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27cec15e BC |
1 | /* |
2 | * Quorum Block filter | |
3 | * | |
4 | * Copyright (C) 2012-2014 Nodalink, EURL. | |
5 | * | |
6 | * Author: | |
7 | * Benoît Canet <benoit.canet@irqsave.net> | |
8 | * | |
9 | * Based on the design and code of blkverify.c (Copyright (C) 2010 IBM, Corp) | |
10 | * and blkmirror.c (Copyright (C) 2011 Red Hat, Inc). | |
11 | * | |
12 | * This work is licensed under the terms of the GNU GPL, version 2 or later. | |
13 | * See the COPYING file in the top-level directory. | |
14 | */ | |
15 | ||
80c71a24 | 16 | #include "qemu/osdep.h" |
98292c61 | 17 | #include "qemu/cutils.h" |
0b8fa32f | 18 | #include "qemu/module.h" |
922a01a0 | 19 | #include "qemu/option.h" |
5df022cf | 20 | #include "qemu/memalign.h" |
27cec15e | 21 | #include "block/block_int.h" |
ef9bba14 | 22 | #include "block/coroutines.h" |
609f45ea | 23 | #include "block/qdict.h" |
e688df6b | 24 | #include "qapi/error.h" |
9af23989 | 25 | #include "qapi/qapi-events-block.h" |
fafcfe22 | 26 | #include "qapi/qmp/qdict.h" |
cc7a8ea7 | 27 | #include "qapi/qmp/qerror.h" |
fafcfe22 HR |
28 | #include "qapi/qmp/qlist.h" |
29 | #include "qapi/qmp/qstring.h" | |
488981a4 | 30 | #include "crypto/hash.h" |
95c6bff3 BC |
31 | |
32 | #define HASH_LENGTH 32 | |
33 | ||
5eb9a3c7 LS |
34 | #define INDEXSTR_LEN 32 |
35 | ||
c88a1de5 BC |
36 | #define QUORUM_OPT_VOTE_THRESHOLD "vote-threshold" |
37 | #define QUORUM_OPT_BLKVERIFY "blkverify" | |
cf29a570 | 38 | #define QUORUM_OPT_REWRITE "rewrite-corrupted" |
a9db86b2 | 39 | #define QUORUM_OPT_READ_PATTERN "read-pattern" |
c88a1de5 | 40 | |
95c6bff3 BC |
41 | /* This union holds a vote hash value */ |
42 | typedef union QuorumVoteValue { | |
488981a4 | 43 | uint8_t h[HASH_LENGTH]; /* SHA-256 hash */ |
95c6bff3 BC |
44 | int64_t l; /* simpler 64 bits hash */ |
45 | } QuorumVoteValue; | |
46 | ||
47 | /* A vote item */ | |
48 | typedef struct QuorumVoteItem { | |
49 | int index; | |
50 | QLIST_ENTRY(QuorumVoteItem) next; | |
51 | } QuorumVoteItem; | |
52 | ||
53 | /* this structure is a vote version. A version is the set of votes sharing the | |
54 | * same vote value. | |
55 | * The set of votes will be tracked with the items field and its cardinality is | |
56 | * vote_count. | |
57 | */ | |
58 | typedef struct QuorumVoteVersion { | |
59 | QuorumVoteValue value; | |
60 | int index; | |
61 | int vote_count; | |
62 | QLIST_HEAD(, QuorumVoteItem) items; | |
63 | QLIST_ENTRY(QuorumVoteVersion) next; | |
64 | } QuorumVoteVersion; | |
65 | ||
66 | /* this structure holds a group of vote versions together */ | |
67 | typedef struct QuorumVotes { | |
68 | QLIST_HEAD(, QuorumVoteVersion) vote_list; | |
69 | bool (*compare)(QuorumVoteValue *a, QuorumVoteValue *b); | |
70 | } QuorumVotes; | |
27cec15e | 71 | |
cadebd7a BC |
72 | /* the following structure holds the state of one quorum instance */ |
73 | typedef struct BDRVQuorumState { | |
0bd6e91a | 74 | BdrvChild **children; /* children BlockDriverStates */ |
cadebd7a | 75 | int num_children; /* children count */ |
98292c61 WC |
76 | unsigned next_child_index; /* the index of the next child that should |
77 | * be added | |
78 | */ | |
cadebd7a BC |
79 | int threshold; /* if less than threshold children reads gave the |
80 | * same result a quorum error occurs. | |
81 | */ | |
82 | bool is_blkverify; /* true if the driver is in blkverify mode | |
83 | * Writes are mirrored on two children devices. | |
84 | * On reads the two children devices' contents are | |
85 | * compared and if a difference is spotted its | |
86 | * location is printed and the code aborts. | |
87 | * It is useful to debug other block drivers by | |
88 | * comparing them with a reference one. | |
89 | */ | |
cf29a570 BC |
90 | bool rewrite_corrupted;/* true if the driver must rewrite-on-read corrupted |
91 | * block if Quorum is reached. | |
92 | */ | |
a9db86b2 LY |
93 | |
94 | QuorumReadPattern read_pattern; | |
cadebd7a BC |
95 | } BDRVQuorumState; |
96 | ||
27cec15e BC |
97 | typedef struct QuorumAIOCB QuorumAIOCB; |
98 | ||
99 | /* Quorum will create one instance of the following structure per operation it | |
100 | * performs on its children. | |
101 | * So for each read/write operation coming from the upper layer there will be | |
102 | * $children_count QuorumChildRequest. | |
103 | */ | |
104 | typedef struct QuorumChildRequest { | |
ce15dc08 | 105 | BlockDriverState *bs; |
27cec15e BC |
106 | QEMUIOVector qiov; |
107 | uint8_t *buf; | |
108 | int ret; | |
109 | QuorumAIOCB *parent; | |
110 | } QuorumChildRequest; | |
111 | ||
112 | /* Quorum will use the following structure to track progress of each read/write | |
113 | * operation received by the upper layer. | |
114 | * This structure hold pointers to the QuorumChildRequest structures instances | |
115 | * used to do operations on each children and track overall progress. | |
116 | */ | |
117 | struct QuorumAIOCB { | |
ce15dc08 KW |
118 | BlockDriverState *bs; |
119 | Coroutine *co; | |
27cec15e BC |
120 | |
121 | /* Request metadata */ | |
6847da38 KW |
122 | uint64_t offset; |
123 | uint64_t bytes; | |
1b1a920b | 124 | int flags; |
27cec15e BC |
125 | |
126 | QEMUIOVector *qiov; /* calling IOV */ | |
127 | ||
128 | QuorumChildRequest *qcrs; /* individual child requests */ | |
129 | int count; /* number of completed AIOCB */ | |
130 | int success_count; /* number of successfully completed AIOCB */ | |
131 | ||
cf29a570 BC |
132 | int rewrite_count; /* number of replica to rewrite: count down to |
133 | * zero once writes are fired | |
134 | */ | |
135 | ||
95c6bff3 BC |
136 | QuorumVotes votes; |
137 | ||
27cec15e BC |
138 | bool is_read; |
139 | int vote_ret; | |
86ec252c | 140 | int children_read; /* how many children have been read from */ |
27cec15e | 141 | }; |
cadebd7a | 142 | |
ce15dc08 KW |
143 | typedef struct QuorumCo { |
144 | QuorumAIOCB *acb; | |
145 | int idx; | |
146 | } QuorumCo; | |
13e7956e | 147 | |
13e7956e BC |
148 | static void quorum_aio_finalize(QuorumAIOCB *acb) |
149 | { | |
13e7956e | 150 | g_free(acb->qcrs); |
0f31977d | 151 | g_free(acb); |
13e7956e BC |
152 | } |
153 | ||
95c6bff3 BC |
154 | static bool quorum_sha256_compare(QuorumVoteValue *a, QuorumVoteValue *b) |
