2019-03-07 15:58:38 +01:00
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#!/usr/bin/env bash
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2021-01-16 14:44:19 +01:00
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# group: rw auto backing quick
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2016-05-17 18:37:39 +02:00
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#
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2016-06-01 23:10:04 +02:00
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# qcow2 specific bdrv_pwrite_zeroes tests with backing files (complements 034)
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2016-05-17 18:37:39 +02:00
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#
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qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
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# Copyright (C) 2016-2017 Red Hat, Inc.
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2016-05-17 18:37:39 +02:00
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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=kwolf@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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_supported_fmt qcow2
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2020-10-27 20:05:59 +01:00
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_supported_proto file fuse
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2016-05-17 18:37:39 +02:00
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_supported_os Linux
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CLUSTER_SIZE=4k
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qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
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size=$((128 * 1024 * 1024))
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# This test requires zero clusters, added in v3 images
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_unsupported_imgopts compat=0.10
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2016-05-17 18:37:39 +02:00
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echo
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echo == backing file contains zeros ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
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iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Make sure that the whole cluster is allocated even for partial write_zeroes
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# when the backing file contains zeros
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# X = non-zero data sector in backing file
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# - = sector unallocated in whole backing chain
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# 0 = sector touched by write_zeroes request
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# 1. Tail unaligned: 00 00 -- --
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# 2. Head unaligned: -- -- 00 00
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# 3. Both unaligned: -- 00 00 --
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# 4. Both, 2 clusters: -- -- -- 00 | 00 -- -- --
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$QEMU_IO -c "write -z 0 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -z 10k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -z 17k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -z 27k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == backing file contains non-zero data before write_zeroes ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
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iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Single cluster; non-zero data at the cluster start
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# ... | XX -- 00 -- | ...
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$QEMU_IO -c "write -P 0x11 32k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 34k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 32k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 33k 3k" "$TEST_IMG" | _filter_qemu_io
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# Single cluster; non-zero data exists, but not at the cluster start
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# ... | -- XX 00 -- | ...
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$QEMU_IO -c "write -P 0x11 65k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 66k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 65k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 64k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 66k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == backing file contains non-zero data after write_zeroes ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
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iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Single cluster; non-zero data directly after request
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# ... | -- 00 XX -- | ...
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$QEMU_IO -c "write -P 0x11 34k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 33k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 32k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 34k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 35k 1k" "$TEST_IMG" | _filter_qemu_io
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# Single cluster; non-zero data exists, but not directly after request
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# ... | -- 00 -- XX | ...
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$QEMU_IO -c "write -P 0x11 43k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 41k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 43k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 40k 3k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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2016-05-26 05:48:48 +02:00
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echo
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echo == write_zeroes covers non-zero data ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
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iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-26 05:48:48 +02:00
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# non-zero data at front of request
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# Backing file: -- XX -- --
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# Active layer: -- 00 00 --
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$QEMU_IO -c "write -P 0x11 5k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 5k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 4k 4k" "$TEST_IMG" | _filter_qemu_io
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# non-zero data at end of request
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# Backing file: -- -- XX --
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# Active layer: -- 00 00 --
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$QEMU_IO -c "write -P 0x11 14k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 13k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 12k 4k" "$TEST_IMG" | _filter_qemu_io
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# non-zero data matches size of request
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# Backing file: -- XX XX --
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# Active layer: -- 00 00 --
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$QEMU_IO -c "write -P 0x11 21k 2k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 21k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 20k 4k" "$TEST_IMG" | _filter_qemu_io
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# non-zero data smaller than request
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# Backing file: -- -X X- --
