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2dbfadf6 VSO |
1 | /* |
2 | * Block node graph modifications tests | |
3 | * | |
d71cc67d | 4 | * Copyright (c) 2019-2021 Virtuozzo International GmbH. All rights reserved. |
2dbfadf6 VSO |
5 | * |
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. | |
10 | * | |
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. | |
15 | * | |
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/>. | |
18 | * | |
19 | */ | |
20 | ||
21 | #include "qemu/osdep.h" | |
22 | #include "qapi/error.h" | |
db725815 | 23 | #include "qemu/main-loop.h" |
2dbfadf6 VSO |
24 | #include "block/block_int.h" |
25 | #include "sysemu/block-backend.h" | |
26 | ||
27 | static BlockDriver bdrv_pass_through = { | |
28 | .format_name = "pass-through", | |
1921b4f7 VSO |
29 | .is_filter = true, |
30 | .filtered_child_is_backing = true, | |
69dca43d | 31 | .bdrv_child_perm = bdrv_default_perms, |
2dbfadf6 VSO |
32 | }; |
33 | ||
34 | static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c, | |
bf8e925e | 35 | BdrvChildRole role, |
2dbfadf6 VSO |
36 | BlockReopenQueue *reopen_queue, |
37 | uint64_t perm, uint64_t shared, | |
38 | uint64_t *nperm, uint64_t *nshared) | |
39 | { | |
40 | *nperm = 0; | |
41 | *nshared = BLK_PERM_ALL; | |
42 | } | |
43 | ||
44 | static BlockDriver bdrv_no_perm = { | |
45 | .format_name = "no-perm", | |
25f78d9e | 46 | .supports_backing = true, |
2dbfadf6 VSO |
47 | .bdrv_child_perm = no_perm_default_perms, |
48 | }; | |
49 | ||
d71cc67d VSO |
50 | static void exclusive_write_perms(BlockDriverState *bs, BdrvChild *c, |
51 | BdrvChildRole role, | |
52 | BlockReopenQueue *reopen_queue, | |
53 | uint64_t perm, uint64_t shared, | |
54 | uint64_t *nperm, uint64_t *nshared) | |
55 | { | |
56 | *nperm = BLK_PERM_WRITE; | |
57 | *nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE; | |
58 | } | |
59 | ||
60 | static BlockDriver bdrv_exclusive_writer = { | |
61 | .format_name = "exclusive-writer", | |
1921b4f7 VSO |
62 | .is_filter = true, |
63 | .filtered_child_is_backing = true, | |
d71cc67d VSO |
64 | .bdrv_child_perm = exclusive_write_perms, |
65 | }; | |
66 | ||
2dbfadf6 VSO |
67 | static BlockDriverState *no_perm_node(const char *name) |
68 | { | |
69 | return bdrv_new_open_driver(&bdrv_no_perm, name, BDRV_O_RDWR, &error_abort); | |
70 | } | |
71 | ||
72 | static BlockDriverState *pass_through_node(const char *name) | |
73 | { | |
74 | return bdrv_new_open_driver(&bdrv_pass_through, name, | |
75 | BDRV_O_RDWR, &error_abort); | |
76 | } | |
77 | ||
d71cc67d VSO |
78 | static BlockDriverState *exclusive_writer_node(const char *name) |
79 | { | |
80 | return bdrv_new_open_driver(&bdrv_exclusive_writer, name, | |
81 | BDRV_O_RDWR, &error_abort); | |
82 | } | |
83 | ||
2dbfadf6 VSO |
84 | /* |
85 | * test_update_perm_tree | |
86 | * | |
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. | |
92 | * | |
93 | * This test firstly create the following graph: | |
94 | * +--------+ | |
95 | * | root | | |
96 | * +--------+ | |
97 | * | | |
98 | * | perm: write, read | |
99 | * | shared: except write | |
100 | * v | |
96420a30 MT |
101 | * +--------------------+ +----------------+ |
102 | * | passthrough filter |--------->| null-co node | | |
103 | * +--------------------+ +----------------+ | |
2dbfadf6 VSO |
104 | * |
