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1 /*
2 * QEMU backup
3 *
4 * Copyright (C) 2013 Proxmox Server Solutions
5 * Copyright (c) 2019 Virtuozzo International GmbH.
6 *
7 * Authors:
8 * Dietmar Maurer (dietmar@proxmox.com)
9 *
10 * This work is licensed under the terms of the GNU GPL, version 2 or later.
11 * See the COPYING file in the top-level directory.
12 *
13 */
14
15 #include "qemu/osdep.h"
16
17 #include "trace.h"
18 #include "block/block.h"
19 #include "block/block_int.h"
20 #include "block/blockjob_int.h"
21 #include "block/block_backup.h"
22 #include "block/block-copy.h"
23 #include "qapi/error.h"
24 #include "qapi/qmp/qerror.h"
25 #include "qemu/cutils.h"
26 #include "sysemu/block-backend.h"
27 #include "qemu/bitmap.h"
28 #include "qemu/error-report.h"
29
30 #include "block/copy-before-write.h"
31
32 typedef struct BackupBlockJob {
33 BlockJob common;
34 BlockDriverState *cbw;
35 BlockDriverState *source_bs;
36 BlockDriverState *target_bs;
37
38 BdrvDirtyBitmap *sync_bitmap;
39
40 MirrorSyncMode sync_mode;
41 BitmapSyncMode bitmap_mode;
42 BlockdevOnError on_source_error;
43 BlockdevOnError on_target_error;
44 uint64_t len;
45 int64_t cluster_size;
46 BackupPerf perf;
47
48 BlockCopyState *bcs;
49
50 bool wait;
51 BlockCopyCallState *bg_bcs_call;
52 } BackupBlockJob;
53
54 static const BlockJobDriver backup_job_driver;
55
56 static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
57 {
58 BdrvDirtyBitmap *bm;
59 bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \
60 && (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER));
61
62 if (sync) {
63 /*
64 * We succeeded, or we always intended to sync the bitmap.
65 * Delete this bitmap and install the child.
66 */
67 bm = bdrv_dirty_bitmap_abdicate(job->sync_bitmap, NULL);
68 } else {
69 /*
70 * We failed, or we never intended to sync the bitmap anyway.
71 * Merge the successor back into the parent, keeping all data.
72 */
73 bm = bdrv_reclaim_dirty_bitmap(job->sync_bitmap, NULL);
74 }
75
76 assert(bm);
77
78 if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) {
79 /* If we failed and synced, merge in the bits we didn't copy: */
80 bdrv_dirty_bitmap_merge_internal(bm, block_copy_dirty_bitmap(job->bcs),
81 NULL, true);
82 }
83 }
84
85 static void backup_commit(Job *job)
86 {
87 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
88 if (s->sync_bitmap) {
89 backup_cleanup_sync_bitmap(s, 0);
90 }
91 }
92
93 static void backup_abort(Job *job)
94 {
95 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
96 if (s->sync_bitmap) {
97 backup_cleanup_sync_bitmap(s, -1);
98 }
99 }
100
101 static void backup_clean(Job *job)
102 {
103 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
104 block_job_remove_all_bdrv(&s->common);
105 bdrv_cbw_drop(s->cbw);
106 }
107
108 void backup_do_checkpoint(BlockJob *job, Error **errp)
109 {
110 BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
111
112 assert(block_job_driver(job) == &backup_job_driver);
113
114 if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
115 error_setg(errp, "The backup job only supports block checkpoint in"
116 " sync=none mode");
117 return;
118 }
119
120 bdrv_set_dirty_bitmap(block_copy_dirty_bitmap(backup_job->bcs), 0,
121 backup_job->len);
122 }
123
124 static BlockErrorAction backup_error_action(BackupBlockJob *job,
125 bool read, int error)
126 {
127 if (read) {
128 return block_job_error_action(&job->common, job->on_source_error,
129 true, error);
130 } else {
131 return block_job_error_action(&job->common, job->on_target_error,
132 false, error);
133 }
134 }
135
136 static void coroutine_fn backup_block_copy_callback(void *opaque)
137 {
138 BackupBlockJob *s = opaque;
139
140 if (s->wait) {
141 s->wait = false;
142 aio_co_wake(s->common.job.co);
143 } else {
144 job_enter(&s->common.job);
145 }
146 }
147
148 static int coroutine_fn backup_loop(BackupBlockJob *job)
149 {
150 BlockCopyCallState *s = NULL;
151 int ret = 0;
152 bool error_is_read;
153 BlockErrorAction act;
154
155 while (true) { /* retry loop */
156 job->bg_bcs_call = s = block_copy_async(job->bcs, 0,
157 QEMU_ALIGN_UP(job->len, job->cluster_size),
158 job->perf.max_workers, job->perf.max_chunk,
159 backup_block_copy_callback, job);
160
161 while (!block_copy_call_finished(s) &&
162 !job_is_cancelled(&job->common.job))
163 {
164 job_yield(&job->common.job);
165 }
166
167 if (!block_copy_call_finished(s)) {
168 assert(job_is_cancelled(&job->common.job));
169 /*
170 * Note that we can't use job_yield() here, as it doesn't work for
171 * cancelled job.
