From d1e2ed07917410e71f10b8dda80ef94a3d333d3c Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Mon, 18 Jun 2018 16:12:12 +0200

Subject: [PATCH 36/54] iotests: Add test for COR across nodes

RH-Author: Max Reitz <mreitz@redhat.com>

Message-id: <20180618161212.14444-11-mreitz@redhat.com>

Patchwork-id: 80771

O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 10/10] iotests: Add test for COR across nodes

Bugzilla: 1518738

RH-Acked-by: John Snow <jsnow@redhat.com>

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

COR across nodes (that is, you have some filter node between the

actually COR target and the node that performs the COR) cannot reliably

work together with the permission system when there is no explicit COR

node that can request the WRITE_UNCHANGED permission for its child.

This is because COR (currently) sneaks its requests by the usual

permission checks, so it can work without a WRITE* permission; but if

there is a filter node in between, that will re-issue the request, which

then passes through the usual check -- and if nobody has requested a

WRITE_UNCHANGED permission, that check will fail.

There is no real direct fix apart from hoping that there is someone who

has requested that permission; in case of just the qemu-io HMP command

(and no guest device), however, that is not the case.  The real real fix

is to implement the copy-on-read flag through an implicitly added COR

node.  Such a node can request the necessary permissions as shown in

this test.

Signed-off-by: Max Reitz <mreitz@redhat.com>

Message-id: 20180421132929.21610-10-mreitz@redhat.com

Reviewed-by: Kevin Wolf <kwolf@redhat.com>

Signed-off-by: Max Reitz <mreitz@redhat.com>

(cherry picked from commit 3e7a95feb9b5d66cff7fee38b3c423135ed245f6)

Signed-off-by: Max Reitz <mreitz@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 tests/qemu-iotests/216     | 115 +++++++++++++++++++++++++++++++++++++++++++++

 tests/qemu-iotests/216.out |  28 +++++++++++

 tests/qemu-iotests/group   |   1 +

 3 files changed, 144 insertions(+)

 create mode 100755 tests/qemu-iotests/216

 create mode 100644 tests/qemu-iotests/216.out

diff --git a/tests/qemu-iotests/216 b/tests/qemu-iotests/216

new file mode 100755

index 0000000..ca9b47a

--- /dev/null

+++ b/tests/qemu-iotests/216

@@ -0,0 +1,115 @@

+#!/usr/bin/env python

+#

+# Copy-on-read tests using a COR filter node

+#

+# Copyright (C) 2018 Red Hat, Inc.

+#

+# This program is free software; you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation; either version 2 of the License, or

+# (at your option) any later version.

+#

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+# GNU General Public License for more details.

+#

+# You should have received a copy of the GNU General Public License

+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

+#

+# Creator/Owner: Max Reitz <mreitz@redhat.com>

+

+import iotests

+from iotests import log, qemu_img_pipe, qemu_io, filter_qemu_io

+

+# Need backing file support

+iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'])

+iotests.verify_platform(['linux'])

+

+log('')

+log('=== Copy-on-read across nodes ===')

+log('')

+

+# The old copy-on-read mechanism without a filter node cannot request

+# WRITE_UNCHANGED permissions for its child.  Therefore it just tries

+# to sneak its write by the usual permission system and holds its

+# fingers crossed.  However, that sneaking does not work so well when

+# there is a filter node in the way: That will receive the write

+# request and re-issue a new one to its child, which this time is a

+# proper write request that will make the permission system cough --

+# unless there is someone at the top (like a guest device) that has

+# requested write permissions.

+#

+# A COR filter node, however, can request the proper permissions for

+# its child and therefore is not hit by this issue.

+

+with iotests.FilePath('base.img') as base_img_path, \

+     iotests.FilePath('top.img') as top_img_path, \

+     iotests.VM() as vm:

+

+    log('--- Setting up images ---')

+    log('')

+

+    qemu_img_pipe('create', '-f', iotests.imgfmt, base_img_path, '64M')

+

+    log(filter_qemu_io(qemu_io(base_img_path, '-c', 'write -P 1 0M 1M')))

+

+    qemu_img_pipe('create', '-f', iotests.imgfmt, '-b', base_img_path,

+                  top_img_path)

+

+    log(filter_qemu_io(qemu_io(top_img_path,  '-c', 'write -P 2 1M 1M')))

+

+    log('')

+    log('--- Doing COR ---')

+    log('')

+

+    # Compare with e.g. the following:

+    #   vm.add_drive_raw('if=none,node-name=node0,copy-on-read=on,driver=raw,' \

+    #                    'file.driver=%s,file.file.filename=%s' %

+    #                       (iotests.imgfmt, top_img_path))

+    # (Remove the blockdev-add instead.)

+    # ((Not tested here because it hits an assertion in the permission

+    #   system.))

+

+    vm.launch()

+

+    log(vm.qmp('blockdev-add',

+                    node_name='node0',

+                    driver='copy-on-read',

+                    file={

+                        'driver': 'raw',

+                        'file': {

+                            'driver': 'copy-on-read',

+                            'file': {

+                                'driver': 'raw',

+                                'file': {

+                                    'driver': iotests.imgfmt,

+                                    'file': {

+                                        'driver': 'file',

+                                        'filename': top_img_path

+                                    },

+                                    'backing': {

+                                        'driver': iotests.imgfmt,

+                                        'file': {

+                                            'driver': 'file',

+                                            'filename': base_img_path

+                                        }

+                                    }

+                                }

+                            }

+                        }

+                    }))

+

+    # Trigger COR

+    log(vm.qmp('human-monitor-command',

+               command_line='qemu-io node0 "read 0 64M"'))

+

+    vm.shutdown()

+

+    log('')

+    log('--- Checking COR result ---')

+    log('')

+

+    log(filter_qemu_io(qemu_io(base_img_path, '-c', 'discard 0 64M')))

+    log(filter_qemu_io(qemu_io(top_img_path,  '-c', 'read -P 1 0M 1M')))

+    log(filter_qemu_io(qemu_io(top_img_path,  '-c', 'read -P 2 1M 1M')))

diff --git a/tests/qemu-iotests/216.out b/tests/qemu-iotests/216.out

new file mode 100644

index 0000000..d3fc590

--- /dev/null

+++ b/tests/qemu-iotests/216.out

@@ -0,0 +1,28 @@

+

+=== Copy-on-read across nodes ===

+

+--- Setting up images ---

+

+wrote 1048576/1048576 bytes at offset 0

+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+

+wrote 1048576/1048576 bytes at offset 1048576

+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+

+

+--- Doing COR ---

+

+{u'return': {}}

+{u'return': u''}

+

+--- Checking COR result ---

+

+discard 67108864/67108864 bytes at offset 0

+64 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+

+read 1048576/1048576 bytes at offset 0

+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+

+read 1048576/1048576 bytes at offset 1048576

+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+

diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group

index cd5d26c..d228008 100644

--- a/tests/qemu-iotests/group

+++ b/tests/qemu-iotests/group

@@ -214,4 +214,5 @@

 213 rw auto quick

 214 rw auto

 215 rw auto quick

+216 rw auto quick

 218 rw auto quick

-- 

1.8.3.1