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#!/usr/bin/env python3
#
# Test for when a backing file is considered overridden (thus, a
# json:{} filename is generated for the overlay) and when it is not
#
# Copyright (C) 2018 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/>.
#
# Creator/Owner: Max Reitz <mreitz@redhat.com>
import iotests
from iotests import log, qemu_img, filter_testfiles, filter_imgfmt, \
filter_qmp_testfiles, filter_qmp_imgfmt
# Need backing file and change-backing-file support
iotests.script_initialize(
supported_fmts=['qcow2', 'qed'],
supported_platforms=['linux'],
)
def log_node_info(node):
log('')
log('bs->filename: ' + node['image']['filename'],
filters=[filter_testfiles, filter_imgfmt])
log('bs->backing_file: ' + node['backing_file'],
filters=[filter_testfiles, filter_imgfmt])
if 'backing-image' in node['image']:
log('bs->backing->bs->filename: ' +
node['image']['backing-image']['filename'],
filters=[filter_testfiles, filter_imgfmt])
else:
log('bs->backing: (none)')
log('')
with iotests.FilePath('base.img') as base_img_path, \
iotests.FilePath('top.img') as top_img_path, \
iotests.VM() as vm:
assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
# Choose a funny way to describe the backing filename
assert qemu_img('create', '-f', iotests.imgfmt, '-b',
'file:' + base_img_path, top_img_path) == 0
vm.launch()
log('--- Implicit backing file ---')
log('')
vm.qmp_log('blockdev-add',
node_name='node0',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': top_img_path
},
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
# Filename should be plain, and the backing filename should not
# contain the "file:" prefix
log_node_info(vm.node_info('node0'))
vm.qmp_log('blockdev-del', node_name='node0')
log('')
log('--- change-backing-file ---')
log('')
vm.qmp_log('blockdev-add',
node_name='node0',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': top_img_path
},
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
# Changing the backing file to a qemu-reported filename should
# result in qemu accepting the corresponding BDS as the implicit
# backing BDS (and thus not generate a json:{} filename).
# So, first, query the backing filename.
backing_filename = \
vm.node_info('node0')['image']['backing-image']['filename']
# Next, change the backing file to something different
vm.qmp_log('change-backing-file',
image_node_name='node0',
device='node0',
backing_file='null-co://',
filters=[filter_qmp_testfiles])
# Now, verify that we get a json:{} filename
# (Image header says "null-co://", actual backing file still is
# base_img_path)
log_node_info(vm.node_info('node0'))
# Change it back
# (To get header and backing file in sync)
vm.qmp_log('change-backing-file',
image_node_name='node0',
device='node0',
backing_file=backing_filename,
filters=[filter_qmp_testfiles])
# And verify that we get our original results
log_node_info(vm.node_info('node0'))
# Finally, try a "file:" prefix. While this is actually what we
# originally had in the image header, qemu will not reopen the
# backing file here, so it cannot verify that this filename
# "resolves" to the actual backing BDS's filename and will thus
# consider both to be different.
# (This may be fixed in the future.)
vm.qmp_log('change-backing-file',
image_node_name='node0',
device='node0',
backing_file=('file:' + backing_filename),
filters=[filter_qmp_testfiles])
# So now we should get a json:{} filename
log_node_info(vm.node_info('node0'))
# Remove and re-attach so we can see that (as in our first try),
# opening the image anew helps qemu resolve the header backing
# filename.
vm.qmp_log('blockdev-del', node_name='node0')
vm.qmp_log('blockdev-add',
node_name='node0',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': top_img_path
},
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
log_node_info(vm.node_info('node0'))
vm.qmp_log('blockdev-del', node_name='node0')
log('')
log('--- Override backing file ---')
log('')
# For this test, we need the plain filename in the image header
# (because qemu cannot "canonicalize"/"resolve" the backing
# filename unless the backing file is opened implicitly with the
# overlay)
assert qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path,
top_img_path) == 0
# You can only reliably override backing options by using a node
# reference (or by specifying file.filename, but, well...)
vm.qmp_log('blockdev-add', node_name='null', driver='null-co')
vm.qmp_log('blockdev-add',
node_name='node0',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': top_img_path
},
backing='null',
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
# Should get a json:{} filename (and bs->backing_file is
# null-co://, because that field actually has not much to do
# with the header backing filename (except that it is changed by
# change-backing-file))
log_node_info(vm.node_info('node0'))
# Detach the backing file by reopening the whole thing
vm.qmp_log('blockdev-del', node_name='node0')
vm.qmp_log('blockdev-del', node_name='null')
vm.qmp_log('blockdev-add',
node_name='node0',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': top_img_path
},
backing=None,
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
# Should get a json:{} filename (because we overrode the backing
# file to not be there)
log_node_info(vm.node_info('node0'))
# Open the original backing file
vm.qmp_log('blockdev-add',
node_name='original-backing',
driver=iotests.imgfmt,
file={
'driver': 'file',
'filename': base_img_path
},
filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
# Attach the original backing file to its overlay
vm.qmp_log('blockdev-snapshot',
node='original-backing',
overlay='node0')
# This should give us the original plain result
log_node_info(vm.node_info('node0'))
vm.qmp_log('blockdev-del', node_name='node0')
vm.qmp_log('blockdev-del', node_name='original-backing')
vm.shutdown()
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