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# Active layer: -- 00 00 --
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$QEMU_IO -c "write -P 0x11 30208 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 29k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 28k 4k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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2016-05-17 18:37:39 +02:00
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echo
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echo == spanning two clusters, non-zero before request ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
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iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Two clusters; non-zero data before request:
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# 1. At cluster start: 32k: XX -- -- 00 | 00 -- -- --
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# 2. Between unallocated space: 48k: -- XX -- 00 | 00 -- -- --
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# 3. Directly before request: 64k: -- -- XX 00 | 00 -- -- --
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$QEMU_IO -c "write -P 0x11 32k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 35k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 32k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 33k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -P 0x11 49k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 51k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 48k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 49k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 50k 6k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -P 0x11 66k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 67k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 64k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 66k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 67k 5k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == spanning two clusters, non-zero after request ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Two clusters; non-zero data after request:
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# 1. Directly after request: 32k: -- -- -- 00 | 00 XX -- --
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# 2. Between unallocated space: 48k: -- -- -- 00 | 00 -- XX --
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# 3. At cluster end: 64k: -- -- -- 00 | 00 -- -- XX
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$QEMU_IO -c "write -P 0x11 37k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 35k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 32k 5k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 37k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 38k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -P 0x11 54k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 51k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 48k 6k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 54k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 55k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "write -P 0x11 71k 1k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 67k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 64k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 71k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == spanning two clusters, partially overwriting backing file ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
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_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
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2016-05-17 18:37:39 +02:00
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# Backing file: -- -- XX XX | XX XX -- --
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# Active layer: -- -- XX 00 | 00 XX -- --
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$QEMU_IO -c "write -P 0x11 2k 4k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 3k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 0k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 2k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 3k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 5k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 6k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == spanning multiple clusters, non-zero in first cluster ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
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|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
|
2016-05-17 18:37:39 +02:00
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# Backing file: 64k: XX XX -- -- | -- -- -- -- | -- -- -- --
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# Active layer: 64k: XX XX 00 00 | 00 00 00 00 | 00 -- -- --
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$QEMU_IO -c "write -P 0x11 64k 2k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 64k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 66k 10k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == spanning multiple clusters, non-zero in intermediate cluster ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
|
2016-05-17 18:37:39 +02:00
|
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# Backing file: 64k: -- -- -- -- | -- XX XX -- | -- -- -- --
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# Active layer: 64k: -- -- 00 00 | 00 00 00 00 | 00 -- -- --
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$QEMU_IO -c "write -P 0x11 69k 2k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 64k 12k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
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echo
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echo == spanning multiple clusters, non-zero in final cluster ==
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CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
|
2016-05-17 18:37:39 +02:00
|
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# Backing file: 64k: -- -- -- -- | -- -- -- -- | -- -- XX XX
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# Active layer: 64k: -- -- 00 00 | 00 00 00 00 | 00 -- XX XX
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$QEMU_IO -c "write -P 0x11 74k 2k" "$TEST_IMG.base" | _filter_qemu_io
|
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$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
|
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$QEMU_IO -c "read -P 0 64k 10k" "$TEST_IMG" | _filter_qemu_io
|
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|
$QEMU_IO -c "read -P 0x11 74k 2k" "$TEST_IMG" | _filter_qemu_io
|
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
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|
echo
|
|
|
|
|
echo == spanning multiple clusters, partially overwriting backing file ==
|
|
|
|
|
|
|
|
|
|
CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT
|
2016-05-17 18:37:39 +02:00
|
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|
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# Backing file: 64k: -- XX XX XX | XX XX XX XX | XX XX XX --
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# Active layer: 64k: -- XX 00 00 | 00 00 00 00 | 00 XX XX --
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$QEMU_IO -c "write -P 0x11 65k 10k" "$TEST_IMG.base" | _filter_qemu_io
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$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 64k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 65k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 66k 7k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0x11 73k 2k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c "read -P 0 75k 1k" "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
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|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
