1#!/usr/bin/env python3 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 22import iotests 23from iotests import log, qemu_img, qemu_io_silent 24 25# Need backing file support 26iotests.script_initialize(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'], 27 supported_platforms=['linux']) 28 29log('') 30log('=== Copy-on-read across nodes ===') 31log('') 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 46with 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 '-F', iotests.imgfmt, 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') 117