It's useful to know how much space can be occupied by qcow2 persistent
bitmaps, even though such metadata is unrelated to the guest-visible
data. Report this value as an additional QMP field, present when
measuring an existing image and output format that both support
bitmaps. Update iotest 178 and 190 to updated output, as well as new
coverage in 190 demonstrating non-zero values made possible with the
recently-added qemu-img bitmap command (see 3b51ab4b
).
The new 'bitmaps size:' field is displayed automatically as part of
'qemu-img measure' any time it is present in QMP (that is, any time
both the source image being measured and destination format support
bitmaps, even if the measurement is 0 because there are no bitmaps
present). If the field is absent, it means that no bitmaps can be
copied (source, destination, or both lack bitmaps, including when
measuring based on size rather than on a source image). This behavior
is compatible with an upcoming patch adding 'qemu-img convert
--bitmaps': that command will fail in the same situations where this
patch omits the field.
The addition of a new field demonstrates why we should always
zero-initialize qapi C structs; while the qcow2 driver still fully
populates all fields, the raw and crypto drivers had to be tweaked to
avoid uninitialized data.
Consideration was also given towards having a 'qemu-img measure
--bitmaps' which errors out when bitmaps are not possible, and
otherwise sums the bitmaps into the existing allocation totals rather
than displaying as a separate field, as a potential convenience
factor. But this was ultimately decided to be more complexity than
necessary when the QMP interface was sufficient enough with bitmaps
remaining a separate field.
See also: https://bugzilla.redhat.com/1779904
Reported-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200521192137.1120211-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
101 lines
3.3 KiB
Bash
Executable file
101 lines
3.3 KiB
Bash
Executable file
#!/usr/bin/env bash
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#
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# qemu-img measure sub-command tests on huge qcow2 files
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#
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# Copyright (C) 2017-2020 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 $seq"
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status=1 # failure is the default!
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_cleanup()
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{
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_cleanup_test_img
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_rm_test_img "$TEST_IMG.converted"
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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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. ./common.pattern
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# See 178 for more extensive tests across more formats
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_supported_fmt qcow2
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_supported_proto file
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echo "== Huge file without bitmaps =="
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echo
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_make_test_img -o 'cluster_size=2M' 2T
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$QEMU_IMG measure -O raw -f qcow2 "$TEST_IMG"
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$QEMU_IMG measure -O qcow2 -o cluster_size=64k -f qcow2 "$TEST_IMG"
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$QEMU_IMG measure -O qcow2 -o cluster_size=2M -f qcow2 "$TEST_IMG"
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echo
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echo "== Huge file with bitmaps =="
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echo
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$QEMU_IMG bitmap --add --granularity 512 -f qcow2 "$TEST_IMG" b1
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$QEMU_IMG bitmap --add -g 2M -f qcow2 "$TEST_IMG" b2
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# No bitmap without a source
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$QEMU_IMG measure -O qcow2 --size 10M
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# No bitmap output, since raw does not support it
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$QEMU_IMG measure -O raw -f qcow2 "$TEST_IMG"
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# No bitmap output, since no bitmaps on raw source. Munge required size, as
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# some filesystems store the qcow2 file with less sparseness than others
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$QEMU_IMG measure -O qcow2 -f raw "$TEST_IMG" |
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sed '/^required size:/ s/[0-9][0-9]*/SIZE/'
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# No bitmap output, since v2 does not support it
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$QEMU_IMG measure -O qcow2 -o compat=0.10 -f qcow2 "$TEST_IMG"
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# Compute expected output: bitmap clusters + bitmap tables + bitmaps directory
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echo
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val2T=$((2*1024*1024*1024*1024))
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cluster=$((64*1024))
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b1clusters=$(( (val2T/512/8 + cluster - 1) / cluster ))
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b2clusters=$(( (val2T/2/1024/1024/8 + cluster - 1) / cluster ))
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echo expected bitmap $((b1clusters * cluster +
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(b1clusters * 8 + cluster - 1) / cluster * cluster +
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b2clusters * cluster +
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(b2clusters * 8 + cluster - 1) / cluster * cluster +
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cluster))
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$QEMU_IMG measure -O qcow2 -o cluster_size=64k -f qcow2 "$TEST_IMG"
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# Compute expected output: bitmap clusters + bitmap tables + bitmaps directory
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echo
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cluster=$((2*1024*1024))
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b1clusters=$(( (val2T/512/8 + cluster - 1) / cluster ))
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b2clusters=$(( (val2T/2/1024/1024/8 + cluster - 1) / cluster ))
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echo expected bitmap $((b1clusters * cluster +
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(b1clusters * 8 + cluster - 1) / cluster * cluster +
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b2clusters * cluster +
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(b2clusters * 8 + cluster - 1) / cluster * cluster +
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cluster))
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$QEMU_IMG measure --output=json -O qcow2 -o cluster_size=2M -f qcow2 "$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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