155 | { | |
156 | return !memcmp(a->h, b->h, HASH_LENGTH); | |
157 | } | |
158 | ||
159 | static bool quorum_64bits_compare(QuorumVoteValue *a, QuorumVoteValue *b) | |
160 | { | |
161 | return a->l == b->l; | |
162 | } | |
163 | ||
2987ae7d PB |
164 | static QuorumAIOCB *coroutine_fn quorum_aio_get(BlockDriverState *bs, |
165 | QEMUIOVector *qiov, | |
166 | uint64_t offset, uint64_t bytes, | |
167 | int flags) | |
13e7956e | 168 | { |
10c85519 | 169 | BDRVQuorumState *s = bs->opaque; |
ce15dc08 | 170 | QuorumAIOCB *acb = g_new(QuorumAIOCB, 1); |
13e7956e BC |
171 | int i; |
172 | ||
7c37f941 KW |
173 | *acb = (QuorumAIOCB) { |
174 | .co = qemu_coroutine_self(), | |
175 | .bs = bs, | |
176 | .offset = offset, | |
177 | .bytes = bytes, | |
1b1a920b | 178 | .flags = flags, |
7c37f941 KW |
179 | .qiov = qiov, |
180 | .votes.compare = quorum_sha256_compare, | |
181 | .votes.vote_list = QLIST_HEAD_INITIALIZER(acb.votes.vote_list), | |
182 | }; | |
13e7956e | 183 | |
7c37f941 | 184 | acb->qcrs = g_new0(QuorumChildRequest, s->num_children); |
13e7956e BC |
185 | for (i = 0; i < s->num_children; i++) { |
186 | acb->qcrs[i].buf = NULL; | |
187 | acb->qcrs[i].ret = 0; | |
188 | acb->qcrs[i].parent = acb; | |
189 | } | |
190 | ||
191 | return acb; | |
192 | } | |
193 | ||
6847da38 KW |
194 | static void quorum_report_bad(QuorumOpType type, uint64_t offset, |
195 | uint64_t bytes, char *node_name, int ret) | |
95c6bff3 | 196 | { |
fe069d9d | 197 | const char *msg = NULL; |
6847da38 KW |
198 | int64_t start_sector = offset / BDRV_SECTOR_SIZE; |
199 | int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); | |
200 | ||
0c762736 | 201 | if (ret < 0) { |
fe069d9d | 202 | msg = strerror(-ret); |
0c762736 | 203 | } |
0ae053b7 | 204 | |
54fde4ff | 205 | qapi_event_send_quorum_report_bad(type, msg, node_name, start_sector, |
3ab72385 | 206 | end_sector - start_sector); |
95c6bff3 BC |
207 | } |
208 | ||
4026f1c4 | 209 | static void GRAPH_RDLOCK quorum_report_failure(QuorumAIOCB *acb) |
95c6bff3 | 210 | { |
ce15dc08 | 211 | const char *reference = bdrv_get_device_or_node_name(acb->bs); |
6847da38 KW |
212 | int64_t start_sector = acb->offset / BDRV_SECTOR_SIZE; |
213 | int64_t end_sector = DIV_ROUND_UP(acb->offset + acb->bytes, | |
214 | BDRV_SECTOR_SIZE); | |
215 | ||
216 | qapi_event_send_quorum_failure(reference, start_sector, | |
3ab72385 | 217 | end_sector - start_sector); |
95c6bff3 BC |
218 | } |
219 | ||
220 | static int quorum_vote_error(QuorumAIOCB *acb); | |
221 | ||
4026f1c4 | 222 | static bool GRAPH_RDLOCK quorum_has_too_much_io_failed(QuorumAIOCB *acb) |
95c6bff3 | 223 | { |
ce15dc08 | 224 | BDRVQuorumState *s = acb->bs->opaque; |
95c6bff3 BC |
225 | |
226 | if (acb->success_count < s->threshold) { | |
227 | acb->vote_ret = quorum_vote_error(acb); | |
228 | quorum_report_failure(acb); | |
229 | return true; | |
230 | } | |
231 | ||
232 | return false; | |
233 | } | |
234 | ||
a9db86b2 LY |
235 | static void quorum_copy_qiov(QEMUIOVector *dest, QEMUIOVector *source) |
236 | { | |
237 | int i; | |
238 | assert(dest->niov == source->niov); | |
239 | assert(dest->size == source->size); | |
240 | for (i = 0; i < source->niov; i++) { | |
241 | assert(dest->iov[i].iov_len == source->iov[i].iov_len); | |
242 | memcpy(dest->iov[i].iov_base, | |
243 | source->iov[i].iov_base, | |
244 | source->iov[i].iov_len); | |
245 | } | |
246 | } | |
247 | ||
1ba7e159 PB |
248 | static void quorum_report_bad_acb(QuorumChildRequest *sacb, int ret) |
249 | { | |
250 | QuorumAIOCB *acb = sacb->parent; | |
251 | QuorumOpType type = acb->is_read ? QUORUM_OP_TYPE_READ : QUORUM_OP_TYPE_WRITE; | |
6847da38 | 252 | quorum_report_bad(type, acb->offset, acb->bytes, sacb->bs->node_name, ret); |
1ba7e159 PB |
253 | } |
254 | ||
95c6bff3 BC |
255 | static void quorum_report_bad_versions(BDRVQuorumState *s, |
256 | QuorumAIOCB *acb, | |
257 | QuorumVoteValue *value) | |
258 | { | |
259 | QuorumVoteVersion *version; | |
260 | QuorumVoteItem *item; | |
261 | ||
262 | QLIST_FOREACH(version, &acb->votes.vote_list, next) { | |
263 | if (acb->votes.compare(&version->value, value)) { | |
264 | continue; | |
265 | } | |
266 | QLIST_FOREACH(item, &version->items, next) { | |
6847da38 | 267 | quorum_report_bad(QUORUM_OP_TYPE_READ, acb->offset, acb->bytes, |
0ae053b7 | 268 | s->children[item->index]->bs->node_name, 0); |
95c6bff3 BC |
269 | } |
270 | } | |
271 | } | |
272 | ||
b9b10c35 KW |
273 | /* |
274 | * This function can count as GRAPH_RDLOCK because read_quorum_children() holds | |
275 | * the graph lock and keeps it until this coroutine has terminated. | |
276 | */ | |
277 | static void coroutine_fn GRAPH_RDLOCK quorum_rewrite_entry(void *opaque) | |
dee66e28 KW |
278 | { |
279 | QuorumCo *co = opaque; | |
280 | QuorumAIOCB *acb = co->acb; | |
281 | BDRVQuorumState *s = acb->bs->opaque; | |
282 | ||
283 | /* Ignore any errors, it's just a correction attempt for already | |
1b1a920b HR |
284 | * corrupted data. |
285 | * Mask out BDRV_REQ_WRITE_UNCHANGED because this overwrites the | |
286 | * area with different data from the other children. */ | |
6847da38 | 287 | bdrv_co_pwritev(s->children[co->idx], acb->offset, acb->bytes, |
1b1a920b | 288 | acb->qiov, acb->flags & ~BDRV_REQ_WRITE_UNCHANGED); |
dee66e28 KW |
289 | |
290 | /* Wake up the caller after the last rewrite */ | |
291 | acb->rewrite_count--; | |
292 | if (!acb->rewrite_count) { | |
293 | qemu_coroutine_enter_if_inactive(acb->co); | |
294 | } | |
295 | } | |
296 | ||
b9b10c35 KW |
297 | static bool coroutine_fn GRAPH_RDLOCK |
298 | quorum_rewrite_bad_versions(QuorumAIOCB *acb, QuorumVoteValue *value) | |
cf29a570 BC |
299 | { |
300 | QuorumVoteVersion *version; | |
301 | QuorumVoteItem *item; | |
302 | int count = 0; | |
303 | ||
304 | /* first count the number of bad versions: done first to avoid concurrency | |
305 | * issues. | |
306 | */ | |
307 | QLIST_FOREACH(version, &acb->votes.vote_list, next) { | |
308 | if (acb->votes.compare(&version->value, value)) { | |
309 | continue; | |
310 | } | |
311 | QLIST_FOREACH(item, &version->items, next) { | |
312 | count++; | |
313 | } | |
314 | } | |
315 | ||
dee66e28 | 316 | /* quorum_rewrite_entry will count down this to zero */ |
