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1 | /* | |
2 | * QEMU backup | |
3 | * | |
4 | * Copyright (C) 2013 Proxmox Server Solutions | |
5 | * | |
6 | * Authors: | |
7 | * Dietmar Maurer (dietmar@proxmox.com) | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. | |
10 | * See the COPYING file in the top-level directory. | |
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 | ||
31 | typedef struct CowRequest { | |
32 | int64_t start_byte; | |
33 | int64_t end_byte; | |
34 | QLIST_ENTRY(CowRequest) list; | |
35 | CoQueue wait_queue; /* coroutines blocked on this request */ | |
36 | } CowRequest; | |
37 | ||
38 | typedef struct BackupBlockJob { | |
39 | BlockJob common; | |
40 | BlockBackend *target; | |
41 | /* bitmap for sync=incremental */ | |
42 | BdrvDirtyBitmap *sync_bitmap; | |
43 | MirrorSyncMode sync_mode; | |
44 | BlockdevOnError on_source_error; | |
45 | BlockdevOnError on_target_error; | |
46 | CoRwlock flush_rwlock; | |
47 | uint64_t len; | |
48 | uint64_t bytes_read; | |
49 | int64_t cluster_size; | |
50 | bool compress; | |
51 | NotifierWithReturn before_write; | |
52 | QLIST_HEAD(, CowRequest) inflight_reqs; | |
53 | ||
54 | HBitmap *copy_bitmap; | |
55 | bool use_copy_range; | |
56 | int64_t copy_range_size; | |
57 | ||
58 | bool serialize_target_writes; | |
59 | } BackupBlockJob; | |
60 | ||
61 | static const BlockJobDriver backup_job_driver; | |
62 | ||
63 | /* See if in-flight requests overlap and wait for them to complete */ | |
64 | static void coroutine_fn wait_for_overlapping_requests(BackupBlockJob *job, | |
65 | int64_t start, | |
66 | int64_t end) | |
67 | { | |
68 | CowRequest *req; | |
69 | bool retry; | |
70 | ||
71 | do { | |
72 | retry = false; | |
73 | QLIST_FOREACH(req, &job->inflight_reqs, list) { | |
74 | if (end > req->start_byte && start < req->end_byte) { | |
75 | qemu_co_queue_wait(&req->wait_queue, NULL); | |
76 | retry = true; | |
77 | break; | |
78 | } | |
79 | } | |
80 | } while (retry); | |
81 | } | |
82 | ||
83 | /* Keep track of an in-flight request */ | |
84 | static void cow_request_begin(CowRequest *req, BackupBlockJob *job, | |
85 | int64_t start, int64_t end) | |
86 | { | |
87 | req->start_byte = start; | |
88 | req->end_byte = end; | |
89 | qemu_co_queue_init(&req->wait_queue); | |
90 | QLIST_INSERT_HEAD(&job->inflight_reqs, req, list); | |
91 | } | |
92 | ||
93 | /* Forget about a completed request */ | |
94 | static void cow_request_end(CowRequest *req) | |
95 | { | |
96 | QLIST_REMOVE(req, list); | |
97 | qemu_co_queue_restart_all(&req->wait_queue); | |
98 | } | |
99 | ||
100 | /* Copy range to target with a bounce buffer and return the bytes copied. If | |
101 | * error occurred, return a negative error number */ | |
102 | static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job, | |
103 | int64_t start, | |
104 | int64_t end, | |
105 | bool is_write_notifier, | |
106 | bool *error_is_read, | |
107 | void **bounce_buffer) | |
108 | { | |
109 | int ret; | |
110 | BlockBackend *blk = job->common.blk; | |
111 | int nbytes; | |
112 | int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0; | |
113 | int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0; | |
114 | ||
115 | assert(QEMU_IS_ALIGNED(start, job->cluster_size)); | |
116 | hbitmap_reset(job->copy_bitmap, start, job->cluster_size); | |
117 | nbytes = MIN(job->cluster_size, job->len - start); | |
118 | if (!*bounce_buffer) { | |
119 | *bounce_buffer = blk_blockalign(blk, job->cluster_size); | |
120 | } | |
121 | ||
122 | ret = blk_co_pread(blk, start, nbytes, *bounce_buffer, read_flags); | |
123 | if (ret < 0) { | |
124 | trace_backup_do_cow_read_fail(job, start, ret); | |
125 | if (error_is_read) { | |
126 | *error_is_read = true; | |
127 | } | |
128 | goto fail; | |
129 | } | |
130 | ||