105 | * | |
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. | |
109 | * | |
110 | * +--------+ | |
111 | * | root | | |
112 | * +--------+ | |
113 | * | | |
114 | * | perm: write, read | |
115 | * | shared: except write | |
116 | * v | |
96420a30 MT |
117 | * +--------------------+ |
118 | * | passthrough filter | | |
119 | * +--------------------+ | |
2dbfadf6 VSO |
120 | * | | |
121 | * perm: write, read | | perm: write, read | |
122 | * shared: except write | | shared: except write | |
123 | * v v | |
124 | * +----------------+ | |
125 | * | null co node | | |
126 | * +----------------+ | |
127 | */ | |
128 | static void test_update_perm_tree(void) | |
129 | { | |
934aee14 | 130 | int ret; |
2dbfadf6 | 131 | |
d861ab3a KW |
132 | BlockBackend *root = blk_new(qemu_get_aio_context(), |
133 | BLK_PERM_WRITE | BLK_PERM_CONSISTENT_READ, | |
2dbfadf6 VSO |
134 | BLK_PERM_ALL & ~BLK_PERM_WRITE); |
135 | BlockDriverState *bs = no_perm_node("node"); | |
136 | BlockDriverState *filter = pass_through_node("filter"); | |
137 | ||
138 | blk_insert_bs(root, bs, &error_abort); | |
139 | ||
a16be3cd | 140 | bdrv_attach_child(filter, bs, "child", &child_of_bds, |
1921b4f7 | 141 | BDRV_CHILD_DATA, &error_abort); |
2dbfadf6 | 142 | |
934aee14 VSO |
143 | ret = bdrv_append(filter, bs, NULL); |
144 | g_assert_cmpint(ret, <, 0); | |
2dbfadf6 | 145 | |
ae9d4417 | 146 | bdrv_unref(filter); |
2dbfadf6 VSO |
147 | blk_unref(root); |
148 | } | |
149 | ||
150 | /* | |
151 | * test_should_update_child | |
152 | * | |
153 | * Test that bdrv_replace_node, and concretely should_update_child | |
154 | * do the right thing, i.e. not creating loops on the graph. | |
155 | * | |
156 | * The test does the following: | |
157 | * 1. initial graph: | |
158 | * | |
159 | * +------+ +--------+ | |
160 | * | root | | filter | | |
161 | * +------+ +--------+ | |
162 | * | | | |
163 | * root| target| | |
164 | * v v | |
165 | * +------+ +--------+ | |
166 | * | node |<---------| target | | |
167 | * +------+ backing +--------+ | |
168 | * | |
169 | * 2. Append @filter above @node. If should_update_child works correctly, | |
170 | * it understands, that backing child of @target should not be updated, | |
171 | * as it will create a loop on node graph. Resulting picture should | |
172 | * be the left one, not the right: | |
173 | * | |
174 | * +------+ +------+ | |
175 | * | root | | root | | |
176 | * +------+ +------+ | |
177 | * | | | |
178 | * root| root| | |
179 | * v v | |
180 | * +--------+ target +--------+ target | |
181 | * | filter |--------------+ | filter |--------------+ | |
182 | * +--------+ | +--------+ | | |
183 | * | | | ^ v | |
184 | * backing| | backing| | +--------+ | |
185 | * v v | +-----------| target | | |
186 | * +------+ +--------+ v backing +--------+ | |
187 | * | node |<---------| target | +------+ | |
188 | * +------+ backing +--------+ | node | | |
189 | * +------+ | |
190 | * | |
191 | * (good picture) (bad picture) | |
192 | * | |
193 | */ | |
194 | static void test_should_update_child(void) | |
195 | { | |
d861ab3a | 196 | BlockBackend *root = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL); |
2dbfadf6 VSO |
197 | BlockDriverState *bs = no_perm_node("node"); |
198 | BlockDriverState *filter = no_perm_node("filter"); | |
