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15#include "qemu/osdep.h"
16#include "qemu/option.h"
17#include "block/nbd.h"
18#include "block/blockjob.h"
19#include "block/block_int.h"
20#include "block/block_backup.h"
21#include "sysemu/block-backend.h"
22#include "qapi/error.h"
23#include "replication.h"
24
25typedef enum {
26 BLOCK_REPLICATION_NONE,
27 BLOCK_REPLICATION_RUNNING,
28 BLOCK_REPLICATION_FAILOVER,
29 BLOCK_REPLICATION_FAILOVER_FAILED,
30 BLOCK_REPLICATION_DONE,
31} ReplicationStage;
32
33typedef struct BDRVReplicationState {
34 ReplicationMode mode;
35 ReplicationStage stage;
36 BdrvChild *active_disk;
37 BdrvChild *hidden_disk;
38 BdrvChild *secondary_disk;
39 char *top_id;
40 ReplicationState *rs;
41 Error *blocker;
42 int orig_hidden_flags;
43 int orig_secondary_flags;
44 int error;
45} BDRVReplicationState;
46
47static void replication_start(ReplicationState *rs, ReplicationMode mode,
48 Error **errp);
49static void replication_do_checkpoint(ReplicationState *rs, Error **errp);
50static void replication_get_error(ReplicationState *rs, Error **errp);
51static void replication_stop(ReplicationState *rs, bool failover,
52 Error **errp);
53
54#define REPLICATION_MODE "mode"
55#define REPLICATION_TOP_ID "top-id"
56static QemuOptsList replication_runtime_opts = {
57 .name = "replication",
58 .head = QTAILQ_HEAD_INITIALIZER(replication_runtime_opts.head),
59 .desc = {
60 {
61 .name = REPLICATION_MODE,
62 .type = QEMU_OPT_STRING,
63 },
64 {
65 .name = REPLICATION_TOP_ID,
66 .type = QEMU_OPT_STRING,
67 },
68 { }
69 },
70};
71
72static ReplicationOps replication_ops = {
73 .start = replication_start,
74 .checkpoint = replication_do_checkpoint,
75 .get_error = replication_get_error,
76 .stop = replication_stop,
77};
78
79static int replication_open(BlockDriverState *bs, QDict *options,
80 int flags, Error **errp)
81{
82 int ret;
83 BDRVReplicationState *s = bs->opaque;
84 Error *local_err = NULL;
85 QemuOpts *opts = NULL;
86 const char *mode;
87 const char *top_id;
88
89 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
90 false, errp);
91 if (!bs->file) {
92 return -EINVAL;
93 }
94
95 ret = -EINVAL;
96 opts = qemu_opts_create(&replication_runtime_opts, NULL, 0, &error_abort);
97 qemu_opts_absorb_qdict(opts, options, &local_err);
98 if (local_err) {
99 goto fail;
100 }
101
102 mode = qemu_opt_get(opts, REPLICATION_MODE);
103 if (!mode) {
104 error_setg(&local_err, "Missing the option mode");
105 goto fail;
106 }
107
108 if (!strcmp(mode, "primary")) {
109 s->mode = REPLICATION_MODE_PRIMARY;
110 top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
111 if (top_id) {
112 error_setg(&local_err, "The primary side does not support option top-id");
113 goto fail;
114 }
115 } else if (!strcmp(mode, "secondary")) {
116 s->mode = REPLICATION_MODE_SECONDARY;
117 top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
118 s->top_id = g_strdup(top_id);
119 if (!s->top_id) {
120 error_setg(&local_err, "Missing the option top-id");
121 goto fail;
122 }
123 } else {
124 error_setg(&local_err,
125 "The option mode's value should be primary or secondary");
126 goto fail;
127 }
128
129 s->rs = replication_new(bs, &replication_ops);
130
131 ret = 0;
132
133fail:
134 qemu_opts_del(opts);
135 error_propagate(errp, local_err);
136
137 return ret;
138}
139
140static void replication_close(BlockDriverState *bs)
141{
142 BDRVReplicationState *s = bs->opaque;
143
144 if (s->stage == BLOCK_REPLICATION_RUNNING) {
145 replication_stop(s->rs, false, NULL);
146 }
147 if (s->stage == BLOCK_REPLICATION_FAILOVER) {
148 job_cancel_sync(&s->active_disk->bs->job->job);
149 }
150
151 if (s->mode == REPLICATION_MODE_SECONDARY) {
152 g_free(s->top_id);
153 }
154
155 replication_remove(s->rs);
156}
157
