xemu/tests/qemu-iotests/177
Eric Blake 81c219ac6c block: Guarantee that *file is set on bdrv_get_block_status()
We document that *file is valid if the return is not an error and
includes BDRV_BLOCK_OFFSET_VALID, but forgot to obey this contract
when a driver (such as blkdebug) lacks a callback.  Messed up in
commit 67a0fd2 (v2.6), when we added the file parameter.

Enhance qemu-iotest 177 to cover this, using a sequence that would
print garbage or even SEGV, because it was dererefencing through
uninitialized memory.  [The resulting test output shows that we
have less-than-ideal block status from the blkdebug driver, but
that's a separate fix coming up soon.]

Setting *file on all paths that return BDRV_BLOCK_OFFSET_VALID is
enough to fix the crash, but we can go one step further: always
setting *file, even on error, means that a broken caller that
blindly dereferences file without checking for error is now more
likely to get a reliable SEGV instead of randomly acting on garbage,
making it easier to diagnose such buggy callers.  Adding an
assertion that file is set where expected doesn't hurt either.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-07-10 13:18:05 +02:00

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#!/bin/bash
#
# Test corner cases with unusual block geometries
#
# Copyright (C) 2016-2017 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=eblake@redhat.com
seq=`basename $0`
echo "QA output created by $seq"
here=`pwd`
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
_supported_fmt qcow2
_supported_proto file
CLUSTER_SIZE=1M
size=128M
options=driver=blkdebug,image.driver=qcow2
nested_opts=image.file.driver=file,image.file.filename=$TEST_IMG
echo
echo "== setting up files =="
TEST_IMG="$TEST_IMG.base" _make_test_img $size
$QEMU_IO -c "write -P 11 0 $size" "$TEST_IMG.base" | _filter_qemu_io
_make_test_img -b "$TEST_IMG.base"
$QEMU_IO -c "write -P 22 0 $size" "$TEST_IMG" | _filter_qemu_io
# Limited to 64k max-transfer
echo
echo "== constrained alignment and max-transfer =="
limits=align=4k,max-transfer=64k
$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
-c "write -P 33 1000 128k" -c "read -P 33 1000 128k" | _filter_qemu_io
echo
echo "== write zero with constrained max-transfer =="
limits=align=512,max-transfer=64k,opt-write-zero=$CLUSTER_SIZE
$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
-c "write -z 8003584 2093056" | _filter_qemu_io
# non-power-of-2 write-zero/discard alignments
echo
echo "== non-power-of-2 write zeroes limits =="
limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
-c "write -z 32M 32M" | _filter_qemu_io
echo
echo "== non-power-of-2 discard limits =="
limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
-c "discard 80000001 30M" | _filter_qemu_io
echo
echo "== verify image content =="
function verify_io()
{
if ($QEMU_IMG info -f "$IMGFMT" "$TEST_IMG" |
grep "compat: 0.10" > /dev/null); then
# For v2 images, discarded clusters are read from the backing file
discarded=11
else
# Discarded clusters are zeroed for v3 or later
discarded=0
fi
echo read -P 22 0 1000
echo read -P 33 1000 128k
echo read -P 22 132072 7871512
echo read -P 0 8003584 2093056
echo read -P 22 10096640 23457792
echo read -P 0 32M 32M
echo read -P 22 64M 13M
echo read -P $discarded 77M 29M
echo read -P 22 106M 22M
}
verify_io | $QEMU_IO -r "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --image-opts "$options,$nested_opts,align=4k" \
| _filter_qemu_img_map
_check_test_img
# success, all done
echo "*** done"
status=0