iotests/block-status-cache: New test
Add a new test to verify that want_zero=false block-status calls do not pollute the block-status cache for want_zero=true calls. We check want_zero=true calls and their results using `qemu-img map` (over NBD), and want_zero=false calls also using `qemu-img map` over NBD, but using the qemu:allocation-depth context. (This test case cannot be integrated into nbd-qemu-allocation, because that is a qcow2 test, and this is a raw test.) Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220118170000.49423-3-hreitz@redhat.com> Reviewed-by: Nir Soffer <nsoffer@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Hanna Reitz
Eric Blake
parent
113b727ce7
commit
6384dd534d
|
|
@ -0,0 +1,139 @@
|
|||
#!/usr/bin/env python3
|
||||
# group: rw quick
|
||||
#
|
||||
# Test cases for the block-status cache.
|
||||
#
|
||||
# Copyright (C) 2022 Red Hat, Inc.
|
||||
#
|
||||
# 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
|
||||
# the Free Software Foundation; either version 2 of the License, or
|
||||
# (at your option) any later version.
|
||||
#
|
||||
# This program is distributed in the hope that it will be useful,
|
||||
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
# GNU General Public License for more details.
|
||||
#
|
||||
# You should have received a copy of the GNU General Public License
|
||||
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
#
|
||||
|
||||
import os
|
||||
import signal
|
||||
import iotests
|
||||
from iotests import qemu_img_create, qemu_img_pipe, qemu_nbd
|
||||
|
||||
|
||||
image_size = 1 * 1024 * 1024
|
||||
test_img = os.path.join(iotests.test_dir, 'test.img')
|
||||
|
||||
nbd_pidfile = os.path.join(iotests.test_dir, 'nbd.pid')
|
||||
nbd_sock = os.path.join(iotests.sock_dir, 'nbd.sock')
|
||||
|
||||
|
||||
class TestBscWithNbd(iotests.QMPTestCase):
|
||||
def setUp(self) -> None:
|
||||
"""Just create an empty image with a read-only NBD server on it"""
|
||||
assert qemu_img_create('-f', iotests.imgfmt, test_img,
|
||||
str(image_size)) == 0
|
||||
|
||||
# Pass --allocation-depth to enable the qemu:allocation-depth context,
|
||||
# which we are going to query to provoke a block-status inquiry with
|
||||
# want_zero=false.
|
||||
assert qemu_nbd(f'--socket={nbd_sock}',
|
||||
f'--format={iotests.imgfmt}',
|
||||
'--persistent',
|
||||
'--allocation-depth',
|
||||
'--read-only',
|
||||
f'--pid-file={nbd_pidfile}',
|
||||
test_img) \
|
||||
== 0
|
||||
|
||||
def tearDown(self) -> None:
|
||||
with open(nbd_pidfile, encoding='utf-8') as f:
|
||||
pid = int(f.read())
|
||||
os.kill(pid, signal.SIGTERM)
|
||||
os.remove(nbd_pidfile)
|
||||
os.remove(test_img)
|
||||
|
||||
def test_with_zero_bug(self) -> None:
|
||||
"""
|
||||
Verify that the block-status cache is not corrupted by a
|
||||
want_zero=false call.
|
||||
We can provoke a want_zero=false call with `qemu-img map` over NBD with
|
||||
x-dirty-bitmap=qemu:allocation-depth, so we first run a normal `map`
|
||||
(which results in want_zero=true), then using said
|
||||
qemu:allocation-depth context, and finally another normal `map` to
|
||||
verify that the cache has not been corrupted.
|
||||
"""
|
||||
|
||||
nbd_img_opts = f'driver=nbd,server.type=unix,server.path={nbd_sock}'
|
||||
nbd_img_opts_alloc_depth = nbd_img_opts + \
|
||||
',x-dirty-bitmap=qemu:allocation-depth'
|
||||
|
||||
# Normal map, results in want_zero=true.
|
||||
# This will probably detect an allocated data sector first (qemu likes
|
||||
# to allocate the first sector to facilitate alignment probing), and
|
||||
# then the rest to be zero. The BSC will thus contain (if anything)
|
||||
# one range covering the first sector.
|
||||
map_pre = qemu_img_pipe('map', '--output=json', '--image-opts',
|
||||
nbd_img_opts)
|
||||
|
||||
# qemu:allocation-depth maps for want_zero=false.
|
||||
# want_zero=false should (with the file driver, which the server is
|
||||
# using) report everything as data. While this is sufficient for
|
||||
# want_zero=false, this is nothing that should end up in the
|
||||
# block-status cache.
|
||||
# Due to a bug, this information did end up in the cache, though, and
|
||||
# this would lead to wrong information being returned on subsequent
|
||||
# want_zero=true calls.
|
||||
#
|
||||
# We need to run this map twice: On the first call, we probably still
|
||||
# have the first sector in the cache, and so this will be served from
|
||||
# the cache; and only the subsequent range will be queried from the
|
||||
# block driver. This subsequent range will then be entered into the
|
||||
# cache.
|
||||
# If we did a want_zero=true call at this point, we would thus get
|
||||
# correct information: The first sector is not covered by the cache, so
|
||||
# we would get fresh block-status information from the driver, which
|
||||
# would return a data range, and this would then go into the cache,
|
||||
# evicting the wrong range from the want_zero=false call before.
|
||||
#
|
||||
# Therefore, we need a second want_zero=false map to reproduce:
|
||||
# Since the first sector is not in the cache, the query for its status
|
||||
# will go to the driver, which will return a result that reports the
|
||||
# whole image to be a single data area. This result will then go into
|
||||
# the cache, and so the cache will then report the whole image to
|
||||
# contain data.
|
||||
#
|
||||
# Note that once the cache reports the whole image to contain data, any
|
||||
# subsequent map operation will be served from the cache, and so we can
|
||||
# never loop too many times here.
|
||||
for _ in range(2):
|
||||
# (Ignore the result, this is just to contaminate the cache)
|
||||
qemu_img_pipe('map', '--output=json', '--image-opts',
|
||||
nbd_img_opts_alloc_depth)
|
||||
|
||||
# Now let's see whether the cache reports everything as data, or
|
||||
# whether we get correct information (i.e. the same as we got on our
|
||||
# first attempt).
|
||||
map_post = qemu_img_pipe('map', '--output=json', '--image-opts',
|
||||
nbd_img_opts)
|
||||
|
||||
if map_pre != map_post:
|
||||
print('ERROR: Map information differs before and after querying ' +
|
||||
'qemu:allocation-depth')
|
||||
print('Before:')
|
||||
print(map_pre)
|
||||
print('After:')
|
||||
print(map_post)
|
||||
|
||||
self.fail("Map information differs")
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
# The block-status cache only works on the protocol layer, so to test it,
|
||||
# we can only use the raw format
|
||||
iotests.main(supported_fmts=['raw'],
|
||||
supported_protocols=['file'])
|
||||
|
|
@ -0,0 +1,5 @@
|
|||
.
|
||||
----------------------------------------------------------------------
|
||||
Ran 1 tests
|
||||
|
||||
OK
|
||||
Loading…
Reference in New Issue