131 | if (buffer_is_zero(*bounce_buffer, nbytes)) { | |
132 | ret = blk_co_pwrite_zeroes(job->target, start, | |
133 | nbytes, write_flags | BDRV_REQ_MAY_UNMAP); | |
134 | } else { | |
135 | ret = blk_co_pwrite(job->target, start, | |
136 | nbytes, *bounce_buffer, write_flags | | |
137 | (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0)); | |
138 | } | |
139 | if (ret < 0) { | |
140 | trace_backup_do_cow_write_fail(job, start, ret); | |
141 | if (error_is_read) { | |
142 | *error_is_read = false; | |
143 | } | |
144 | goto fail; | |
145 | } | |
146 | ||
147 | return nbytes; | |
148 | fail: | |
149 | hbitmap_set(job->copy_bitmap, start, job->cluster_size); | |
150 | return ret; | |
151 | ||
152 | } | |
153 | ||
154 | /* Copy range to target and return the bytes copied. If error occurred, return a | |
155 | * negative error number. */ | |
156 | static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job, | |
157 | int64_t start, | |
158 | int64_t end, | |
159 | bool is_write_notifier) | |
160 | { | |
161 | int ret; | |
162 | int nr_clusters; | |
163 | BlockBackend *blk = job->common.blk; | |
164 | int nbytes; | |
165 | int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0; | |
166 | int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0; | |
167 | ||
168 | assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size)); | |
169 | assert(QEMU_IS_ALIGNED(start, job->cluster_size)); | |
170 | nbytes = MIN(job->copy_range_size, end - start); | |
171 | nr_clusters = DIV_ROUND_UP(nbytes, job->cluster_size); | |
172 | hbitmap_reset(job->copy_bitmap, start, job->cluster_size * nr_clusters); | |
173 | ret = blk_co_copy_range(blk, start, job->target, start, nbytes, | |
174 | read_flags, write_flags); | |
175 | if (ret < 0) { | |
176 | trace_backup_do_cow_copy_range_fail(job, start, ret); | |
177 | hbitmap_set(job->copy_bitmap, start, job->cluster_size * nr_clusters); | |
178 | return ret; | |
179 | } | |
180 | ||
181 | return nbytes; | |
182 | } | |
183 | ||
184 | static int coroutine_fn backup_do_cow(BackupBlockJob *job, | |
185 | int64_t offset, uint64_t bytes, | |
186 | bool *error_is_read, | |
187 | bool is_write_notifier) | |
188 | { | |
189 | CowRequest cow_request; | |
190 | int ret = 0; | |
191 | int64_t start, end; /* bytes */ | |
192 | void *bounce_buffer = NULL; | |
193 | ||
194 | qemu_co_rwlock_rdlock(&job->flush_rwlock); | |
195 | ||
196 | start = QEMU_ALIGN_DOWN(offset, job->cluster_size); | |
197 | end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size); | |
198 | ||
199 | trace_backup_do_cow_enter(job, start, offset, bytes); | |
200 | ||
201 | wait_for_overlapping_requests(job, start, end); | |
202 | cow_request_begin(&cow_request, job, start, end); | |
203 | ||
204 | while (start < end) { | |
205 | if (!hbitmap_get(job->copy_bitmap, start)) { | |
206 | trace_backup_do_cow_skip(job, start); | |
207 | start += job->cluster_size; | |
208 | continue; /* already copied */ | |
209 | } | |
210 | ||
211 | trace_backup_do_cow_process(job, start); | |
212 | ||
213 | if (job->use_copy_range) { | |
214 | ret = backup_cow_with_offload(job, start, end, is_write_notifier); | |
215 | if (ret < 0) { | |
216 | job->use_copy_range = false; | |
217 | } | |
218 | } | |
219 | if (!job->use_copy_range) { | |
220 | ret = backup_cow_with_bounce_buffer(job, start, end, is_write_notifier, | |
221 | error_is_read, &bounce_buffer); | |
222 | } | |
223 | if (ret < 0) { | |
224 | break; | |
225 | } | |
226 | ||
227 | /* Publish progress, guest I/O counts as progress too. Note that the | |
228 | * offset field is an opaque progress value, it is not a disk offset. | |
229 | */ | |
230 | start += ret; | |
231 | job->bytes_read += ret; | |
232 | job_progress_update(&job->common.job, ret); | |
233 | ret = 0; | |
234 | } | |
235 | ||
236 | if (bounce_buffer) { | |
