2 * Block node graph modifications tests
4 * Copyright (c) 2019-2021 Virtuozzo International GmbH. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include "qemu/osdep.h"
22 #include "qapi/error.h"
23 #include "qemu/main-loop.h"
24 #include "block/block_int.h"
25 #include "sysemu/block-backend.h"
27 static BlockDriver bdrv_pass_through
= {
28 .format_name
= "pass-through",
29 .bdrv_child_perm
= bdrv_default_perms
,
32 static void no_perm_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
34 BlockReopenQueue
*reopen_queue
,
35 uint64_t perm
, uint64_t shared
,
36 uint64_t *nperm
, uint64_t *nshared
)
39 *nshared
= BLK_PERM_ALL
;
42 static BlockDriver bdrv_no_perm
= {
43 .format_name
= "no-perm",
44 .bdrv_child_perm
= no_perm_default_perms
,
47 static void exclusive_write_perms(BlockDriverState
*bs
, BdrvChild
*c
,
49 BlockReopenQueue
*reopen_queue
,
50 uint64_t perm
, uint64_t shared
,
51 uint64_t *nperm
, uint64_t *nshared
)
53 *nperm
= BLK_PERM_WRITE
;
54 *nshared
= BLK_PERM_ALL
& ~BLK_PERM_WRITE
;
57 static BlockDriver bdrv_exclusive_writer
= {
58 .format_name
= "exclusive-writer",
59 .bdrv_child_perm
= exclusive_write_perms
,
62 static BlockDriverState
*no_perm_node(const char *name
)
64 return bdrv_new_open_driver(&bdrv_no_perm
, name
, BDRV_O_RDWR
, &error_abort
);
67 static BlockDriverState
*pass_through_node(const char *name
)
69 return bdrv_new_open_driver(&bdrv_pass_through
, name
,
70 BDRV_O_RDWR
, &error_abort
);
73 static BlockDriverState
*exclusive_writer_node(const char *name
)
75 return bdrv_new_open_driver(&bdrv_exclusive_writer
, name
,
76 BDRV_O_RDWR
, &error_abort
);
80 * test_update_perm_tree
82 * When checking node for a possibility to update permissions, it's subtree
83 * should be correctly checked too. New permissions for each node should be
84 * calculated and checked in context of permissions of other nodes. If we
85 * check new permissions of the node only in context of old permissions of
86 * its neighbors, we can finish up with wrong permission graph.
88 * This test firstly create the following graph:
94 * | shared: except write
96 * +-------------------+ +----------------+
97 * | passtrough filter |---------->| null-co node |
98 * +-------------------+ +----------------+
101 * and then, tries to append filter under node. Expected behavior: fail.
102 * Otherwise we'll get the following picture, with two BdrvChild'ren, having
103 * write permission to one node, without actually sharing it.
109 * | perm: write, read
110 * | shared: except write
112 * +-------------------+
113 * | passtrough filter |
114 * +-------------------+
116 * perm: write, read | | perm: write, read
117 * shared: except write | | shared: except write
123 static void test_update_perm_tree(void)
127 BlockBackend
*root
= blk_new(qemu_get_aio_context(),
128 BLK_PERM_WRITE
| BLK_PERM_CONSISTENT_READ
,
129 BLK_PERM_ALL
& ~BLK_PERM_WRITE
);
130 BlockDriverState
*bs
= no_perm_node("node");
131 BlockDriverState
*filter
= pass_through_node("filter");
133 blk_insert_bs(root
, bs
, &error_abort
);
135 bdrv_attach_child(filter
, bs
, "child", &child_of_bds
,
136 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
, &error_abort
);
138 ret
= bdrv_append(filter
, bs
, NULL
);
139 g_assert_cmpint(ret
, <, 0);
146 * test_should_update_child
148 * Test that bdrv_replace_node, and concretely should_update_child
149 * do the right thing, i.e. not creating loops on the graph.
151 * The test does the following:
154 * +------+ +--------+
155 * | root | | filter |
156 * +------+ +--------+
160 * +------+ +--------+
161 * | node |<---------| target |
162 * +------+ backing +--------+
164 * 2. Append @filter above @node. If should_update_child works correctly,
165 * it understands, that backing child of @target should not be updated,
166 * as it will create a loop on node graph. Resulting picture should
167 * be the left one, not the right:
175 * +--------+ target +--------+ target
176 * | filter |--------------+ | filter |--------------+
177 * +--------+ | +--------+ |
179 * backing| | backing| | +--------+
180 * v v | +-----------| target |
181 * +------+ +--------+ v backing +--------+
182 * | node |<---------| target | +------+
183 * +------+ backing +--------+ | node |
186 * (good picture) (bad picture)
189 static void test_should_update_child(void)
191 BlockBackend
*root
= blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL
);
192 BlockDriverState
*bs
= no_perm_node("node");
193 BlockDriverState
*filter
= no_perm_node("filter");
194 BlockDriverState
*target
= no_perm_node("target");
196 blk_insert_bs(root
, bs
, &error_abort
);
198 bdrv_set_backing_hd(target
, bs
, &error_abort
);
200 g_assert(target
->backing
->bs
== bs
);
201 bdrv_attach_child(filter
, target
, "target", &child_of_bds
,
202 BDRV_CHILD_DATA
, &error_abort
);
203 bdrv_append(filter
, bs
, &error_abort
);
204 g_assert(target
->backing
->bs
== bs
);
212 * test_parallel_exclusive_write
214 * Check that when we replace node, old permissions of the node being removed
215 * doesn't break the replacement.
