # reboot -f -d !!! don't have reboot yet
-        fail
-    fi
+        # !!! Really quick hack to support bind mounts, i.e., where
+        # the "device" should be taken relative to /mnt/root, not /.
+        # Assume that every device that doesn't start with /dev or
+        # LABEL= is a bind mount.
+        case $device in
+            /dev/*)
+                ;;
+            LABEL=*)
+                ;;
+            *)
+                device=/mnt/root$device
+                ;;
+        esac
 
-    if test $(($fsckResult | 4)) = $fsckResult; then
-        echo "$rootDevice has unrepaired errors, please fix them manually."
-        fail
-    fi
-
-    if test $fsckResult -ge 8; then
-        echo "fsck on $rootDevice failed."
-        fail
-    fi
-
-    # Mount read-writable.
-    mount -n -o rw "$rootDevice" /mnt/root || fail
+        echo "mounting $device on $mountPoint..."
 
+        mountFS "$device" "$mountPoint" "$options"
+    done
+    
 fi
 
 
@@ -148,8 +196,6 @@ mount --move . /
 umount /proc # cleanup
 umount /sys
 
-echo "INIT = $stage2Init"
-
 if test -z "$stage2Init"; then fail; fi
 
 exec chroot . $stage2Init

boot/boot-stage-1.nix

@@ -10,8 +10,15 @@
 , # Whether to find root device automatically using its label.
   autoDetectRootDevice
   
-, # If not scanning, the root must be specified explicitly.
-  rootDevice
+, # If not scanning, the root must be specified explicitly.  Actually,
+  # stage 1 can mount multiple file systems.  This is necessary if,
+  # for instance, /nix (necessary for stage 2) is on a different file
+  # system than /.
+  #
+  # This is a list of {mountPoint, device|label} attribute sets, i.e.,
+  # the format used by the fileSystems configuration option.  There
+  # must at least be a file system for the / mount point in this list.
+  fileSystems ? []
 
   # If scanning, we need a disk label.
 , rootLabel
@@ -21,12 +28,23 @@
   stage2Init ? "/init"
 }:
 
+let
+
+  # !!! use XML; copy&pasted from upstart-jobs/filesystems.nix.
+  mountPoints = map (fs: fs.mountPoint) fileSystems;
+  devices = map (fs: if fs ? device then fs.device else "LABEL=" + fs.label) fileSystems;
+  fsTypes = map (fs: if fs ? fsType then fs.fsType else "auto") fileSystems;
+  optionss = map (fs: if fs ? options then fs.options else "defaults") fileSystems;
+
+in
+
+assert autoDetectRootDevice -> mountPoints != [];
+
 substituteAll {
   src = ./boot-stage-1-init.sh;
   isExecutable = true;
   inherit staticShell modules modulesDir;
-  inherit autoDetectRootDevice;
-  rootDevice = if !autoDetectRootDevice then rootDevice else "";
+  inherit autoDetectRootDevice mountPoints devices fsTypes optionss;
   rootLabel = if autoDetectRootDevice then rootLabel else "";
   path = [
     staticTools

system/system.nix

@@ -68,12 +68,10 @@ rec {
     inherit (pkgsDiet) module_init_tools;
     inherit extraUtils;
     autoDetectRootDevice = config.get ["boot" "autoDetectRootDevice"];
-    rootDevice =
-      let rootFS = 
-        (pkgs.library.findSingle (fs: fs.mountPoint == "/")
-          (abort "No root mount point declared.")
-          (config.get ["fileSystems"]));
-      in if rootFS ? device then rootFS.device else "LABEL=" + rootFS.label;
+    fileSystems =
+      pkgs.lib.filter
+        (fs: fs.mountPoint == "/" || (fs ? neededForBoot && fs.neededForBoot))
+        (config.get ["fileSystems"]);
     rootLabel = config.get ["boot" "rootLabel"];
     inherit stage2Init;
     modulesDir = modulesClosure;