237 | qemu_vfree(bounce_buffer); | |
238 | } | |
239 | ||
240 | cow_request_end(&cow_request); | |
241 | ||
242 | trace_backup_do_cow_return(job, offset, bytes, ret); | |
243 | ||
244 | qemu_co_rwlock_unlock(&job->flush_rwlock); | |
245 | ||
246 | return ret; | |
247 | } | |
248 | ||
249 | static int coroutine_fn backup_before_write_notify( | |
250 | NotifierWithReturn *notifier, | |
251 | void *opaque) | |
252 | { | |
253 | BackupBlockJob *job = container_of(notifier, BackupBlockJob, before_write); | |
254 | BdrvTrackedRequest *req = opaque; | |
255 | ||
256 | assert(req->bs == blk_bs(job->common.blk)); | |
257 | assert(QEMU_IS_ALIGNED(req->offset, BDRV_SECTOR_SIZE)); | |
258 | assert(QEMU_IS_ALIGNED(req->bytes, BDRV_SECTOR_SIZE)); | |
259 | ||
260 | return backup_do_cow(job, req->offset, req->bytes, NULL, true); | |
261 | } | |
262 | ||
263 | static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret) | |
264 | { | |
265 | BdrvDirtyBitmap *bm; | |
266 | BlockDriverState *bs = blk_bs(job->common.blk); | |
267 | ||
268 | if (ret < 0) { | |
269 | /* Merge the successor back into the parent, delete nothing. */ | |
270 | bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL); | |
271 | assert(bm); | |
272 | } else { | |
273 | /* Everything is fine, delete this bitmap and install the backup. */ | |
274 | bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL); | |
275 | assert(bm); | |
276 | } | |
277 | } | |
278 | ||
279 | static void backup_commit(Job *job) | |
280 | { | |
281 | BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); | |
282 | if (s->sync_bitmap) { | |
283 | backup_cleanup_sync_bitmap(s, 0); | |
284 | } | |
285 | } | |
286 | ||
287 | static void backup_abort(Job *job) | |
288 | { | |
289 | BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); | |
290 | if (s->sync_bitmap) { | |
291 | backup_cleanup_sync_bitmap(s, -1); | |
292 | } | |
293 | } | |
294 | ||
295 | static void backup_clean(Job *job) | |
296 | { | |
297 | BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); | |
298 | assert(s->target); | |
299 | blk_unref(s->target); | |
300 | s->target = NULL; | |
301 | ||
302 | if (s->copy_bitmap) { | |
303 | hbitmap_free(s->copy_bitmap); | |
304 | s->copy_bitmap = NULL; | |
305 | } | |
306 | } | |
307 | ||
308 | void backup_do_checkpoint(BlockJob *job, Error **errp) | |
309 | { | |
310 | BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common); | |
311 | ||
312 | assert(block_job_driver(job) == &backup_job_driver); | |
313 | ||
314 | if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) { | |
315 | error_setg(errp, "The backup job only supports block checkpoint in" | |
316 | " sync=none mode"); | |
317 | return; | |
318 | } | |
319 | ||
320 | hbitmap_set(backup_job->copy_bitmap, 0, backup_job->len); | |
321 | } | |
322 | ||
323 | static void backup_drain(BlockJob *job) | |
324 | { | |
325 | BackupBlockJob *s = container_of(job, BackupBlockJob, common); | |
326 | ||
327 | /* Need to keep a reference in case blk_drain triggers execution | |
328 | * of backup_complete... | |
329 | */ | |
330 | if (s->target) { | |
331 | BlockBackend *target = s->target; | |
332 | blk_ref(target); | |
333 | blk_drain(target); | |
334 | blk_unref(target); | |
335 | } | |
336 | } | |
337 | ||
338 | static BlockErrorAction backup_error_action(BackupBlockJob *job, | |
339 | bool read, int error) | |
340 | { | |
341 | if (read) { | |
342 | return block_job_error_action(&job->common, job->on_source_error, | |
343 | true, error); | |
344 | } else { | |
345 | return block_job_error_action(&job->common, job->on_target_error, | |
346 | false, error); | |
347 | } | |
348 | } | |
349 | ||
350 | static bool coroutine_fn yield_and_check(BackupBlockJob *job) | |
351 | { | |
352 | uint64_t delay_ns; | |
353 | ||
354 | if (job_is_cancelled(&job->common.job)) { | |
