btrfs: EDQUOTA leaks reserved data space

When btrfs hits EDQUOTA when reserving data space, it will leak
already reserved data space.

This test case will check it by using more restrict enospc_debug
mount option to trigger kernel warning at umount time.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/btrfs/126

@@ -0,0 +1,73 @@
+#! /bin/bash
+# FS QA Test 126
+#
+# Regression test for leaking data space after hitting EDQUOTA
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016 Fujitsu.  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
+
+_scratch_mkfs
+# Use enospc_debug mount option to trigger restrict space info check
+_scratch_mount "-o enospc_debug"
+
+_run_btrfs_util_prog quota enable $SCRATCH_MNT
+_run_btrfs_util_prog quota rescan -w $SCRATCH_MNT
+_run_btrfs_util_prog qgroup limit 512K 0/5 $SCRATCH_MNT
+
+# The amount of written data may change due to different nodesize at mkfs time,
+# so redirect stdout to seqres.full.
+# Also, EDQUOTA is expected, which can't be redirected due to the limitation
+# of _filter_xfs_io, so golden output will include EDQUOTA error message
+_pwrite_byte 0xcdcdcdcd 0 1M $SCRATCH_MNT/test_file | _filter_xfs_io \
+	>> $seqres.full
+
+# Fstests will umount the fs, and at umount time, kernel warning will be
+# triggered
+
+# success, all done
+status=0
+exit

tests/btrfs/126.out

@@ -0,0 +1,2 @@
+QA output created by 126
+pwrite64: Disk quota exceeded

tests/btrfs/group

@@ -128,3 +128,4 @@
 123 auto quick qgroup
 124 auto replace
 125 auto replace
+126 auto quick qgroup