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",
30 .filtered_child_is_backing
= true,
31 .bdrv_child_perm
= bdrv_default_perms
,
34 static void no_perm_default_perms(BlockDriverState
*bs
, BdrvChild
*c
,
36 BlockReopenQueue
*reopen_queue
,
37 uint64_t perm
, uint64_t shared
,
38 uint64_t *nperm
, uint64_t *nshared
)
41 *nshared
= BLK_PERM_ALL
;
44 static BlockDriver bdrv_no_perm
= {
45 .format_name
= "no-perm",
46 .supports_backing
= true,
47 .bdrv_child_perm
= no_perm_default_perms
,
50 static void exclusive_write_perms(BlockDriverState
*bs
, BdrvChild
*c
,
52 BlockReopenQueue
*reopen_queue
,
53 uint64_t perm
, uint64_t shared
,
54 uint64_t *nperm
, uint64_t *nshared
)
56 *nperm
= BLK_PERM_WRITE
;
57 *nshared
= BLK_PERM_ALL
& ~BLK_PERM_WRITE
;
60 static BlockDriver bdrv_exclusive_writer
= {
61 .format_name
= "exclusive-writer",
63 .filtered_child_is_backing
= true,
64 .bdrv_child_perm
= exclusive_write_perms
,
67 static BlockDriverState
*no_perm_node(const char *name
)
69 return bdrv_new_open_driver(&bdrv_no_perm
, name
, BDRV_O_RDWR
, &error_abort
);
72 static BlockDriverState
*pass_through_node(const char *name
)
74 return bdrv_new_open_driver(&bdrv_pass_through
, name
,
75 BDRV_O_RDWR
, &error_abort
);
78 static BlockDriverState
*exclusive_writer_node(const char *name
)
80 return bdrv_new_open_driver(&bdrv_exclusive_writer
, name
,
81 BDRV_O_RDWR
, &error_abort
);
85 * test_update_perm_tree
87 * When checking node for a possibility to update permissions, it's subtree
88 * should be correctly checked too. New permissions for each node should be
89 * calculated and checked in context of permissions of other nodes. If we
90 * check new permissions of the node only in context of old permissions of
91 * its neighbors, we can finish up with wrong permission graph.
93 * This test firstly create the following graph:
99 * | shared: except write
101 * +--------------------+ +----------------+
102 * | passthrough filter |--------->| null-co node |
103 * +--------------------+ +----------------+
106 * and then, tries to append filter under node. Expected behavior: fail.
107 * Otherwise we'll get the following picture, with two BdrvChild'ren, having
108 * write permission to one node, without actually sharing it.
114 * | perm: write, read
115 * | shared: except write
117 * +--------------------+
118 * | passthrough filter |
119 * +--------------------+
121 * perm: write, read | | perm: write, read
122 * shared: except write | | shared: except write
128 static void test_update_perm_tree(void)
132 BlockBackend
*root
= blk_new(qemu_get_aio_context(),
133 BLK_PERM_WRITE
| BLK_PERM_CONSISTENT_READ
,
134 BLK_PERM_ALL
& ~BLK_PERM_WRITE
);
135 BlockDriverState
*bs
= no_perm_node("node");
136 BlockDriverState
*filter
= pass_through_node("filter");
138 blk_insert_bs(root
, bs
, &error_abort
);
140 bdrv_graph_wrlock(NULL
);
141 bdrv_attach_child(filter
, bs
, "child", &child_of_bds
,
142 BDRV_CHILD_DATA
, &error_abort
);
143 bdrv_graph_wrunlock();
145 aio_context_acquire(qemu_get_aio_context());
146 ret
= bdrv_append(filter
, bs
, NULL
);
147 g_assert_cmpint(ret
, <, 0);
148 aio_context_release(qemu_get_aio_context());
155 * test_should_update_child
157 * Test that bdrv_replace_node, and concretely should_update_child
158 * do the right thing, i.e. not creating loops on the graph.