cf29a570 BC |
317 | acb->rewrite_count = count; |
318 | ||
319 | /* now fire the correcting rewrites */ | |
320 | QLIST_FOREACH(version, &acb->votes.vote_list, next) { | |
321 | if (acb->votes.compare(&version->value, value)) { | |
322 | continue; | |
323 | } | |
324 | QLIST_FOREACH(item, &version->items, next) { | |
dee66e28 KW |
325 | Coroutine *co; |
326 | QuorumCo data = { | |
327 | .acb = acb, | |
328 | .idx = item->index, | |
329 | }; | |
330 | ||
331 | co = qemu_coroutine_create(quorum_rewrite_entry, &data); | |
332 | qemu_coroutine_enter(co); | |
cf29a570 BC |
333 | } |
334 | } | |
335 | ||
336 | /* return true if any rewrite is done else false */ | |
337 | return count; | |
338 | } | |
339 | ||
95c6bff3 BC |
340 | static void quorum_count_vote(QuorumVotes *votes, |
341 | QuorumVoteValue *value, | |
342 | int index) | |
343 | { | |
344 | QuorumVoteVersion *v = NULL, *version = NULL; | |
345 | QuorumVoteItem *item; | |
346 | ||
347 | /* look if we have something with this hash */ | |
348 | QLIST_FOREACH(v, &votes->vote_list, next) { | |
349 | if (votes->compare(&v->value, value)) { | |
350 | version = v; | |
351 | break; | |
352 | } | |
353 | } | |
354 | ||
355 | /* It's a version not yet in the list add it */ | |
356 | if (!version) { | |
357 | version = g_new0(QuorumVoteVersion, 1); | |
358 | QLIST_INIT(&version->items); | |
359 | memcpy(&version->value, value, sizeof(version->value)); | |
360 | version->index = index; | |
361 | version->vote_count = 0; | |
362 | QLIST_INSERT_HEAD(&votes->vote_list, version, next); | |
363 | } | |
364 | ||
365 | version->vote_count++; | |
366 | ||
367 | item = g_new0(QuorumVoteItem, 1); | |
368 | item->index = index; | |
369 | QLIST_INSERT_HEAD(&version->items, item, next); | |
370 | } | |
371 | ||
372 | static void quorum_free_vote_list(QuorumVotes *votes) | |
373 | { | |
374 | QuorumVoteVersion *version, *next_version; | |
375 | QuorumVoteItem *item, *next_item; | |
376 | ||
377 | QLIST_FOREACH_SAFE(version, &votes->vote_list, next, next_version) { | |
378 | QLIST_REMOVE(version, next); | |
379 | QLIST_FOREACH_SAFE(item, &version->items, next, next_item) { | |
380 | QLIST_REMOVE(item, next); | |
381 | g_free(item); | |
382 | } | |
383 | g_free(version); | |
384 | } | |
385 | } | |
386 | ||
387 | static int quorum_compute_hash(QuorumAIOCB *acb, int i, QuorumVoteValue *hash) | |
388 | { | |
95c6bff3 | 389 | QEMUIOVector *qiov = &acb->qcrs[i].qiov; |
488981a4 DB |
390 | size_t len = sizeof(hash->h); |
391 | uint8_t *data = hash->h; | |
95c6bff3 | 392 | |
488981a4 DB |
393 | /* XXX - would be nice if we could pass in the Error ** |
394 | * and propagate that back, but this quorum code is | |
395 | * restricted to just errno values currently */ | |
396 | if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_SHA256, | |
397 | qiov->iov, qiov->niov, | |
398 | &data, &len, | |
399 | NULL) < 0) { | |
400 | return -EINVAL; | |
95c6bff3 BC |
401 | } |
402 | ||
488981a4 | 403 | return 0; |
95c6bff3 BC |
404 | } |
405 | ||
406 | static QuorumVoteVersion *quorum_get_vote_winner(QuorumVotes *votes) | |
407 | { | |
408 | int max = 0; | |
409 | QuorumVoteVersion *candidate, *winner = NULL; | |
410 | ||
411 | QLIST_FOREACH(candidate, &votes->vote_list, next) { | |
412 | if (candidate->vote_count > max) { | |
413 | max = candidate->vote_count; | |
414 | winner = candidate; | |
415 | } | |
416 | } | |
417 | ||
418 | return winner; | |
419 | } | |
420 | ||
421 | /* qemu_iovec_compare is handy for blkverify mode because it returns the first | |
422 | * differing byte location. Yet it is handcoded to compare vectors one byte | |
423 | * after another so it does not benefit from the libc SIMD optimizations. | |
424 | * quorum_iovec_compare is written for speed and should be used in the non | |
425 | * blkverify mode of quorum. | |
426 | */ | |
427 | static bool quorum_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) | |
428 | { | |
429 | int i; | |
430 | int result; | |
431 | ||
432 | assert(a->niov == b->niov); | |
433 | for (i = 0; i < a->niov; i++) { | |
434 | assert(a->iov[i].iov_len == b->iov[i].iov_len); | |
435 | result = memcmp(a->iov[i].iov_base, | |
436 | b->iov[i].iov_base, | |
437 | a->iov[i].iov_len); | |
438 | if (result) { | |
439 | return false; | |
440 | } | |
441 | } | |
442 | ||
443 | return true; | |
444 | } | |
445 | ||
6840e8d8 | 446 | static bool quorum_compare(QuorumAIOCB *acb, QEMUIOVector *a, QEMUIOVector *b) |
95c6bff3 | 447 | { |
ce15dc08 | 448 | BDRVQuorumState *s = acb->bs->opaque; |
95c6bff3 BC |
449 | ssize_t offset; |
450 | ||
451 | /* This driver will replace blkverify in this particular case */ | |
452 | if (s->is_blkverify) { | |
453 | offset = qemu_iovec_compare(a, b); | |
454 | if (offset != -1) { | |
6840e8d8 AG |
455 | fprintf(stderr, "quorum: offset=%" PRIu64 " bytes=%" PRIu64 |
456 | " contents mismatch at offset %" PRIu64 "\n", | |
457 | acb->offset, acb->bytes, acb->offset + offset); | |
458 | exit(1); | |
95c6bff3 BC |
459 | } |
460 | return true; | |
461 | } | |
462 | ||
463 | return quorum_iovec_compare(a, b); | |
464 | } | |
465 | ||
466 | /* Do a vote to get the error code */ | |
467 | static int quorum_vote_error(QuorumAIOCB *acb) | |
468 | { | |
ce15dc08 | 469 | BDRVQuorumState *s = acb->bs->opaque; |
95c6bff3 BC |
470 | QuorumVoteVersion *winner = NULL; |
471 | QuorumVotes error_votes; | |
472 | QuorumVoteValue result_value; | |
473 | int i, ret = 0; | |
474 | bool error = false; | |
475 | ||
476 | QLIST_INIT(&error_votes.vote_list); | |
477 | error_votes.compare = quorum_64bits_compare; | |
478 | ||
479 | for (i = 0; i < s->num_children; i++) { | |
480 | ret = acb->qcrs[i].ret; | |
481 | if (ret) { | |
482 | error = true; | |
483 | result_value.l = ret; | |
484 | quorum_count_vote(&error_votes, &result_value, i); | |
485 | } | |
486 | } | |
487 | ||
488 | if (error) { | |
489 | winner = quorum_get_vote_winner(&error_votes); | |
490 | ret = winner->value.l; | |
491 | } | |
492 | ||
493 | quorum_free_vote_list(&error_votes); | |
494 | ||
495 | return ret; | |
496 | } | |
497 | ||
b9b10c35 | 498 | static void coroutine_fn GRAPH_RDLOCK quorum_vote(QuorumAIOCB *acb) |
95c6bff3 BC |
499 | { |
500 | bool quorum = true; | |
501 | int i, j, ret; | |