158static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
159 const BdrvChildRole *role,
160 BlockReopenQueue *reopen_queue,
161 uint64_t perm, uint64_t shared,
162 uint64_t *nperm, uint64_t *nshared)
163{
164 *nperm = BLK_PERM_CONSISTENT_READ;
165 if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) {
166 *nperm |= BLK_PERM_WRITE;
167 }
168 *nshared = BLK_PERM_CONSISTENT_READ \
169 | BLK_PERM_WRITE \
170 | BLK_PERM_WRITE_UNCHANGED;
171 return;
172}
173
174static int64_t replication_getlength(BlockDriverState *bs)
175{
176 return bdrv_getlength(bs->file->bs);
177}
178
179static int replication_get_io_status(BDRVReplicationState *s)
180{
181 switch (s->stage) {
182 case BLOCK_REPLICATION_NONE:
183 return -EIO;
184 case BLOCK_REPLICATION_RUNNING:
185 return 0;
186 case BLOCK_REPLICATION_FAILOVER:
187 return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
188 case BLOCK_REPLICATION_FAILOVER_FAILED:
189 return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1;
190 case BLOCK_REPLICATION_DONE:
191
192
193
194
195 return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
196 default:
197 abort();
198 }
199}
200
201static int replication_return_value(BDRVReplicationState *s, int ret)
202{
203 if (s->mode == REPLICATION_MODE_SECONDARY) {
204 return ret;
205 }
206
207 if (ret < 0) {
208 s->error = ret;
209 ret = 0;
210 }
211
212 return ret;
213}
214
215static coroutine_fn int replication_co_readv(BlockDriverState *bs,
216 int64_t sector_num,
217 int remaining_sectors,
218 QEMUIOVector *qiov)
219{
220 BDRVReplicationState *s = bs->opaque;
221 BdrvChild *child = s->secondary_disk;
222 BlockJob *job = NULL;
223 CowRequest req;
224 int ret;
225
226 if (s->mode == REPLICATION_MODE_PRIMARY) {
227
228 return -EIO;
229 }
230
231 ret = replication_get_io_status(s);
232 if (ret < 0) {
233 return ret;
234 }
235
236 if (child && child->bs) {
237 job = child->bs->job;
238 }
239
240 if (job) {
241 uint64_t remaining_bytes = remaining_sectors * BDRV_SECTOR_SIZE;
242
243 backup_wait_for_overlapping_requests(child->bs->job,
244 sector_num * BDRV_SECTOR_SIZE,
245 remaining_bytes);
246 backup_cow_request_begin(&req, child->bs->job,
247 sector_num * BDRV_SECTOR_SIZE,
248 remaining_bytes);
249 ret = bdrv_co_preadv(bs->file, sector_num * BDRV_SECTOR_SIZE,
250 remaining_bytes, qiov, 0);
251 backup_cow_request_end(&req);
252 goto out;
253 }
254
255 ret = bdrv_co_preadv(bs->file, sector_num * BDRV_SECTOR_SIZE,
256 remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
257out:
258 return replication_return_value(s, ret);
259}
260
261static coroutine_fn int replication_co_writev(BlockDriverState *bs,
262 int64_t sector_num,
263 int remaining_sectors,
264 QEMUIOVector *qiov,
265 int flags)
266{
267 BDRVReplicationState *s = bs->opaque;
268 QEMUIOVector hd_qiov;
269 uint64_t bytes_done = 0;
270 BdrvChild *top = bs->file;
271 BdrvChild *base = s->secondary_disk;
272 BdrvChild *target;
273 int ret;
274 int64_t n;
275
276 assert(!flags);
277 ret = replication_get_io_status(s);
278 if (ret < 0) {
279 goto out;
280 }
281
282 if (ret == 0) {
283 ret = bdrv_co_pwritev(top, sector_num * BDRV_SECTOR_SIZE,
284 remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
285 return replication_return_value(s, ret);
286 }
287
288
289
290
291
292 qemu_iovec_init(&hd_qiov, qiov->niov);
293 while (remaining_sectors > 0) {
294 int64_t count;
295
296 ret = bdrv_is_allocated_above(top->bs, base->bs,
297 sector_num * BDRV_SECTOR_SIZE,
298 remaining_sectors * BDRV_SECTOR_SIZE,
299 &count);
300 if (ret < 0) {
301 goto out1;
302 }
303
304 assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
305 n = count >> BDRV_SECTOR_BITS;
306 qemu_iovec_reset(&hd_qiov);
307 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
308
309 target = ret ? top : base;