160 * The test does the following:
163 * +------+ +--------+
164 * | root | | filter |
165 * +------+ +--------+
169 * +------+ +--------+
170 * | node |<---------| target |
171 * +------+ backing +--------+
173 * 2. Append @filter above @node. If should_update_child works correctly,
174 * it understands, that backing child of @target should not be updated,
175 * as it will create a loop on node graph. Resulting picture should
176 * be the left one, not the right:
184 * +--------+ target +--------+ target
185 * | filter |--------------+ | filter |--------------+
186 * +--------+ | +--------+ |
188 * backing| | backing| | +--------+
189 * v v | +-----------| target |
190 * +------+ +--------+ v backing +--------+
191 * | node |<---------| target | +------+
192 * +------+ backing +--------+ | node |
195 * (good picture) (bad picture)
198 static void test_should_update_child(void)
200 BlockBackend
*root
= blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL
);
201 BlockDriverState
*bs
= no_perm_node("node");
202 BlockDriverState
*filter
= no_perm_node("filter");
203 BlockDriverState
*target
= no_perm_node("target");
205 blk_insert_bs(root
, bs
, &error_abort
);
207 bdrv_set_backing_hd(target
, bs
, &error_abort
);
209 g_assert(target
->backing
->bs
== bs
);
210 bdrv_graph_wrlock(NULL
);
211 bdrv_attach_child(filter
, target
, "target", &child_of_bds
,
212 BDRV_CHILD_DATA
, &error_abort
);
213 bdrv_graph_wrunlock();
214 aio_context_acquire(qemu_get_aio_context());
215 bdrv_append(filter
, bs
, &error_abort
);
216 aio_context_release(qemu_get_aio_context());
217 g_assert(target
->backing
->bs
== bs
);
225 * test_parallel_exclusive_write
227 * Check that when we replace node, old permissions of the node being removed
228 * doesn't break the replacement.
230 static void test_parallel_exclusive_write(void)
232 BlockDriverState
*top
= exclusive_writer_node("top");
233 BlockDriverState
*base
= no_perm_node("base");
234 BlockDriverState
*fl1
= pass_through_node("fl1");
235 BlockDriverState
*fl2
= pass_through_node("fl2");
238 * bdrv_attach_child() eats child bs reference, so we need two @base
239 * references for two filters:
243 bdrv_graph_wrlock(NULL
);
244 bdrv_attach_child(top
, fl1
, "backing", &child_of_bds
,
245 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
247 bdrv_attach_child(fl1
, base
, "backing", &child_of_bds
,
248 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
250 bdrv_attach_child(fl2
, base
, "backing", &child_of_bds
,
251 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
253 bdrv_graph_wrunlock();
255 bdrv_replace_node(fl1
, fl2
, &error_abort
);
262 * write-to-selected node may have several DATA children, one of them may be
263 * "selected". Exclusive write permission is taken on selected child.
265 * We don't realize write handler itself, as we need only to test how permission
268 typedef struct BDRVWriteToSelectedState
{
270 } BDRVWriteToSelectedState
;
272 static void write_to_selected_perms(BlockDriverState
*bs
, BdrvChild
*c
,
274 BlockReopenQueue
*reopen_queue
,
275 uint64_t perm
, uint64_t shared
,
276 uint64_t *nperm
, uint64_t *nshared
)
278 BDRVWriteToSelectedState
*s
= bs
->opaque
;
280 if (s
->selected
&& c
== s
->selected
) {
281 *nperm
= BLK_PERM_WRITE
;
282 *nshared
= BLK_PERM_ALL
& ~BLK_PERM_WRITE
;
285 *nshared
= BLK_PERM_ALL
;
289 static BlockDriver bdrv_write_to_selected
= {
290 .format_name
= "write-to-selected",
291 .instance_size
= sizeof(BDRVWriteToSelectedState
),
292 .bdrv_child_perm
= write_to_selected_perms
,
297 * The following test shows that topological-sort order is required for
298 * permission update, simple DFS is not enough.
300 * Consider the block driver (write-to-selected) which has two children: one is
301 * selected so we have exclusive write access to it and for the other one we
302 * don't need any specific permissions.
304 * And, these two children has a common base child, like this:
305 * (additional "top" on top is used in test just because the only public
306 * function to update permission should get a specific child to update.
307 * Making bdrv_refresh_perms() public just for this test isn't worth it)
309 * ┌─────┐ ┌───────────────────┐ ┌─────┐
310 * │ fl2 │ ◀── │ write-to-selected │ ◀── │ top │
311 * └─────┘ └───────────────────┘ └─────┘
325 * So, exclusive write is propagated.
327 * Assume, we want to select fl2 instead of fl1.
328 * So, we set some option for write-to-selected driver and do permission update.