502 | QuorumVoteValue hash; | |
ce15dc08 | 503 | BDRVQuorumState *s = acb->bs->opaque; |
95c6bff3 BC |
504 | QuorumVoteVersion *winner; |
505 | ||
506 | if (quorum_has_too_much_io_failed(acb)) { | |
7cd9b396 | 507 | return; |
95c6bff3 BC |
508 | } |
509 | ||
510 | /* get the index of the first successful read */ | |
511 | for (i = 0; i < s->num_children; i++) { | |
512 | if (!acb->qcrs[i].ret) { | |
513 | break; | |
514 | } | |
515 | } | |
516 | ||
517 | assert(i < s->num_children); | |
518 | ||
519 | /* compare this read with all other successful reads stopping at quorum | |
520 | * failure | |
521 | */ | |
522 | for (j = i + 1; j < s->num_children; j++) { | |
523 | if (acb->qcrs[j].ret) { | |
524 | continue; | |
525 | } | |
526 | quorum = quorum_compare(acb, &acb->qcrs[i].qiov, &acb->qcrs[j].qiov); | |
527 | if (!quorum) { | |
528 | break; | |
529 | } | |
530 | } | |
531 | ||
532 | /* Every successful read agrees */ | |
533 | if (quorum) { | |
534 | quorum_copy_qiov(acb->qiov, &acb->qcrs[i].qiov); | |
7cd9b396 | 535 | return; |
95c6bff3 BC |
536 | } |
537 | ||
538 | /* compute hashes for each successful read, also store indexes */ | |
539 | for (i = 0; i < s->num_children; i++) { | |
540 | if (acb->qcrs[i].ret) { | |
541 | continue; | |
542 | } | |
543 | ret = quorum_compute_hash(acb, i, &hash); | |
544 | /* if ever the hash computation failed */ | |
545 | if (ret < 0) { | |
546 | acb->vote_ret = ret; | |
547 | goto free_exit; | |
548 | } | |
549 | quorum_count_vote(&acb->votes, &hash, i); | |
550 | } | |
551 | ||
552 | /* vote to select the most represented version */ | |
553 | winner = quorum_get_vote_winner(&acb->votes); | |
554 | ||
555 | /* if the winner count is smaller than threshold the read fails */ | |
556 | if (winner->vote_count < s->threshold) { | |
557 | quorum_report_failure(acb); | |
558 | acb->vote_ret = -EIO; | |
559 | goto free_exit; | |
560 | } | |
561 | ||
562 | /* we have a winner: copy it */ | |
563 | quorum_copy_qiov(acb->qiov, &acb->qcrs[winner->index].qiov); | |
564 | ||
565 | /* some versions are bad print them */ | |
566 | quorum_report_bad_versions(s, acb, &winner->value); | |
567 | ||
cf29a570 BC |
568 | /* corruption correction is enabled */ |
569 | if (s->rewrite_corrupted) { | |
dee66e28 | 570 | quorum_rewrite_bad_versions(acb, &winner->value); |
cf29a570 BC |
571 | } |
572 | ||
95c6bff3 BC |
573 | free_exit: |
574 | /* free lists */ | |
575 | quorum_free_vote_list(&acb->votes); | |
576 | } | |
577 | ||
b9b10c35 KW |
578 | /* |
579 | * This function can count as GRAPH_RDLOCK because read_quorum_children() holds | |
580 | * the graph lock and keeps it until this coroutine has terminated. | |
581 | */ | |
582 | static void coroutine_fn GRAPH_RDLOCK read_quorum_children_entry(void *opaque) | |
7db6982a | 583 | { |
ce15dc08 KW |
584 | QuorumCo *co = opaque; |
585 | QuorumAIOCB *acb = co->acb; | |
586 | BDRVQuorumState *s = acb->bs->opaque; | |
587 | int i = co->idx; | |
7cd9b396 KW |
588 | QuorumChildRequest *sacb = &acb->qcrs[i]; |
589 | ||
590 | sacb->bs = s->children[i]->bs; | |
6847da38 | 591 | sacb->ret = bdrv_co_preadv(s->children[i], acb->offset, acb->bytes, |
7cd9b396 KW |
592 | &acb->qcrs[i].qiov, 0); |
593 | ||
594 | if (sacb->ret == 0) { | |
595 | acb->success_count++; | |
596 | } else { | |
597 | quorum_report_bad_acb(sacb, sacb->ret); | |
598 | } | |
ce15dc08 | 599 | |
7cd9b396 KW |
600 | acb->count++; |
601 | assert(acb->count <= s->num_children); | |
602 | assert(acb->success_count <= s->num_children); | |
603 | ||
604 | /* Wake up the caller after the last read */ | |
605 | if (acb->count == s->num_children) { | |
606 | qemu_coroutine_enter_if_inactive(acb->co); | |
607 | } | |
ce15dc08 KW |
608 | } |
609 | ||
b9b10c35 | 610 | static int coroutine_fn GRAPH_RDLOCK read_quorum_children(QuorumAIOCB *acb) |
ce15dc08 KW |
611 | { |
612 | BDRVQuorumState *s = acb->bs->opaque; | |
4a4ff4c5 | 613 | int i; |
7db6982a | 614 | |
86ec252c | 615 | acb->children_read = s->num_children; |
7db6982a | 616 | for (i = 0; i < s->num_children; i++) { |
0bd6e91a | 617 | acb->qcrs[i].buf = qemu_blockalign(s->children[i]->bs, acb->qiov->size); |
a9db86b2 LY |
618 | qemu_iovec_init(&acb->qcrs[i].qiov, acb->qiov->niov); |
619 | qemu_iovec_clone(&acb->qcrs[i].qiov, acb->qiov, acb->qcrs[i].buf); | |
7db6982a BC |
620 | } |
621 | ||
622 | for (i = 0; i < s->num_children; i++) { | |
ce15dc08 KW |
623 | Coroutine *co; |
624 | QuorumCo data = { | |
625 | .acb = acb, | |
626 | .idx = i, | |
627 | }; | |
628 | ||
629 | co = qemu_coroutine_create(read_quorum_children_entry, &data); | |
630 | qemu_coroutine_enter(co); | |
7db6982a BC |
631 | } |
632 | ||
7cd9b396 KW |
633 | while (acb->count < s->num_children) { |
634 | qemu_coroutine_yield(); | |
635 | } | |
636 | ||
637 | /* Do the vote on read */ | |
638 | quorum_vote(acb); | |
639 | for (i = 0; i < s->num_children; i++) { | |
640 | qemu_vfree(acb->qcrs[i].buf); | |
641 | qemu_iovec_destroy(&acb->qcrs[i].qiov); | |
642 | } | |
643 | ||
644 | while (acb->rewrite_count) { | |
ce15dc08 KW |
645 | qemu_coroutine_yield(); |
646 | } | |
647 | ||
4a4ff4c5 | 648 | return acb->vote_ret; |
7db6982a BC |
649 | } |
650 | ||
b9b10c35 | 651 | static int coroutine_fn GRAPH_RDLOCK read_fifo_child(QuorumAIOCB *acb) |
a9db86b2 | 652 | { |
ce15dc08 | 653 | BDRVQuorumState *s = acb->bs->opaque; |
a7e15902 KW |
654 | int n, ret; |
655 | ||
656 | /* We try to read the next child in FIFO order if we failed to read */ | |
657 | do { | |
658 | n = acb->children_read++; | |
659 | acb->qcrs[n].bs = s->children[n]->bs; | |
660 | ret = bdrv_co_preadv(s->children[n], acb->offset, acb->bytes, | |
661 | acb->qiov, 0); | |
662 | if (ret < 0) { | |
663 | quorum_report_bad_acb(&acb->qcrs[n], ret); | |
664 | } | |
665 | } while (ret < 0 && acb->children_read < s->num_children); | |
a9db86b2 | 666 | |
a7e15902 | 667 | /* FIXME: rewrite failed children if acb->children_read > 1? */ |
a9db86b2 | 668 | |
ce15dc08 | 669 | return ret; |
a9db86b2 LY |
670 | } |
671 | ||
b9b10c35 KW |
672 | static int coroutine_fn GRAPH_RDLOCK |
673 | quorum_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
674 | QEMUIOVector *qiov, BdrvRequestFlags flags) | |
a9db86b2 LY |
675 | { |