355 | return true; | |
356 | } | |
357 | ||
358 | /* We need to yield even for delay_ns = 0 so that bdrv_drain_all() can | |
359 | * return. Without a yield, the VM would not reboot. */ | |
360 | delay_ns = block_job_ratelimit_get_delay(&job->common, job->bytes_read); | |
361 | job->bytes_read = 0; | |
362 | job_sleep_ns(&job->common.job, delay_ns); | |
363 | ||
364 | if (job_is_cancelled(&job->common.job)) { | |
365 | return true; | |
366 | } | |
367 | ||
368 | return false; | |
369 | } | |
370 | ||
371 | static bool bdrv_is_unallocated_range(BlockDriverState *bs, | |
372 | int64_t offset, int64_t bytes) | |
373 | { | |
374 | int64_t end = offset + bytes; | |
375 | ||
376 | while (offset < end && !bdrv_is_allocated(bs, offset, bytes, &bytes)) { | |
377 | if (bytes == 0) { | |
378 | return true; | |
379 | } | |
380 | offset += bytes; | |
381 | bytes = end - offset; | |
382 | } | |
383 | ||
384 | return offset >= end; | |
385 | } | |
386 | ||
387 | static int coroutine_fn backup_loop(BackupBlockJob *job) | |
388 | { | |
389 | int ret; | |
390 | bool error_is_read; | |
391 | int64_t offset; | |
392 | HBitmapIter hbi; | |
393 | BlockDriverState *bs = blk_bs(job->common.blk); | |
394 | ||
395 | hbitmap_iter_init(&hbi, job->copy_bitmap, 0); | |
396 | while ((offset = hbitmap_iter_next(&hbi)) != -1) { | |
397 | if (job->sync_mode == MIRROR_SYNC_MODE_TOP && | |
398 | bdrv_is_unallocated_range(bs, offset, job->cluster_size)) | |
399 | { | |
400 | hbitmap_reset(job->copy_bitmap, offset, job->cluster_size); | |
401 | continue; | |
402 | } | |
403 | ||
404 | do { | |
405 | if (yield_and_check(job)) { | |
406 | return 0; | |
407 | } | |
408 | ret = backup_do_cow(job, offset, | |
409 | job->cluster_size, &error_is_read, false); | |
410 | if (ret < 0 && backup_error_action(job, error_is_read, -ret) == | |
411 | BLOCK_ERROR_ACTION_REPORT) | |
412 | { | |
413 | return ret; | |
414 | } | |
415 | } while (ret < 0); | |
416 | } | |
417 | ||
418 | return 0; | |
419 | } | |
420 | ||
421 | /* init copy_bitmap from sync_bitmap */ | |
422 | static void backup_incremental_init_copy_bitmap(BackupBlockJob *job) | |
423 | { | |
424 | uint64_t offset = 0; | |
425 | uint64_t bytes = job->len; | |
426 | ||
427 | while (bdrv_dirty_bitmap_next_dirty_area(job->sync_bitmap, | |
428 | &offset, &bytes)) | |
429 | { | |
430 | hbitmap_set(job->copy_bitmap, offset, bytes); | |
431 | ||
432 | offset += bytes; | |
433 | if (offset >= job->len) { | |
434 | break; | |
435 | } | |
436 | bytes = job->len - offset; | |
437 | } | |
438 | ||
439 | /* TODO job_progress_set_remaining() would make more sense */ | |
440 | job_progress_update(&job->common.job, | |
441 | job->len - hbitmap_count(job->copy_bitmap)); | |
442 | } | |
443 | ||
444 | static int coroutine_fn backup_run(Job *job, Error **errp) | |
445 | { | |
446 | BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); | |
447 | BlockDriverState *bs = blk_bs(s->common.blk); | |
448 | int ret = 0; | |
449 | ||
450 | QLIST_INIT(&s->inflight_reqs); | |
451 | qemu_co_rwlock_init(&s->flush_rwlock); | |
452 | ||
453 | job_progress_set_remaining(job, s->len); | |
454 | ||
455 | if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) { | |
456 | backup_incremental_init_copy_bitmap(s); | |
457 | } else { | |
458 | hbitmap_set(s->copy_bitmap, 0, s->len); | |
459 | } | |
460 | ||
461 | s->before_write.notify = backup_before_write_notify; | |
462 | bdrv_add_before_write_notifier(bs, &s->before_write); | |
463 | ||
464 | if (s->sync_mode == MIRROR_SYNC_MODE_NONE) { | |
465 | /* All bits are set in copy_bitmap to allow any cluster to be copied. | |
466 | * This does not actually require them to be copied. */ | |
467 | while (!job_is_cancelled(job)) { | |
468 | /* Yield until the job is cancelled. We just let our before_write | |
