ZoL additions and modifications:

* Get first line of grub-probe only (to avoid multiple lines fead to mkmapfs).
* Only copy the zpool.cache file if it exists.
* STDERR from lvdisplay in pipe to grep.
* Grub needs a device.map to be able to find a filesystem on a partition which is part of a ZFS pool

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>

debian/changelog

@@ -1,3 +1,9 @@
+grub-installer (1.101.ZOL1) unstable; urgency=medium
+
+  * If finding multiple [br]ootfs, only use the first one.
+
+ -- Turbo Fredriksson <turbo@bayour.com>  Tue, 11 Nov 2014 16:07:06 +0100
+
 grub-installer (1.101) unstable; urgency=medium
 
   [ Steve McIntyre ]

grub-installer

@@ -155,7 +155,7 @@ update_grub () {
 }
 
 findfs () {
-	if ! grub_probe -t device $1; then
+	if ! grub_probe -t device $1 | head -n1; then
 		mount | grep "on $ROOT${1%/} " | tail -n1 | cut -d' ' -f1
 	fi
 }
@@ -296,7 +296,7 @@ elif type multipath >/dev/null 2>&1; then
 		$chroot $ROOT dmsetup mknodes
 	fi
 elif type lvdisplay >/dev/null 2>&1 && \
-     (lvdisplay "$disc_offered" | grep -q 'LV Name' 2>/dev/null || \
+     (lvdisplay "$disc_offered" 2>&1 | grep -q 'LV Name' 2>/dev/null || \
       [ -e "$(dirname "$disc_offered")/control" ]); then
 	# Don't set frdev/frdisk here, otherwise you'll end up in different
 	# code paths below ...
@@ -911,6 +911,11 @@ make_active_partition () {
 			bootdev_split="$(split_device "$bootdev")"
 			bootdisk="${bootdev_split%% *}"
 			bootpart="${bootdev_split#* }"
+			if [ "$bootfstype" = "zfs" ] || [ "$rootfstype" = "zfs" ] ; then
+			    # Grub needs a device.map to be able to find a filesystem
+			    # on a partition which is part of a ZFS pool
+			    make_device_map "$bootdev"
+			fi
 			;;
 		\([hf]d[0-9]*\))
 			make_device_map "$bootdev"
@@ -981,7 +986,8 @@ db_progress INFO grub-installer/progress/step_config_loader
 if [ "$bootfstype" = "zfs" ] || [ "$rootfstype" = "zfs" ] ; then
 	# Required by update-grub on ZFS
 	mkdir -p $ROOT/boot/zfs
-	cp /boot/zfs/zpool.cache $ROOT/boot/zfs/
+	[ -f /boot/zfs/zpool.cache ] && \
+	    cp /boot/zfs/zpool.cache $ROOT/boot/zfs/
 fi
 
 # Delete for idempotency