217 static void test_parallel_exclusive_write(void)
219 BlockDriverState
*top
= exclusive_writer_node("top");
220 BlockDriverState
*base
= no_perm_node("base");
221 BlockDriverState
*fl1
= pass_through_node("fl1");
222 BlockDriverState
*fl2
= pass_through_node("fl2");
225 * bdrv_attach_child() eats child bs reference, so we need two @base
226 * references for two filters:
230 bdrv_attach_child(top
, fl1
, "backing", &child_of_bds
, BDRV_CHILD_DATA
,
232 bdrv_attach_child(fl1
, base
, "backing", &child_of_bds
, BDRV_CHILD_FILTERED
,
234 bdrv_attach_child(fl2
, base
, "backing", &child_of_bds
, BDRV_CHILD_FILTERED
,
237 bdrv_replace_node(fl1
, fl2
, &error_abort
);
243 static void write_to_file_perms(BlockDriverState
*bs
, BdrvChild
*c
,
245 BlockReopenQueue
*reopen_queue
,
246 uint64_t perm
, uint64_t shared
,
247 uint64_t *nperm
, uint64_t *nshared
)
249 if (bs
->file
&& c
== bs
->file
) {
250 *nperm
= BLK_PERM_WRITE
;
251 *nshared
= BLK_PERM_ALL
& ~BLK_PERM_WRITE
;
254 *nshared
= BLK_PERM_ALL
;
258 static BlockDriver bdrv_write_to_file
= {
259 .format_name
= "tricky-perm",
260 .bdrv_child_perm
= write_to_file_perms
,
265 * The following test shows that topological-sort order is required for
266 * permission update, simple DFS is not enough.
268 * Consider the block driver which has two filter children: one active
269 * with exclusive write access and one inactive with no specific
272 * And, these two children has a common base child, like this:
275 * │ fl2 │ ◀── │ top │
290 * So, exclusive write is propagated.
292 * Assume, we want to make fl2 active instead of fl1.
293 * So, we set some option for top driver and do permission update.
295 * With simple DFS, if permission update goes first through
296 * top->fl1->base branch it will succeed: it firstly drop exclusive write
297 * permissions and than apply them for another BdrvChildren.
298 * But if permission update goes first through top->fl2->base branch it
299 * will fail, as when we try to update fl2->base child, old not yet
300 * updated fl1->base child will be in conflict.
302 * With topological-sort order we always update parents before children, so fl1
303 * and fl2 are both updated when we update base and there is no conflict.
305 static void test_parallel_perm_update(void)
307 BlockDriverState
*top
= no_perm_node("top");
308 BlockDriverState
*tricky
=
309 bdrv_new_open_driver(&bdrv_write_to_file
, "tricky", BDRV_O_RDWR
,
311 BlockDriverState
*base
= no_perm_node("base");
312 BlockDriverState
*fl1
= pass_through_node("fl1");
313 BlockDriverState
*fl2
= pass_through_node("fl2");
314 BdrvChild
*c_fl1
, *c_fl2
;
317 * bdrv_attach_child() eats child bs reference, so we need two @base
318 * references for two filters:
322 bdrv_attach_child(top
, tricky
, "file", &child_of_bds
, BDRV_CHILD_DATA
,
324 c_fl1
= bdrv_attach_child(tricky
, fl1
, "first", &child_of_bds
,
325 BDRV_CHILD_FILTERED
, &error_abort
);
326 c_fl2
= bdrv_attach_child(tricky
, fl2
, "second", &child_of_bds
,
327 BDRV_CHILD_FILTERED
, &error_abort
);
328 bdrv_attach_child(fl1
, base
, "backing", &child_of_bds
, BDRV_CHILD_FILTERED
,
330 bdrv_attach_child(fl2
, base
, "backing", &child_of_bds
, BDRV_CHILD_FILTERED
,
333 /* Select fl1 as first child to be active */
334 tricky
->file
= c_fl1
;
335 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
337 assert(c_fl1
->perm
& BLK_PERM_WRITE
);
338 assert(!(c_fl2
->perm
& BLK_PERM_WRITE
));
340 /* Now, try to switch active child and update permissions */
341 tricky
->file
= c_fl2
;
342 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
344 assert(c_fl2
->perm
& BLK_PERM_WRITE
);
345 assert(!(c_fl1
->perm
& BLK_PERM_WRITE
));
347 /* Switch once more, to not care about real child order in the list */
348 tricky
->file
= c_fl1
;
349 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
351 assert(c_fl1
->perm
& BLK_PERM_WRITE
);
352 assert(!(c_fl2
->perm
& BLK_PERM_WRITE
));
358 * It's possible that filter required permissions allows to insert it to backing
361 * 1. [top] -> [filter] -> [base]
363 * but doesn't allow to add it as a branch:
369 * So, inserting such filter should do all graph modifications and only then
370 * update permissions. If we try to go through intermediate state [2] and update
371 * permissions on it we'll fail.
373 * Let's check that bdrv_append() can append such a filter.
375 static void test_append_greedy_filter(void)
377 BlockDriverState
*top
= exclusive_writer_node("top");
378 BlockDriverState
*base
= no_perm_node("base");
379 BlockDriverState
*fl
= exclusive_writer_node("fl1");
381 bdrv_attach_child(top
, base
, "backing", &child_of_bds
, BDRV_CHILD_COW
,
384 bdrv_append(fl
, base
, &error_abort
);
389 int main(int argc
, char *argv
[])
392 qemu_init_main_loop(&error_abort
);
394 g_test_init(&argc
, &argv
, NULL
);
396 g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree
);
397 g_test_add_func("/bdrv-graph-mod/should-update-child",
398 test_should_update_child
);
399 g_test_add_func("/bdrv-graph-mod/parallel-perm-update",
400 test_parallel_perm_update
);
401 g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
402 test_parallel_exclusive_write
);
403 g_test_add_func("/bdrv-graph-mod/append-greedy-filter",
404 test_append_greedy_filter
);