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iotests: port 141 to Python for reliable QMP testing
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The common.qemu bash functions allow tests to interact with the QMP
monitor of a QEMU process. I spent two days trying to update 141 when
the order of the test output changed, but found it would still fail
occassionally because printf() and QMP events race with synchronous QMP
communication.

I gave up and ported 141 to the existing Python API for QMP tests. The
Python API is less affected by the order in which QEMU prints output
because it does not print all QMP traffic by default.

The next commit changes the order in which QMP messages are received.
Make 141 reliable first.

Cc: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240118144823.1497953-3-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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@stefanhaRH @kevmw
stefanhaRH authored and kevmw committed Jan 19, 2024
1 parent 5dea5d6 commit 8b57e45
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307 changes: 131 additions & 176 deletions tests/qemu-iotests/141
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Original file line number Diff line number Diff line change
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#!/usr/bin/env bash
#!/usr/bin/env python3
# group: rw auto quick
#
# Test case for ejecting BDSs with block jobs still running on them
#
# Copyright (C) 2016 Red Hat, Inc.
# Originally written in bash by Hanna Czenczek, ported to Python by Stefan
# Hajnoczi.
#
# Copyright Red Hat
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
Expand All @@ -19,177 +22,129 @@
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#

# creator
owner=hreitz@redhat.com

seq="$(basename $0)"
echo "QA output created by $seq"

status=1 # failure is the default!

_cleanup()
{
_cleanup_qemu
_cleanup_test_img
for img in "$TEST_DIR"/{b,m,o}.$IMGFMT; do
_rm_test_img "$img"
done
}
trap "_cleanup; exit \$status" 0 1 2 3 15

# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.qemu

# Needs backing file and backing format support
_supported_fmt qcow2 qed
_supported_proto file
_supported_os Linux


test_blockjob()
{
_send_qemu_cmd $QEMU_HANDLE \
"{'execute': 'blockdev-add',
'arguments': {
'node-name': 'drv0',
'driver': '$IMGFMT',
'file': {
'driver': 'file',
'filename': '$TEST_IMG'
}}}" \
'return'

# If "$2" is an event, we may or may not see it before the
# {"return": {}}. Therefore, filter the {"return": {}} out both
# here and in the next command. (Naturally, if we do not see it
# here, we will see it before the next command can be executed,
# so it will appear in the next _send_qemu_cmd's output.)
_send_qemu_cmd $QEMU_HANDLE \
"$1" \
"$2" \
| _filter_img_create | _filter_qmp_empty_return

# We want this to return an error because the block job is still running
_send_qemu_cmd $QEMU_HANDLE \
"{'execute': 'blockdev-del',
'arguments': {'node-name': 'drv0'}}" \
'error' | _filter_generated_node_ids | _filter_qmp_empty_return

_send_qemu_cmd $QEMU_HANDLE \
"{'execute': 'block-job-cancel',
'arguments': {'device': 'job0'}}" \
"$3"

_send_qemu_cmd $QEMU_HANDLE \
"{'execute': 'blockdev-del',
'arguments': {'node-name': 'drv0'}}" \
'return'
}


TEST_IMG="$TEST_DIR/b.$IMGFMT" _make_test_img 1M
TEST_IMG="$TEST_DIR/m.$IMGFMT" _make_test_img -b "$TEST_DIR/b.$IMGFMT" -F $IMGFMT 1M
_make_test_img -b "$TEST_DIR/m.$IMGFMT" 1M -F $IMGFMT

_launch_qemu -nodefaults

_send_qemu_cmd $QEMU_HANDLE \
"{'execute': 'qmp_capabilities'}" \
'return'

echo
echo '=== Testing drive-backup ==='
echo

# drive-backup will not send BLOCK_JOB_READY by itself, and cancelling the job
# will consequently result in BLOCK_JOB_CANCELLED being emitted.

test_blockjob \
"{'execute': 'drive-backup',
'arguments': {'job-id': 'job0',
'device': 'drv0',
'target': '$TEST_DIR/o.$IMGFMT',
'format': '$IMGFMT',
'sync': 'none'}}" \
'return' \
'"status": "null"'

echo
echo '=== Testing drive-mirror ==='
echo

# drive-mirror will send BLOCK_JOB_READY basically immediately, and cancelling
# the job will consequently result in BLOCK_JOB_COMPLETED being emitted.

test_blockjob \
"{'execute': 'drive-mirror',
'arguments': {'job-id': 'job0',
'device': 'drv0',
'target': '$TEST_DIR/o.$IMGFMT',
'format': '$IMGFMT',
'sync': 'none'}}" \
'BLOCK_JOB_READY' \
'"status": "null"'

echo
echo '=== Testing active block-commit ==='
echo

# An active block-commit will send BLOCK_JOB_READY basically immediately, and
# cancelling the job will consequently result in BLOCK_JOB_COMPLETED being
# emitted.

test_blockjob \
"{'execute': 'block-commit',
'arguments': {'job-id': 'job0', 'device': 'drv0'}}" \
'BLOCK_JOB_READY' \
'"status": "null"'

echo
echo '=== Testing non-active block-commit ==='
echo

# Give block-commit something to work on, otherwise it would be done
# immediately, send a BLOCK_JOB_COMPLETED and ejecting the BDS would work just
# fine without the block job still running.