172 */
173 block_copy_call_cancel(s);
174 job->wait = true;
175 qemu_coroutine_yield();
176 assert(block_copy_call_finished(s));
177 ret = 0;
178 goto out;
179 }
180
181 if (job_is_cancelled(&job->common.job) ||
182 block_copy_call_succeeded(s))
183 {
184 ret = 0;
185 goto out;
186 }
187
188 if (block_copy_call_cancelled(s)) {
189 /*
190 * Job is not cancelled but only block-copy call. This is possible
191 * after job pause. Now the pause is finished, start new block-copy
192 * iteration.
193 */
194 block_copy_call_free(s);
195 continue;
196 }
197
198 /* The only remaining case is failed block-copy call. */
199 assert(block_copy_call_failed(s));
200
201 ret = block_copy_call_status(s, &error_is_read);
202 act = backup_error_action(job, error_is_read, -ret);
203 switch (act) {
204 case BLOCK_ERROR_ACTION_REPORT:
205 goto out;
206 case BLOCK_ERROR_ACTION_STOP:
207 /*
208 * Go to pause prior to starting new block-copy call on the next
209 * iteration.
210 */
211 job_pause_point(&job->common.job);
212 break;
213 case BLOCK_ERROR_ACTION_IGNORE:
214 /* Proceed to new block-copy call to retry. */
215 break;
216 default:
217 abort();
218 }
219
220 block_copy_call_free(s);
221 }
222
223 out:
224 block_copy_call_free(s);
225 job->bg_bcs_call = NULL;
226 return ret;
227 }
228
229 static void backup_init_bcs_bitmap(BackupBlockJob *job)
230 {
231 uint64_t estimate;
232 BdrvDirtyBitmap *bcs_bitmap = block_copy_dirty_bitmap(job->bcs);
233
234 if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) {
235 bdrv_clear_dirty_bitmap(bcs_bitmap, NULL);
236 bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap, NULL,
237 true);
238 } else if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
239 /*
240 * We can't hog the coroutine to initialize this thoroughly.
241 * Set a flag and resume work when we are able to yield safely.
242 */
243 block_copy_set_skip_unallocated(job->bcs, true);
244 }
245
246 estimate = bdrv_get_dirty_count(bcs_bitmap);
247 job_progress_set_remaining(&job->common.job, estimate);
248 }
249
250 static int coroutine_fn backup_run(Job *job, Error **errp)
251 {
252 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
253 int ret;
254
255 backup_init_bcs_bitmap(s);
256
257 if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
258 int64_t offset = 0;
259 int64_t count;
260
261 for (offset = 0; offset < s->len; ) {
262 if (job_is_cancelled(job)) {
263 return -ECANCELED;
264 }
265
266 job_pause_point(job);
267
268 if (job_is_cancelled(job)) {
269 return -ECANCELED;
270 }
271
272 ret = block_copy_reset_unallocated(s->bcs, offset, &count);
273 if (ret < 0) {
274 return ret;
275 }
276
277 offset += count;
278 }
279 block_copy_set_skip_unallocated(s->bcs, false);
280 }
281
282 if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
283 /*
284 * All bits are set in bcs bitmap to allow any cluster to be copied.
285 * This does not actually require them to be copied.
286 */
287 while (!job_is_cancelled(job)) {
288 /*
289 * Yield until the job is cancelled. We just let our before_write
290 * notify callback service CoW requests.
291 */
292 job_yield(job);
293 }
294 } else {
295 return backup_loop(s);
296 }
297
298 return 0;
299 }
300
301 static void coroutine_fn backup_pause(Job *job)
302 {
303 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
304
305 if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) {
306 block_copy_call_cancel(s->bg_bcs_call);
307 s->wait = true;
308 qemu_coroutine_yield();
309 }
310 }
311
312 static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed)
313 {
314 BackupBlockJob *s = container_of(job, BackupBlockJob, common);
315
316 /*
317 * block_job_set_speed() is called first from block_job_create(), when we
318 * don't yet have s->bcs.
