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