btrfs: add test case for qgroup account on shared extents

This is a regression test of
'commit fcebe4562dec ("Btrfs: rework qgroup accounting")',
it's used to verify that removing shared extents can end up incorrect
qgroup accounting.

It can produce qgroup related warnings.

The fix is https://patchwork.kernel.org/patch/5499981/
"Btrfs: fix a warning of qgroup account on shared extents"

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Tested-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/btrfs/017

@@ -0,0 +1,82 @@
+#! /bin/bash
+# FS QA Test No. 017
+#
+# Verify that removing shared extents can end up incorrect qgroup accounting.
+#
+# Regression of 'commit fcebe4562dec ("Btrfs: rework qgroup accounting")',
+# this will throw a warning into dmesg.
+#
+# The issue is fixed by https://patchwork.kernel.org/patch/5499981/
+# "Btrfs: fix a warning of qgroup account on shared extents"
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2014 Liu Bo.  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
+
+# real QA test starts here
+
+_need_to_be_root
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch
+_require_cloner
+
+rm -f $seqres.full
+
+_scratch_mkfs "--nodesize 4096"
+_scratch_mount
+
+$XFS_IO_PROG -f -d -c "pwrite 0 8K" $SCRATCH_MNT/foo | _filter_xfs_io
+
+_run_btrfs_util_prog subvolume snapshot $SCRATCH_MNT $SCRATCH_MNT/snap
+
+$CLONER_PROG -s 0 -d 0 -l 8192 $SCRATCH_MNT/foo $SCRATCH_MNT/foo-reflink
+$CLONER_PROG -s 0 -d 0 -l 8192 $SCRATCH_MNT/foo $SCRATCH_MNT/snap/foo-reflink
+$CLONER_PROG -s 0 -d 0 -l 8192 $SCRATCH_MNT/foo $SCRATCH_MNT/snap/foo-reflink2
+
+_run_btrfs_util_prog quota enable $SCRATCH_MNT
+_run_btrfs_util_prog quota rescan -w $SCRATCH_MNT
+
+rm -fr $SCRATCH_MNT/foo*
+rm -fr $SCRATCH_MNT/snap/foo*
+
+sync
+
+$BTRFS_UTIL_PROG qgroup show $SCRATCH_MNT | $AWK_PROG '/[0-9]/ {print $2" "$3}'
+
+# success, all done
+status=0
+exit

tests/btrfs/017.out

@@ -0,0 +1,5 @@
+QA output created by 017
+wrote 8192/8192 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+4096 4096
+4096 4096

tests/btrfs/group

@@ -19,6 +19,7 @@
 014 auto balance
 015 auto quick snapshot
 016 auto quick send
+017 auto quick qgroup
 018 auto quick subvol
 019 auto quick send
 020 auto quick replace