469 | * notify callback service CoW requests. */ | |
470 | job_yield(job); | |
471 | } | |
472 | } else { | |
473 | ret = backup_loop(s); | |
474 | } | |
475 | ||
476 | notifier_with_return_remove(&s->before_write); | |
477 | ||
478 | /* wait until pending backup_do_cow() calls have completed */ | |
479 | qemu_co_rwlock_wrlock(&s->flush_rwlock); | |
480 | qemu_co_rwlock_unlock(&s->flush_rwlock); | |
481 | ||
482 | return ret; | |
483 | } | |
484 | ||
485 | static const BlockJobDriver backup_job_driver = { | |
486 | .job_driver = { | |
487 | .instance_size = sizeof(BackupBlockJob), | |
488 | .job_type = JOB_TYPE_BACKUP, | |
489 | .free = block_job_free, | |
490 | .user_resume = block_job_user_resume, | |
491 | .drain = block_job_drain, | |
492 | .run = backup_run, | |
493 | .commit = backup_commit, | |
494 | .abort = backup_abort, | |
495 | .clean = backup_clean, | |
496 | }, | |
497 | .drain = backup_drain, | |
498 | }; | |
499 | ||
500 | static int64_t backup_calculate_cluster_size(BlockDriverState *target, | |
501 | Error **errp) | |
502 | { | |
503 | int ret; | |
504 | BlockDriverInfo bdi; | |
505 | ||
506 | /* | |
507 | * If there is no backing file on the target, we cannot rely on COW if our | |
508 | * backup cluster size is smaller than the target cluster size. Even for | |
509 | * targets with a backing file, try to avoid COW if possible. | |
510 | */ | |
511 | ret = bdrv_get_info(target, &bdi); | |
512 | if (ret == -ENOTSUP && !target->backing) { | |
513 | /* Cluster size is not defined */ | |
514 | warn_report("The target block device doesn't provide " | |
515 | "information about the block size and it doesn't have a " | |
516 | "backing file. The default block size of %u bytes is " | |
517 | "used. If the actual block size of the target exceeds " | |
518 | "this default, the backup may be unusable", | |
519 | BACKUP_CLUSTER_SIZE_DEFAULT); | |
520 | return BACKUP_CLUSTER_SIZE_DEFAULT; | |
521 | } else if (ret < 0 && !target->backing) { | |
522 | error_setg_errno(errp, -ret, | |
523 | "Couldn't determine the cluster size of the target image, " | |
524 | "which has no backing file"); | |
525 | error_append_hint(errp, | |
526 | "Aborting, since this may create an unusable destination image\n"); | |
527 | return ret; | |
528 | } else if (ret < 0 && target->backing) { | |
529 | /* Not fatal; just trudge on ahead. */ | |
530 | return BACKUP_CLUSTER_SIZE_DEFAULT; | |
531 | } | |
532 | ||
533 | return MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size); | |
534 | } | |
535 | ||
536 | BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, | |
537 | BlockDriverState *target, int64_t speed, | |
538 | MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap, | |
539 | bool compress, | |
540 | BlockdevOnError on_source_error, | |
541 | BlockdevOnError on_target_error, | |
542 | int creation_flags, | |
543 | BlockCompletionFunc *cb, void *opaque, | |
544 | JobTxn *txn, Error **errp) | |
545 | { | |
546 | int64_t len; | |
547 | BackupBlockJob *job = NULL; | |
548 | int ret; | |
549 | int64_t cluster_size; | |
550 | HBitmap *copy_bitmap = NULL; | |
551 | ||
552 | assert(bs); | |
553 | assert(target); | |
554 | ||
555 | if (bs == target) { | |
556 | error_setg(errp, "Source and target cannot be the same"); | |
557 | return NULL; | |
558 | } | |
559 | ||
560 | if (!bdrv_is_inserted(bs)) { | |
561 | error_setg(errp, "Device is not inserted: %s", | |
562 | bdrv_get_device_name(bs)); | |
563 | return NULL; | |
564 | } | |
565 | ||
566 | if (!bdrv_is_inserted(target)) { | |
567 | error_setg(errp, "Device is not inserted: %s", | |
568 | bdrv_get_device_name(target)); | |
569 | return NULL; | |
570 | } | |
571 | ||
572 | if (compress && target->drv->bdrv_co_pwritev_compressed == NULL) { | |
573 | error_setg(errp, "Compression is not supported for this drive %s", | |
