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4c2e5f8f46
If lazy refcounts are enabled for a backing file, committing to this backing file may leave it in a dirty state even if the commit succeeds. The reason is that the bdrv_flush() call in bdrv_commit() doesn't flush refcount updates with lazy refcounts enabled, and qcow2_reopen_prepare() doesn't take care to flush metadata. In order to fix this, this patch also fixes qcow2_mark_clean(), which contains another ineffective bdrv_flush() call beause lazy refcounts are disabled only afterwards. All existing callers of qcow2_mark_clean() either don't modify refcounts or already flush manually, so that this fixes only a latent, but not yet actually triggerable bug. Another instance of the same problem is live snapshots. Again, a real corruption is prevented by an explicit flush for non-read-only images in external_snapshot_prepare(), but images using lazy refcounts stay dirty. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
159 lines
4.0 KiB
Bash
Executable File
159 lines
4.0 KiB
Bash
Executable File
#!/bin/bash
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#
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# Test qcow2 lazy refcounts
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#
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# Copyright (C) 2012 Red Hat, Inc.
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# Copyright IBM, Corp. 2010
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#
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# Based on test 038.
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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=stefanha@linux.vnet.ibm.com
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seq=`basename $0`
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echo "QA output created by $seq"
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here=`pwd`
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tmp=/tmp/$$
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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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_supported_fmt qcow2
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_supported_proto file
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_supported_os Linux
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_default_cache_mode "writethrough"
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_supported_cache_modes "writethrough"
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size=128M
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echo
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echo "== Checking that image is clean on shutdown =="
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IMGOPTS="compat=1.1,lazy_refcounts=on"
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_make_test_img $size
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$QEMU_IO -c "write -P 0x5a 0 512" "$TEST_IMG" | _filter_qemu_io
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# The dirty bit must not be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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_check_test_img
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echo
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echo "== Creating a dirty image file =="
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IMGOPTS="compat=1.1,lazy_refcounts=on"
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_make_test_img $size
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old_ulimit=$(ulimit -c)
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ulimit -c 0 # do not produce a core dump on abort(3)
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$QEMU_IO -c "write -P 0x5a 0 512" -c "abort" "$TEST_IMG" | _filter_qemu_io
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ulimit -c "$old_ulimit"
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# The dirty bit must be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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_check_test_img
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echo
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echo "== Read-only access must still work =="
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$QEMU_IO -r -c "read -P 0x5a 0 512" "$TEST_IMG" | _filter_qemu_io
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# The dirty bit must be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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echo
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echo "== Repairing the image file must succeed =="
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_check_test_img -r all
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# The dirty bit must not be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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echo
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echo "== Data should still be accessible after repair =="
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$QEMU_IO -c "read -P 0x5a 0 512" "$TEST_IMG" | _filter_qemu_io
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echo
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echo "== Opening a dirty image read/write should repair it =="
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IMGOPTS="compat=1.1,lazy_refcounts=on"
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_make_test_img $size
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old_ulimit=$(ulimit -c)
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ulimit -c 0 # do not produce a core dump on abort(3)
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$QEMU_IO -c "write -P 0x5a 0 512" -c "abort" "$TEST_IMG" | _filter_qemu_io
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ulimit -c "$old_ulimit"
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# The dirty bit must be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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$QEMU_IO -c "write 0 512" "$TEST_IMG" | _filter_qemu_io
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# The dirty bit must not be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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echo
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echo "== Creating an image file with lazy_refcounts=off =="
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IMGOPTS="compat=1.1,lazy_refcounts=off"
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_make_test_img $size
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old_ulimit=$(ulimit -c)
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ulimit -c 0 # do not produce a core dump on abort(3)
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$QEMU_IO -c "write -P 0x5a 0 512" -c "abort" "$TEST_IMG" | _filter_qemu_io
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ulimit -c "$old_ulimit"
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# The dirty bit must not be set since lazy_refcounts=off
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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_check_test_img
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echo
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echo "== Committing to a backing file with lazy_refcounts=on =="
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IMGOPTS="compat=1.1,lazy_refcounts=on"
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TEST_IMG="$TEST_IMG".base _make_test_img $size
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IMGOPTS="compat=1.1,lazy_refcounts=on,backing_file=$TEST_IMG.base"
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_make_test_img $size
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$QEMU_IO -c "write 0 512" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG commit "$TEST_IMG"
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# The dirty bit must not be set
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./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
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./qcow2.py "$TEST_IMG".base dump-header | grep incompatible_features
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_check_test_img
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TEST_IMG="$TEST_IMG".base _check_test_img
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# success, all done
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echo "*** done"
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rm -f $seq.full
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status=0
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