tests/qemu-iotests/228

   1 #!/usr/bin/env python3
   2 #
   3 # Test for when a backing file is considered overridden (thus, a
   4 # json:{} filename is generated for the overlay) and when it is not
   5 #
   6 # Copyright (C) 2018 Red Hat, Inc.
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 #
  21 # Creator/Owner: Max Reitz <mreitz@redhat.com>
  22
  23 import iotests
  24 from iotests import log, qemu_img, filter_testfiles, filter_imgfmt, \
  25         filter_qmp_testfiles, filter_qmp_imgfmt
  26
  27 # Need backing file and change-backing-file support
  28 iotests.script_initialize(
  29     supported_fmts=['qcow2', 'qed'],
  30     supported_platforms=['linux'],
  31 )
  32
  33
  34 def log_node_info(node):
  35     log('')
  36
  37     log('bs->filename: ' + node['image']['filename'],
  38         filters=[filter_testfiles, filter_imgfmt])
  39     log('bs->backing_file: ' + node['backing_file'],
  40         filters=[filter_testfiles, filter_imgfmt])
  41
  42     if 'backing-image' in node['image']:
  43         log('bs->backing->bs->filename: ' +
  44             node['image']['backing-image']['filename'],
  45             filters=[filter_testfiles, filter_imgfmt])
  46     else:
  47         log('bs->backing: (none)')
  48
  49     log('')
  50
  51
  52 with iotests.FilePath('base.img') as base_img_path, \
  53      iotests.FilePath('top.img') as top_img_path, \
  54      iotests.VM() as vm:
  55
  56     assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
  57     # Choose a funny way to describe the backing filename
  58     assert qemu_img('create', '-f', iotests.imgfmt, '-b',
  59                     'file:' + base_img_path, top_img_path) == 0
  60
  61     vm.launch()
  62
  63     log('--- Implicit backing file ---')
  64     log('')
  65
  66     vm.qmp_log('blockdev-add',
  67                 node_name='node0',
  68                 driver=iotests.imgfmt,
  69                 file={
  70                     'driver': 'file',
  71                     'filename': top_img_path
  72                 },
  73                 filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
  74
  75     # Filename should be plain, and the backing filename should not
  76     # contain the "file:" prefix
  77     log_node_info(vm.node_info('node0'))
  78
  79     vm.qmp_log('blockdev-del', node_name='node0')
  80
  81     log('')
  82     log('--- change-backing-file ---')
  83     log('')
  84
  85     vm.qmp_log('blockdev-add',
  86                node_name='node0',
  87                driver=iotests.imgfmt,
  88                file={
  89                    'driver': 'file',
  90                    'filename': top_img_path
  91                },
  92                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
  93
  94     # Changing the backing file to a qemu-reported filename should
  95     # result in qemu accepting the corresponding BDS as the implicit
  96     # backing BDS (and thus not generate a json:{} filename).
  97     # So, first, query the backing filename.
  98
  99     backing_filename = \
 100         vm.node_info('node0')['image']['backing-image']['filename']
 101
 102     # Next, change the backing file to something different
 103
 104     vm.qmp_log('change-backing-file',
 105                image_node_name='node0',
 106                device='node0',
 107                backing_file='null-co://',
 108                filters=[filter_qmp_testfiles])
 109
 110     # Now, verify that we get a json:{} filename
 111     # (Image header says "null-co://", actual backing file still is
 112     # base_img_path)
 113
 114     log_node_info(vm.node_info('node0'))
 115
 116     # Change it back
 117     # (To get header and backing file in sync)
 118
 119     vm.qmp_log('change-backing-file',
 120                image_node_name='node0',
 121                device='node0',
 122                backing_file=backing_filename,
 123                filters=[filter_qmp_testfiles])
 124
 125     # And verify that we get our original results
 126
 127     log_node_info(vm.node_info('node0'))
 128
 129     # Finally, try a "file:" prefix.  While this is actually what we
 130     # originally had in the image header, qemu will not reopen the
 131     # backing file here, so it cannot verify that this filename
 132     # "resolves" to the actual backing BDS's filename and will thus
 133     # consider both to be different.
 134     # (This may be fixed in the future.)
 135
 136     vm.qmp_log('change-backing-file',
 137                image_node_name='node0',
 138                device='node0',
 139                backing_file=('file:' + backing_filename),
 140                filters=[filter_qmp_testfiles])
 141
 142     # So now we should get a json:{} filename
 143
 144     log_node_info(vm.node_info('node0'))
 145
 146     # Remove and re-attach so we can see that (as in our first try),
 147     # opening the image anew helps qemu resolve the header backing
 148     # filename.
 149
 150     vm.qmp_log('blockdev-del', node_name='node0')
 151
 152     vm.qmp_log('blockdev-add',
 153                node_name='node0',
 154                driver=iotests.imgfmt,
 155                file={
 156                    'driver': 'file',
 157                    'filename': top_img_path
 158                },
 159                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 160
 161     log_node_info(vm.node_info('node0'))
 162
 163     vm.qmp_log('blockdev-del', node_name='node0')
 164
 165     log('')
 166     log('--- Override backing file ---')
 167     log('')
 168
 169     # For this test, we need the plain filename in the image header
 170     # (because qemu cannot "canonicalize"/"resolve" the backing
 171     # filename unless the backing file is opened implicitly with the
 172     # overlay)
 173     assert qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path,
 174                     top_img_path) == 0
 175
 176     # You can only reliably override backing options by using a node
 177     # reference (or by specifying file.filename, but, well...)
 178     vm.qmp_log('blockdev-add', node_name='null', driver='null-co')
 179
 180     vm.qmp_log('blockdev-add',
 181                node_name='node0',
 182                driver=iotests.imgfmt,
 183                file={
 184                    'driver': 'file',
 185                    'filename': top_img_path
 186                },
 187                backing='null',
 188                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 189
 190     # Should get a json:{} filename (and bs->backing_file is
 191     # null-co://, because that field actually has not much to do
 192     # with the header backing filename (except that it is changed by
 193     # change-backing-file))
 194
 195     log_node_info(vm.node_info('node0'))
 196
 197     # Detach the backing file by reopening the whole thing
 198
 199     vm.qmp_log('blockdev-del', node_name='node0')
 200     vm.qmp_log('blockdev-del', node_name='null')
 201
 202     vm.qmp_log('blockdev-add',
 203                node_name='node0',
 204                driver=iotests.imgfmt,
 205                file={
 206                    'driver': 'file',
 207                    'filename': top_img_path
 208                },
 209                backing=None,
 210                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 211
 212     # Should get a json:{} filename (because we overrode the backing
 213     # file to not be there)
 214
 215     log_node_info(vm.node_info('node0'))
 216
 217     # Open the original backing file
 218
 219     vm.qmp_log('blockdev-add',
 220                node_name='original-backing',
 221                driver=iotests.imgfmt,
 222                file={
 223                    'driver': 'file',
 224                    'filename': base_img_path
 225                },
 226                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 227
 228     # Attach the original backing file to its overlay
 229
 230     vm.qmp_log('blockdev-snapshot',
 231                node='original-backing',
 232                overlay='node0')
 233
 234     # This should give us the original plain result
 235
 236     log_node_info(vm.node_info('node0'))
 237
 238     vm.qmp_log('blockdev-del', node_name='node0')
 239     vm.qmp_log('blockdev-del', node_name='original-backing')
 240
 241     vm.shutdown()