generic: test fsync after succession of renames and unlink

Test that after a combination of file renames, linking and creating
a new file with the old name of a renamed file, if we fsync the new
file, after a power failure we are able to mount the filesystem and
all file names correspond to the correct inodes.

This test is motivated by a bug found in btrfs, which is fixed by
applying the following two patches to the linux kernel:

 "[PATCH 1/2] Btrfs: fix fsync after succession of renames of different files"
 "[PATCH 2/2] Btrfs: fix fsync after succession of renames and unlink/rmdir"

The test passes on ext4, xfs and patched btrfs, however at least in
a 5.0-rc5 linux kernel, it fails on f2fs.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/generic/527

@@ -0,0 +1,71 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2018 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FS QA Test No. 527
+#
+# Test that after a combination of file renames, deletions, linking and creating
+# new files with names that were previously deleted, if we fsync the new file,
+# after a power failure we are able to mount the filesystem and all file names
+# correspond to the correct inodes.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	_cleanup_flakey
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_dm_target flakey
+
+rm -f $seqres.full
+
+_scratch_mkfs >>$seqres.full 2>&1
+_require_metadata_journaling $SCRATCH_DEV
+_init_flakey
+_mount_flakey
+
+mkdir $SCRATCH_MNT/testdir
+echo -n "foo" > $SCRATCH_MNT/testdir/fname1
+echo -n "hello" > $SCRATCH_MNT/testdir/fname2
+
+# Make sure everything done so far is durably persisted.
+sync
+
+# Rename, remove and link files such that one new name corresponds to the name
+# of a deleted file and one new file has the old name of the renamed file. Then
+# fsync only the new file.
+mv $SCRATCH_MNT/testdir/fname1 $SCRATCH_MNT/testdir/fname3
+rm -f $SCRATCH_MNT/testdir/fname2
+ln $SCRATCH_MNT/testdir/fname3 $SCRATCH_MNT/testdir/fname2
+echo -n "bar" > $SCRATCH_MNT/testdir/fname1
+$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir/fname1
+
+# Simulate a power failure and mount the filesystem to check that all file names
+# exist and correspond to the correct inodes.
+_flakey_drop_and_remount
+
+echo "File fname1 data after power failure: $(cat $SCRATCH_MNT/testdir/fname1)"
+echo "File fname2 data after power failure: $(cat $SCRATCH_MNT/testdir/fname2)"
+echo "File fname3 data after power failure: $(cat $SCRATCH_MNT/testdir/fname3)"
+
+_unmount_flakey
+
+status=0
+exit

tests/generic/527.out

@@ -0,0 +1,4 @@
+QA output created by 527
+File fname1 data after power failure: bar
+File fname2 data after power failure: foo
+File fname3 data after power failure: foo

tests/generic/group

@@ -529,3 +529,4 @@
 524 auto quick
 525 auto quick rw
 526 auto quick log
+527 auto quick log