1
2
3
4
5
6
7
8
9
10
11
12
13
14#include "qemu/osdep.h"
15
16#include "trace.h"
17#include "block/block.h"
18#include "block/block_int.h"
19#include "block/blockjob_int.h"
20#include "block/block_backup.h"
21#include "qapi/error.h"
22#include "qapi/qmp/qerror.h"
23#include "qemu/ratelimit.h"
24#include "qemu/cutils.h"
25#include "sysemu/block-backend.h"
26#include "qemu/bitmap.h"
27#include "qemu/error-report.h"
28
29#define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16)
30#define SLICE_TIME 100000000ULL
31
32typedef struct BackupBlockJob {
33 BlockJob common;
34 BlockBackend *target;
35
36 BdrvDirtyBitmap *sync_bitmap;
37 MirrorSyncMode sync_mode;
38 RateLimit limit;
39 BlockdevOnError on_source_error;
40 BlockdevOnError on_target_error;
41 CoRwlock flush_rwlock;
42 uint64_t bytes_read;
43 int64_t cluster_size;
44 bool compress;
45 NotifierWithReturn before_write;
46 QLIST_HEAD(, CowRequest) inflight_reqs;
47
48 HBitmap *copy_bitmap;
49} BackupBlockJob;
50
51
52static void coroutine_fn wait_for_overlapping_requests(BackupBlockJob *job,
53 int64_t start,
54 int64_t end)
55{
56 CowRequest *req;
57 bool retry;
58
59 do {
60 retry = false;
61 QLIST_FOREACH(req, &job->inflight_reqs, list) {
62 if (end > req->start_byte && start < req->end_byte) {
63 qemu_co_queue_wait(&req->wait_queue, NULL);
64 retry = true;
65 break;
66 }
67 }
68 } while (retry);
69}
70
71
72static void cow_request_begin(CowRequest *req, BackupBlockJob *job,
73 int64_t start, int64_t end)
74{
75 req->start_byte = start;
76 req->end_byte = end;
77 qemu_co_queue_init(&req->wait_queue);
78 QLIST_INSERT_HEAD(&job->inflight_reqs, req, list);
79}
80
81
82static void cow_request_end(CowRequest *req)
83{
84 QLIST_REMOVE(req, list);
85 qemu_co_queue_restart_all(&req->wait_queue);
86}
87
88static int coroutine_fn backup_do_cow(BackupBlockJob *job,
89 int64_t offset, uint64_t bytes,
90 bool *error_is_read,
91 bool is_write_notifier)
92{
93 BlockBackend *blk = job->common.blk;
94 CowRequest cow_request;
95 struct iovec iov;
96 QEMUIOVector bounce_qiov;
97 void *bounce_buffer = NULL;
98 int ret = 0;
99 int64_t start, end;
100 int n;
101
102 qemu_co_rwlock_rdlock(&job->flush_rwlock);
103
104 start = QEMU_ALIGN_DOWN(offset, job->cluster_size);
105 end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size);
106
107 trace_backup_do_cow_enter(job, start, offset, bytes);
108
109 wait_for_overlapping_requests(job, start, end);
110 cow_request_begin(&cow_request, job, start, end);
111
112 for (; start < end; start += job->cluster_size) {
113 if (!hbitmap_get(job->copy_bitmap, start / job->cluster_size)) {
114 trace_backup_do_cow_skip(job, start);
115 continue;
116 }
117 hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1);
118
119 trace_backup_do_cow_process(job, start);
120
121 n = MIN(job->cluster_size, job->common.len - start);
122
123 if (!bounce_buffer) {
124 bounce_buffer = blk_blockalign(blk, job->cluster_size);
125 }
126 iov.iov_base = bounce_buffer;
127 iov.iov_len = n;
128 qemu_iovec_init_external(&bounce_qiov, &iov, 1);
129
130 ret = blk_co_preadv(blk, start, bounce_qiov.size, &bounce_qiov,
131 is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
132 if (ret < 0) {
133 trace_backup_do_cow_read_fail(job, start, ret);
134 if (error_is_read) {
135 *error_is_read = true;
136 }
137 hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
138 goto out;
139 }
140
141 if (buffer_is_zero(iov.iov_base, iov.iov_len)) {
142 ret = blk_co_pwrite_zeroes(job->target, start,
