scripts: do not use stat to discover fs type in systemd-autofs-restart.sh

Unfortunatelly, autofs doesn't allow to discover it's type. At least without
accessing master process. That means, that stat can be used to determine
whether some other file system is mounted on top of autofs (which we need to
take a decision whether to move restore fs aside or not), because it simply
stuck.
This patch does fs type discovering by parsing CTs mountinfo.
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

scripts/systemd-autofs-restart.sh

@@ -56,7 +56,25 @@ function check_fs_type {
 	local mountpoint=$1
 	local fs_type=$2
 
-	[  "$($JOIN_CT stat -f --printf=%T $mountpoint)" = "$fs_type" ]
+	local top_mount_id=""
+	local top_mount_fs_type=""
+
+	while IFS='' read -r line || [[ -n "$line" ]]; do
+		# Skip those entries which do not match the mountpoint
+		[ $(echo $line | awk '{print $5;}') = $mountpoint ] || continue
+
+		local mnt_id=$(echo $line | awk '{print $1;}')
+		local mnt_parent_id=$(echo $line | awk '{print $2;}')
+		local mnt_fs_type=$(echo $line | awk '{print $9;}')
+
+		# Skip mount entry, if not the first one and not a child
+		[ -n "$top_mount_id" ] && [ "$mnt_parent_id" != "$top_mount_id" ] && continue
+
+		top_mount_id=$mnt_id
+		top_mount_fs_type=$mnt_fs_type
+	done < "/proc/$CRTOOLS_INIT_PID/mountinfo"
+
+	[ $top_mount_fs_type = $fs_type ]
 }
 
 function bind_mount {