generic: test fsync of directory with renamed symlink

Test that if we fsync a directory, create a symlink inside it, rename
the symlink, fsync again the directory and then power fail, after the
filesystem is mounted again, the symlink exists with the new name and
it has the correct content.

This currently fails on btrfs, because the symlink ends up empty (which
is illegal on Linux), but it is fixed by kernel commit:

    d0e64a981fd841 ("btrfs: always log symlinks in full mode")

Reviewed-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

diff --git a/tests/generic/690 b/tests/generic/690
new file mode 100755 (executable)
index 0000000..f03295a
--- /dev/null
+++ b/tests/generic/690
@@ -0,0 +1,90 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 SUSE Linux Products GmbH.  All Rights Reserved.
+#
+# FS QA Test 690
+#
+# Test that if we fsync a directory, create a symlink inside it, rename the
+# symlink, fsync again the directory and then power fail, after the filesystem
+# is mounted again, the symlink exists with the new name and it has the correct
+# content.
+#
+# On btrfs this used to result in the symlink being empty (i_size 0), and it was
+# fixed by kernel commit:
+#
+#    d0e64a981fd841 ("btrfs: always log symlinks in full mode")
+#
+. ./common/preamble
+_begin_fstest auto quick log
+
+_cleanup()
+{
+       _cleanup_flakey
+       cd /
+       rm -r -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# real QA test starts here
+
+_supported_fs generic
+_require_scratch
+_require_symlinks
+_require_dm_target flakey
+
+rm -f $seqres.full
+
+# f2fs doesn't support fs-op level transaction functionality, so it has no way
+# to persist all metadata updates in one transaction. We have to use its mount
+# option "fastboot" so that it triggers a metadata checkpoint to persist all
+# metadata updates that happen before a fsync call. Without this, after the
+# last fsync in the test, the symlink named "baz" will not exist.
+if [ $FSTYP = "f2fs" ]; then
+       export MOUNT_OPTIONS="-o fastboot $MOUNT_OPTIONS"
+fi
+
+_scratch_mkfs >>$seqres.full 2>&1
+_require_metadata_journaling $SCRATCH_DEV
+_init_flakey
+_mount_flakey
+
+# Create our test directory.
+mkdir "$SCRATCH_MNT"/testdir
+
+# Commit the current transaction and persist the directory.
+sync
+
+# Create a file in the test directory, so that the next fsync on the directory
+# actually does something (it logs the directory).
+echo -n > "$SCRATCH_MNT"/testdir/foo
+
+# Fsync the directory.
+$XFS_IO_PROG -c "fsync" "$SCRATCH_MNT"/testdir
+
+# Now create a symlink inside the test directory.
+ln -s "$SCRATCH_MNT"/testdir/foo "$SCRATCH_MNT"/testdir/bar
+
+# Rename the symlink.
+mv "$SCRATCH_MNT"/testdir/bar "$SCRATCH_MNT"/testdir/baz
+
+# Fsync again the directory.
+$XFS_IO_PROG -c "fsync" "$SCRATCH_MNT"/testdir
+
+# Simulate a power failure and then mount again the filesystem to replay the
+# journal/log.
+_flakey_drop_and_remount
+
+# The symlink should exist, with the name "baz" and its content must be
+# "$SCRATCH_MNT/testdir/foo".
+[ -L "$SCRATCH_MNT"/testdir/baz ] || echo "symlink 'baz' is missing"
+symlink_content=$(readlink "$SCRATCH_MNT"/testdir/baz | _filter_scratch)
+echo "symlink content: ${symlink_content}"
+
+_unmount_flakey
+
+# success, all done
+status=0
+exit

diff --git a/tests/generic/690.out b/tests/generic/690.out
new file mode 100644 (file)
index 0000000..84be124
--- /dev/null
+++ b/tests/generic/690.out
@@ -0,0 +1,2 @@
+QA output created by 690
+symlink content: SCRATCH_MNT/testdir/foo