#! /bin/bash
# FS QA Test 10
#
# Test delayed allocation with a large number of extents that are merged.
# Regression test for patch "Btrfs: fix delalloc accounting leak caused
# by u32 overflow".
#
#-----------------------------------------------------------------------
# Copyright (c) 2017 Facebook.  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

test_file="$TEST_DIR/$seq"

_cleanup()
{
	cd /
	rm -f $tmp.* "$test_file"
}

. ./common/rc
. ./common/filter

rm -f $seqres.full

_supported_fs btrfs
_supported_os Linux
_require_test

# Create 32k extents. All of these extents will be accounted as outstanding and
# reserved.
for ((i = 0; i < 32 * 1024; i++)); do
	$XFS_IO_PROG -f -c "pwrite $((2 * 4096 * i)) 4096" "$test_file" >>"$seqres.full"
done

# Fill in the gaps between the created extents. The outstanding extents will
# all be merged into 1, but there will still be 32k reserved.
for ((i = 0; i < 32 * 1024; i++)); do
	$XFS_IO_PROG -f -c "pwrite $((2 * 4096 * i + 1)) 4096" "$test_file" >>"$seqres.full"
done

# Flush the delayed allocations.
sync

# Make sure that we didn't leak any metadata space.
uuid="$(findmnt -n -o UUID "$TEST_DIR")"
cd "/sys/fs/btrfs/$uuid/allocation"
echo "$(($(cat metadata/bytes_may_use) - $(cat global_rsv_reserved))) bytes leaked" | grep -v '^0 '

echo "Silence is golden"

status=0
exit