310 ret = bdrv_co_pwritev(target, sector_num * BDRV_SECTOR_SIZE,
311 n * BDRV_SECTOR_SIZE, &hd_qiov, 0);
312 if (ret < 0) {
313 goto out1;
314 }
315
316 remaining_sectors -= n;
317 sector_num += n;
318 bytes_done += count;
319 }
320
321out1:
322 qemu_iovec_destroy(&hd_qiov);
323out:
324 return ret;
325}
326
327static bool replication_recurse_is_first_non_filter(BlockDriverState *bs,
328 BlockDriverState *candidate)
329{
330 return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
331}
332
333static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
334{
335 Error *local_err = NULL;
336 int ret;
337
338 if (!s->secondary_disk->bs->job) {
339 error_setg(errp, "Backup job was cancelled unexpectedly");
340 return;
341 }
342
343 backup_do_checkpoint(s->secondary_disk->bs->job, &local_err);
344 if (local_err) {
345 error_propagate(errp, local_err);
346 return;
347 }
348
349 if (!s->active_disk->bs->drv) {
350 error_setg(errp, "Active disk %s is ejected",
351 s->active_disk->bs->node_name);
352 return;
353 }
354
355 ret = s->active_disk->bs->drv->bdrv_make_empty(s->active_disk->bs);
356 if (ret < 0) {
357 error_setg(errp, "Cannot make active disk empty");
358 return;
359 }
360
361 if (!s->hidden_disk->bs->drv) {
362 error_setg(errp, "Hidden disk %s is ejected",
363 s->hidden_disk->bs->node_name);
364 return;
365 }
366
367 ret = s->hidden_disk->bs->drv->bdrv_make_empty(s->hidden_disk->bs);
368 if (ret < 0) {
369 error_setg(errp, "Cannot make hidden disk empty");
370 return;
371 }
372}
373
374static void reopen_backing_file(BlockDriverState *bs, bool writable,
375 Error **errp)
376{
377 BDRVReplicationState *s = bs->opaque;
378 BlockReopenQueue *reopen_queue = NULL;
379 int orig_hidden_flags, orig_secondary_flags;
380 int new_hidden_flags, new_secondary_flags;
381 Error *local_err = NULL;
382
383 if (writable) {
384 orig_hidden_flags = s->orig_hidden_flags =
385 bdrv_get_flags(s->hidden_disk->bs);
386 new_hidden_flags = (orig_hidden_flags | BDRV_O_RDWR) &
387 ~BDRV_O_INACTIVE;
388 orig_secondary_flags = s->orig_secondary_flags =
389 bdrv_get_flags(s->secondary_disk->bs);
390 new_secondary_flags = (orig_secondary_flags | BDRV_O_RDWR) &
391 ~BDRV_O_INACTIVE;
392 } else {
393 orig_hidden_flags = (s->orig_hidden_flags | BDRV_O_RDWR) &
394 ~BDRV_O_INACTIVE;
395 new_hidden_flags = s->orig_hidden_flags;
396 orig_secondary_flags = (s->orig_secondary_flags | BDRV_O_RDWR) &
397 ~BDRV_O_INACTIVE;
398 new_secondary_flags = s->orig_secondary_flags;
399 }
400
401 bdrv_subtree_drained_begin(s->hidden_disk->bs);
402 bdrv_subtree_drained_begin(s->secondary_disk->bs);
403
404 if (orig_hidden_flags != new_hidden_flags) {
405 reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs, NULL,
406 new_hidden_flags);
407 }
408
409 if (!(orig_secondary_flags & BDRV_O_RDWR)) {
410 reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
411 NULL, new_secondary_flags);
412 }
413
414 if (reopen_queue) {
415 bdrv_reopen_multiple(bdrv_get_aio_context(bs),
416 reopen_queue, &local_err);
417 error_propagate(errp, local_err);
418 }
419
420 bdrv_subtree_drained_end(s->hidden_disk->bs);
421 bdrv_subtree_drained_end(s->secondary_disk->bs);
422}
423
424static void backup_job_cleanup(BlockDriverState *bs)
425{
426 BDRVReplicationState *s = bs->opaque;
427 BlockDriverState *top_bs;
428
429 top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
430 if (!top_bs) {
431 return;
432 }
433 bdrv_op_unblock_all(top_bs, s->blocker);
434 error_free(s->blocker);
435 reopen_backing_file(bs, false, NULL);
436}
437
438static void backup_job_completed(void *opaque, int ret)
439{
440 BlockDriverState *bs = opaque;
441 BDRVReplicationState *s = bs->opaque;
442
443 if (s->stage != BLOCK_REPLICATION_FAILOVER) {
444
445 s->error = -EIO;
446 }
447
448 backup_job_cleanup(bs);
449}
