btrfs: test direct IO write against raid5/6 filesystems

Test that a direct IO write works against raid5/6 filesystems and that
after the write operation we are able to read back the correct data
and scrub operations don't find any errors.

This test is motivated by a regression introduced in the merge window
for the 4.13 linux kernel, which was undetected by the current set of
test cases. The issue is fixed by the following patch:

  "Btrfs: fix write corruption due to bio cloning on raid5/6"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/btrfs/148

@@ -0,0 +1,86 @@
+#! /bin/bash
+# FS QA Test No. btrfs/148
+#
+# Test that direct IO writes work on RAID5 and RAID6 filesystems.
+#
+#-----------------------------------------------------------------------
+#
+# Copyright (C) 2017 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"
+
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch
+_require_scratch_dev_pool 4
+_require_odirect
+
+_scratch_dev_pool_get 4
+
+rm -f $seqres.full
+
+test_direct_io_write()
+{
+	local mkfs_options=$1
+
+	_scratch_pool_mkfs $mkfs_options >>$seqres.full 2>&1
+	_scratch_mount
+
+	$XFS_IO_PROG -f -d -c "pwrite -S 0xab 0 1M" $SCRATCH_MNT/foo \
+		| _filter_xfs_io
+
+	# Now read back the same data, we expect to get what we wrote before.
+	echo "File data after direct IO write:"
+	od -t x1 $SCRATCH_MNT/foo | _filter_scratch
+	_scratch_cycle_mount
+	echo "File data after umounting and mounting again the filesystem:"
+	od -t x1 $SCRATCH_MNT/foo | _filter_scratch
+
+	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
+	if [ $? -ne 0 ]; then
+		echo "Scrub found errors" | tee -a $seqres.full
+	fi
+
+	_scratch_unmount
+}
+
+echo "Testing RAID5..."
+test_direct_io_write "-m raid5 -d raid5"
+echo "Testing RAID6..."
+test_direct_io_write "-m raid6 -d raid6"
+
+status=0
+exit

tests/btrfs/148.out

@@ -0,0 +1,23 @@
+QA output created by 148
+Testing RAID5...
+wrote 1048576/1048576 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+File data after direct IO write:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+4000000
+File data after umounting and mounting again the filesystem:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+4000000
+Testing RAID6...
+wrote 1048576/1048576 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+File data after direct IO write:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+4000000
+File data after umounting and mounting again the filesystem:
+0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
+*
+4000000

tests/btrfs/group

@@ -150,3 +150,4 @@
 145 auto quick send
 146 auto quick
 147 auto quick send
+148 auto quick rw