From a83becdee89dbb6fca3cf886526b6ba35b401c52 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Fri, 8 Aug 2008 23:01:30 +0000
Subject: [PATCH] * When booting from the installation CD, just mount  
 /dev/disk/by-label/<label>.  This makes the whole  
 autoDetectRootDevice/rootLabel machinery unnecessary.

svn path=/nixos/trunk/; revision=12561
---
 boot/boot-stage-1-init.sh   | 88 ++++++++++---------------------------
 boot/boot-stage-1.nix       |  8 ++--
 configuration/rescue-cd.nix | 17 ++++---
 system/options.nix          | 22 +---------
 4 files changed, 38 insertions(+), 97 deletions(-)

diff --git a/boot/boot-stage-1-init.sh b/boot/boot-stage-1-init.sh
index 126761f2192..83a06c7d7dd 100644
--- a/boot/boot-stage-1-init.sh
+++ b/boot/boot-stage-1-init.sh
@@ -158,74 +158,34 @@ mkdir /mnt-root
 echo "mounting the root device.... (fix: sleeping 5 seconds to wait for upcoming usb drivers)"
 sleep 5
 
-if test -n "@autoDetectRootDevice@"; then
+# Hard-coded root device(s).
+mountPoints=(@mountPoints@)
+devices=(@devices@)
+fsTypes=(@fsTypes@)
+optionss=(@optionss@)
 
-    # Look for the root device by label.
-    echo "probing for the NixOS installation CD..."
+for ((n = 0; n < ${#mountPoints[*]}; n++)); do
+    mountPoint=${mountPoints[$n]}
+    device=${devices[$n]}
+    fsType=${fsTypes[$n]}
+    options=${optionss[$n]}
 
-    for i in /sys/block/*; do
-        if test "$(cat $i/removable)" = "1"; then
+    # !!! 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 start with / but doesn't start with /dev
+    # or LABEL= is a bind mount.
+    case $device in
+        /dev/*)
+            ;;
+        /*)
+            device=/mnt-root$device
+            ;;
+    esac
 
-            echo "  in $i..."
+    echo "mounting $device on $mountPoint..."
 
-            set -- $(IFS=: ; echo $(cat $i/dev))
-            major="$1"
-            minor="$2"
-
-            # Create a device node for this device.
-            nuke /dev/tmpdev # don't have `rm' in klibc
-            mknod /dev/tmpdev b "$major" "$minor"
-
-            if mount -o ro -t iso9660 /dev/tmpdev /mnt-root; then
-                if test -e "/mnt-root/@rootLabel@"; then
-                    found=1
-                    break
-                fi
-                umount /mnt-root
-            fi
-        
-        fi
-    done
-
-    if test -z "$found"; then
-        echo "CD not found!"
-        fail
-    fi
-
-else
-
-    # Hard-coded root device(s).
-    mountPoints=(@mountPoints@)
-    devices=(@devices@)
-    fsTypes=(@fsTypes@)
-    optionss=(@optionss@)
-
-    for ((n = 0; n < ${#mountPoints[*]}; n++)); do
-        mountPoint=${mountPoints[$n]}
-        device=${devices[$n]}
-        fsType=${fsTypes[$n]}
-        options=${optionss[$n]}
-
-        # !!! 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 start with / but doesn't
-        # start with /dev or LABEL= is a bind mount.
-        case $device in
-            /dev/*)
-                ;;
-            LABEL=*)
-                ;;
-            /*)
-                device=/mnt-root$device
-                ;;
-        esac
-
-        echo "mounting $device on $mountPoint..."
-
-        mountFS "$device" "$mountPoint" "$options" "$fsType"
-    done
-    
-fi
+    mountFS "$device" "$mountPoint" "$options" "$fsType"
+done
 
 
 # If this is a live-CD/DVD, then union-mount a tmpfs on top of the
diff --git a/boot/boot-stage-1.nix b/boot/boot-stage-1.nix
index 3195ca81a0a..3e707f9e141 100644
--- a/boot/boot-stage-1.nix
+++ b/boot/boot-stage-1.nix
@@ -109,19 +109,17 @@ rec {
     
     inherit modulesClosure udevConf;
     
