Bug#513504: flash-kernel should handle LVM roots better

[Martin Michlmayr <tbm@cyrius.com>]

* Paul Jakma <paul+debianbugs@jakma.org> [2009-01-29 17:45]:
> A workaround, according to tbm, would be to have flash-kernel
> canonicalise LVM devices to their /dev/mapper/... form - I gather.

It's not a workaround; it's the proper solution.

maks, can you comment on this patch.  I've attached the full hook for
context.  Maybe you'll find other cases that need to be handled in a
special way.

Index: initramfs-tools/hooks/flash_kernel_set_root
===================================================================
--- initramfs-tools/hooks/flash_kernel_set_root	(revision 56152)
+++ initramfs-tools/hooks/flash_kernel_set_root	(working copy)
@@ -43,6 +43,13 @@
 # Record the root filesystem device for use during boot
 rootdev=$(egrep '^[^# 	]+[ 	]+/[ 	]' /etc/fstab | awk '{print $1}') || true
 
+# Map LVM devices in the form of /dev/vg/lv to /dev/mapper/, otherwise
+# initramfs won't initialize them.
+link=$(readlink -f $rootdev)
+if echo "$link" | grep -q "^/dev/mapper/"; then
+	rootdev=$link
+fi
+
 # Translate LABEL and UUID entries into a proper device name.
 if echo "$rootdev" | grep -q "="; then
 	a=$(echo "$rootdev" | cut -d "=" -f 1)

-- 
Martin Michlmayr
http://www.cyrius.com/

#!/bin/sh

# This code is covered by the GNU General Public License (GPLv2 or higher)

PREREQ=""

prereqs() {
	echo "$PREREQ"
}

pause_error() {
	#exit 1 # won't work; initramfs-tools ignores hook script exit code
	echo "" >&2
	if [ "$DEBIAN_FRONTEND" = "noninteractive" ] ; then
		echo "Unable to abort; system will probably be broken!" >&2
	else
		echo "Press Ctrl-C to abort build, or Enter to continue" >&2
		read
	fi
}

case $1 in
prereqs)
	prereqs
	exit 0
	;;
esac

. /usr/share/initramfs-tools/hook-functions

# Only run on some machines
machine=$(grep "^Hardware" /proc/cpuinfo | sed 's/Hardware\s*:\s*//')
case "$machine" in
	"Buffalo Linkstation Pro/Live" | "Buffalo/Revogear Kurobox Pro" | "D-Link DNS-323" | "GLAN Tank" | "HP Media Vault mv2120" | "Linksys NSLU2" | "QNAP TS-109/TS-209" | "QNAP TS-409" | "Thecus N2100")
		# Pass the check and continue below
	;;
	*)
		# If the machine is not listed, don't run this hook
		exit 0
	;;
esac

# Record the root filesystem device for use during boot
rootdev=$(egrep '^[^# 	]+[ 	]+/[ 	]' /etc/fstab | awk '{print $1}') || true

# Map LVM devices in the form of /dev/vg/lv to /dev/mapper/, otherwise
# initramfs won't initialize them.
link=$(readlink -f $rootdev)
if echo "$link" | grep -q "^/dev/mapper/"; then
	rootdev=$link
fi

# Translate LABEL and UUID entries into a proper device name.
if echo "$rootdev" | grep -q "="; then
	a=$(echo "$rootdev" | cut -d "=" -f 1)
	b=$(echo "$rootdev" | cut -d "=" -f 2- | sed -e 's/^"\(.*\)"$/\1/')
	case "$a" in
		LABEL)
			c=$(echo "$b" | sed 's#/#\\x2f#g')
			if [ -e /dev/disk/by-label/$c ]; then
				rootdev="/dev/disk/by-label/$c"
			else
				echo "Label $b not found in /dev/disk/by-label" >&2
			fi
		;;
		UUID)
			rootdev=/dev/disk/by-uuid/$b
			if [ ! -e $rootdev ]; then
				echo "UUID $b doesn't exist in /dev/disk/by-uuid" >&2
			fi
		;;
		*)
			echo "/etc/fstab parse error; cannot recognize root $rootdev" >&2
		;;
	esac
fi

if [ ! -e "$rootdev" ]; then
	rootdev=/dev/sda2
	echo "Warning: /etc/fstab parse error; guessing that the root device is $rootdev" >&2
	pause_error
fi
case "$machine" in
	# The boot loader doesn't pass root= on the command line, so
	# provide a default.
	"Linksys NSLU2")
		install -d $DESTDIR/conf/conf.d
		echo "ROOT=\"$rootdev\"" > $DESTDIR/conf/conf.d/default_root
	;;
	# The boot loader passes a bogus root= (e.g. root=/dev/ram), so
	# override the command line parameter.
	"Buffalo Linkstation Pro/Live" | "Buffalo/Revogear Kurobox Pro" | "D-Link DNS-323" | "GLAN Tank" | "HP Media Vault mv2120" | "QNAP TS-109/TS-209" | "QNAP TS-409" | "Thecus N2100")
		install -d $DESTDIR/conf
		echo "ROOT=\"$rootdev\"" >> $DESTDIR/conf/param.conf
	;;
	# This shouldn't happen - only if a device from the case statement
	# above wasn't added here.
	*)
		echo "Device $machine not supported.  Please file a bug." >&2
		pause_error
	;;
esac