676 | BDRVQuorumState *s = bs->opaque; | |
1b1a920b | 677 | QuorumAIOCB *acb = quorum_aio_get(bs, qiov, offset, bytes, flags); |
ce15dc08 KW |
678 | int ret; |
679 | ||
a9db86b2 | 680 | acb->is_read = true; |
86ec252c | 681 | acb->children_read = 0; |
a9db86b2 LY |
682 | |
683 | if (s->read_pattern == QUORUM_READ_PATTERN_QUORUM) { | |
ce15dc08 KW |
684 | ret = read_quorum_children(acb); |
685 | } else { | |
686 | ret = read_fifo_child(acb); | |
a9db86b2 | 687 | } |
0f31977d KW |
688 | quorum_aio_finalize(acb); |
689 | ||
ce15dc08 KW |
690 | return ret; |
691 | } | |
a9db86b2 | 692 | |
abaf8b75 KW |
693 | /* |
694 | * This function can count as GRAPH_RDLOCK because quorum_co_pwritev() holds the | |
695 | * graph lock and keeps it until this coroutine has terminated. | |
696 | */ | |
697 | static void coroutine_fn GRAPH_RDLOCK write_quorum_entry(void *opaque) | |
ce15dc08 KW |
698 | { |
699 | QuorumCo *co = opaque; | |
700 | QuorumAIOCB *acb = co->acb; | |
701 | BDRVQuorumState *s = acb->bs->opaque; | |
702 | int i = co->idx; | |
7cd9b396 KW |
703 | QuorumChildRequest *sacb = &acb->qcrs[i]; |
704 | ||
705 | sacb->bs = s->children[i]->bs; | |
5cddb2e9 AG |
706 | if (acb->flags & BDRV_REQ_ZERO_WRITE) { |
707 | sacb->ret = bdrv_co_pwrite_zeroes(s->children[i], acb->offset, | |
708 | acb->bytes, acb->flags); | |
709 | } else { | |
710 | sacb->ret = bdrv_co_pwritev(s->children[i], acb->offset, acb->bytes, | |
711 | acb->qiov, acb->flags); | |
712 | } | |
7cd9b396 KW |
713 | if (sacb->ret == 0) { |
714 | acb->success_count++; | |
715 | } else { | |
716 | quorum_report_bad_acb(sacb, sacb->ret); | |
717 | } | |
718 | acb->count++; | |
719 | assert(acb->count <= s->num_children); | |
720 | assert(acb->success_count <= s->num_children); | |
ce15dc08 | 721 | |
7cd9b396 KW |
722 | /* Wake up the caller after the last write */ |
723 | if (acb->count == s->num_children) { | |
724 | qemu_coroutine_enter_if_inactive(acb->co); | |
725 | } | |
a9db86b2 LY |
726 | } |
727 | ||
7b1fb72e KW |
728 | static int coroutine_fn GRAPH_RDLOCK |
729 | quorum_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
730 | QEMUIOVector *qiov, BdrvRequestFlags flags) | |
13e7956e BC |
731 | { |
732 | BDRVQuorumState *s = bs->opaque; | |
1b1a920b | 733 | QuorumAIOCB *acb = quorum_aio_get(bs, qiov, offset, bytes, flags); |
ce15dc08 | 734 | int i, ret; |
13e7956e BC |
735 | |
736 | for (i = 0; i < s->num_children; i++) { | |
ce15dc08 KW |
737 | Coroutine *co; |
738 | QuorumCo data = { | |
739 | .acb = acb, | |
740 | .idx = i, | |
741 | }; | |
742 | ||
743 | co = qemu_coroutine_create(write_quorum_entry, &data); | |
744 | qemu_coroutine_enter(co); | |
13e7956e BC |
745 | } |
746 | ||
7cd9b396 | 747 | while (acb->count < s->num_children) { |
ce15dc08 KW |
748 | qemu_coroutine_yield(); |
749 | } | |
750 | ||
7cd9b396 KW |
751 | quorum_has_too_much_io_failed(acb); |
752 | ||
ce15dc08 | 753 | ret = acb->vote_ret; |
0f31977d | 754 | quorum_aio_finalize(acb); |
ce15dc08 KW |
755 | |
756 | return ret; | |
13e7956e BC |
757 | } |
758 | ||
abaf8b75 KW |
759 | static int coroutine_fn GRAPH_RDLOCK |
760 | quorum_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, | |
761 | BdrvRequestFlags flags) | |
5cddb2e9 AG |
762 | { |
763 | return quorum_co_pwritev(bs, offset, bytes, NULL, | |
764 | flags | BDRV_REQ_ZERO_WRITE); | |
765 | } | |
766 | ||
8ab8140a KW |
767 | static int64_t coroutine_fn GRAPH_RDLOCK |
768 | quorum_co_getlength(BlockDriverState *bs) | |
d55dee20 BC |
769 | { |
770 | BDRVQuorumState *s = bs->opaque; | |
771 | int64_t result; | |
772 | int i; | |
773 | ||
774 | /* check that all file have the same length */ | |
c86422c5 | 775 | result = bdrv_co_getlength(s->children[0]->bs); |
d55dee20 BC |
776 | if (result < 0) { |
777 | return result; | |
778 | } | |
779 | for (i = 1; i < s->num_children; i++) { | |
c86422c5 | 780 | int64_t value = bdrv_co_getlength(s->children[i]->bs); |
d55dee20 BC |
781 | if (value < 0) { |
782 | return value; | |
783 | } | |
784 | if (value != result) { | |
785 | return -EIO; | |
786 | } | |
787 | } | |
788 | ||
789 | return result; | |
790 | } | |
791 | ||
88095349 | 792 | static coroutine_fn GRAPH_RDLOCK int quorum_co_flush(BlockDriverState *bs) |
1c508d17 BC |
793 | { |
794 | BDRVQuorumState *s = bs->opaque; | |
795 | QuorumVoteVersion *winner = NULL; | |
796 | QuorumVotes error_votes; | |
797 | QuorumVoteValue result_value; | |
798 | int i; | |
799 | int result = 0; | |
924e8a2b | 800 | int success_count = 0; |
1c508d17 BC |
801 | |
802 | QLIST_INIT(&error_votes.vote_list); | |
803 | error_votes.compare = quorum_64bits_compare; | |
804 | ||
805 | for (i = 0; i < s->num_children; i++) { | |
0bd6e91a | 806 | result = bdrv_co_flush(s->children[i]->bs); |
924e8a2b | 807 | if (result) { |
795be062 | 808 | quorum_report_bad(QUORUM_OP_TYPE_FLUSH, 0, 0, |
924e8a2b CX |
809 | s->children[i]->bs->node_name, result); |
810 | result_value.l = result; | |
811 | quorum_count_vote(&error_votes, &result_value, i); | |
812 | } else { | |
813 | success_count++; | |
814 | } | |
1c508d17 BC |
815 | } |
816 | ||
924e8a2b CX |
817 | if (success_count >= s->threshold) { |
818 | result = 0; | |
819 | } else { | |
820 | winner = quorum_get_vote_winner(&error_votes); | |
821 | result = winner->value.l; | |
822 | } | |
1c508d17 BC |
823 | quorum_free_vote_list(&error_votes); |
824 | ||
825 | return result; | |
826 | } | |
827 | ||
533c6e4e KW |
828 | static bool GRAPH_RDLOCK |
829 | quorum_recurse_can_replace(BlockDriverState *bs, BlockDriverState *to_replace) | |
a3ed794b HR |
830 | { |
831 | BDRVQuorumState *s = bs->opaque; | |
832 | int i; | |
833 | ||
834 | for (i = 0; i < s->num_children; i++) { | |
835 | /* | |
836 | * We have no idea whether our children show the same data as | |
837 | * this node (@bs). It is actually highly likely that | |
838 | * @to_replace does not, because replacing a broken child is | |
839 | * one of the main use cases here. | |
840 | * | |
841 | * We do know that the new BDS will match @bs, so replacing | |
842 | * any of our children by it will be safe. It cannot change | |
843 | * the data this quorum node presents to its parents. | |
844 | * | |
845 | * However, replacing @to_replace by @bs in any of our | |