330 * With simple DFS, if permission update goes first through
331 * write-to-selected -> fl1 -> base branch it will succeed: it firstly drop
332 * exclusive write permissions and than apply them for another BdrvChildren.
333 * But if permission update goes first through write-to-selected -> fl2 -> base
334 * branch it will fail, as when we try to update fl2->base child, old not yet
335 * updated fl1->base child will be in conflict.
337 * With topological-sort order we always update parents before children, so fl1
338 * and fl2 are both updated when we update base and there is no conflict.
340 static void test_parallel_perm_update(void)
342 BlockDriverState
*top
= no_perm_node("top");
343 BlockDriverState
*ws
=
344 bdrv_new_open_driver(&bdrv_write_to_selected
, "ws", BDRV_O_RDWR
,
346 BDRVWriteToSelectedState
*s
= ws
->opaque
;
347 BlockDriverState
*base
= no_perm_node("base");
348 BlockDriverState
*fl1
= pass_through_node("fl1");
349 BlockDriverState
*fl2
= pass_through_node("fl2");
350 BdrvChild
*c_fl1
, *c_fl2
;
353 * bdrv_attach_child() eats child bs reference, so we need two @base
354 * references for two filters:
358 bdrv_graph_wrlock(NULL
);
359 bdrv_attach_child(top
, ws
, "file", &child_of_bds
, BDRV_CHILD_DATA
,
361 c_fl1
= bdrv_attach_child(ws
, fl1
, "first", &child_of_bds
,
362 BDRV_CHILD_DATA
, &error_abort
);
363 c_fl2
= bdrv_attach_child(ws
, fl2
, "second", &child_of_bds
,
364 BDRV_CHILD_DATA
, &error_abort
);
365 bdrv_attach_child(fl1
, base
, "backing", &child_of_bds
,
366 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
368 bdrv_attach_child(fl2
, base
, "backing", &child_of_bds
,
369 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
371 bdrv_graph_wrunlock();
373 /* Select fl1 as first child to be active */
376 bdrv_graph_rdlock_main_loop();
378 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
380 assert(c_fl1
->perm
& BLK_PERM_WRITE
);
381 assert(!(c_fl2
->perm
& BLK_PERM_WRITE
));
383 /* Now, try to switch active child and update permissions */
385 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
387 assert(c_fl2
->perm
& BLK_PERM_WRITE
);
388 assert(!(c_fl1
->perm
& BLK_PERM_WRITE
));
390 /* Switch once more, to not care about real child order in the list */
392 bdrv_child_refresh_perms(top
, top
->children
.lh_first
, &error_abort
);
394 assert(c_fl1
->perm
& BLK_PERM_WRITE
);
395 assert(!(c_fl2
->perm
& BLK_PERM_WRITE
));
397 bdrv_graph_rdunlock_main_loop();
402 * It's possible that filter required permissions allows to insert it to backing
405 * 1. [top] -> [filter] -> [base]
407 * but doesn't allow to add it as a branch:
413 * So, inserting such filter should do all graph modifications and only then
414 * update permissions. If we try to go through intermediate state [2] and update
415 * permissions on it we'll fail.
417 * Let's check that bdrv_append() can append such a filter.
419 static void test_append_greedy_filter(void)
421 BlockDriverState
*top
= exclusive_writer_node("top");
422 BlockDriverState
*base
= no_perm_node("base");
423 BlockDriverState
*fl
= exclusive_writer_node("fl1");
425 bdrv_graph_wrlock(NULL
);
426 bdrv_attach_child(top
, base
, "backing", &child_of_bds
,
427 BDRV_CHILD_FILTERED
| BDRV_CHILD_PRIMARY
,
429 bdrv_graph_wrunlock();
431 aio_context_acquire(qemu_get_aio_context());
432 bdrv_append(fl
, base
, &error_abort
);
433 aio_context_release(qemu_get_aio_context());
438 int main(int argc
, char *argv
[])
441 qemu_init_main_loop(&error_abort
);
443 g_test_init(&argc
, &argv
, NULL
);
445 g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree
);
446 g_test_add_func("/bdrv-graph-mod/should-update-child",
447 test_should_update_child
);
448 g_test_add_func("/bdrv-graph-mod/parallel-perm-update",
449 test_parallel_perm_update
);
450 g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
451 test_parallel_exclusive_write
);
452 g_test_add_func("/bdrv-graph-mod/append-greedy-filter",
453 test_append_greedy_filter
);