461743390d
Add a test for qcow2 copy-on-read behavior, including exposure for the just-fixed bugs. The copy-on-read behavior is always to a qcow2 image, but the test is careful to allow running with most image protocol/format combos as the backing file being copied from (luks being the exception, as it is harder to pass the right secret to all the right places). In fact, for './check nbd', this appears to be the first time we've had a qcow2 image wrapping NBD, requiring an additional line in _filter_img_create to match the similar line in _filter_img_info. Invoking blkdebug to prove we don't write too much took some effort to get working; and it requires that $TEST_WRAP (based on $TEST_DIR) not be subject to word splitting. We may decide later to have the entire iotests suite use relative rather than absolute names, to avoid problems inherited by the absolute name of $PWD or $TEST_DIR, at which point the sanity check in this commit could be simplified. This test requires at least 2G of consecutive memory to succeed; as such, it is prone to spurious failures, particularly on 32-bit machines under load. This situation is detected and triggers an early exit to skip the test, rather than a failure. To manually provoke this setup on a beefier machine, I used: $ (ulimit -S -v 1000000; ./check -qcow2 197) Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
110 lines
3.4 KiB
Bash
Executable file
110 lines
3.4 KiB
Bash
Executable file
#!/bin/bash
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#
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# Test case for copy-on-read into qcow2
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#
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# Copyright (C) 2017 Red Hat, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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# creator
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owner=eblake@redhat.com
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seq="$(basename $0)"
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echo "QA output created by $seq"
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here="$PWD"
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status=1 # failure is the default!
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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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TEST_WRAP="$TEST_DIR/t.wrap.qcow2"
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BLKDBG_CONF="$TEST_DIR/blkdebug.conf"
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# Sanity check: our use of blkdebug fails if $TEST_DIR contains spaces
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# or other problems
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case "$TEST_DIR" in
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*[^-_a-zA-Z0-9/]*)
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_notrun "Suspicious TEST_DIR='$TEST_DIR', cowardly refusing to run" ;;
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esac
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_cleanup()
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{
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_cleanup_test_img
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rm -f "$BLKDBG_CONF"
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# Test is supported for any backing file; but we force qcow2 for our wrapper.
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_supported_fmt generic
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_supported_proto generic
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_supported_os Linux
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# LUKS support may be possible, but it complicates things.
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_unsupported_fmt luks
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echo
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echo '=== Copy-on-read ==='
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echo
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# Prep the images
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_make_test_img 4G
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$QEMU_IO -c "write -P 55 3G 1k" "$TEST_IMG" | _filter_qemu_io
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IMGPROTO=file IMGFMT=qcow2 IMGOPTS= TEST_IMG_FILE="$TEST_WRAP" \
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_make_test_img -F "$IMGFMT" -b "$TEST_IMG" | _filter_img_create
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$QEMU_IO -f qcow2 -c "write -z -u 1M 64k" "$TEST_WRAP" | _filter_qemu_io
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# Ensure that a read of two clusters, but where one is already allocated,
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# does not re-write the allocated cluster
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cat > "$BLKDBG_CONF" <<EOF
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[inject-error]
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event = "cor_write"
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sector = "2048"
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EOF
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$QEMU_IO -c "open -C \
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-o driver=blkdebug,config=$BLKDBG_CONF,image.driver=qcow2 $TEST_WRAP" \
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-c "read -P 0 1M 128k" | _filter_qemu_io
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# Read the areas we want copied. A zero-length read should still be a
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# no-op. The next read is under 2G, but aligned so that rounding to
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# clusters copies more than 2G of zeroes. The final read will pick up
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# the non-zero data in the same cluster. Since a 2G read may exhaust
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# memory on some machines (particularly 32-bit), we skip the test if
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# that fails due to memory pressure.
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$QEMU_IO -f qcow2 -C -c "read 0 0" "$TEST_WRAP" | _filter_qemu_io
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output=$($QEMU_IO -f qcow2 -C -c "read -P 0 1k $((2*1024*1024*1024 - 512))" \
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"$TEST_WRAP" 2>&1 | _filter_qemu_io)
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case $output in
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*allocate*)
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_notrun "Insufficent memory to run test" ;;
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*) printf '%s\n' "$output" ;;
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esac
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$QEMU_IO -f qcow2 -C -c "read -P 0 $((3*1024*1024*1024 + 1024)) 1k" \
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"$TEST_WRAP" | _filter_qemu_io
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# Copy-on-read is incompatible with read-only
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$QEMU_IO -f qcow2 -C -r "$TEST_WRAP" 2>&1 | _filter_testdir
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# Break the backing chain, and show that images are identical, and that
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# we properly copied over explicit zeros.
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$QEMU_IMG rebase -u -b "" -f qcow2 "$TEST_WRAP"
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$QEMU_IO -f qcow2 -c map "$TEST_WRAP"
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_check_test_img
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$QEMU_IMG compare -f $IMGFMT -F qcow2 "$TEST_IMG" "$TEST_WRAP"
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# success, all done
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echo '*** done'
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status=0
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