1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
/*
* Block node graph modifications tests
*
* Copyright (c) 2019 Virtuozzo International GmbH. All rights reserved.
*
* 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/>.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/main-loop.h"
#include "block/block_int.h"
#include "sysemu/block-backend.h"
static BlockDriver bdrv_pass_through = {
.format_name = "pass-through",
.bdrv_child_perm = bdrv_filter_default_perms,
};
static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
*nperm = 0;
*nshared = BLK_PERM_ALL;
}
static BlockDriver bdrv_no_perm = {
.format_name = "no-perm",
.bdrv_child_perm = no_perm_default_perms,
};
static BlockDriverState *no_perm_node(const char *name)
{
return bdrv_new_open_driver(&bdrv_no_perm, name, BDRV_O_RDWR, &error_abort);
}
static BlockDriverState *pass_through_node(const char *name)
{
return bdrv_new_open_driver(&bdrv_pass_through, name,
BDRV_O_RDWR, &error_abort);
}
/*
* test_update_perm_tree
*
* When checking node for a possibility to update permissions, it's subtree
* should be correctly checked too. New permissions for each node should be
* calculated and checked in context of permissions of other nodes. If we
* check new permissions of the node only in context of old permissions of
* its neighbors, we can finish up with wrong permission graph.
*
* This test firstly create the following graph:
* +--------+
* | root |
* +--------+
* |
* | perm: write, read
* | shared: except write
* v
* +-------------------+ +----------------+
* | passtrough filter |---------->| null-co node |
* +-------------------+ +----------------+
*
*
* and then, tries to append filter under node. Expected behavior: fail.
* Otherwise we'll get the following picture, with two BdrvChild'ren, having
* write permission to one node, without actually sharing it.
*
* +--------+
* | root |
* +--------+
* |
* | perm: write, read
* | shared: except write
* v
* +-------------------+
* | passtrough filter |
* +-------------------+
* | |
* perm: write, read | | perm: write, read
* shared: except write | | shared: except write
* v v
* +----------------+
* | null co node |
* +----------------+
*/
static void test_update_perm_tree(void)
{
Error *local_err = NULL;
BlockBackend *root = blk_new(qemu_get_aio_context(),
BLK_PERM_WRITE | BLK_PERM_CONSISTENT_READ,
BLK_PERM_ALL & ~BLK_PERM_WRITE);
BlockDriverState *bs = no_perm_node("node");
BlockDriverState *filter = pass_through_node("filter");
blk_insert_bs(root, bs, &error_abort);
bdrv_attach_child(filter, bs, "child", &child_file, &error_abort);
bdrv_append(filter, bs, &local_err);
g_assert_nonnull(local_err);
error_free(local_err);
blk_unref(root);
}
/*
* test_should_update_child
*
* Test that bdrv_replace_node, and concretely should_update_child
* do the right thing, i.e. not creating loops on the graph.
*
* The test does the following:
* 1. initial graph:
*
* +------+ +--------+
* | root | | filter |
* +------+ +--------+
* | |
* root| target|
* v v
* +------+ +--------+
* | node |<---------| target |
* +------+ backing +--------+
*
* 2. Append @filter above @node. If should_update_child works correctly,
* it understands, that backing child of @target should not be updated,
* as it will create a loop on node graph. Resulting picture should
* be the left one, not the right:
*
* +------+ +------+
* | root | | root |
* +------+ +------+
* | |
* root| root|
* v v
* +--------+ target +--------+ target
* | filter |--------------+ | filter |--------------+
* +--------+ | +--------+ |
* | | | ^ v
* backing| | backing| | +--------+
* v v | +-----------| target |
* +------+ +--------+ v backing +--------+
* | node |<---------| target | +------+
* +------+ backing +--------+ | node |
* +------+
*
* (good picture) (bad picture)
*
*/
static void test_should_update_child(void)
{
BlockBackend *root = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
BlockDriverState *bs = no_perm_node("node");
BlockDriverState *filter = no_perm_node("filter");
BlockDriverState *target = no_perm_node("target");
blk_insert_bs(root, bs, &error_abort);
bdrv_set_backing_hd(target, bs, &error_abort);
g_assert(target->backing->bs == bs);
bdrv_attach_child(filter, target, "target", &child_file, &error_abort);
bdrv_append(filter, bs, &error_abort);
g_assert(target->backing->bs == bs);
bdrv_unref(bs);
blk_unref(root);
}
int main(int argc, char *argv[])
{
bdrv_init();
qemu_init_main_loop(&error_abort);
g_test_init(&argc, &argv, NULL);
g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree);
g_test_add_func("/bdrv-graph-mod/should-update-child",
test_should_update_child);
return g_test_run();
}
|