846 | * children's chains may change visible data somewhere in | |
847 | * there. We therefore cannot recurse down those chains with | |
848 | * bdrv_recurse_can_replace(). | |
849 | * (More formally, bdrv_recurse_can_replace() requires that | |
850 | * @to_replace will be replaced by something matching the @bs | |
851 | * passed to it. We cannot guarantee that.) | |
852 | * | |
853 | * Thus, we can only check whether any of our immediate | |
854 | * children matches @to_replace. | |
855 | * | |
856 | * (In the future, we might add a function to recurse down a | |
857 | * chain that checks that nothing there cares about a change | |
858 | * in data from the respective child in question. For | |
859 | * example, most filters do not care when their child's data | |
860 | * suddenly changes, as long as their parents do not care.) | |
861 | */ | |
862 | if (s->children[i]->bs == to_replace) { | |
863 | /* | |
864 | * We now have to ensure that there is no other parent | |
865 | * that cares about replacing this child by a node with | |
866 | * potentially different data. | |
867 | * We do so by checking whether there are any other parents | |
868 | * at all, which is stricter than necessary, but also very | |
869 | * simple. (We may decide to implement something more | |
870 | * complex and permissive when there is an actual need for | |
871 | * it.) | |
872 | */ | |
873 | return QLIST_FIRST(&to_replace->parents) == s->children[i] && | |
874 | QLIST_NEXT(s->children[i], next_parent) == NULL; | |
875 | } | |
876 | } | |
877 | ||
878 | return false; | |
879 | } | |
880 | ||
c88a1de5 BC |
881 | static int quorum_valid_threshold(int threshold, int num_children, Error **errp) |
882 | { | |
883 | ||
884 | if (threshold < 1) { | |
c6bd8c70 | 885 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, |
6cc0667d | 886 | "vote-threshold", "a value >= 1"); |
c88a1de5 BC |
887 | return -ERANGE; |
888 | } | |
889 | ||
890 | if (threshold > num_children) { | |
891 | error_setg(errp, "threshold may not exceed children count"); | |
892 | return -ERANGE; | |
893 | } | |
894 | ||
895 | return 0; | |
896 | } | |
897 | ||
898 | static QemuOptsList quorum_runtime_opts = { | |
899 | .name = "quorum", | |
900 | .head = QTAILQ_HEAD_INITIALIZER(quorum_runtime_opts.head), | |
901 | .desc = { | |
902 | { | |
903 | .name = QUORUM_OPT_VOTE_THRESHOLD, | |
904 | .type = QEMU_OPT_NUMBER, | |
905 | .help = "The number of vote needed for reaching quorum", | |
906 | }, | |
907 | { | |
908 | .name = QUORUM_OPT_BLKVERIFY, | |
909 | .type = QEMU_OPT_BOOL, | |
910 | .help = "Trigger block verify mode if set", | |
911 | }, | |
cf29a570 BC |
912 | { |
913 | .name = QUORUM_OPT_REWRITE, | |
914 | .type = QEMU_OPT_BOOL, | |
915 | .help = "Rewrite corrupted block on read quorum", | |
916 | }, | |
a9db86b2 LY |
917 | { |
918 | .name = QUORUM_OPT_READ_PATTERN, | |
919 | .type = QEMU_OPT_STRING, | |
920 | .help = "Allowed pattern: quorum, fifo. Quorum is default", | |
921 | }, | |
c88a1de5 BC |
922 | { /* end of list */ } |
923 | }, | |
924 | }; | |
925 | ||
5cddb2e9 AG |
926 | static void quorum_refresh_flags(BlockDriverState *bs) |
927 | { | |
928 | BDRVQuorumState *s = bs->opaque; | |
929 | int i; | |
930 | ||
931 | bs->supported_zero_flags = | |
932 | BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK; | |
933 | ||
934 | for (i = 0; i < s->num_children; i++) { | |
935 | bs->supported_zero_flags &= s->children[i]->bs->supported_zero_flags; | |
936 | } | |
937 | ||
938 | bs->supported_zero_flags |= BDRV_REQ_WRITE_UNCHANGED; | |
939 | } | |
940 | ||
c88a1de5 BC |
941 | static int quorum_open(BlockDriverState *bs, QDict *options, int flags, |
942 | Error **errp) | |
943 | { | |
944 | BDRVQuorumState *s = bs->opaque; | |
8df3abfc | 945 | QemuOpts *opts = NULL; |
8d5fb199 | 946 | const char *pattern_str; |
c88a1de5 | 947 | bool *opened; |
c88a1de5 BC |
948 | int i; |
949 | int ret = 0; | |
950 | ||
951 | qdict_flatten(options); | |
c88a1de5 | 952 | |
ea6828d8 KW |
953 | /* count how many different children are present */ |
954 | s->num_children = qdict_array_entries(options, "children."); | |
955 | if (s->num_children < 0) { | |
dcfe4805 | 956 | error_setg(errp, "Option children is not a valid array"); |
8a87f3d7 HR |
957 | ret = -EINVAL; |
958 | goto exit; | |
959 | } | |
98292c61 | 960 | if (s->num_children < 1) { |
dcfe4805 | 961 | error_setg(errp, "Number of provided children must be 1 or more"); |
c88a1de5 BC |
962 | ret = -EINVAL; |
963 | goto exit; | |
964 | } | |
965 | ||
966 | opts = qemu_opts_create(&quorum_runtime_opts, NULL, 0, &error_abort); | |
a5f9b9df | 967 | if (!qemu_opts_absorb_qdict(opts, options, errp)) { |
c88a1de5 BC |
968 | ret = -EINVAL; |
969 | goto exit; | |
970 | } | |
971 | ||
972 | s->threshold = qemu_opt_get_number(opts, QUORUM_OPT_VOTE_THRESHOLD, 0); | |
834cb2ad | 973 | /* and validate it against s->num_children */ |
dcfe4805 | 974 | ret = quorum_valid_threshold(s->threshold, s->num_children, errp); |
834cb2ad WC |
975 | if (ret < 0) { |
976 | goto exit; | |
977 | } | |
978 | ||
8d5fb199 MAL |
979 | pattern_str = qemu_opt_get(opts, QUORUM_OPT_READ_PATTERN); |
980 | if (!pattern_str) { | |
981 | ret = QUORUM_READ_PATTERN_QUORUM; | |
982 | } else { | |
f7abe0ec | 983 | ret = qapi_enum_parse(&QuorumReadPattern_lookup, pattern_str, |
8d5fb199 MAL |
984 | -EINVAL, NULL); |
985 | } | |
c88a1de5 | 986 | if (ret < 0) { |
dcfe4805 | 987 | error_setg(errp, "Please set read-pattern as fifo or quorum"); |
c88a1de5 BC |
988 | goto exit; |
989 | } | |
a9db86b2 | 990 | s->read_pattern = ret; |
c88a1de5 | 991 | |
a9db86b2 | 992 | if (s->read_pattern == QUORUM_READ_PATTERN_QUORUM) { |
83aedca8 AG |
993 | s->is_blkverify = qemu_opt_get_bool(opts, QUORUM_OPT_BLKVERIFY, false); |
994 | if (s->is_blkverify && (s->num_children != 2 || s->threshold != 2)) { | |
dcfe4805 | 995 | error_setg(errp, "blkverify=on can only be set if there are " |
83aedca8 AG |
996 | "exactly two files and vote-threshold is 2"); |
997 | ret = -EINVAL; | |
998 | goto exit; | |
a9db86b2 LY |
999 | } |
1000 | ||
1001 | s->rewrite_corrupted = qemu_opt_get_bool(opts, QUORUM_OPT_REWRITE, | |
1002 | false); | |
1003 | if (s->rewrite_corrupted && s->is_blkverify) { | |
dcfe4805 | 1004 | error_setg(errp, |
