[PATCH] fstests: generic test for fsync after adding xattr to a file

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

This test is motivated by an issue found in btrfs.

It tests that after syncing the filesystem, adding a xattr to a file,
syncing the filesystem again, writing to the file and then doing a fsync
against that file, the xattr still exists after a power failure. That is,
after the fsync log/journal is replayed, the xattr still exists and with
the correct value.

The btrfs issue is fixed by the patch titled:

  "Btrfs: fix fsync xattr loss in the fast fsync path"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 tests/generic/094     | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/094.out |  29 +++++++++++++
 tests/generic/group   |   1 +
 3 files changed, 142 insertions(+)
 create mode 100755 tests/generic/094
 create mode 100644 tests/generic/094.out

diff --git a/tests/generic/094 b/tests/generic/094
new file mode 100755
index 0000000..1c6d113
--- /dev/null
+++ b/tests/generic/094
@@ -0,0 +1,112 @@
+#! /bin/bash
+# FS QA Test No. 094
+#
+# Test that after syncing the filesystem, adding a xattr to a file, syncing
+# the filesystem again, writing to the file and then doing a fsync against that
+# file, the xattr still exists after a power failure. That is, after the fsync
+# log/journal is replayed, the xattr still exists and with the correct value.
+#
+# This test is motivated by a bug found in btrfs.
+#
+#-----------------------------------------------------------------------
+# 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
+
+rm -f $seqres.full
+
+_scratch_mkfs >> $seqres.full 2>&1
+_init_flakey
+_mount_flakey
+
+# Create the test file with some initial data and make sure everything is
+# durably persisted. We do fsync before calling sync to make sure that if the
+# filesystem is btrfs, we get the flag BTRFS_INODE_NEEDS_FULL_SYNC cleared
+# from the btrfs inode - a condition necessary to trigger the issue in btrfs.
+$XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" \
+		-c "fsync" \
+		$SCRATCH_MNT/foo | _filter_xfs_io
+sync
+
+# Add a xattr to our file.
+$SETFATTR_PROG -n user.attr -v somevalue $SCRATCH_MNT/foo
+
+# Sync the filesystem to force a commit of the current btrfs transaction, this
+# is a necessary condition to trigger the bug on btrfs.
+sync
+
+# Now update our file's data and fsync the file.
+# After a successful fsync, if the fsync log/journal is replayed we expect to
+# see the xattr named "user.attr" with a value of "somevalue" (and the updated
+# file data of course). Btrfs used to remove the xattr when it replayed the
+# fsync log/journal.
+$XFS_IO_PROG -c "pwrite -S 0xbb 8K 16K" \
+		-c "fsync" \
+		$SCRATCH_MNT/foo | _filter_xfs_io
+
+echo "File content after fsync and before crash:"
+od -t x1 $SCRATCH_MNT/foo
+
+echo "File xattrs after fsync and before crash:"
+$GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foo | _filter_scratch
+
+# Simulate a crash/power loss.
+_load_flakey_table $FLAKEY_DROP_WRITES
+_unmount_flakey
+
+# Allow writes again and mount. This makes the fs replay its fsync log.
+_load_flakey_table $FLAKEY_ALLOW_WRITES
+_mount_flakey
+
+echo "File content after crash and log replay:"
+od -t x1 $SCRATCH_MNT/foo
+
+echo "File xattrs after crash and log replay:"
+$GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foo | _filter_scratch
+
+status=0
+exit
diff --git a/tests/generic/094.out b/tests/generic/094.out
new file mode 100644
index 0000000..2e5e0fa
--- /dev/null
+++ b/tests/generic/094.out
@@ -0,0 +1,29 @@
+QA output created by 094
+wrote 32768/32768 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 8192
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+File content after fsync and before crash:
+0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
+*
+0020000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
+*
+0060000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
+*
+0100000
+File xattrs after fsync and before crash:
+# file: SCRATCH_MNT/foo
+user.attr="somevalue"
+
+File content after crash and log replay:
+0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
+*
+0020000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
+*
+0060000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
+*
+0100000
+File xattrs after crash and log replay:
+# file: SCRATCH_MNT/foo
+user.attr="somevalue"
+
diff --git a/tests/generic/group b/tests/generic/group
index ae40fed..18f31a7 100644
--- a/tests/generic/group
+++ b/tests/generic/group
@@ -96,6 +96,7 @@
 091 rw auto quick
 092 auto quick prealloc
 093 attr cap udf auto
+094 metadata auto quick
 097 udf auto
 099 udf auto
 100 udf auto
-- 
2.1.3