574 | bdrv_get_device_name(target)); | |
575 | return NULL; | |
576 | } | |
577 | ||
578 | if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) { | |
579 | return NULL; | |
580 | } | |
581 | ||
582 | if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) { | |
583 | return NULL; | |
584 | } | |
585 | ||
586 | if (sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) { | |
587 | if (!sync_bitmap) { | |
588 | error_setg(errp, "must provide a valid bitmap name for " | |
589 | "\"incremental\" sync mode"); | |
590 | return NULL; | |
591 | } | |
592 | ||
593 | /* Create a new bitmap, and freeze/disable this one. */ | |
594 | if (bdrv_dirty_bitmap_create_successor(bs, sync_bitmap, errp) < 0) { | |
595 | return NULL; | |
596 | } | |
597 | } else if (sync_bitmap) { | |
598 | error_setg(errp, | |
599 | "a sync_bitmap was provided to backup_run, " | |
600 | "but received an incompatible sync_mode (%s)", | |
601 | MirrorSyncMode_str(sync_mode)); | |
602 | return NULL; | |
603 | } | |
604 | ||
605 | len = bdrv_getlength(bs); | |
606 | if (len < 0) { | |
607 | error_setg_errno(errp, -len, "unable to get length for '%s'", | |
608 | bdrv_get_device_name(bs)); | |
609 | goto error; | |
610 | } | |
611 | ||
612 | cluster_size = backup_calculate_cluster_size(target, errp); | |
613 | if (cluster_size < 0) { | |
614 | goto error; | |
615 | } | |
616 | ||
617 | copy_bitmap = hbitmap_alloc(len, ctz32(cluster_size)); | |
618 | ||
619 | /* job->len is fixed, so we can't allow resize */ | |
620 | job = block_job_create(job_id, &backup_job_driver, txn, bs, | |
621 | BLK_PERM_CONSISTENT_READ, | |
622 | BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE | | |
623 | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD, | |
624 | speed, creation_flags, cb, opaque, errp); | |
625 | if (!job) { | |
626 | goto error; | |
627 | } | |
628 | ||
629 | /* The target must match the source in size, so no resize here either */ | |
630 | job->target = blk_new(job->common.job.aio_context, | |
631 | BLK_PERM_WRITE, | |
632 | BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE | | |
633 | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD); | |
634 | ret = blk_insert_bs(job->target, target, errp); | |
635 | if (ret < 0) { | |
636 | goto error; | |
637 | } | |
638 | ||
639 | job->on_source_error = on_source_error; | |
640 | job->on_target_error = on_target_error; | |
641 | job->sync_mode = sync_mode; | |
642 | job->sync_bitmap = sync_mode == MIRROR_SYNC_MODE_INCREMENTAL ? | |
643 | sync_bitmap : NULL; | |
644 | job->compress = compress; | |
645 | ||
646 | /* Detect image-fleecing (and similar) schemes */ | |
647 | job->serialize_target_writes = bdrv_chain_contains(target, bs); | |
648 | job->cluster_size = cluster_size; | |
649 | job->copy_bitmap = copy_bitmap; | |
650 | copy_bitmap = NULL; | |
651 | job->use_copy_range = true; | |
652 | job->copy_range_size = MIN_NON_ZERO(blk_get_max_transfer(job->common.blk), | |
653 | blk_get_max_transfer(job->target)); | |
654 | job->copy_range_size = MAX(job->cluster_size, | |
655 | QEMU_ALIGN_UP(job->copy_range_size, | |
656 | job->cluster_size)); | |
657 | ||
658 | /* Required permissions are already taken with target's blk_new() */ | |
659 | block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL, | |
660 | &error_abort); | |
661 | job->len = len; | |
662 | ||
663 | return &job->common; | |
664 | ||
665 | error: | |
666 | if (copy_bitmap) { | |
667 | assert(!job || !job->copy_bitmap); | |
668 | hbitmap_free(copy_bitmap); | |
669 | } | |
670 | if (sync_bitmap) { | |
671 | bdrv_reclaim_dirty_bitmap(bs, sync_bitmap, NULL); | |
672 | } | |
673 | if (job) { | |
674 | backup_clean(&job->common.job); | |
675 | job_early_fail(&job->common.job); | |
676 | } | |
677 | ||
678 | return NULL; | |
679 | } |