143 bounce_qiov.size, BDRV_REQ_MAY_UNMAP);
144 } else {
145 ret = blk_co_pwritev(job->target, start,
146 bounce_qiov.size, &bounce_qiov,
147 job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
148 }
149 if (ret < 0) {
150 trace_backup_do_cow_write_fail(job, start, ret);
151 if (error_is_read) {
152 *error_is_read = false;
153 }
154 hbitmap_set(job->copy_bitmap, start / job->cluster_size, 1);
155 goto out;
156 }
157
158
159
160
161 job->bytes_read += n;
162 job->common.offset += n;
163 }
164
165out:
166 if (bounce_buffer) {
167 qemu_vfree(bounce_buffer);
168 }
169
170 cow_request_end(&cow_request);
171
172 trace_backup_do_cow_return(job, offset, bytes, ret);
173
174 qemu_co_rwlock_unlock(&job->flush_rwlock);
175
176 return ret;
177}
178
179static int coroutine_fn backup_before_write_notify(
180 NotifierWithReturn *notifier,
181 void *opaque)
182{
183 BackupBlockJob *job = container_of(notifier, BackupBlockJob, before_write);
184 BdrvTrackedRequest *req = opaque;
185
186 assert(req->bs == blk_bs(job->common.blk));
187 assert(QEMU_IS_ALIGNED(req->offset, BDRV_SECTOR_SIZE));
188 assert(QEMU_IS_ALIGNED(req->bytes, BDRV_SECTOR_SIZE));
189
190 return backup_do_cow(job, req->offset, req->bytes, NULL, true);
191}
192
193static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
194{
195 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
196
197 if (speed < 0) {
198 error_setg(errp, QERR_INVALID_PARAMETER, "speed");
199 return;
200 }
201 ratelimit_set_speed(&s->limit, speed, SLICE_TIME);
202}
203
204static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
205{
206 BdrvDirtyBitmap *bm;
207 BlockDriverState *bs = blk_bs(job->common.blk);
208
209 if (ret < 0) {
210
211 bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
212 assert(bm);
213 } else {
214
215 bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL);
216 assert(bm);
217 }
218}
219
220static void backup_commit(BlockJob *job)
221{
222 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
223 if (s->sync_bitmap) {
224 backup_cleanup_sync_bitmap(s, 0);
225 }
226}
227
228static void backup_abort(BlockJob *job)
229{
230 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
231 if (s->sync_bitmap) {
232 backup_cleanup_sync_bitmap(s, -1);
233 }
234}
235
236static void backup_clean(BlockJob *job)
237{
238 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
239 assert(s->target);
240 blk_unref(s->target);
241 s->target = NULL;
242}
243
244static void backup_attached_aio_context(BlockJob *job, AioContext *aio_context)
245{
246 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
247
248 blk_set_aio_context(s->target, aio_context);
249}
250
251void backup_do_checkpoint(BlockJob *job, Error **errp)
252{
253 BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
254 int64_t len;
255
256 assert(job->driver->job_type == BLOCK_JOB_TYPE_BACKUP);
257
258 if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
259 error_setg(errp, "The backup job only supports block checkpoint in"
260 " sync=none mode");
261 return;
262 }
263
264 len = DIV_ROUND_UP(backup_job->common.len, backup_job->cluster_size);
265 hbitmap_set(backup_job->copy_bitmap, 0, len);
266}
267
268void backup_wait_for_overlapping_requests(BlockJob *job, int64_t offset,
269 uint64_t bytes)
270{
271 BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
272 int64_t start, end;
273
274 assert(job->driver->job_type == BLOCK_JOB_TYPE_BACKUP);
275
276 start = QEMU_ALIGN_DOWN(offset, backup_job->cluster_size);
277 end = QEMU_ALIGN_UP(offset + bytes, backup_job->cluster_size);