a9db86b2 LY |
1005 | "rewrite-corrupted=on cannot be used with blkverify=on"); |
1006 | ret = -EINVAL; | |
1007 | goto exit; | |
1008 | } | |
cf29a570 BC |
1009 | } |
1010 | ||
0bd6e91a KW |
1011 | /* allocate the children array */ |
1012 | s->children = g_new0(BdrvChild *, s->num_children); | |
c88a1de5 BC |
1013 | opened = g_new0(bool, s->num_children); |
1014 | ||
ea6828d8 | 1015 | for (i = 0; i < s->num_children; i++) { |
5eb9a3c7 LS |
1016 | char indexstr[INDEXSTR_LEN]; |
1017 | ret = snprintf(indexstr, INDEXSTR_LEN, "children.%d", i); | |
1018 | assert(ret < INDEXSTR_LEN); | |
8a87f3d7 | 1019 | |
0bd6e91a | 1020 | s->children[i] = bdrv_open_child(NULL, options, indexstr, bs, |
36ee58d1 | 1021 | &child_of_bds, BDRV_CHILD_DATA, false, |
bc520249 VSO |
1022 | errp); |
1023 | if (!s->children[i]) { | |
0bd6e91a | 1024 | ret = -EINVAL; |
8a87f3d7 | 1025 | goto close_exit; |
c88a1de5 | 1026 | } |
ea6828d8 | 1027 | |
8a87f3d7 | 1028 | opened[i] = true; |
c88a1de5 | 1029 | } |
98292c61 | 1030 | s->next_child_index = s->num_children; |
c88a1de5 | 1031 | |
1b1a920b | 1032 | bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED; |
5cddb2e9 | 1033 | quorum_refresh_flags(bs); |
1b1a920b | 1034 | |
c88a1de5 BC |
1035 | g_free(opened); |
1036 | goto exit; | |
1037 | ||
1038 | close_exit: | |
1039 | /* cleanup on error */ | |
32a8aba3 | 1040 | bdrv_graph_wrlock(NULL); |
c88a1de5 BC |
1041 | for (i = 0; i < s->num_children; i++) { |
1042 | if (!opened[i]) { | |
1043 | continue; | |
1044 | } | |
0bd6e91a | 1045 | bdrv_unref_child(bs, s->children[i]); |
c88a1de5 | 1046 | } |
6bc0bcc8 | 1047 | bdrv_graph_wrunlock(NULL); |
0bd6e91a | 1048 | g_free(s->children); |
c88a1de5 BC |
1049 | g_free(opened); |
1050 | exit: | |
8df3abfc | 1051 | qemu_opts_del(opts); |
c88a1de5 BC |
1052 | return ret; |
1053 | } | |
1054 | ||
1055 | static void quorum_close(BlockDriverState *bs) | |
1056 | { | |
1057 | BDRVQuorumState *s = bs->opaque; | |
1058 | int i; | |
1059 | ||
32a8aba3 | 1060 | bdrv_graph_wrlock(NULL); |
c88a1de5 | 1061 | for (i = 0; i < s->num_children; i++) { |
0bd6e91a | 1062 | bdrv_unref_child(bs, s->children[i]); |
c88a1de5 | 1063 | } |
6bc0bcc8 | 1064 | bdrv_graph_wrunlock(NULL); |
c88a1de5 | 1065 | |
0bd6e91a | 1066 | g_free(s->children); |
c88a1de5 BC |
1067 | } |
1068 | ||
9def6082 KW |
1069 | static void GRAPH_WRLOCK |
1070 | quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs, Error **errp) | |
98292c61 WC |
1071 | { |
1072 | BDRVQuorumState *s = bs->opaque; | |
1073 | BdrvChild *child; | |
5eb9a3c7 | 1074 | char indexstr[INDEXSTR_LEN]; |
98292c61 WC |
1075 | int ret; |
1076 | ||
808b27d4 AG |
1077 | if (s->is_blkverify) { |
1078 | error_setg(errp, "Cannot add a child to a quorum in blkverify mode"); | |
1079 | return; | |
1080 | } | |
1081 | ||
98292c61 WC |
1082 | assert(s->num_children <= INT_MAX / sizeof(BdrvChild *)); |
1083 | if (s->num_children == INT_MAX / sizeof(BdrvChild *) || | |
1084 | s->next_child_index == UINT_MAX) { | |
1085 | error_setg(errp, "Too many children"); | |
1086 | return; | |
1087 | } | |
1088 | ||
5eb9a3c7 LS |
1089 | ret = snprintf(indexstr, INDEXSTR_LEN, "children.%u", s->next_child_index); |
1090 | if (ret < 0 || ret >= INDEXSTR_LEN) { | |
98292c61 WC |
1091 | error_setg(errp, "cannot generate child name"); |
1092 | return; | |
1093 | } | |
1094 | s->next_child_index++; | |
1095 | ||
98292c61 WC |
1096 | /* We can safely add the child now */ |
1097 | bdrv_ref(child_bs); | |
8b2ff529 | 1098 | |
36ee58d1 HR |
1099 | child = bdrv_attach_child(bs, child_bs, indexstr, &child_of_bds, |
1100 | BDRV_CHILD_DATA, errp); | |
8b2ff529 KW |
1101 | if (child == NULL) { |
1102 | s->next_child_index--; | |
9def6082 | 1103 | return; |
8b2ff529 | 1104 | } |
98292c61 WC |
1105 | s->children = g_renew(BdrvChild *, s->children, s->num_children + 1); |
1106 | s->children[s->num_children++] = child; | |
5cddb2e9 | 1107 | quorum_refresh_flags(bs); |
98292c61 WC |
1108 | } |
1109 | ||
9def6082 KW |
1110 | static void GRAPH_WRLOCK |
1111 | quorum_del_child(BlockDriverState *bs, BdrvChild *child, Error **errp) | |
98292c61 WC |
1112 | { |
1113 | BDRVQuorumState *s = bs->opaque; | |
5eb9a3c7 | 1114 | char indexstr[INDEXSTR_LEN]; |
98292c61 WC |
1115 | int i; |
1116 | ||
1117 | for (i = 0; i < s->num_children; i++) { | |
1118 | if (s->children[i] == child) { | |
1119 | break; | |
1120 | } | |
1121 | } | |
1122 | ||
1123 | /* we have checked it in bdrv_del_child() */ | |
1124 | assert(i < s->num_children); | |
1125 | ||
1126 | if (s->num_children <= s->threshold) { | |
1127 | error_setg(errp, | |
1128 | "The number of children cannot be lower than the vote threshold %d", | |
1129 | s->threshold); | |
1130 | return; | |
1131 | } | |
1132 | ||
808b27d4 AG |
1133 | /* We know now that num_children > threshold, so blkverify must be false */ |
1134 | assert(!s->is_blkverify); | |
1135 | ||
5eb9a3c7 LS |
1136 | snprintf(indexstr, INDEXSTR_LEN, "children.%u", s->next_child_index - 1); |
1137 | if (!strncmp(child->name, indexstr, INDEXSTR_LEN)) { | |
1138 | s->next_child_index--; | |
1139 | } | |
1140 | ||
98292c61 WC |
1141 | /* We can safely remove this child now */ |
1142 | memmove(&s->children[i], &s->children[i + 1], | |
1143 | (s->num_children - i - 1) * sizeof(BdrvChild *)); | |
1144 | s->children = g_renew(BdrvChild *, s->children, --s->num_children); | |
9def6082 | 1145 | |
98292c61 WC |
1146 | bdrv_unref_child(bs, child); |
1147 | ||
5cddb2e9 | 1148 | quorum_refresh_flags(bs); |
98292c61 WC |
1149 | } |
1150 | ||
abc521a9 HR |
1151 | static void quorum_gather_child_options(BlockDriverState *bs, QDict *target, |
1152 | bool backing_overridden) | |
1153 | { | |
1154 | BDRVQuorumState *s = bs->opaque; | |
1155 | QList *children_list; | |
1156 | int i; | |
1157 | ||
1158 | /* | |
1159 | * The generic implementation for gathering child options in | |
1160 | * bdrv_refresh_filename() would use the names of the children | |
1161 | * as specified for bdrv_open_child() or bdrv_attach_child(), | |
1162 | * which is "children.%u" with %u being a value | |
1163 | * (s->next_child_index) that is incremented each time a new child | |
1164 | * is added (and never decremented). Since children can be | |
