tests/qemu-iotests/138

#!/bin/bash
#
# General test case for qcow2's image check
#
# Copyright (C) 2015 Red Hat, Inc.
#
# 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=mreitz@redhat.com

seq="$(basename $0)"
echo "QA output created by $seq"

here="$PWD"
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

# This tests qocw2-specific low-level functionality
_supported_fmt qcow2
_supported_proto file
_supported_os Linux

echo
echo '=== Check on an image with a multiple of 2^32 clusters ==='
echo

IMGOPTS=$(_optstr_add "$IMGOPTS" "cluster_size=512") \
    _make_test_img 512

# Allocate L2 table
$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

# Put the data cluster at a multiple of 2 TB, resulting in the image apparently
# having a multiple of 2^32 clusters
# (To be more specific: It is at 32 PB)
poke_file "$TEST_IMG" 2048 "\x80\x80\x00\x00\x00\x00\x00\x00"

# An offset of 32 PB results in qemu-img check having to allocate an in-memory
# refcount table of 128 TB (16 bit refcounts, 512 byte clusters).
# This should be generally too much for any system and thus fail.
# What this test is checking is that the qcow2 driver actually tries to allocate
# such a large amount of memory (and is consequently aborting) instead of having
# truncated the cluster count somewhere (which would result in much less memory
# being allocated and then a segfault occurring).
_check_test_img

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