[PATCH v2] generic/707: Test moving directory while being grown

[Jan Kara <jack@suse.cz>]

Test how the filesystem can handle moving a directory to a different
directory (so that parent pointer gets updated) while it is grown. Ext4
and UDF had a bug where if the directory got converted to a different
type due to growth while rename is running, the filesystem got
corrupted.

Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 tests/generic/707     | 63 +++++++++++++++++++++++++++++++++++++++++++
 tests/generic/707.out |  2 ++
 2 files changed, 65 insertions(+)
 create mode 100755 tests/generic/707
 create mode 100644 tests/generic/707.out

Changes since v1:
* Added TIME_FACTOR multiplier
* Handle background process in _cleanup
* Use absolute paths where possible

diff --git a/tests/generic/707 b/tests/generic/707
new file mode 100755
index 000000000000..d1d299563813
--- /dev/null
+++ b/tests/generic/707
@@ -0,0 +1,63 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 Jan Kara, SUSE Linux.  All Rights Reserved.
+#
+# FS QA Test 707
+#
+# This is a test verifying whether the filesystem can gracefully handle
+# modifying of a directory while it is being moved, in particular the cases
+# where directory format changes
+# 
+. ./common/preamble
+_begin_fstest auto
+
+_supported_fs generic
+_require_scratch
+
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+_cleanup()
+{
+	if [ -n "$BGPID" ]; then
+		# Stop background process
+		kill -9 $BGPID &>/dev/null
+		wait
+	fi
+}
+
+# Loop multiple times trying to hit the race
+loops=$((100*TIME_FACTOR))
+files=500
+moves=500
+
+create_files()
+{
+	# We use slightly longer file name to make directory grow faster and
+	# hopefully convert between various types
+	for (( i = 0; i < $files; i++ )); do
+		touch somewhatlongerfilename$i
+	done
+}
+
+for (( i = 0; i <= $moves; i++ )); do
+	mkdir $SCRATCH_MNT/dir$i
+done
+
+for (( l = 0; l < $loops; l++ )); do
+	mkdir $SCRATCH_MNT/dir0/dir
+	pushd $SCRATCH_MNT/dir0/dir &>/dev/null
+	create_files &
+	BGPID=$!
+	popd &>/dev/null
+	for (( i = 0; i < $moves; i++ )); do
+		mv $SCRATCH_MNT/dir$i/dir $SCRATCH_MNT/dir$((i+1))/dir
+	done
+	wait
+	BGPID=""
+	rm -r $SCRATCH_MNT/dir$moves/dir
+done
+
+echo "Silence is golden"
+status=0
+exit
diff --git a/tests/generic/707.out b/tests/generic/707.out
new file mode 100644
index 000000000000..8e57a1d8c971
--- /dev/null
+++ b/tests/generic/707.out
@@ -0,0 +1,2 @@
+QA output created by 707
+Silence is golden
-- 
2.35.3