qemu/tests/qemu-iotests/250

#!/usr/bin/env bash
# group: rw quick
#
# Test big discard in qcow2 shrink
#
# Copyright (c) 2019 Virtuozzo International GmbH. 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; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
#

# creator
owner=vsementsov@virtuozzo.com

seq=`basename $0`
echo "QA output created by $seq"

status=1	# failure is the default!

_cleanup()
{
    _cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15

# get standard environment, filters and checks
. ./common.rc
. ./common.filter

_supported_fmt qcow2
_supported_proto file fuse
_supported_os Linux
# This test does not make much sense with external data files
_unsupported_imgopts data_file

# This test checks that qcow2_process_discards does not truncate a discard
# request > 2G.
# To reproduce bug we need to overflow int by one sequential discard, so we
# need size > 2G, bigger cluster size (as with default 64k we may have maximum
# of 512M sequential data, corresponding to one L1 entry), and we need some
# data of the beginning of the disk mapped to the end of file to prevent
# bdrv_co_truncate(bs->file) call in qcow2_co_truncate(), which might succeed
# anyway.

disk_usage()
{
    du --block-size=1 $1 | awk '{print $1}'
}

size=2100M

_make_test_img -o "cluster_size=1M,preallocation=metadata" $size
$QEMU_IO -c 'discard 0 10M' -c 'discard 2090M 10M' \
         -c 'write 2090M 10M' -c 'write 0 10M' "$TEST_IMG" | _filter_qemu_io

# Check that our trick with swapping first and last 10M chunks succeeded.
# Otherwise test may pass even if bdrv_pdiscard() fails in
# qcow2_process_discards()
$QEMU_IMG map "$TEST_IMG" | _filter_testdir

before=$(disk_usage "$TEST_IMG")
$QEMU_IMG resize --shrink "$TEST_IMG" 5M
after=$(disk_usage "$TEST_IMG")

echo "Disk usage delta: $((before - after))"

# success, all done
echo "*** done"
rm -f $seq.full
status=0