generic: test fsync of directory with renamed symlink

Commit Message

Filipe Manana April 21, 2022, 9:57 a.m. UTC

From: Filipe Manana <[e-mail]>

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 a patch that has the subject:

    "btrfs: always log symlinks in full mode"

Signed-off-by: Filipe Manana <[e-mail]>
---
 tests/generic/683     | 89 +++++++++++++++++++++++++++++++++++++++++++
 tests/generic/683.out |  2 +
 2 files changed, 91 insertions(+)
 create mode 100755 tests/generic/683
 create mode 100644 tests/generic/683.out

Patch

diff --git a/tests/generic/683 b/tests/generic/683
new file mode 100755
index 00000000..b9a955a3
--- /dev/null
+++ b/tests/generic/683
@@ -0,0 +1,89 @@ 
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 SUSE Linux Products GmbH.  All Rights Reserved.
+#
+# FS QA Test 683
+#
+# 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 a patch with the subject:
+#
+#    "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"
+echo "symlink content: $(readlink $SCRATCH_MNT/testdir/baz | _filter_scratch)"
+
+_unmount_flakey
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/683.out b/tests/generic/683.out
new file mode 100644
index 00000000..1167be40
--- /dev/null
+++ b/tests/generic/683.out
@@ -0,0 +1,2 @@ 
+QA output created by 683
+symlink content: SCRATCH_MNT/testdir/foo