278 wait_for_overlapping_requests(backup_job, start, end);
279}
280
281void backup_cow_request_begin(CowRequest *req, BlockJob *job,
282 int64_t offset, uint64_t bytes)
283{
284 BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
285 int64_t start, end;
286
287 assert(job->driver->job_type == BLOCK_JOB_TYPE_BACKUP);
288
289 start = QEMU_ALIGN_DOWN(offset, backup_job->cluster_size);
290 end = QEMU_ALIGN_UP(offset + bytes, backup_job->cluster_size);
291 cow_request_begin(req, backup_job, start, end);
292}
293
294void backup_cow_request_end(CowRequest *req)
295{
296 cow_request_end(req);
297}
298
299static void backup_drain(BlockJob *job)
300{
301 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
302
303
304
305
306 if (s->target) {
307 BlockBackend *target = s->target;
308 blk_ref(target);
309 blk_drain(target);
310 blk_unref(target);
311 }
312}
313
314static BlockErrorAction backup_error_action(BackupBlockJob *job,
315 bool read, int error)
316{
317 if (read) {
318 return block_job_error_action(&job->common, job->on_source_error,
319 true, error);
320 } else {
321 return block_job_error_action(&job->common, job->on_target_error,
322 false, error);
323 }
324}
325
326typedef struct {
327 int ret;
328} BackupCompleteData;
329
330static void backup_complete(BlockJob *job, void *opaque)
331{
332 BackupCompleteData *data = opaque;
333
334 block_job_completed(job, data->ret);
335 g_free(data);
336}
337
338static bool coroutine_fn yield_and_check(BackupBlockJob *job)
339{
340 if (block_job_is_cancelled(&job->common)) {
341 return true;
342 }
343
344
345
346
347 if (job->common.speed) {
348 uint64_t delay_ns = ratelimit_calculate_delay(&job->limit,
349 job->bytes_read);
350 job->bytes_read = 0;
351 block_job_sleep_ns(&job->common, delay_ns);
352 } else {
353 block_job_sleep_ns(&job->common, 0);
354 }
355
356 if (block_job_is_cancelled(&job->common)) {
357 return true;
358 }
359
360 return false;
361}
362
363static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
364{
365 int ret;
366 bool error_is_read;
367 int64_t cluster;
368 HBitmapIter hbi;
369
370 hbitmap_iter_init(&hbi, job->copy_bitmap, 0);
371 while ((cluster = hbitmap_iter_next(&hbi)) != -1) {
372 do {
373 if (yield_and_check(job)) {
374 return 0;
375 }
376 ret = backup_do_cow(job, cluster * job->cluster_size,
377 job->cluster_size, &error_is_read, false);
378 if (ret < 0 && backup_error_action(job, error_is_read, -ret) ==
379 BLOCK_ERROR_ACTION_REPORT)
380 {
381 return ret;
382 }
383 } while (ret < 0);
384 }
385
386 return 0;
387}
388
389
390static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
391{
392 BdrvDirtyBitmapIter *dbi;
393 int64_t offset;
394 int64_t end = DIV_ROUND_UP(bdrv_dirty_bitmap_size(job->sync_bitmap),
395 job->cluster_size);
396
397 dbi = bdrv_dirty_iter_new(job->sync_bitmap);
398 while ((offset = bdrv_dirty_iter_next(dbi)) != -1) {
399 int64_t cluster = offset / job->cluster_size;
400 int64_t next_cluster;
401
402 offset += bdrv_dirty_bitmap_granularity(job->sync_bitmap);
403 if (offset >= bdrv_dirty_bitmap_size(job->sync_bitmap)) {
404 hbitmap_set(job->copy_bitmap, cluster, end - cluster);
405 break;
406 }
407
408 offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
409 if (offset == -1) {
410 hbitmap_set(job->copy_bitmap, cluster, end - cluster);
411 break;
412 }
413
414 next_cluster = DIV_ROUND_UP(offset, job->cluster_size);
415 hbitmap_set(job->copy_bitmap, cluster, next_cluster - cluster);
416 if (next_cluster >= end) {
417 break;
418 }
419