450
451static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs)
452{
453 BdrvChild *child;
454
455
456 if (top_bs == bs) {
457 return true;
458 }
459
460
461 QLIST_FOREACH(child, &top_bs->children, next) {
462 if (child->bs == bs || check_top_bs(child->bs, bs)) {
463 return true;
464 }
465 }
466
467 return false;
468}
469
470static void replication_start(ReplicationState *rs, ReplicationMode mode,
471 Error **errp)
472{
473 BlockDriverState *bs = rs->opaque;
474 BDRVReplicationState *s;
475 BlockDriverState *top_bs;
476 int64_t active_length, hidden_length, disk_length;
477 AioContext *aio_context;
478 Error *local_err = NULL;
479 BlockJob *job;
480
481 aio_context = bdrv_get_aio_context(bs);
482 aio_context_acquire(aio_context);
483 s = bs->opaque;
484
485 if (s->stage != BLOCK_REPLICATION_NONE) {
486 error_setg(errp, "Block replication is running or done");
487 aio_context_release(aio_context);
488 return;
489 }
490
491 if (s->mode != mode) {
492 error_setg(errp, "The parameter mode's value is invalid, needs %d,"
493 " but got %d", s->mode, mode);
494 aio_context_release(aio_context);
495 return;
496 }
497
498 switch (s->mode) {
499 case REPLICATION_MODE_PRIMARY:
500 break;
501 case REPLICATION_MODE_SECONDARY:
502 s->active_disk = bs->file;
503 if (!s->active_disk || !s->active_disk->bs ||
504 !s->active_disk->bs->backing) {
505 error_setg(errp, "Active disk doesn't have backing file");
506 aio_context_release(aio_context);
507 return;
508 }
509
510 s->hidden_disk = s->active_disk->bs->backing;
511 if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) {
512 error_setg(errp, "Hidden disk doesn't have backing file");
513 aio_context_release(aio_context);
514 return;
515 }
516
517 s->secondary_disk = s->hidden_disk->bs->backing;
518 if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) {
519 error_setg(errp, "The secondary disk doesn't have block backend");
520 aio_context_release(aio_context);
521 return;
522 }
523
524
525 active_length = bdrv_getlength(s->active_disk->bs);
526 hidden_length = bdrv_getlength(s->hidden_disk->bs);
527 disk_length = bdrv_getlength(s->secondary_disk->bs);
528 if (active_length < 0 || hidden_length < 0 || disk_length < 0 ||
529 active_length != hidden_length || hidden_length != disk_length) {
530 error_setg(errp, "Active disk, hidden disk, secondary disk's length"
531 " are not the same");
532 aio_context_release(aio_context);
533 return;
534 }
535
536
537 assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv);
538
539 if (!s->active_disk->bs->drv->bdrv_make_empty ||
540 !s->hidden_disk->bs->drv->bdrv_make_empty) {
541 error_setg(errp,
542 "Active disk or hidden disk doesn't support make_empty");
543 aio_context_release(aio_context);
544 return;
545 }
546
547
548 reopen_backing_file(bs, true, &local_err);
549 if (local_err) {
550 error_propagate(errp, local_err);
551 aio_context_release(aio_context);
552 return;
553 }
554
555
556 error_setg(&s->blocker,
557 "Block device is in use by internal backup job");
558
559 top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
560 if (!top_bs || !bdrv_is_root_node(top_bs) ||
561 !check_top_bs(top_bs, bs)) {
562 error_setg(errp, "No top_bs or it is invalid");
563 reopen_backing_file(bs, false, NULL);
564 aio_context_release(aio_context);
565 return;
566 }
567 bdrv_op_block_all(top_bs, s->blocker);
568 bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
569
570 job = backup_job_create(NULL, s->secondary_disk->bs, s->hidden_disk->bs,
571 0, MIRROR_SYNC_MODE_NONE, NULL, false,
572 BLOCKDEV_ON_ERROR_REPORT,
573 BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
574 backup_job_completed, bs, NULL, &local_err);
575 if (local_err) {
576 error_propagate(errp, local_err);
577 backup_job_cleanup(bs);
578 aio_context_release(aio_context);
