1#!/usr/bin/env python3 2# group: rw quick 3# 4# Copy-on-read tests using a COR filter node 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: Hanna Reitz <hreitz@redhat.com> 22 23import iotests 24from iotests import log, qemu_img, qemu_io 25 26# Need backing file support 27iotests.script_initialize(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'], 28 supported_platforms=['linux']) 29 30log('') 31log('=== Copy-on-read across nodes ===') 32log('') 33 34# The old copy-on-read mechanism without a filter node cannot request 35# WRITE_UNCHANGED permissions for its child. Therefore it just tries 36# to sneak its write by the usual permission system and holds its 37# fingers crossed. However, that sneaking does not work so well when 38# there is a filter node in the way: That will receive the write 39# request and re-issue a new one to its child, which this time is a 40# proper write request that will make the permission system cough -- 41# unless there is someone at the top (like a guest device) that has 42# requested write permissions. 43# 44# A COR filter node, however, can request the proper permissions for 45# its child and therefore is not hit by this issue. 46 47with iotests.FilePath('base.img') as base_img_path, \ 48 iotests.FilePath('top.img') as top_img_path, \ 49 iotests.VM() as vm: 50 51 log('--- Setting up images ---') 52 log('') 53 54 qemu_img('create', '-f', iotests.imgfmt, base_img_path, '64M') 55 qemu_io(base_img_path, '-c', 'write -P 1 0M 1M') 56 qemu_img('create', '-f', iotests.imgfmt, '-b', base_img_path, 57 '-F', iotests.imgfmt, top_img_path) 58 qemu_io(top_img_path, '-c', 'write -P 2 1M 1M') 59 60 log('Done') 61 62 log('') 63 log('--- Doing COR ---') 64 log('') 65 66 # Compare with e.g. the following: 67 # vm.add_drive_raw('if=none,node-name=node0,copy-on-read=on,driver=raw,' \ 68 # 'file.driver=%s,file.file.filename=%s' % 69 # (iotests.imgfmt, top_img_path)) 70 # (Remove the blockdev-add instead.) 71 # ((Not tested here because it hits an assertion in the permission 72 # system.)) 73 74 vm.launch() 75 76 log(vm.qmp('blockdev-add', 77 node_name='node0', 78 driver='copy-on-read', 79 file={ 80 'driver': 'raw', 81 'file': { 82 'driver': 'copy-on-read', 83 'file': { 84 'driver': 'raw', 85 'file': { 86 'driver': iotests.imgfmt, 87 'file': { 88 'driver': 'file', 89 'filename': top_img_path 90 }, 91 'backing': { 92 'driver': iotests.imgfmt, 93 'file': { 94 'driver': 'file', 95 'filename': base_img_path 96 } 97 } 98 } 99 } 100 } 101 })) 102 103 # Trigger COR 104 log(vm.qmp('human-monitor-command', 105 command_line='qemu-io node0 "read 0 64M"')) 106 107 vm.shutdown() 108 109 log('') 110 log('--- Checking COR result ---') 111 log('') 112 113 qemu_io(base_img_path, '-c', 'discard 0 64M') 114 qemu_io(top_img_path, '-c', 'read -P 1 0M 1M') 115 qemu_io(top_img_path, '-c', 'read -P 2 1M 1M') 116 117 log('Done') 118