-    inherit (config.boot) autoDetectRootDevice isLiveCD resumeDevice;
+    inherit (config.boot) isLiveCD resumeDevice;
 
     # !!! copy&pasted from upstart-jobs/filesystems.nix.
     mountPoints =
-      if !config.boot.autoDetectRootDevice && fileSystems == []
+      if fileSystems == []
       then abort "You must specify the fileSystems option!"
       else map (fs: fs.mountPoint) fileSystems;
-    devices = map (fs: if fs ? device then fs.device else "LABEL=" + fs.label) fileSystems;
+    devices = map (fs: if fs ? device then fs.device else "/dev/disk/by-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;
 
-    rootLabel = if config.boot.autoDetectRootDevice then config.boot.rootLabel else "";
-
     path = [
       # `extraUtils' comes first because it overrides the `mount'
       # command provided by klibc (which isn't capable of
diff --git a/configuration/rescue-cd.nix b/configuration/rescue-cd.nix
index 9a28e671989..f3d9822ad83 100644
--- a/configuration/rescue-cd.nix
+++ b/configuration/rescue-cd.nix
@@ -9,14 +9,14 @@
 
 rec {
 
+
+  cdLabel = "NIXOS_INSTALLATION_CD";
+
   
   configuration = {
   
     boot = {
-      autoDetectRootDevice = true;
       isLiveCD = true;
-      # The label used to identify the installation CD.
-      rootLabel = "NIXOS";
       extraTTYs = [7 8]; # manual, rogue
       extraModulePackages = [system.kernelPackages.aufs];
       
@@ -69,6 +69,12 @@ rec {
       };
     };
 
+    fileSystems = [
+      { mountPoint = "/";
+        label = cdLabel;
+      }
+    ];
+
     networking = {
       enableIntel3945ABGFirmware = true;
     };
@@ -277,9 +283,6 @@ rec {
       { source = nixpkgsTarball + "/nixpkgs.tar.bz2";
         target = "/install/nixpkgs.tar.bz2";
       }
-      { source = pkgs.writeText "label" "";
-        target = "/${configuration.boot.rootLabel}";
-      }
     ];
 
     # Closures to be copied to the Nix store on the CD.
@@ -301,7 +304,7 @@ rec {
 
     inherit compressImage;
 
-    volumeID = "NIXOS_INSTALLATION_CD";
+    volumeID = cdLabel;
   };
 
 
diff --git a/system/options.nix b/system/options.nix
index 4df60a5150c..70f7bcb5faf 100644
--- a/system/options.nix
+++ b/system/options.nix
@@ -46,15 +46,6 @@ in
   
   boot = {
 
-    autoDetectRootDevice = mkOption {
-      default = false;
-      description = "
-        Whether to find the root device automatically by searching for a
-        device with the right label.  If this option is off, then a root
-        file system must be specified using <option>fileSystems</option>.
-      ";
-    };
-
     isLiveCD = mkOption {
       default = false;
       description = "
@@ -65,16 +56,6 @@ in
       ";
     };
 
-    rootLabel = mkOption {
-      description = "
-        When auto-detecting the root device (see
-        <option>boot.autoDetectRootDevice</option>), this option
-        specifies the label of the root device.  Right now, this is
-        merely a file name that should exist in the root directory of
-        the file system.  It is used to find the boot CD-ROM.
-      ";
-    };
-
     grubDevice = mkOption {
       default = "";
       example = "/dev/hda";
@@ -588,8 +569,7 @@ in
     ];
     description = "
       The file systems to be mounted.  It must include an entry for
-      the root directory (<literal>mountPoint = \"/\"</literal>) if
-      <literal>boot.autoDetectRootDevice</literal> is not set.  Each
+      the root directory (<literal>mountPoint = \"/\"</literal>).  Each
       entry in the list is an attribute set with the following fields:
       <literal>mountPoint</literal>, <literal>device</literal>,
       <literal>fsType</literal> (a file system type recognised by