echo
|
|
|
|
|
echo == unaligned image tail cluster, no allocation needed ==
|
|
|
|
|
|
|
|
|
|
# With no backing file, write to all or part of unallocated partial cluster
|
|
|
|
|
# will mark the cluster as zero, but does not allocate.
|
|
|
|
|
# Re-create the image each time to get back to unallocated clusters.
|
|
|
|
|
|
|
|
|
|
# Write at the front: sector-wise, the request is: 128m... | 00 -- -- --
|
|
|
|
|
_make_test_img $((size + 2048))
|
|
|
|
|
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at the back: sector-wise, the request is: 128m... | -- -- -- 00
|
|
|
|
|
_make_test_img $((size + 2048))
|
|
|
|
|
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at middle: sector-wise, the request is: 128m... | -- 00 00 --
|
|
|
|
|
_make_test_img $((size + 2048))
|
|
|
|
|
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write entire cluster: sector-wise, the request is: 128m... | 00 00 00 00
|
|
|
|
|
_make_test_img $((size + 2048))
|
|
|
|
|
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Repeat with backing file holding unallocated cluster.
|
|
|
|
|
CLUSTER_SIZE=2048 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))
|
|
|
|
|
|
|
|
|
|
# Write at the front: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | -- --
|
|
|
|
|
# active: 128m... | 00 -- -- --
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at the back: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | -- --
|
|
|
|
|
# active: 128m... | -- -- -- 00
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at middle: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | -- --
|
|
|
|
|
# active: 128m... | -- 00 00 --
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write entire cluster: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | -- --
|
|
|
|
|
# active: 128m... | 00 00 00 00
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Repeat with backing file holding zero'd cluster
|
|
|
|
|
$QEMU_IO -c "write -z $size 512" "$TEST_IMG.base" | _filter_qemu_io
|
|
|
|
|
|
|
|
|
|
# Write at the front: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | 00 00
|
|
|
|
|
# active: 128m... | 00 -- -- --
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at the back: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | 00 00
|
|
|
|
|
# active: 128m... | -- -- -- 00
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write at middle: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | 00 00
|
|
|
|
|
# active: 128m... | -- 00 00 --
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Write entire cluster: sector-wise, the request is:
|
|
|
|
|
# backing: 128m... | 00 00
|
|
|
|
|
# active: 128m... | 00 00 00 00
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# A preallocated cluster maintains its allocation, whether it stays as
|
|
|
|
|
# data due to a partial write:
|
|
|
|
|
# Convert 128m... | XX XX => ... | XX 00
|
|
|
|
|
_make_test_img $((size + 1024))
|
|
|
|
|
$QEMU_IO -c "write -P 1 $((size)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "write -z $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 1 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# or because it is the entire cluster and can use the zero flag:
|
|
|
|
|
# Convert 128m... | XX XX => ... | 00 00
|
|
|
|
|
$QEMU_IO -c "write -z $((size)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "alloc $size 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $size 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
echo
|
|
|
|
|
echo == unaligned image tail cluster, allocation required ==
|
|
|
|
|
|
|
|
|
|
# Write beyond backing file must COW
|
|
|
|
|
# Backing file: 128m... | XX --
|
|
|
|
|
# Active layer: 128m... | -- -- 00 --
|
|
|
|
|
CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -P 1 $((size)) 512" "$TEST_IMG.base" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "write -z $((size + 1024)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 1 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size + 512)) 1536" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
|
|
|
|
# Writes at boundaries of (partial) cluster must not lose mid-cluster data
|
|
|
|
|
# Backing file: 128m: ... | -- XX
|
|
|
|
|
# Active layer: 128m: ... | 00 -- -- 00
|
|
|
|
|
CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))
|
iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.
The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.
iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-06 22:39:52 +02:00
|
|
|
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $((size + 2048))
|
qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes. The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.
However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero. It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).
Update test 154 to cover the new scenarios, using two images of
intentionally differing length.
While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-07 02:05:50 +02:00
|
|
|
$QEMU_IO -c "write -P 1 $((size + 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "write -z $((size)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 1 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size + 1024)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 1 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IO -c "read -P 0 $((size + 1024)) 1024" "$TEST_IMG" | _filter_qemu_io
|
|
|
|
|
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map
|
|
|
|
|
|
2016-05-17 18:37:39 +02:00
|
|
|
# success, all done
|
|
|
|
|
echo "*** done"
|
|
|
|
|
rm -f $seq.full
|
|
|
|
|
status=0
|