qapi: Speed up frontend tests
[qemu/ar7.git] / block / backup.c
blobdddcf77f53024d33bbe76d6cd2fa00fae545dd85
1 /*
2 * QEMU backup
4 * Copyright (C) 2013 Proxmox Server Solutions
5 * Copyright (c) 2019 Virtuozzo International GmbH.
7 * Authors:
8 * Dietmar Maurer (dietmar@proxmox.com)
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.
15 #include "qemu/osdep.h"
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/ratelimit.h"
26 #include "qemu/cutils.h"
27 #include "sysemu/block-backend.h"
28 #include "qemu/bitmap.h"
29 #include "qemu/error-report.h"
31 #include "block/backup-top.h"
33 #define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16)
35 typedef struct BackupBlockJob {
36 BlockJob common;
37 BlockDriverState *backup_top;
38 BlockDriverState *source_bs;
40 BdrvDirtyBitmap *sync_bitmap;
42 MirrorSyncMode sync_mode;
43 BitmapSyncMode bitmap_mode;
44 BlockdevOnError on_source_error;
45 BlockdevOnError on_target_error;
46 uint64_t len;
47 uint64_t bytes_read;
48 int64_t cluster_size;
50 BlockCopyState *bcs;
51 } BackupBlockJob;
53 static const BlockJobDriver backup_job_driver;
55 static void backup_progress_bytes_callback(int64_t bytes, void *opaque)
57 BackupBlockJob *s = opaque;
59 s->bytes_read += bytes;
60 job_progress_update(&s->common.job, bytes);
63 static void backup_progress_reset_callback(void *opaque)
65 BackupBlockJob *s = opaque;
66 uint64_t estimate = bdrv_get_dirty_count(s->bcs->copy_bitmap);
68 job_progress_set_remaining(&s->common.job, estimate);
71 static int coroutine_fn backup_do_cow(BackupBlockJob *job,
72 int64_t offset, uint64_t bytes,
73 bool *error_is_read)
75 int ret = 0;
76 int64_t start, end; /* bytes */
78 start = QEMU_ALIGN_DOWN(offset, job->cluster_size);
79 end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size);
81 trace_backup_do_cow_enter(job, start, offset, bytes);
83 ret = block_copy(job->bcs, start, end - start, error_is_read);
85 trace_backup_do_cow_return(job, offset, bytes, ret);
87 return ret;
90 static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
92 BdrvDirtyBitmap *bm;
93 bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \
94 && (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER));
96 if (sync) {
98 * We succeeded, or we always intended to sync the bitmap.
99 * Delete this bitmap and install the child.
101 bm = bdrv_dirty_bitmap_abdicate(job->sync_bitmap, NULL);
102 } else {
104 * We failed, or we never intended to sync the bitmap anyway.
105 * Merge the successor back into the parent, keeping all data.
107 bm = bdrv_reclaim_dirty_bitmap(job->sync_bitmap, NULL);
110 assert(bm);
112 if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) {
113 /* If we failed and synced, merge in the bits we didn't copy: */
114 bdrv_dirty_bitmap_merge_internal(bm, job->bcs->copy_bitmap,
115 NULL, true);
119 static void backup_commit(Job *job)
121 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
122 if (s->sync_bitmap) {
123 backup_cleanup_sync_bitmap(s, 0);
127 static void backup_abort(Job *job)
129 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
130 if (s->sync_bitmap) {
131 backup_cleanup_sync_bitmap(s, -1);
135 static void backup_clean(Job *job)
137 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
139 bdrv_backup_top_drop(s->backup_top);
142 void backup_do_checkpoint(BlockJob *job, Error **errp)
144 BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
146 assert(block_job_driver(job) == &backup_job_driver);
148 if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
149 error_setg(errp, "The backup job only supports block checkpoint in"
150 " sync=none mode");
151 return;
154 bdrv_set_dirty_bitmap(backup_job->bcs->copy_bitmap, 0, backup_job->len);
157 static BlockErrorAction backup_error_action(BackupBlockJob *job,
158 bool read, int error)
160 if (read) {
161 return block_job_error_action(&job->common, job->on_source_error,
162 true, error);
163 } else {
164 return block_job_error_action(&job->common, job->on_target_error,
165 false, error);
169 static bool coroutine_fn yield_and_check(BackupBlockJob *job)
171 uint64_t delay_ns;
173 if (job_is_cancelled(&job->common.job)) {
174 return true;
178 * We need to yield even for delay_ns = 0 so that bdrv_drain_all() can
179 * return. Without a yield, the VM would not reboot.
