Bug#378332: Update-initramfs: suggested patch to make scripts/local-top/lvm understand "/dev/vg/lv"

[Struan Bartlett <struan.bartlett@NewsNow.co.uk>]

The following patch is employed at our company to enable the use of 
/dev/vg/lv syntax in the root argument on the kernel command line. It 
simply adds an extra case check, for the alternative syntax. I realise 
that /dev/vg/lv is a symlink and not the 'real' root device node. But 
given the symlink is widely deployed in fstab - after all why else does 
dm-mapper create this convenient symlink? - I don't suppose it does any 
harm to make this an option on the kernel command line too.

# diff -ubw initramfs-tools/scripts/local-top/lvm 
initramfs-tools.new/scripts/local-top/lvm
--- initramfs-tools/scripts/local-top/lvm       2007-04-13 
12:17:29.000000000 +0100
+++ initramfs-tools.new/scripts/local-top/lvm   2009-02-17 
17:23:29.000000000 +0000
@@ -37,11 +37,9 @@
               ;;
       esac

-       # Make sure that we have a d-m path
+       # See if we have a /dev/mapper/vg-lv path
       vg=${vg#/dev/mapper/}
-       if [ "$vg" = "$1" ]; then
-               return 1
-       fi
+       if [ "$vg" != "$1" ]; then

       # Make sure that the device includes at least one dash
       if [ "$(echo -n "$vg" | tr -d -)" = "$vg" ]; then
@@ -54,6 +52,21 @@
       vg=$(echo ${vg} | sed -e 's#--#-#g')

       vgchange -ay ${vg}
+               return 0
+       fi
+
+       # See if we have a /dev/vg/lv path
+       vg=${1#/dev/}
+       if [ "$vg" != "$1" ]; then
+
+               # Split volume group from logical volume.
+               vg=$(echo ${vg} | sed -e 's#\(.*\)\([^/]\)/[^/].*#\1\2#')
+
+               vgchange -ay ${vg}
+               return 0
+       fi
+
+       return 1
}

if [ -e /scripts/local-top/lvm2 ]; then