tests/qemu-iotests/216

   1 #!/usr/bin/env python
   2 #
   3 # Copy-on-read tests using a COR filter node
   4 #
   5 # Copyright (C) 2018 Red Hat, Inc.
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 2 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 #
  20 # Creator/Owner: Max Reitz <mreitz@redhat.com>
  21
  22 import iotests
  23 from iotests import log, qemu_img, qemu_io_silent
  24
  25 # Need backing file support
  26 iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'])
  27 iotests.verify_platform(['linux'])
  28
  29 log('')
  30 log('=== Copy-on-read across nodes ===')
  31 log('')
  32
  33 # The old copy-on-read mechanism without a filter node cannot request
  34 # WRITE_UNCHANGED permissions for its child.  Therefore it just tries
  35 # to sneak its write by the usual permission system and holds its
  36 # fingers crossed.  However, that sneaking does not work so well when
  37 # there is a filter node in the way: That will receive the write
  38 # request and re-issue a new one to its child, which this time is a
  39 # proper write request that will make the permission system cough --
  40 # unless there is someone at the top (like a guest device) that has
  41 # requested write permissions.
  42 #
  43 # A COR filter node, however, can request the proper permissions for
  44 # its child and therefore is not hit by this issue.
  45
  46 with iotests.FilePath('base.img') as base_img_path, \
  47      iotests.FilePath('top.img') as top_img_path, \
  48      iotests.VM() as vm:
  49
  50     log('--- Setting up images ---')
  51     log('')
  52
  53     assert qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') == 0
  54     assert qemu_io_silent(base_img_path, '-c', 'write -P 1 0M 1M') == 0
  55     assert qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path,
  56                     top_img_path) == 0
  57     assert qemu_io_silent(top_img_path,  '-c', 'write -P 2 1M 1M') == 0
  58
  59     log('Done')
  60
  61     log('')
  62     log('--- Doing COR ---')
  63     log('')
  64
  65     # Compare with e.g. the following:
  66     #   vm.add_drive_raw('if=none,node-name=node0,copy-on-read=on,driver=raw,' \
  67     #                    'file.driver=%s,file.file.filename=%s' %
  68     #                       (iotests.imgfmt, top_img_path))
  69     # (Remove the blockdev-add instead.)
  70     # ((Not tested here because it hits an assertion in the permission
  71     #   system.))
  72
  73     vm.launch()
  74
  75     log(vm.qmp('blockdev-add',
  76                     node_name='node0',
  77                     driver='copy-on-read',
  78                     file={
  79                         'driver': 'raw',
  80                         'file': {
  81                             'driver': 'copy-on-read',
  82                             'file': {
  83                                 'driver': 'raw',
  84                                 'file': {
  85                                     'driver': iotests.imgfmt,
  86                                     'file': {
  87                                         'driver': 'file',
  88                                         'filename': top_img_path
  89                                     },
  90                                     'backing': {
  91                                         'driver': iotests.imgfmt,
  92                                         'file': {
  93                                             'driver': 'file',
  94                                             'filename': base_img_path
  95                                         }
  96                                     }
  97                                 }
  98                             }
  99                         }
 100                     }))
 101
 102     # Trigger COR
 103     log(vm.qmp('human-monitor-command',
 104                command_line='qemu-io node0 "read 0 64M"'))
 105
 106     vm.shutdown()
 107
 108     log('')
 109     log('--- Checking COR result ---')
 110     log('')
 111
 112     assert qemu_io_silent(base_img_path, '-c', 'discard 0 64M') == 0
 113     assert qemu_io_silent(top_img_path,  '-c', 'read -P 1 0M 1M') == 0
 114     assert qemu_io_silent(top_img_path,  '-c', 'read -P 2 1M 1M') == 0
 115
 116     log('Done')