80f5c01183
A discard request deallocates the selected clusters so they read back as zeroes. This is done by clearing the cluster offset field and setting QCOW_OFLAG_ZERO in the L2 entry. This flag is however only supported when qcow_version >= 3. In older images the cluster is simply deallocated, exposing any possible stale data from the backing file. Since discard is an advisory operation it's safer to simply forbid it in this scenario. Note that we are adding this check to qcow2_co_pdiscard() and not to qcow2_cluster_discard() or discard_in_l2_slice() because the last two are also used by qcow2_snapshot_create() to discard the clusters used by the VM state. In this case there's no risk of exposing stale data to the guest and we really want that the clusters are always discarded. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200331114345.29993-1-berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
118 lines
3.3 KiB
Bash
Executable file
118 lines
3.3 KiB
Bash
Executable file
#!/usr/bin/env bash
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#
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# Test corner cases with unusual block geometries
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#
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# Copyright (C) 2016-2018 Red Hat, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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# creator
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owner=eblake@redhat.com
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seq=`basename $0`
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echo "QA output created by $seq"
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status=1 # failure is the default!
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_cleanup()
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{
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_cleanup_test_img
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# get standard environment, filters and checks
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. ./common.rc
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. ./common.filter
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# This test is runnable under compat=0.10; see test 204 for additional
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# tests specific to compat=1.1.
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_supported_fmt qcow2
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_supported_proto file
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CLUSTER_SIZE=1M
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size=128M
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options=driver=blkdebug,image.driver=qcow2
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echo
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echo "== setting up files =="
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TEST_IMG="$TEST_IMG.base" _make_test_img $size
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$QEMU_IO -c "write -P 11 0 $size" "$TEST_IMG.base" | _filter_qemu_io
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_make_test_img -b "$TEST_IMG.base"
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$QEMU_IO -c "write -P 22 0 $size" "$TEST_IMG" | _filter_qemu_io
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# Limited to 64k max-transfer
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echo
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echo "== constrained alignment and max-transfer =="
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limits=align=4k,max-transfer=64k
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$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
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-c "write -P 33 1000 128k" -c "read -P 33 1000 128k" | _filter_qemu_io
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echo
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echo "== write zero with constrained max-transfer =="
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limits=align=512,max-transfer=64k,opt-write-zero=$CLUSTER_SIZE
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$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
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-c "write -z 8003584 2093056" | _filter_qemu_io
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# non-power-of-2 write-zero/discard alignments
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echo
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echo "== non-power-of-2 write zeroes limits =="
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limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
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$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
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-c "write -z 32M 32M" | _filter_qemu_io
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echo
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echo "== non-power-of-2 discard limits =="
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limits=align=512,opt-write-zero=15M,max-write-zero=15M,opt-discard=15M,max-discard=15M
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$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
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-c "discard 80000001 30M" | _filter_qemu_io
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echo
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echo "== verify image content =="
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verify_io()
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{
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if ($QEMU_IMG info -f "$IMGFMT" "$TEST_IMG" |
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grep "compat: 0.10" > /dev/null); then
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# In v2 images clusters are not discarded when there is a backing file
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# so the previous value is read
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discarded=22
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else
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# Discarded clusters are zeroed for v3 or later
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discarded=0
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fi
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echo read -P 22 0 1000
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echo read -P 33 1000 128k
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echo read -P 22 132072 7871512
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echo read -P 0 8003584 2093056
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echo read -P 22 10096640 23457792
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echo read -P 0 32M 32M
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echo read -P 22 64M 13M
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echo read -P $discarded 77M 29M
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echo read -P 22 106M 22M
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}
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verify_io | $QEMU_IO -r "$TEST_IMG" | _filter_qemu_io
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_check_test_img
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# success, all done
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echo "*** done"
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status=0
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