tests/qemu-iotests/228

   1 #!/usr/bin/env python3
   2 # group: rw quick
   3 #
   4 # Test for when a backing file is considered overridden (thus, a
   5 # json:{} filename is generated for the overlay) and when it is not
   6 #
   7 # Copyright (C) 2018 Red Hat, Inc.
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 #
  22 # Creator/Owner: Max Reitz <mreitz@redhat.com>
  23
  24 import iotests
  25 from iotests import log, qemu_img, filter_testfiles, filter_imgfmt, \
  26         filter_qmp_testfiles, filter_qmp_imgfmt
  27
  28 # Need backing file and change-backing-file support
  29 iotests.script_initialize(
  30     supported_fmts=['qcow2', 'qed'],
  31     supported_platforms=['linux'],
  32 )
  33
  34
  35 def log_node_info(node):
  36     log('')
  37
  38     log('bs->filename: ' + node['image']['filename'],
  39         filters=[filter_testfiles, filter_imgfmt])
  40     log('bs->backing_file: ' + node['image']['full-backing-filename'],
  41         filters=[filter_testfiles, filter_imgfmt])
  42
  43     if 'backing-image' in node['image']:
  44         log('bs->backing->bs->filename: ' +
  45             node['image']['backing-image']['filename'],
  46             filters=[filter_testfiles, filter_imgfmt])
  47     else:
  48         log('bs->backing: (none)')
  49
  50     log('')
  51
  52
  53 with iotests.FilePath('base.img') as base_img_path, \
  54      iotests.FilePath('top.img') as top_img_path, \
  55      iotests.VM() as vm:
  56
  57     assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
  58     # Choose a funny way to describe the backing filename
  59     assert qemu_img('create', '-f', iotests.imgfmt, '-b',
  60                     'file:' + base_img_path, '-F', iotests.imgfmt,
  61                     top_img_path) == 0
  62
  63     vm.launch()
  64
  65     log('--- Implicit backing file ---')
  66     log('')
  67
  68     vm.qmp_log('blockdev-add',
  69                 node_name='node0',
  70                 driver=iotests.imgfmt,
  71                 file={
  72                     'driver': 'file',
  73                     'filename': top_img_path
  74                 },
  75                 filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
  76
  77     # Filename should be plain, and the backing node filename should
  78     # not contain the "file:" prefix
  79     log_node_info(vm.node_info('node0'))
  80
  81     vm.qmp_log('blockdev-del', node_name='node0')
  82
  83     log('')
  84     log('--- change-backing-file ---')
  85     log('')
  86
  87     vm.qmp_log('blockdev-add',
  88                node_name='node0',
  89                driver=iotests.imgfmt,
  90                file={
  91                    'driver': 'file',
  92                    'filename': top_img_path
  93                },
  94                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
  95
  96     # Changing the backing file to a qemu-reported filename should
  97     # result in qemu accepting the corresponding BDS as the implicit
  98     # backing BDS (and thus not generate a json:{} filename).
  99     # So, first, query the backing filename.
 100
 101     backing_filename = \
 102         vm.node_info('node0')['image']['backing-image']['filename']
 103
 104     # Next, change the backing file to something different
 105
 106     vm.qmp_log('change-backing-file',
 107                image_node_name='node0',
 108                device='node0',
 109                backing_file='null-co://',
 110                filters=[filter_qmp_testfiles])
 111
 112     # Now, verify that we get a json:{} filename
 113     # (Image header says "null-co://", actual backing file still is
 114     # base_img_path)
 115
 116     log_node_info(vm.node_info('node0'))
 117
 118     # Change it back
 119     # (To get header and backing file in sync)
 120
 121     vm.qmp_log('change-backing-file',
 122                image_node_name='node0',
 123                device='node0',
 124                backing_file=backing_filename,
 125                filters=[filter_qmp_testfiles])
 126
 127     # And verify that we get our original results
 128
 129     log_node_info(vm.node_info('node0'))
 130
 131     # Finally, try a "file:" prefix.  While this is actually what we
 132     # originally had in the image header, qemu will not reopen the
 133     # backing file here, so it cannot verify that this filename
 134     # "resolves" to the actual backing BDS's filename and will thus
 135     # consider both to be different.
 136     # (This may be fixed in the future.)
 137
 138     vm.qmp_log('change-backing-file',
 139                image_node_name='node0',
 140                device='node0',
 141                backing_file=('file:' + backing_filename),
 142                filters=[filter_qmp_testfiles])
 143
 144     # So now we should get a json:{} filename
 145
 146     log_node_info(vm.node_info('node0'))
 147
 148     # Remove and re-attach so we can see that (as in our first try),
 149     # opening the image anew helps qemu resolve the header backing
 150     # filename.
 151
 152     vm.qmp_log('blockdev-del', node_name='node0')
 153
 154     vm.qmp_log('blockdev-add',
 155                node_name='node0',
 156                driver=iotests.imgfmt,
 157                file={
 158                    'driver': 'file',
 159                    'filename': top_img_path
 160                },
 161                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 162
 163     log_node_info(vm.node_info('node0'))
 164
 165     vm.qmp_log('blockdev-del', node_name='node0')
 166
 167     log('')
 168     log('--- Override backing file ---')
 169     log('')
 170
 171     # For this test, we need the plain filename in the image header
 172     # (because qemu cannot "canonicalize"/"resolve" the backing
 173     # filename unless the backing file is opened implicitly with the
 174     # overlay)
 175     assert qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path,
 176                     '-F', iotests.imgfmt, top_img_path) == 0
 177
 178     # You can only reliably override backing options by using a node
 179     # reference (or by specifying file.filename, but, well...)
 180     vm.qmp_log('blockdev-add', node_name='null', driver='null-co')
 181
 182     vm.qmp_log('blockdev-add',
 183                node_name='node0',
 184                driver=iotests.imgfmt,
 185                file={
 186                    'driver': 'file',
 187                    'filename': top_img_path
 188                },
 189                backing='null',
 190                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 191
 192     # Should get a json:{} filename (and bs->backing_file is
 193     # null-co://, because that field actually has not much to do
 194     # with the header backing filename (except that it is changed by
 195     # change-backing-file))
 196
 197     log_node_info(vm.node_info('node0'))
 198
 199     # Detach the backing file by reopening the whole thing
 200
 201     vm.qmp_log('blockdev-del', node_name='node0')
 202     vm.qmp_log('blockdev-del', node_name='null')
 203
 204     vm.qmp_log('blockdev-add',
 205                node_name='node0',
 206                driver=iotests.imgfmt,
 207                file={
 208                    'driver': 'file',
 209                    'filename': top_img_path
 210                },
 211                backing=None,
 212                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 213
 214     # Should get a json:{} filename (because we overrode the backing
 215     # file to not be there)
 216
 217     log_node_info(vm.node_info('node0'))
 218
 219     # Open the original backing file
 220
 221     vm.qmp_log('blockdev-add',
 222                node_name='original-backing',
 223                driver=iotests.imgfmt,
 224                file={
 225                    'driver': 'file',
 226                    'filename': base_img_path
 227                },
 228                filters=[filter_qmp_testfiles, filter_qmp_imgfmt])
 229
 230     # Attach the original backing file to its overlay
 231
 232     vm.qmp_log('blockdev-snapshot',
 233                node='original-backing',
 234                overlay='node0')
 235
 236     # This should give us the original plain result
 237
 238     log_node_info(vm.node_info('node0'))
 239
 240     vm.qmp_log('blockdev-del', node_name='node0')
 241     vm.qmp_log('blockdev-del', node_name='original-backing')
 242
 243     vm.shutdown()