420 bdrv_set_dirty_iter(dbi, next_cluster * job->cluster_size);
421 }
422
423 job->common.offset = job->common.len -
424 hbitmap_count(job->copy_bitmap) * job->cluster_size;
425
426 bdrv_dirty_iter_free(dbi);
427}
428
429static void coroutine_fn backup_run(void *opaque)
430{
431 BackupBlockJob *job = opaque;
432 BackupCompleteData *data;
433 BlockDriverState *bs = blk_bs(job->common.blk);
434 int64_t offset, nb_clusters;
435 int ret = 0;
436
437 QLIST_INIT(&job->inflight_reqs);
438 qemu_co_rwlock_init(&job->flush_rwlock);
439
440 nb_clusters = DIV_ROUND_UP(job->common.len, job->cluster_size);
441 job->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
442 if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
443 backup_incremental_init_copy_bitmap(job);
444 } else {
445 hbitmap_set(job->copy_bitmap, 0, nb_clusters);
446 }
447
448
449 job->before_write.notify = backup_before_write_notify;
450 bdrv_add_before_write_notifier(bs, &job->before_write);
451
452 if (job->sync_mode == MIRROR_SYNC_MODE_NONE) {
453
454
455 while (!block_job_is_cancelled(&job->common)) {
456
457
458 block_job_yield(&job->common);
459 }
460 } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
461 ret = backup_run_incremental(job);
462 } else {
463
464 for (offset = 0; offset < job->common.len;
465 offset += job->cluster_size) {
466 bool error_is_read;
467 int alloced = 0;
468
469 if (yield_and_check(job)) {
470 break;
471 }
472
473 if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
474 int i;
475 int64_t n;
476
477
478
479
480 for (i = 0; i < job->cluster_size;) {
481
482
483
484
485
486
487 alloced =
488 bdrv_is_allocated(bs, offset + i,
489 job->cluster_size - i, &n);
490 i += n;
491
492 if (alloced || n == 0) {
493 break;
494 }
495 }
496
497
498
499 if (alloced == 0) {
500 continue;
501 }
502 }
503
504 if (alloced < 0) {
505 ret = alloced;
506 } else {
507 ret = backup_do_cow(job, offset, job->cluster_size,
508 &error_is_read, false);
509 }
510 if (ret < 0) {
511
512 BlockErrorAction action =
513 backup_error_action(job, error_is_read, -ret);
514 if (action == BLOCK_ERROR_ACTION_REPORT) {
515 break;
516 } else {
517 offset -= job->cluster_size;
518 continue;
519 }
520 }
521 }
522 }
523
524 notifier_with_return_remove(&job->before_write);
525
526
527 qemu_co_rwlock_wrlock(&job->flush_rwlock);
528 qemu_co_rwlock_unlock(&job->flush_rwlock);
529 hbitmap_free(job->copy_bitmap);
530
531 data = g_malloc(sizeof(*data));
532 data->ret = ret;
533 block_job_defer_to_main_loop(&job->common, backup_complete, data);
534}
535
536static const BlockJobDriver backup_job_driver = {
537 .instance_size = sizeof(BackupBlockJob),
538 .job_type = BLOCK_JOB_TYPE_BACKUP,
539 .start = backup_run,
540 .set_speed = backup_set_speed,
541 .commit = backup_commit,
542 .abort = backup_abort,
543 .clean = backup_clean,
544 .attached_aio_context = backup_attached_aio_context,
545 .drain = backup_drain,
546};
547
548BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
549 BlockDriverState *target, int64_t speed,
550 MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
551 bool compress,
552 BlockdevOnError on_source_error,
553 BlockdevOnError on_target_error,
554 int creation_flags,
555 BlockCompletionFunc *cb, void *opaque,
556 BlockJobTxn *txn, Error **errp)
557{
558 int64_t len;
559 BlockDriverInfo bdi;
560 BackupBlockJob *job = NULL;
561 int ret;
562
563 assert(bs);
564 assert(target);
565
566 if (bs == target) {
567 error_setg(errp, "Source and target cannot be the same");
568 return NULL;
569 }
