overlay: correct scratch dirs check

Tests that use _overlay_scratch_mount_dirs instead of _scratch_mount
should use _require_scratch_nocheck instead of _require_scratch
because these tests are either mounting with multiple lower dirs or
mounting with non-default lower/upper/work dir, so
_check_overlay_scratch_fs won't handle these cases correctly. So we
introduce _overlay_check_scratch_dirs helper and should call this
helper with the correct dir arguments for these non-default cases.

This patch modify these tests to optionally call
_overlay_check_scratch_dirs at the end of the test or after
_scratch_umount to mount base filesystem only and run the checker.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

common/overlay

@@ -219,6 +219,35 @@ _overlay_check_dirs()
 	return $err
 }
 
+# Check the same mnt/dev of _check_overlay_scratch_fs but non-default
+# underlying scratch dirs of overlayfs, it needs lower/upper/work dirs
+# provided as arguments, and it's useful for non-default setups such
+# as multiple lower layers
+_overlay_check_scratch_dirs()
+{
+	local lowerdir=$1
+	local upperdir=$2
+	local workdir=$3
+	shift 3
+
+	# Need to umount overlay for scratch dir check
+	local ovl_mounted=`_is_dir_mountpoint $SCRATCH_MNT`
+	[ -z "$ovl_mounted" ] || $UMOUNT_PROG $SCRATCH_MNT
+
+	# Check dirs with extra overlay options
+	_overlay_check_dirs $lowerdir $upperdir $workdir $*
+	local ret=$?
+
+	if [ $ret -eq 0 -a -n "$ovl_mounted" ]; then
+		# overlay was mounted, remount with extra mount options
+		_overlay_scratch_mount_dirs $lowerdir $upperdir \
+					    $workdir $*
+		ret=$?
+	fi
+
+	return $ret
+}
+
 _overlay_check_fs()
 {
 	# The first arguments is overlay mount point use for checking