$QEMU_IO -c 'write 0 1M' "$TEST_DIR/m.$IMGFMT" | _filter_qemu_io

test_blockjob \
"{'execute': 'block-commit',
'arguments': {'job-id': 'job0',
'device': 'drv0',
'top': '$TEST_DIR/m.$IMGFMT',
'speed': 1}}" \
'return' \
'"status": "null"'

echo
echo '=== Testing block-stream ==='
echo

# Give block-stream something to work on, otherwise it would be done
# immediately, send a BLOCK_JOB_COMPLETED and ejecting the BDS would work just
# fine without the block job still running.

$QEMU_IO -c 'write 0 1M' "$TEST_DIR/b.$IMGFMT" | _filter_qemu_io

# With some data to stream (and @speed set to 1), block-stream will not complete
# until we send the block-job-cancel command.

test_blockjob \
"{'execute': 'block-stream',
'arguments': {'job-id': 'job0',
'device': 'drv0',
'speed': 1}}" \
'return' \
'"status": "null"'

_cleanup_qemu

# success, all done
echo "*** done"
rm -f $seq.full
status=0
import iotests

# Common filters to mask values that vary in the test output
QMP_FILTERS = [iotests.filter_qmp_testfiles, \
iotests.filter_qmp_imgfmt]


class TestCase:
def __init__(self, name, vm, image_path, cancel_event):
self.name = name
self.vm = vm
self.image_path = image_path
self.cancel_event = cancel_event

def __enter__(self):
iotests.log(f'=== Testing {self.name} ===')
self.vm.qmp_log('blockdev-add', \
node_name='drv0', \
driver=iotests.imgfmt, \
file={'driver': 'file', 'filename': self.image_path}, \
filters=QMP_FILTERS)

def __exit__(self, *exc_details):
# This is expected to fail because the job still exists
self.vm.qmp_log('blockdev-del', node_name='drv0', \
filters=[iotests.filter_qmp_generated_node_ids])

self.vm.qmp_log('block-job-cancel', device='job0')
event = self.vm.event_wait(self.cancel_event)
iotests.log(event, filters=[iotests.filter_qmp_event])

# This time it succeeds
self.vm.qmp_log('blockdev-del', node_name='drv0')

# Separate test cases in output
iotests.log('')


def main() -> None:
with iotests.FilePath('bottom', 'middle', 'top', 'target') as \
(bottom_path, middle_path, top_path, target_path), \
iotests.VM() as vm:

iotests.log('Creating bottom <- middle <- top backing file chain...')
IMAGE_SIZE='1M'
iotests.qemu_img_create('-f', iotests.imgfmt, bottom_path, IMAGE_SIZE)
iotests.qemu_img_create('-f', iotests.imgfmt, \
'-F', iotests.imgfmt, \
'-b', bottom_path, \
middle_path, \
IMAGE_SIZE)
iotests.qemu_img_create('-f', iotests.imgfmt, \
'-F', iotests.imgfmt, \
'-b', middle_path, \
top_path, \
IMAGE_SIZE)

iotests.log('Starting VM...')
vm.add_args('-nodefaults')
vm.launch()

# drive-backup will not send BLOCK_JOB_READY by itself, and cancelling
# the job will consequently result in BLOCK_JOB_CANCELLED being
# emitted.
with TestCase('drive-backup', vm, top_path, 'BLOCK_JOB_CANCELLED'):
vm.qmp_log('drive-backup', \
job_id='job0', \
device='drv0', \
target=target_path, \
format=iotests.imgfmt, \
sync='none', \
filters=QMP_FILTERS)

# drive-mirror will send BLOCK_JOB_READY basically immediately, and
# cancelling the job will consequently result in BLOCK_JOB_COMPLETED
# being emitted.
with TestCase('drive-mirror', vm, top_path, 'BLOCK_JOB_COMPLETED'):
vm.qmp_log('drive-mirror', \
job_id='job0', \
device='drv0', \
target=target_path, \
format=iotests.imgfmt, \
sync='none', \
filters=QMP_FILTERS)
event = vm.event_wait('BLOCK_JOB_READY')
assert event is not None # silence mypy
iotests.log(event, filters=[iotests.filter_qmp_event])

# An active block-commit will send BLOCK_JOB_READY basically
# immediately, and cancelling the job will consequently result in
# BLOCK_JOB_COMPLETED being emitted.
with TestCase('active block-commit', vm, top_path, \
'BLOCK_JOB_COMPLETED'):
vm.qmp_log('block-commit', \
job_id='job0', \
device='drv0')
event = vm.event_wait('BLOCK_JOB_READY')
assert event is not None # silence mypy
iotests.log(event, filters=[iotests.filter_qmp_event])

# Give block-commit something to work on, otherwise it would be done
# immediately, send a BLOCK_JOB_COMPLETED and ejecting the BDS would
# work just fine without the block job still running.
iotests.qemu_io(middle_path, '-c', f'write 0 {IMAGE_SIZE}')
with TestCase('non-active block-commit', vm, top_path, \
'BLOCK_JOB_CANCELLED'):
vm.qmp_log('block-commit', \
job_id='job0', \
device='drv0', \
top=middle_path, \
speed=1, \
filters=[iotests.filter_qmp_testfiles])

# Give block-stream something to work on, otherwise it would be done
# immediately, send a BLOCK_JOB_COMPLETED and ejecting the BDS would
# work just fine without the block job still running.
iotests.qemu_io(bottom_path, '-c', f'write 0 {IMAGE_SIZE}')
with TestCase('block-stream', vm, top_path, 'BLOCK_JOB_CANCELLED'):
vm.qmp_log('block-stream', \
job_id='job0', \
device='drv0', \
speed=1)

if __name__ == '__main__':
iotests.script_main(main, supported_fmts=['qcow2', 'qed'],
supported_protocols=['file'])

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