1165 | * deleted at runtime, there may be gaps in that enumeration. | |
1166 | * When creating a new quorum BDS and specifying the children for | |
1167 | * it through runtime options, the enumeration used there may not | |
1168 | * have any gaps, though. | |
1169 | * | |
1170 | * Therefore, we have to create a new gap-less enumeration here | |
1171 | * (which we can achieve by simply putting all of the children's | |
1172 | * full_open_options into a QList). | |
1173 | * | |
1174 | * XXX: Note that there are issues with the current child option | |
1175 | * structure quorum uses (such as the fact that children do | |
1176 | * not really have unique permanent names). Therefore, this | |
1177 | * is going to have to change in the future and ideally we | |
1178 | * want quorum to be covered by the generic implementation. | |
1179 | */ | |
1180 | ||
1181 | children_list = qlist_new(); | |
1182 | qdict_put(target, "children", children_list); | |
1183 | ||
1184 | for (i = 0; i < s->num_children; i++) { | |
1185 | qlist_append(children_list, | |
1186 | qobject_ref(s->children[i]->bs->full_open_options)); | |
1187 | } | |
1188 | } | |
1189 | ||
f3037bd2 HR |
1190 | static char *quorum_dirname(BlockDriverState *bs, Error **errp) |
1191 | { | |
1192 | /* In general, there are multiple BDSs with different dirnames below this | |
1193 | * one; so there is no unique dirname we could return (unless all are equal | |
1194 | * by chance, or there is only one). Therefore, to be consistent, just | |
1195 | * always return NULL. */ | |
1196 | error_setg(errp, "Cannot generate a base directory for quorum nodes"); | |
1197 | return NULL; | |
1198 | } | |
1199 | ||
37a3791b | 1200 | static void quorum_child_perm(BlockDriverState *bs, BdrvChild *c, |
bf8e925e | 1201 | BdrvChildRole role, |
37a3791b HR |
1202 | BlockReopenQueue *reopen_queue, |
1203 | uint64_t perm, uint64_t shared, | |
1204 | uint64_t *nperm, uint64_t *nshared) | |
1205 | { | |
9ca5b0e8 HR |
1206 | BDRVQuorumState *s = bs->opaque; |
1207 | ||
37a3791b | 1208 | *nperm = perm & DEFAULT_PERM_PASSTHROUGH; |
9ca5b0e8 HR |
1209 | if (s->rewrite_corrupted) { |
1210 | *nperm |= BLK_PERM_WRITE; | |
1211 | } | |
37a3791b HR |
1212 | |
1213 | /* | |
1214 | * We cannot share RESIZE or WRITE, as this would make the | |
1215 | * children differ from each other. | |
1216 | */ | |
1217 | *nshared = (shared & (BLK_PERM_CONSISTENT_READ | | |
1218 | BLK_PERM_WRITE_UNCHANGED)) | |
1219 | | DEFAULT_PERM_UNCHANGED; | |
1220 | } | |
1221 | ||
ef9bba14 AG |
1222 | /* |
1223 | * Each one of the children can report different status flags even | |
1224 | * when they contain the same data, so what this function does is | |
1225 | * return BDRV_BLOCK_ZERO if *all* children agree that a certain | |
1226 | * region contains zeroes, and BDRV_BLOCK_DATA otherwise. | |
1227 | */ | |
7ff9579e KW |
1228 | static int coroutine_fn GRAPH_RDLOCK |
1229 | quorum_co_block_status(BlockDriverState *bs, bool want_zero, | |
1230 | int64_t offset, int64_t count, | |
1231 | int64_t *pnum, int64_t *map, BlockDriverState **file) | |
ef9bba14 AG |
1232 | { |
1233 | BDRVQuorumState *s = bs->opaque; | |
1234 | int i, ret; | |
1235 | int64_t pnum_zero = count; | |
1236 | int64_t pnum_data = 0; | |
1237 | ||
1238 | for (i = 0; i < s->num_children; i++) { | |
1239 | int64_t bytes; | |
1240 | ret = bdrv_co_common_block_status_above(s->children[i]->bs, NULL, false, | |
1241 | want_zero, offset, count, | |
1242 | &bytes, NULL, NULL, NULL); | |
1243 | if (ret < 0) { | |
1244 | quorum_report_bad(QUORUM_OP_TYPE_READ, offset, count, | |
1245 | s->children[i]->bs->node_name, ret); | |
1246 | pnum_data = count; | |
1247 | break; | |
1248 | } | |
1249 | /* | |
1250 | * Even if all children agree about whether there are zeroes | |
1251 | * or not at @offset they might disagree on the size, so use | |
1252 | * the smallest when reporting BDRV_BLOCK_ZERO and the largest | |
1253 | * when reporting BDRV_BLOCK_DATA. | |
1254 | */ | |
1255 | if (ret & BDRV_BLOCK_ZERO) { | |
1256 | pnum_zero = MIN(pnum_zero, bytes); | |
1257 | } else { | |
1258 | pnum_data = MAX(pnum_data, bytes); | |
1259 | } | |
1260 | } | |
1261 | ||
1262 | if (pnum_data) { | |
1263 | *pnum = pnum_data; | |
1264 | return BDRV_BLOCK_DATA; | |
1265 | } else { | |
1266 | *pnum = pnum_zero; | |
1267 | return BDRV_BLOCK_ZERO; | |
1268 | } | |
1269 | } | |
1270 | ||
2654267c HR |
1271 | static const char *const quorum_strong_runtime_opts[] = { |
1272 | QUORUM_OPT_VOTE_THRESHOLD, | |
1273 | QUORUM_OPT_BLKVERIFY, | |
1274 | QUORUM_OPT_REWRITE, | |
1275 | QUORUM_OPT_READ_PATTERN, | |
1276 | ||
1277 | NULL | |
1278 | }; | |
1279 | ||
cadebd7a | 1280 | static BlockDriver bdrv_quorum = { |
e3625d3d | 1281 | .format_name = "quorum", |
e3625d3d SH |
1282 | |
1283 | .instance_size = sizeof(BDRVQuorumState), | |
cadebd7a | 1284 | |
65d2c3e2 | 1285 | .bdrv_open = quorum_open, |
e3625d3d | 1286 | .bdrv_close = quorum_close, |
abc521a9 | 1287 | .bdrv_gather_child_options = quorum_gather_child_options, |
f3037bd2 | 1288 | .bdrv_dirname = quorum_dirname, |
ef9bba14 | 1289 | .bdrv_co_block_status = quorum_co_block_status, |
13e7956e | 1290 | |
5529b02d | 1291 | .bdrv_co_flush = quorum_co_flush, |
c88a1de5 | 1292 | |
c86422c5 | 1293 | .bdrv_co_getlength = quorum_co_getlength, |
1c508d17 | 1294 | |
6847da38 KW |
1295 | .bdrv_co_preadv = quorum_co_preadv, |
1296 | .bdrv_co_pwritev = quorum_co_pwritev, | |
5cddb2e9 | 1297 | .bdrv_co_pwrite_zeroes = quorum_co_pwrite_zeroes, |
d55dee20 | 1298 | |
98292c61 WC |
1299 | .bdrv_add_child = quorum_add_child, |
1300 | .bdrv_del_child = quorum_del_child, | |
1301 | ||
37a3791b | 1302 | .bdrv_child_perm = quorum_child_perm, |
d7010dfb | 1303 | |
a3ed794b | 1304 | .bdrv_recurse_can_replace = quorum_recurse_can_replace, |
2654267c HR |
1305 | |
1306 | .strong_runtime_opts = quorum_strong_runtime_opts, | |
cadebd7a BC |
1307 | }; |
1308 | ||
1309 | static void bdrv_quorum_init(void) | |
1310 | { | |
e94867ed SS |
1311 | if (!qcrypto_hash_supports(QCRYPTO_HASH_ALG_SHA256)) { |
1312 | /* SHA256 hash support is required for quorum device */ | |
1313 | return; | |
1314 | } | |
cadebd7a BC |
1315 | bdrv_register(&bdrv_quorum); |
1316 | } | |
1317 | ||
1318 | block_init(bdrv_quorum_init); |