diff -ru os-prober-1.54/common.sh os-prober-1.54.new/common.sh
--- os-prober-1.54/common.sh	2012-03-28 01:01:05.000000000 +0000
+++ os-prober-1.54.new/common.sh	2012-07-28 13:05:55.428647379 +0000
@@ -1,3 +1,5 @@
+btrfs_subvol=__active
+
 newns () {
   [ "$OS_PROBER_NEWNS" ] || exec /usr/lib/os-prober/newns "$0" "$@"
 }
diff -ru os-prober-1.54/linux-boot-probes/common/50mounted-tests os-prober-1.54.new/linux-boot-probes/common/50mounted-tests
--- os-prober-1.54/linux-boot-probes/common/50mounted-tests	2012-03-28 01:01:05.000000000 +0000
+++ os-prober-1.54.new/linux-boot-probes/common/50mounted-tests	2012-07-28 14:32:12.127361440 +0000
@@ -40,6 +40,21 @@
 	mounted=1
 	type="$(grub-probe -d "$partition" -t fs)"
 	[ "$type" ] || type=fuseblk
+	case "$type" in
+		btrfs|fuse)
+			if [ -x "$tmpmnt/${btrfs_subvol}/lib" ]; then
+				if ! mount --bind "$tmpmnt/${btrfs_subvol}" "$tmpmnt"; then
+					warn "failed to bind mount" "the subvolume:${btrfs_subvol} on $partition"
+					if ! umount $tmpmnt; then
+						warn "failed to" "unmount $tmpmnt"
+					fi
+					mounted=
+				fi
+			fi
+			;;
+		*)
+			;;
+	esac 
 else
 	ro_partition "$partition"
 	for type in $types; do
@@ -64,6 +79,20 @@
 				if ! umount "$tmpmnt"; then
 					warn "failed to umount $tmpmnt"
 				fi
+				case $type in
+					btrfs|fuse)
+						if [ -x "$tmpmnt/${btrfs_subvol}/lib" ]; then
+							# umount to account
+							# for the mount-bind
+							if ! umount $tmpmnt; then
+								warn "failed to " "umount $tmpmnt"
+							fi
+						fi
+						;;
+					*)
+						;;
+				esac
+
 				rmdir "$tmpmnt" || true
 				exit 0
 			fi
diff -ru os-prober-1.54/os-probes/common/50mounted-tests os-prober-1.54.new/os-probes/common/50mounted-tests
--- os-prober-1.54/os-probes/common/50mounted-tests	2012-04-21 01:01:42.000000000 +0000
+++ os-prober-1.54.new/os-probes/common/50mounted-tests	2012-07-28 14:30:30.750595142 +0000
@@ -53,6 +53,21 @@
 	type="$(grub-probe -d "$partition" -t fs)"
 	if [ "$type" ]; then
 		debug "mounted using GRUB $type filesystem driver"
+		case "$type" in
+			btrfs|fuse)
+				if [ -x "$tmpmnt/${btrfs_subvol}/lib" ]; then
+					if ! mount --bind "$tmpmnt/${btrfs_subvol}" "$tmpmnt"; then
+						warn "failed to bind mount" "the subvolume:${btrfs_subvol} on $partition"
+						if ! umount $tmpmnt; then
+							warn "failed to" "unmount $tmpmnt"
+						fi
+						mounted=
+					fi
+				fi
+				;;
+			*)
+				;;
+		esac
 	else
 		debug "mounted using GRUB, but unknown filesystem?"
 		type=fuseblk
@@ -77,6 +92,19 @@
 				if ! umount "$tmpmnt"; then
 					warn "failed to umount $tmpmnt"
 				fi
+				case "$type" in
+					btrfs|fuse)
+						if [ -x "$tmpmnt/${btrfs_subvol}/lib" ]; then
+							# umount to account
+							# for the mount-bind
+							if ! umount $tmpmnt; then
+								warn "failed to " "umount $tmpmnt"
+							fi
+						fi
+						;;
+					*)
+						;;
+				esac
 				rmdir "$tmpmnt" || true
 				exit 0
 			fi