3be2024aef
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20191107163708.833192-22-mreitz@redhat.com [mreitz: Also disable 273] Signed-off-by: Max Reitz <mreitz@redhat.com>
124 lines
4.2 KiB
Bash
Executable File
124 lines
4.2 KiB
Bash
Executable File
#!/usr/bin/env bash
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#
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# Test cases for qcow2 refcount table growth
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#
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# Copyright (C) 2015 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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status=1 # failure is the default!
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_cleanup()
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{
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_cleanup_test_img
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# get standard environment, filters and checks
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. ./common.rc
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. ./common.filter
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_supported_fmt qcow2
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_supported_proto file
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_supported_os Linux
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# Refcount structures are used much differently with external data
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# files
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_unsupported_imgopts data_file
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echo
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echo '=== New refcount structures may not conflict with existing structures ==='
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echo
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echo '--- Test 1 ---'
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echo
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# Preallocation speeds up the write operation, but preallocating everything will
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# destroy the purpose of the write; so preallocate one KB less than what would
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# cause a reftable growth...
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_make_test_img -o 'preallocation=metadata,cluster_size=1k' 64512K
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# ...and make the image the desired size afterwards.
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$QEMU_IMG resize "$TEST_IMG" 65M
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# The first write results in a growth of the refcount table during an allocation
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# which has precisely the required size so that the new refcount block allocated
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# in alloc_refcount_block() is right after cluster_index; this did lead to a
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# different refcount block being written to disk (a zeroed cluster) than what is
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# cached (a refblock with one entry having a refcount of 1), and the second
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# write would then result in that cached cluster being marked dirty and then
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# in it being written to disk.
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# This should not happen, the new refcount structures may not conflict with
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# new_block.
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# (Note that for some reason, 'write 63M 1K' does not trigger the problem)
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$QEMU_IO -c 'write 62M 1025K' -c 'write 64M 1M' "$TEST_IMG" | _filter_qemu_io
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_check_test_img
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echo
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echo '--- Test 2 ---'
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echo
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_make_test_img -o 'preallocation=metadata,cluster_size=1k' 64513K
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# This results in an L1 table growth which in turn results in some clusters at
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# the start of the image becoming free
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$QEMU_IMG resize "$TEST_IMG" 65M
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# This write results in a refcount table growth; but the refblock allocated
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# immediately before that (new_block) takes cluster index 4 (which is now free)
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# and is thus not self-describing (in contrast to test 1, where new_block was
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# self-describing). The refcount table growth algorithm then used to place the
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# new refcount structures at cluster index 65536 (which is the same as the
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# cluster_index parameter in this case), allocating a new refcount block for
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# that cluster while new_block already existed, leaking new_block.
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# Therefore, the new refcount structures may not be put at cluster_index
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# (because new_block already describes that cluster, and the new structures try
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# to be self-describing).
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$QEMU_IO -c 'write 63M 130K' "$TEST_IMG" | _filter_qemu_io
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_check_test_img
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echo
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echo '=== Allocating a new refcount block must not leave holes in the image ==='
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echo
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_make_test_img -o 'cluster_size=512,refcount_bits=16' 1M
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# This results in an image with 256 used clusters: the qcow2 header,
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# the refcount table, one refcount block, the L1 table, four L2 tables
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# and 248 data clusters
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$QEMU_IO -c 'write 0 124k' "$TEST_IMG" | _filter_qemu_io
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# 256 clusters of 512 bytes each give us a 128K image
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stat -c "size=%s (expected 131072)" $TEST_IMG
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# All 256 entries of the refcount block are used, so writing a new
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# data cluster also allocates a new refcount block
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$QEMU_IO -c 'write 124k 512' "$TEST_IMG" | _filter_qemu_io
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# Two more clusters, the image size should be 129K now
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stat -c "size=%s (expected 132096)" $TEST_IMG
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# success, all done
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echo
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echo '*** done'
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rm -f $seq.full
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status=0
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