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1104d83c72
The NBD spec says that clients should not try to write/trim to an export advertised as read-only by the server. But we failed to check that, and would allow the block layer to use NBD with BDRV_O_RDWR even when the server is read-only, which meant we were depending on the server sending a proper EPERM failure for various commands, and also exposes a leaky abstraction: using qemu-io in read-write mode would succeed on 'w -z 0 0' because of local short-circuiting logic, but 'w 0 0' would send a request over the wire (where it then depends on the server, and fails at least for qemu-nbd but might pass for other NBD implementations). With this patch, a client MUST request read-only mode to access a server that is doing a read-only export, or else it will get a message like: can't open device nbd://localhost:10809/foo: request for write access conflicts with read-only export It is no longer possible to even attempt writes over the wire (including the corner case of 0-length writes), because the block layer enforces the explicit read-only request; this matches the behavior of qcow2 when backed by a read-only POSIX file. Fix several iotests to comply with the new behavior (since qemu-nbd of an internal snapshot, as well as nbd-server-add over QMP, default to a read-only export, we must tell blockdev-add/qemu-io to set up a read-only client). CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20171108215703.9295-3-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
148 lines
4.1 KiB
Bash
Executable File
148 lines
4.1 KiB
Bash
Executable File
#!/bin/bash
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#
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# Test export internal snapshot by qemu-nbd, convert it by qemu-img.
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#
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# Copyright (C) 2013 IBM, Inc.
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#
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# Based on 029.
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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=xiawenc@linux.vnet.ibm.com
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seq=`basename $0`
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echo "QA output created by $seq"
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here=`pwd`
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status=1 # failure is the default!
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nbd_unix_socket=$TEST_DIR/test_qemu_nbd_socket
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nbd_snapshot_img="nbd:unix:$nbd_unix_socket"
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rm -f "${TEST_DIR}/qemu-nbd.pid"
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_cleanup_nbd()
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{
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local NBD_SNAPSHOT_PID
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if [ -f "${TEST_DIR}/qemu-nbd.pid" ]; then
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read NBD_SNAPSHOT_PID < "${TEST_DIR}/qemu-nbd.pid"
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rm -f "${TEST_DIR}/qemu-nbd.pid"
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if [ -n "$NBD_SNAPSHOT_PID" ]; then
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kill "$NBD_SNAPSHOT_PID"
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fi
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fi
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rm -f "$nbd_unix_socket"
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}
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_wait_for_nbd()
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{
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for ((i = 0; i < 300; i++))
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do
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if [ -r "$nbd_unix_socket" ]; then
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return
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fi
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sleep 0.1
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done
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echo "Failed in check of unix socket created by qemu-nbd"
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exit 1
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}
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converted_image=$TEST_IMG.converted
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_export_nbd_snapshot()
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{
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_cleanup_nbd
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$QEMU_NBD -v -t -k "$nbd_unix_socket" "$TEST_IMG" -l $1 &
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_wait_for_nbd
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}
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_export_nbd_snapshot1()
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{
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_cleanup_nbd
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$QEMU_NBD -v -t -k "$nbd_unix_socket" "$TEST_IMG" -l snapshot.name=$1 &
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_wait_for_nbd
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}
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_cleanup()
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{
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_cleanup_nbd
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_cleanup_test_img
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rm -f "$converted_image"
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# get standard environment, filters and checks
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. ./common.rc
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. ./common.filter
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. ./common.pattern
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_supported_fmt qcow2
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_supported_proto file
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_supported_os Linux
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_require_command QEMU_NBD
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# Internal snapshots are (currently) impossible with refcount_bits=1
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_unsupported_imgopts 'refcount_bits=1[^0-9]'
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# Use -f raw instead of -f $IMGFMT for the NBD connection
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QEMU_IO_NBD="$QEMU_IO -f raw --cache=$CACHEMODE"
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echo
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echo "== preparing image =="
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_make_test_img 64M
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$QEMU_IO -c 'write -P 0xa 0x1000 0x1000' "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c 'write -P 0xb 0x2000 0x1000' "$TEST_IMG" | _filter_qemu_io
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$QEMU_IMG snapshot -c sn1 "$TEST_IMG"
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$QEMU_IO -c 'write -P 0xc 0x1000 0x1000' "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c 'write -P 0xd 0x2000 0x1000' "$TEST_IMG" | _filter_qemu_io
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_check_test_img
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echo
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echo "== verifying the image file with patterns =="
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$QEMU_IO -c 'read -P 0xc 0x1000 0x1000' "$TEST_IMG" | _filter_qemu_io
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$QEMU_IO -c 'read -P 0xd 0x2000 0x1000' "$TEST_IMG" | _filter_qemu_io
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_export_nbd_snapshot sn1
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echo
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echo "== verifying the exported snapshot with patterns, method 1 =="
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$QEMU_IO_NBD -r -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
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$QEMU_IO_NBD -r -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
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_export_nbd_snapshot1 sn1
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echo
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echo "== verifying the exported snapshot with patterns, method 2 =="
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$QEMU_IO_NBD -r -c 'read -P 0xa 0x1000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
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$QEMU_IO_NBD -r -c 'read -P 0xb 0x2000 0x1000' "$nbd_snapshot_img" | _filter_qemu_io
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$QEMU_IMG convert "$TEST_IMG" -l sn1 -O qcow2 "$converted_image"
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echo
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echo "== verifying the converted snapshot with patterns, method 1 =="
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$QEMU_IO -c 'read -P 0xa 0x1000 0x1000' "$converted_image" | _filter_qemu_io
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$QEMU_IO -c 'read -P 0xb 0x2000 0x1000' "$converted_image" | _filter_qemu_io
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$QEMU_IMG convert "$TEST_IMG" -l snapshot.name=sn1 -O qcow2 "$converted_image"
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echo
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echo "== verifying the converted snapshot with patterns, method 2 =="
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$QEMU_IO -c 'read -P 0xa 0x1000 0x1000' "$converted_image" | _filter_qemu_io
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$QEMU_IO -c 'read -P 0xb 0x2000 0x1000' "$converted_image" | _filter_qemu_io
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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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