579 return;
580 }
581 job_start(&job->job);
582 break;
583 default:
584 aio_context_release(aio_context);
585 abort();
586 }
587
588 s->stage = BLOCK_REPLICATION_RUNNING;
589
590 if (s->mode == REPLICATION_MODE_SECONDARY) {
591 secondary_do_checkpoint(s, errp);
592 }
593
594 s->error = 0;
595 aio_context_release(aio_context);
596}
597
598static void replication_do_checkpoint(ReplicationState *rs, Error **errp)
599{
600 BlockDriverState *bs = rs->opaque;
601 BDRVReplicationState *s;
602 AioContext *aio_context;
603
604 aio_context = bdrv_get_aio_context(bs);
605 aio_context_acquire(aio_context);
606 s = bs->opaque;
607
608 if (s->mode == REPLICATION_MODE_SECONDARY) {
609 secondary_do_checkpoint(s, errp);
610 }
611 aio_context_release(aio_context);
612}
613
614static void replication_get_error(ReplicationState *rs, Error **errp)
615{
616 BlockDriverState *bs = rs->opaque;
617 BDRVReplicationState *s;
618 AioContext *aio_context;
619
620 aio_context = bdrv_get_aio_context(bs);
621 aio_context_acquire(aio_context);
622 s = bs->opaque;
623
624 if (s->stage != BLOCK_REPLICATION_RUNNING) {
625 error_setg(errp, "Block replication is not running");
626 aio_context_release(aio_context);
627 return;
628 }
629
630 if (s->error) {
631 error_setg(errp, "I/O error occurred");
632 aio_context_release(aio_context);
633 return;
634 }
635 aio_context_release(aio_context);
636}
637
638static void replication_done(void *opaque, int ret)
639{
640 BlockDriverState *bs = opaque;
641 BDRVReplicationState *s = bs->opaque;
642
643 if (ret == 0) {
644 s->stage = BLOCK_REPLICATION_DONE;
645
646
647 bdrv_refresh_filename(bs);
648 s->active_disk = NULL;
649 s->secondary_disk = NULL;
650 s->hidden_disk = NULL;
651 s->error = 0;
652 } else {
653 s->stage = BLOCK_REPLICATION_FAILOVER_FAILED;
654 s->error = -EIO;
655 }
656}
657
658static void replication_stop(ReplicationState *rs, bool failover, Error **errp)
659{
660 BlockDriverState *bs = rs->opaque;
661 BDRVReplicationState *s;
662 AioContext *aio_context;
663
664 aio_context = bdrv_get_aio_context(bs);
665 aio_context_acquire(aio_context);
666 s = bs->opaque;
667
668 if (s->stage != BLOCK_REPLICATION_RUNNING) {
669 error_setg(errp, "Block replication is not running");
670 aio_context_release(aio_context);
671 return;
672 }
673
674 switch (s->mode) {
675 case REPLICATION_MODE_PRIMARY:
676 s->stage = BLOCK_REPLICATION_DONE;
677 s->error = 0;
678 break;
679 case REPLICATION_MODE_SECONDARY:
680
681
682
683
684
685 if (s->secondary_disk->bs->job) {
686 job_cancel_sync(&s->secondary_disk->bs->job->job);
687 }
688
689 if (!failover) {
690 secondary_do_checkpoint(s, errp);
691 s->stage = BLOCK_REPLICATION_DONE;
692 aio_context_release(aio_context);
693 return;
694 }
695
696 s->stage = BLOCK_REPLICATION_FAILOVER;
697 commit_active_start(NULL, s->active_disk->bs, s->secondary_disk->bs,
698 JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT,
699 NULL, replication_done, bs, true, errp);
700 break;
701 default:
702 aio_context_release(aio_context);
703 abort();
704 }
705 aio_context_release(aio_context);
706}
707
708BlockDriver bdrv_replication = {
709 .format_name = "replication",
710 .instance_size = sizeof(BDRVReplicationState),
711
712 .bdrv_open = replication_open,
713 .bdrv_close = replication_close,
714 .bdrv_child_perm = replication_child_perm,
715
716 .bdrv_getlength = replication_getlength,
717 .bdrv_co_readv = replication_co_readv,
718 .bdrv_co_writev = replication_co_writev,
719
720 .is_filter = true,
721 .bdrv_recurse_is_first_non_filter = replication_recurse_is_first_non_filter,
722
723 .has_variable_length = true,
724};
725
726static void bdrv_replication_init(void)
727{
728 bdrv_register(&bdrv_replication);
729}
730
731block_init(bdrv_replication_init);
732
