fstests: generic test for fsync after removing xattrs

This test is motivated by an fsync issue discovered in btrfs.
The issue was that the fsync log replay code did not remove xattrs that
were deleted before the inode was fsynced. The result was unexpected
and differed from xfs and ext3/4 for example.

The btrfs issue was fixed by the following linux kernel patch:

   Btrfs: remove deleted xattrs on fsync log replay

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/generic/066

@@ -0,0 +1,121 @@
+#! /bin/bash
+# FS QA Test No. 066
+#
+# This test is motivated by an fsync issue discovered in btrfs.
+# The issue was that the fsync log replay code did not remove xattrs that were
+# deleted before the inode was fsynced. So verify that if we delete a xattr from
+# a file and then fsync the file, after log replay the file does not have that
+# xattr anymore. Also test the case where a file is fsynced, one of its xattrs
+# is removed, a hard link to that file is created and the fsync log is committed
+# by issuing an fsync on another file. This indirect case should also result in
+# not having the xattr anymore after the fsync log is replayed.
+#
+# The btrfs issue was fixed by the following linux kernel patch:
+#
+#  Btrfs: remove deleted xattrs on fsync log replay
+#
+#-----------------------------------------------------------------------
+# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
+# Author: Filipe Manana <fdmanana@suse.com>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_flakey
+	rm -f $tmp.*
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+. ./common/attr
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_need_to_be_root
+_require_scratch
+_require_dm_flakey
+_require_attrs
+_require_metadata_journaling $SCRATCH_DEV
+
+_crash_and_mount()
+{
+	# Simulate a crash/power loss.
+	_load_flakey_table $FLAKEY_DROP_WRITES
+	_unmount_flakey
+	_load_flakey_table $FLAKEY_ALLOW_WRITES
+	_mount_flakey
+}
+
+rm -f $seqres.full
+
+_scratch_mkfs >> $seqres.full 2>&1
+_init_flakey
+_mount_flakey
+
+# Create out test file and add 3 xattrs to it.
+touch $SCRATCH_MNT/foobar
+$SETFATTR_PROG -n user.attr1 -v val1 $SCRATCH_MNT/foobar
+$SETFATTR_PROG -n user.attr2 -v val2 $SCRATCH_MNT/foobar
+$SETFATTR_PROG -n user.attr3 -v val3 $SCRATCH_MNT/foobar
+
+# Make sure everything is durably persisted.
+sync
+
+# Now delete the second xattr and fsync the inode.
+$SETFATTR_PROG -x user.attr2 $SCRATCH_MNT/foobar
+$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar
+
+_crash_and_mount
+
+# After the fsync log is replayed, the file should have only 2 xattrs, the ones
+# named user.attr1 and user.attr3. The btrfs fsync log replay bug left the file
+# with the 3 xattrs that we had before deleting the second one and fsyncing the
+# file.
+echo "xattr names and values after first fsync log replay:"
+$GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foobar | _filter_scratch
+
+# Now write some data to our file, fsync it, remove the first xattr, add a new
+# hard link to our file and commit the fsync log by fsyncing some other new
+# file. This is to verify that after log replay our first xattr does not exist
+# anymore.
+echo "hello world!" >> $SCRATCH_MNT/foobar
+$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar
+$SETFATTR_PROG -x user.attr1 $SCRATCH_MNT/foobar
+ln $SCRATCH_MNT/foobar $SCRATCH_MNT/foobar_link
+touch $SCRATCH_MNT/qwerty
+$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/qwerty
+
+_crash_and_mount
+
+# Now only the xattr with name user.attr3 should be set in our file.
+echo "xattr names and values after second fsync log replay:"
+$GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foobar | _filter_scratch
+
+status=0
+exit

tests/generic/066.out

@@ -0,0 +1,10 @@
+QA output created by 066
+xattr names and values after first fsync log replay:
+# file: SCRATCH_MNT/foobar
+user.attr1="val1"
+user.attr3="val3"
+
+xattr names and values after second fsync log replay:
+# file: SCRATCH_MNT/foobar
+user.attr3="val3"
+

tests/generic/group

@@ -68,6 +68,7 @@
 063 auto quick prealloc
 064 auto quick prealloc
 065 metadata auto quick
+066 metadata auto quick
 068 other auto freeze dangerous stress
 069 rw udf auto quick
 070 attr udf auto quick stress