[PATCH v3 1/9] fstests: add _loop_image_create_clone() helper

[Anand Jain <asj@kernel.org>]

Introduce _loop_image_create_clone() and _loop_image_destroy() to mkfs an
image file and clone it to another image file, and attach a loop device to
them. And its destroy part.

Signed-off-by: Anand Jain <asj@kernel.org>
---
 common/rc | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/common/rc b/common/rc
index 9632b211b58f..0e7b7eb1d98f 100644
--- a/common/rc
+++ b/common/rc
@@ -1503,6 +1503,50 @@ _scratch_resvblks()
 	esac
 }
 
+_loop_image_create_clone()
+{
+	local -n _ret=$1
+	local pre_clone_tune_func=$2
+	local img_file=$TEST_DIR/${seq}.img
+	local img_file_clone=$TEST_DIR/${seq}_clone.img
+	local size=$(_small_fs_size_mb 128) # Smallest possible
+	local loop_devs
+
+	size=$((size * 1024 * 1024))
+	$XFS_IO_PROG -f -c "truncate $size" $img_file
+
+	loop_devs=$(_create_loop_device $img_file)
+	_ret=($loop_devs)
+
+	case $FSTYP in
+	xfs)
+		_mkfs_dev "-s size=4096" $img_file
+		;;
+	btrfs)
+		_mkfs_dev $img_file
+		;;
+	*)
+		_mkfs_dev $img_file
+		;;
+	esac
+
+	($pre_clone_tune_func)
+
+	cp $img_file $img_file_clone
+
+	loop_devs="$loop_devs $(_create_loop_device $img_file_clone)"
+
+	_ret=($loop_devs)
+}
+
+_loop_image_destroy()
+{
+	for d in "$@"; do
+		local f=$(losetup --noheadings --output BACK-FILE $d)
+		_destroy_loop_device "$d"
+		[ -n "$f" ] && rm -f "$f"
+	done
+}
 
 # Repair scratch filesystem.  Returns 0 if the FS is good to go (either no
 # errors found or errors were fixed) and nonzero otherwise; also spits out
-- 
2.43.0