199 | BlockDriverState *target = no_perm_node("target"); | |
200 | ||
201 | blk_insert_bs(root, bs, &error_abort); | |
202 | ||
203 | bdrv_set_backing_hd(target, bs, &error_abort); | |
204 | ||
205 | g_assert(target->backing->bs == bs); | |
a16be3cd HR |
206 | bdrv_attach_child(filter, target, "target", &child_of_bds, |
207 | BDRV_CHILD_DATA, &error_abort); | |
2dbfadf6 VSO |
208 | bdrv_append(filter, bs, &error_abort); |
209 | g_assert(target->backing->bs == bs); | |
210 | ||
ae9d4417 | 211 | bdrv_unref(filter); |
2dbfadf6 VSO |
212 | bdrv_unref(bs); |
213 | blk_unref(root); | |
214 | } | |
215 | ||
d71cc67d VSO |
216 | /* |
217 | * test_parallel_exclusive_write | |
218 | * | |
219 | * Check that when we replace node, old permissions of the node being removed | |
220 | * doesn't break the replacement. | |
221 | */ | |
222 | static void test_parallel_exclusive_write(void) | |
223 | { | |
224 | BlockDriverState *top = exclusive_writer_node("top"); | |
225 | BlockDriverState *base = no_perm_node("base"); | |
226 | BlockDriverState *fl1 = pass_through_node("fl1"); | |
227 | BlockDriverState *fl2 = pass_through_node("fl2"); | |
228 | ||
229 | /* | |
230 | * bdrv_attach_child() eats child bs reference, so we need two @base | |
231 | * references for two filters: | |
232 | */ | |
233 | bdrv_ref(base); | |
234 | ||
1921b4f7 VSO |
235 | bdrv_attach_child(top, fl1, "backing", &child_of_bds, |
236 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
d71cc67d | 237 | &error_abort); |
1921b4f7 VSO |
238 | bdrv_attach_child(fl1, base, "backing", &child_of_bds, |
239 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
d71cc67d | 240 | &error_abort); |
1921b4f7 VSO |
241 | bdrv_attach_child(fl2, base, "backing", &child_of_bds, |
242 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
d71cc67d VSO |
243 | &error_abort); |
244 | ||
245 | bdrv_replace_node(fl1, fl2, &error_abort); | |
246 | ||
247 | bdrv_unref(fl2); | |
248 | bdrv_unref(top); | |
249 | } | |
250 | ||
1dcea719 VSO |
251 | /* |
252 | * write-to-selected node may have several DATA children, one of them may be | |
253 | * "selected". Exclusive write permission is taken on selected child. | |
254 | * | |
255 | * We don't realize write handler itself, as we need only to test how permission | |
256 | * update works. | |
257 | */ | |
258 | typedef struct BDRVWriteToSelectedState { | |
259 | BdrvChild *selected; | |
260 | } BDRVWriteToSelectedState; | |
261 | ||
262 | static void write_to_selected_perms(BlockDriverState *bs, BdrvChild *c, | |
263 | BdrvChildRole role, | |
264 | BlockReopenQueue *reopen_queue, | |
265 | uint64_t perm, uint64_t shared, | |
266 | uint64_t *nperm, uint64_t *nshared) | |
e6af4f0e | 267 | { |
1dcea719 VSO |
268 | BDRVWriteToSelectedState *s = bs->opaque; |
269 | ||
270 | if (s->selected && c == s->selected) { | |
e6af4f0e VSO |
271 | *nperm = BLK_PERM_WRITE; |
272 | *nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE; | |
273 | } else { | |
274 | *nperm = 0; | |
275 | *nshared = BLK_PERM_ALL; | |
276 | } | |
277 | } | |
278 | ||
1dcea719 VSO |
279 | static BlockDriver bdrv_write_to_selected = { |
280 | .format_name = "write-to-selected", | |
281 | .instance_size = sizeof(BDRVWriteToSelectedState), | |
282 | .bdrv_child_perm = write_to_selected_perms, | |
e6af4f0e VSO |
283 | }; |
284 | ||
285 | ||
286 | /* | |