570
571 if (!bdrv_is_inserted(bs)) {
572 error_setg(errp, "Device is not inserted: %s",
573 bdrv_get_device_name(bs));
574 return NULL;
575 }
576
577 if (!bdrv_is_inserted(target)) {
578 error_setg(errp, "Device is not inserted: %s",
579 bdrv_get_device_name(target));
580 return NULL;
581 }
582
583 if (compress && target->drv->bdrv_co_pwritev_compressed == NULL) {
584 error_setg(errp, "Compression is not supported for this drive %s",
585 bdrv_get_device_name(target));
586 return NULL;
587 }
588
589 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
590 return NULL;
591 }
592
593 if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
594 return NULL;
595 }
596
597 if (sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
598 if (!sync_bitmap) {
599 error_setg(errp, "must provide a valid bitmap name for "
600 "\"incremental\" sync mode");
601 return NULL;
602 }
603
604
605 if (bdrv_dirty_bitmap_create_successor(bs, sync_bitmap, errp) < 0) {
606 return NULL;
607 }
608 } else if (sync_bitmap) {
609 error_setg(errp,
610 "a sync_bitmap was provided to backup_run, "
611 "but received an incompatible sync_mode (%s)",
612 MirrorSyncMode_str(sync_mode));
613 return NULL;
614 }
615
616 len = bdrv_getlength(bs);
617 if (len < 0) {
618 error_setg_errno(errp, -len, "unable to get length for '%s'",
619 bdrv_get_device_name(bs));
620 goto error;
621 }
622
623
624 job = block_job_create(job_id, &backup_job_driver, txn, bs,
625 BLK_PERM_CONSISTENT_READ,
626 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
627 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD,
628 speed, creation_flags, cb, opaque, errp);
629 if (!job) {
630 goto error;
631 }
632
633
634 job->target = blk_new(BLK_PERM_WRITE,
635 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
636 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD);
637 ret = blk_insert_bs(job->target, target, errp);
638 if (ret < 0) {
639 goto error;
640 }
641
642 job->on_source_error = on_source_error;
643 job->on_target_error = on_target_error;
644 job->sync_mode = sync_mode;
645 job->sync_bitmap = sync_mode == MIRROR_SYNC_MODE_INCREMENTAL ?
646 sync_bitmap : NULL;
647 job->compress = compress;
648
649
650
651
652 ret = bdrv_get_info(target, &bdi);
653 if (ret == -ENOTSUP && !target->backing) {
654
655 warn_report("The target block device doesn't provide "
656 "information about the block size and it doesn't have a "
657 "backing file. The default block size of %u bytes is "
658 "used. If the actual block size of the target exceeds "
659 "this default, the backup may be unusable",
660 BACKUP_CLUSTER_SIZE_DEFAULT);
661 job->cluster_size = BACKUP_CLUSTER_SIZE_DEFAULT;
662 } else if (ret < 0 && !target->backing) {
663 error_setg_errno(errp, -ret,
664 "Couldn't determine the cluster size of the target image, "
665 "which has no backing file");
666 error_append_hint(errp,
667 "Aborting, since this may create an unusable destination image\n");
668 goto error;
669 } else if (ret < 0 && target->backing) {
670
671 job->cluster_size = BACKUP_CLUSTER_SIZE_DEFAULT;
672 } else {
673 job->cluster_size = MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);
674 }
675
676
677 block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
678 &error_abort);
679 job->common.len = len;
680
681 return &job->common;
682
683 error:
684 if (sync_bitmap) {
685 bdrv_reclaim_dirty_bitmap(bs, sync_bitmap, NULL);
686 }
687 if (job) {
688 backup_clean(&job->common);
689 block_job_early_fail(&job->common);
690 }
691
692 return NULL;
693}
694