319 */
320 if (s->bcs) {
321 block_copy_set_speed(s->bcs, speed);
322 if (s->bg_bcs_call) {
323 block_copy_kick(s->bg_bcs_call);
324 }
325 }
326 }
327
328 static bool backup_cancel(Job *job, bool force)
329 {
330 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
331
332 bdrv_cancel_in_flight(s->target_bs);
333 return true;
334 }
335
336 static const BlockJobDriver backup_job_driver = {
337 .job_driver = {
338 .instance_size = sizeof(BackupBlockJob),
339 .job_type = JOB_TYPE_BACKUP,
340 .free = block_job_free,
341 .user_resume = block_job_user_resume,
342 .run = backup_run,
343 .commit = backup_commit,
344 .abort = backup_abort,
345 .clean = backup_clean,
346 .pause = backup_pause,
347 .cancel = backup_cancel,
348 },
349 .set_speed = backup_set_speed,
350 };
351
352 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
353 BlockDriverState *target, int64_t speed,
354 MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
355 BitmapSyncMode bitmap_mode,
356 bool compress,
357 const char *filter_node_name,
358 BackupPerf *perf,
359 BlockdevOnError on_source_error,
360 BlockdevOnError on_target_error,
361 int creation_flags,
362 BlockCompletionFunc *cb, void *opaque,
363 JobTxn *txn, Error **errp)
364 {
365 int64_t len, target_len;
366 BackupBlockJob *job = NULL;
367 int64_t cluster_size;
368 BlockDriverState *cbw = NULL;
369 BlockCopyState *bcs = NULL;
370
371 assert(bs);
372 assert(target);
373 GLOBAL_STATE_CODE();
374
375 /* QMP interface protects us from these cases */
376 assert(sync_mode != MIRROR_SYNC_MODE_INCREMENTAL);
377 assert(sync_bitmap || sync_mode != MIRROR_SYNC_MODE_BITMAP);
378
379 if (bs == target) {
380 error_setg(errp, "Source and target cannot be the same");
381 return NULL;
382 }
383
384 if (!bdrv_is_inserted(bs)) {
385 error_setg(errp, "Device is not inserted: %s",
386 bdrv_get_device_name(bs));
387 return NULL;
388 }
389
390 if (!bdrv_is_inserted(target)) {
391 error_setg(errp, "Device is not inserted: %s",
392 bdrv_get_device_name(target));
393 return NULL;
394 }
395
396 if (compress && !bdrv_supports_compressed_writes(target)) {
397 error_setg(errp, "Compression is not supported for this drive %s",
398 bdrv_get_device_name(target));
399 return NULL;
400 }
401
402 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
403 return NULL;
404 }
405
406 if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
407 return NULL;
408 }
409
410 if (perf->max_workers < 1 || perf->max_workers > INT_MAX) {
411 error_setg(errp, "max-workers must be between 1 and %d", INT_MAX);
412 return NULL;
413 }
414
415 if (perf->max_chunk < 0) {
416 error_setg(errp, "max-chunk must be zero (which means no limit) or "
417 "positive");
418 return NULL;
419 }
420
421 if (sync_bitmap) {
422 /* If we need to write to this bitmap, check that we can: */
423 if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
424 bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) {
425 return NULL;
426 }
427
428 /* Create a new bitmap, and freeze/disable this one. */
429 if (bdrv_dirty_bitmap_create_successor(sync_bitmap, errp) < 0) {
430 return NULL;
431 }
432 }
433
434 len = bdrv_getlength(bs);
435 if (len < 0) {
436 error_setg_errno(errp, -len, "Unable to get length for '%s'",
437 bdrv_get_device_or_node_name(bs));
438 goto error;
439 }
440
441 target_len = bdrv_getlength(target);
442 if (target_len < 0) {
443 error_setg_errno(errp, -target_len, "Unable to get length for '%s'",
444 bdrv_get_device_or_node_name(bs));
445 goto error;
446 }
447
448 if (target_len != len) {
449 error_setg(errp, "Source and target image have different sizes");
450 goto error;
451 }
452
453 cbw = bdrv_cbw_append(bs, target, filter_node_name, &bcs, errp);
454 if (!cbw) {
455 goto error;
456 }
457
458 cluster_size = block_copy_cluster_size(bcs);
459
460 if (perf->max_chunk && perf->max_chunk < cluster_size) {
461 error_setg(errp, "Required max-chunk (%" PRIi64 ") is less than backup "
462 "cluster size (%" PRIi64 ")", perf->max_chunk, cluster_size);
463 goto error;
464 }
465
466 /* job->len is fixed, so we can't allow resize */
467 job = block_job_create(job_id, &backup_job_driver, txn, cbw,
468 0, BLK_PERM_ALL,
469 speed, creation_flags, cb, opaque, errp);
470 if (!job) {
471 goto error;
472 }
473
474 job->cbw = cbw;
475 job->source_bs = bs;
476 job->target_bs = target;
477 job->on_source_error = on_source_error;
478 job->on_target_error = on_target_error;
479 job->sync_mode = sync_mode;
480 job->sync_bitmap = sync_bitmap;
481 job->bitmap_mode = bitmap_mode;
482 job->bcs = bcs;
483 job->cluster_size = cluster_size;
484 job->len = len;
485 job->perf = *perf;
486
487 block_copy_set_copy_opts(bcs, perf->use_copy_range, compress);
488 block_copy_set_progress_meter(bcs, &job->common.job.progress);
489 block_copy_set_speed(bcs, speed);
490
491 /* Required permissions are taken by copy-before-write filter target */
492 block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
493 &error_abort);
494
495 return &job->common;
496
497 error:
498 if (sync_bitmap) {
499 bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL);
500 }
501 if (cbw) {
502 bdrv_cbw_drop(cbw);
503 }
504
505 return NULL;
506 }