287 | * The following test shows that topological-sort order is required for | |
288 | * permission update, simple DFS is not enough. | |
289 | * | |
1dcea719 VSO |
290 | * Consider the block driver (write-to-selected) which has two children: one is |
291 | * selected so we have exclusive write access to it and for the other one we | |
292 | * don't need any specific permissions. | |
e6af4f0e VSO |
293 | * |
294 | * And, these two children has a common base child, like this: | |
1dcea719 VSO |
295 | * (additional "top" on top is used in test just because the only public |
296 | * function to update permission should get a specific child to update. | |
297 | * Making bdrv_refresh_perms() public just for this test isn't worth it) | |
e6af4f0e | 298 | * |
1dcea719 VSO |
299 | * ┌─────┐ ┌───────────────────┐ ┌─────┐ |
300 | * │ fl2 │ ◀── │ write-to-selected │ ◀── │ top │ | |
301 | * └─────┘ └───────────────────┘ └─────┘ | |
e6af4f0e VSO |
302 | * │ │ |
303 | * │ │ w | |
304 | * │ ▼ | |
305 | * │ ┌──────┐ | |
306 | * │ │ fl1 │ | |
307 | * │ └──────┘ | |
308 | * │ │ | |
309 | * │ │ w | |
310 | * │ ▼ | |
311 | * │ ┌──────┐ | |
312 | * └───────▶ │ base │ | |
313 | * └──────┘ | |
314 | * | |
315 | * So, exclusive write is propagated. | |
316 | * | |
1dcea719 VSO |
317 | * Assume, we want to select fl2 instead of fl1. |
318 | * So, we set some option for write-to-selected driver and do permission update. | |
e6af4f0e VSO |
319 | * |
320 | * With simple DFS, if permission update goes first through | |
1dcea719 VSO |
321 | * write-to-selected -> fl1 -> base branch it will succeed: it firstly drop |
322 | * exclusive write permissions and than apply them for another BdrvChildren. | |
323 | * But if permission update goes first through write-to-selected -> fl2 -> base | |
324 | * branch it will fail, as when we try to update fl2->base child, old not yet | |
e6af4f0e VSO |
325 | * updated fl1->base child will be in conflict. |
326 | * | |
327 | * With topological-sort order we always update parents before children, so fl1 | |
328 | * and fl2 are both updated when we update base and there is no conflict. | |
329 | */ | |
330 | static void test_parallel_perm_update(void) | |
331 | { | |
332 | BlockDriverState *top = no_perm_node("top"); | |
1dcea719 VSO |
333 | BlockDriverState *ws = |
334 | bdrv_new_open_driver(&bdrv_write_to_selected, "ws", BDRV_O_RDWR, | |
e6af4f0e | 335 | &error_abort); |
1dcea719 | 336 | BDRVWriteToSelectedState *s = ws->opaque; |
e6af4f0e VSO |
337 | BlockDriverState *base = no_perm_node("base"); |
338 | BlockDriverState *fl1 = pass_through_node("fl1"); | |
339 | BlockDriverState *fl2 = pass_through_node("fl2"); | |
340 | BdrvChild *c_fl1, *c_fl2; | |
341 | ||
342 | /* | |
343 | * bdrv_attach_child() eats child bs reference, so we need two @base | |
344 | * references for two filters: | |
345 | */ | |
346 | bdrv_ref(base); | |
347 | ||
1dcea719 | 348 | bdrv_attach_child(top, ws, "file", &child_of_bds, BDRV_CHILD_DATA, |
e6af4f0e | 349 | &error_abort); |
1dcea719 VSO |
350 | c_fl1 = bdrv_attach_child(ws, fl1, "first", &child_of_bds, |
351 | BDRV_CHILD_DATA, &error_abort); | |
352 | c_fl2 = bdrv_attach_child(ws, fl2, "second", &child_of_bds, | |
353 | BDRV_CHILD_DATA, &error_abort); | |
1921b4f7 VSO |
354 | bdrv_attach_child(fl1, base, "backing", &child_of_bds, |
