550830f935
This patch removes support for the cow file format. Normally we do not break backwards compatibility but in this case there is no impact and it is the most logical option. Extraordinary claims require extraordinary evidence so I will show why removing the cow block driver is the right thing to do. The cow file format is the disk image format for Usermode Linux, a way of running a Linux system in userspace. The performance of UML was never great and it was hacky, but it enjoyed some popularity before hardware virtualization support became mainstream. QEMU's block/cow.c is supposed to read this image file format. Unfortunately the file format was underspecified: 1. Earlier Linux versions used the MAXPATHLEN constant for the backing filename field. The value of MAXPATHLEN can change, so Linux switched to a 4096 literal but QEMU has a 1024 literal. 2. Padding was not used on the header struct (both in the Linux kernel and in QEMU) so the struct layout varied across architectures. In particular, i386 and x86_64 were different due to int64_t alignment differences. Linux now uses __attribute__((packed)), QEMU does not. Therefore: 1. QEMU cow images do not conform to the Linux cow image file format. 2. cow images cannot be shared between different host architectures. This means QEMU cow images are useless and QEMU has not had bug reports from users actually hitting these issues. Let's get rid of this thing, it serves no purpose and no one will be affected. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: 1410877464-20481-1-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
117 lines
3.2 KiB
Bash
Executable File
117 lines
3.2 KiB
Bash
Executable File
#!/bin/bash
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#
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# Test valid filenames for blkdebug and blkverify representatively for
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# other protocols (such as NBD) when queried
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#
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# Copyright (C) 2014 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=mreitz@redhat.com
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seq="$(basename $0)"
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echo "QA output created by $seq"
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here="$PWD"
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tmp=/tmp/$$
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status=1 # failure is the default!
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_cleanup()
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{
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_cleanup_test_img
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# get standard environment, filters and checks
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. ./common.rc
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. ./common.filter
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# Basically all formats, but "raw" has issues with _filter_imgfmt regarding the
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# raw comparison image for blkverify; also, all images have to support creation
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_supported_fmt qcow qcow2 qed vdi vhdx vmdk vpc
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_supported_proto file
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_supported_os Linux
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function do_run_qemu()
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{
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$QEMU -nographic -qmp stdio -serial none "$@"
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}
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function run_qemu()
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{
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# Get the "file": "foo" entry ($foo may only contain escaped double quotes,
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# which is how we can extract it)
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do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_imgfmt | _filter_qmp \
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| grep "drv0" \
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| sed -e 's/^.*"file": "\(\(\\"\|[^"]\)*\)".*$/\1/' -e 's/\\"/"/g'
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}
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function test_qemu()
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{
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run_qemu -drive "if=none,id=drv0,$1" <<EOF
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{ 'execute': 'qmp_capabilities' }
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{ 'execute': 'query-block' }
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{ 'execute': 'quit' }
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EOF
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}
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IMG_SIZE=128K
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_make_test_img $IMG_SIZE
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$QEMU_IMG create -f raw "$TEST_IMG.compare" $IMG_SIZE \
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| _filter_testdir | _filter_imgfmt
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echo
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echo '=== Testing simple filename for blkverify ==='
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echo
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# This should return simply the filename itself
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test_qemu "file=blkverify:$TEST_IMG.compare:$TEST_IMG"
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echo
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echo '=== Testing filename reconstruction for blkverify ==='
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echo
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# This should return the same filename as above
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test_qemu "file.driver=blkverify,file.raw.filename=$TEST_IMG.compare,file.test.file.filename=$TEST_IMG"
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echo
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echo '=== Testing JSON filename for blkdebug ==='
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echo
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# blkdebug cannot create a configuration file, therefore it is unable to
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# generate a plain filename here; thus this should return a JSON filename
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test_qemu "file.driver=blkdebug,file.image.filename=$TEST_IMG,file.inject-error.0.event=l1_update"
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echo
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echo '=== Testing indirectly enforced JSON filename ==='
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echo
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# Because blkdebug cannot return a plain filename, blkverify is forced to
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# generate a JSON object here as well
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test_qemu "file.driver=blkverify,file.raw.filename=$TEST_IMG.compare,file.test.file.driver=blkdebug,file.test.file.image.filename=$TEST_IMG,file.test.file.inject-error.0.event=l1_update"
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rm -f "$TEST_IMG.compare"
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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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