btrfs: make sure scrub fixes raid6 corruption

This is to reproduce a bug of scrub, with which scrub is unable to
repair raid6 corruption as expected.

The kernel side fixes are
  Btrfs: make raid6 rebuild retry more
  Btrfs: fix scrub to repair raid6 corruption

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

3 files changed, 125 insertions, 0 deletions

diff --git a/tests/btrfs/158 b/tests/btrfs/158
new file mode 100755
index 0000000000..3bcc21ee51
--- /dev/null
+++ b/tests/btrfs/158
@@ -0,0 +1,114 @@
+#! /bin/bash
+# FS QA Test 158
+#
+# The test case is check if scrub is able fix raid6 data corruption,
+# ie. if there is data corruption on two disks in the same horizontal
+# stripe, e.g.  due to bitrot.
+#
+# The kernel fixes are
+#	Btrfs: make raid6 rebuild retry more
+#	Btrfs: fix scrub to repair raid6 corruption
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017 Oracle.  All Rights Reserved.
+#
+# 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!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch_dev_pool 4
+_require_btrfs_command inspect-internal dump-tree
+
+get_physical_stripe0()
+{
+	$BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
+	grep " DATA\|RAID6" -A 10 | \
+	$AWK_PROG '($1 ~ /stripe/ && $3 ~ /devid/ && $2 ~ /0/) { print $6 }'
+}
+
+get_physical_stripe1()
+{
+	$BTRFS_UTIL_PROG inspect-internal dump-tree -t 3 $SCRATCH_DEV | \
+	grep " DATA\|RAID6" -A 10 | \
+	$AWK_PROG '($1 ~ /stripe/ && $3 ~ /devid/ && $2 ~ /1/) { print $6 }'
+}
+
+_scratch_dev_pool_get 4
+# step 1: create a raid6 btrfs and create a 4K file
+echo "step 1......mkfs.btrfs" >>$seqres.full
+
+mkfs_opts="-d raid6 -b 1G"
+_scratch_pool_mkfs $mkfs_opts >>$seqres.full 2>&1
+
+# -o nospace_cache makes sure data is written to the start position of the data
+# chunk
+_scratch_mount -o nospace_cache
+
+# [0,64K) is written to stripe 0 and [64K, 128K) is written to stripe 1
+$XFS_IO_PROG -f -d -c "pwrite -S 0xaa 0 128K" -c "fsync" \
+	"$SCRATCH_MNT/foobar" | _filter_xfs_io
+
+_scratch_unmount
+
+stripe_0=`get_physical_stripe0`
+stripe_1=`get_physical_stripe1`
+dev4=`echo $SCRATCH_DEV_POOL | awk '{print $4}'`
+dev3=`echo $SCRATCH_DEV_POOL | awk '{print $3}'`
+
+# step 2: corrupt the 1st and 2nd stripe (stripe 0 and 1)
+echo "step 2......simulate bitrot at offset $stripe_0 of device_4($dev4) and offset $stripe_1 of device_3($dev3)" >>$seqres.full
+
+$XFS_IO_PROG -f -d -c "pwrite -S 0xbb $stripe_0 64K" $dev4 | _filter_xfs_io
+$XFS_IO_PROG -f -d -c "pwrite -S 0xbb $stripe_1 64K" $dev3 | _filter_xfs_io
+
+# step 3: scrub filesystem to repair the bitrot
+echo "step 3......repair the bitrot" >> $seqres.full
+_scratch_mount -o nospace_cache
+
+$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >> $seqres.full 2>&1
+
+od -x $SCRATCH_MNT/foobar
+
+_scratch_dev_pool_put
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/158.out b/tests/btrfs/158.out
new file mode 100644
index 0000000000..1f5ad3f769
--- /dev/null
+++ b/tests/btrfs/158.out
@@ -0,0 +1,10 @@
+QA output created by 158
+wrote 131072/131072 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 9437184
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset 9437184
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+0000000 aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa
+*
+0400000
diff --git a/tests/btrfs/group b/tests/btrfs/group
index 6324c54d76..8007e07e9c 100644
--- a/tests/btrfs/group
+++ b/tests/btrfs/group
@@ -160,3 +160,4 @@
 155 auto quick send
 156 auto quick trim
 157 auto quick raid
+158 auto quick raid scrub