355 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
e6af4f0e | 356 | &error_abort); |
1921b4f7 VSO |
357 | bdrv_attach_child(fl2, base, "backing", &child_of_bds, |
358 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
e6af4f0e VSO |
359 | &error_abort); |
360 | ||
361 | /* Select fl1 as first child to be active */ | |
1dcea719 | 362 | s->selected = c_fl1; |
e6af4f0e VSO |
363 | bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); |
364 | ||
365 | assert(c_fl1->perm & BLK_PERM_WRITE); | |
366 | assert(!(c_fl2->perm & BLK_PERM_WRITE)); | |
367 | ||
368 | /* Now, try to switch active child and update permissions */ | |
1dcea719 | 369 | s->selected = c_fl2; |
e6af4f0e VSO |
370 | bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); |
371 | ||
372 | assert(c_fl2->perm & BLK_PERM_WRITE); | |
373 | assert(!(c_fl1->perm & BLK_PERM_WRITE)); | |
374 | ||
375 | /* Switch once more, to not care about real child order in the list */ | |
1dcea719 | 376 | s->selected = c_fl1; |
e6af4f0e VSO |
377 | bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort); |
378 | ||
379 | assert(c_fl1->perm & BLK_PERM_WRITE); | |
380 | assert(!(c_fl2->perm & BLK_PERM_WRITE)); | |
381 | ||
382 | bdrv_unref(top); | |
383 | } | |
384 | ||
397f7cc0 VSO |
385 | /* |
386 | * It's possible that filter required permissions allows to insert it to backing | |
387 | * chain, like: | |
388 | * | |
389 | * 1. [top] -> [filter] -> [base] | |
390 | * | |
391 | * but doesn't allow to add it as a branch: | |
392 | * | |
393 | * 2. [filter] --\ | |
394 | * v | |
395 | * [top] -> [base] | |
396 | * | |
397 | * So, inserting such filter should do all graph modifications and only then | |
398 | * update permissions. If we try to go through intermediate state [2] and update | |
399 | * permissions on it we'll fail. | |
400 | * | |
401 | * Let's check that bdrv_append() can append such a filter. | |
402 | */ | |
403 | static void test_append_greedy_filter(void) | |
404 | { | |
405 | BlockDriverState *top = exclusive_writer_node("top"); | |
406 | BlockDriverState *base = no_perm_node("base"); | |
407 | BlockDriverState *fl = exclusive_writer_node("fl1"); | |
408 | ||
1921b4f7 VSO |
409 | bdrv_attach_child(top, base, "backing", &child_of_bds, |
410 | BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, | |
397f7cc0 VSO |
411 | &error_abort); |
412 | ||
413 | bdrv_append(fl, base, &error_abort); | |
ae9d4417 | 414 | bdrv_unref(fl); |
397f7cc0 VSO |
415 | bdrv_unref(top); |
416 | } | |
417 | ||
2dbfadf6 VSO |
418 | int main(int argc, char *argv[]) |
419 | { | |
420 | bdrv_init(); | |
421 | qemu_init_main_loop(&error_abort); | |
422 | ||
423 | g_test_init(&argc, &argv, NULL); | |
424 | ||
425 | g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree); | |
426 | g_test_add_func("/bdrv-graph-mod/should-update-child", | |
427 | test_should_update_child); | |
bd57f8f7 VSO |
428 | g_test_add_func("/bdrv-graph-mod/parallel-perm-update", |
429 | test_parallel_perm_update); | |
3bb0e298 VSO |
430 | g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write", |
431 | test_parallel_exclusive_write); | |
2272edcf VSO |
432 | g_test_add_func("/bdrv-graph-mod/append-greedy-filter", |
433 | test_append_greedy_filter); | |
d71cc67d | 434 | |
2dbfadf6 VSO |
435 | return g_test_run(); |
436 | } |