181 delay_ns = block_job_ratelimit_get_delay(&job->common, job->bytes_read);
182 job->bytes_read = 0;
183 job_sleep_ns(&job->common.job, delay_ns);
185 if (job_is_cancelled(&job->common.job)) {
186 return true;
189 return false;
192 static int coroutine_fn backup_loop(BackupBlockJob *job)
194 bool error_is_read;
195 int64_t offset;
196 BdrvDirtyBitmapIter *bdbi;
197 int ret = 0;
199 bdbi = bdrv_dirty_iter_new(job->bcs->copy_bitmap);
200 while ((offset = bdrv_dirty_iter_next(bdbi)) != -1) {
201 do {
202 if (yield_and_check(job)) {
203 goto out;
205 ret = backup_do_cow(job, offset, job->cluster_size, &error_is_read);
206 if (ret < 0 && backup_error_action(job, error_is_read, -ret) ==
207 BLOCK_ERROR_ACTION_REPORT)
209 goto out;
211 } while (ret < 0);
214 out:
215 bdrv_dirty_iter_free(bdbi);
216 return ret;
219 static void backup_init_copy_bitmap(BackupBlockJob *job)
221 bool ret;
222 uint64_t estimate;
224 if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) {
225 ret = bdrv_dirty_bitmap_merge_internal(job->bcs->copy_bitmap,
226 job->sync_bitmap,
227 NULL, true);
228 assert(ret);
229 } else {
230 if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
232 * We can't hog the coroutine to initialize this thoroughly.
233 * Set a flag and resume work when we are able to yield safely.
235 job->bcs->skip_unallocated = true;
237 bdrv_set_dirty_bitmap(job->bcs->copy_bitmap, 0, job->len);
240 estimate = bdrv_get_dirty_count(job->bcs->copy_bitmap);
241 job_progress_set_remaining(&job->common.job, estimate);
244 static int coroutine_fn backup_run(Job *job, Error **errp)
246 BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
247 int ret = 0;
249 backup_init_copy_bitmap(s);
251 if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
252 int64_t offset = 0;
253 int64_t count;
255 for (offset = 0; offset < s->len; ) {
256 if (yield_and_check(s)) {
257 ret = -ECANCELED;
258 goto out;
261 ret = block_copy_reset_unallocated(s->bcs, offset, &count);
262 if (ret < 0) {
263 goto out;
266 offset += count;
268 s->bcs->skip_unallocated = false;
271 if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
273 * All bits are set in copy_bitmap to allow any cluster to be copied.
274 * This does not actually require them to be copied.
276 while (!job_is_cancelled(job)) {
278 * Yield until the job is cancelled. We just let our before_write
279 * notify callback service CoW requests.
281 job_yield(job);
283 } else {
284 ret = backup_loop(s);
287 out:
288 return ret;
291 static const BlockJobDriver backup_job_driver = {
292 .job_driver = {
293 .instance_size = sizeof(BackupBlockJob),
294 .job_type = JOB_TYPE_BACKUP,
295 .free = block_job_free,
296 .user_resume = block_job_user_resume,
297 .run = backup_run,
298 .commit = backup_commit,
299 .abort = backup_abort,
300 .clean = backup_clean,
304 static int64_t backup_calculate_cluster_size(BlockDriverState *target,
305 Error **errp)
307 int ret;
308 BlockDriverInfo bdi;
311 * If there is no backing file on the target, we cannot rely on COW if our
312 * backup cluster size is smaller than the target cluster size. Even for
313 * targets with a backing file, try to avoid COW if possible.
315 ret = bdrv_get_info(target, &bdi);
316 if (ret == -ENOTSUP && !target->backing) {
317 /* Cluster size is not defined */
318 warn_report("The target block device doesn't provide "
319 "information about the block size and it doesn't have a "
320 "backing file. The default block size of %u bytes is "
321 "used. If the actual block size of the target exceeds "
322 "this default, the backup may be unusable",
323 BACKUP_CLUSTER_SIZE_DEFAULT);
324 return BACKUP_CLUSTER_SIZE_DEFAULT;
325 } else if (ret < 0 && !target->backing) {
326 error_setg_errno(errp, -ret,
327 "Couldn't determine the cluster size of the target image, "
328 "which has no backing file");
329 error_append_hint(errp,
330 "Aborting, since this may create an unusable destination image\n");
331 return ret;
332 } else if (ret < 0 && target->backing) {
333 /* Not fatal; just trudge on ahead. */
334 return BACKUP_CLUSTER_SIZE_DEFAULT;
337 return MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);
340 BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
341 BlockDriverState *target, int64_t speed,
342 MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
343 BitmapSyncMode bitmap_mode,
344 bool compress,
345 const char *filter_node_name,
346 BlockdevOnError on_source_error,
347 BlockdevOnError on_target_error,
348 int creation_flags,
349 BlockCompletionFunc *cb, void *opaque,
350 JobTxn *txn, Error **errp)
352 int64_t len;
353 BackupBlockJob *job = NULL;
354 int64_t cluster_size;
355 BdrvRequestFlags write_flags;
356 BlockDriverState *backup_top = NULL;
357 BlockCopyState *bcs = NULL;
359 assert(bs);
360 assert(target);
362 /* QMP interface protects us from these cases */
363 assert(sync_mode != MIRROR_SYNC_MODE_INCREMENTAL);
364 assert(sync_bitmap || sync_mode != MIRROR_SYNC_MODE_BITMAP);
366 if (bs == target) {
367 error_setg(errp, "Source and target cannot be the same");
368 return NULL;
371 if (!bdrv_is_inserted(bs)) {
372 error_setg(errp, "Device is not inserted: %s",
373 bdrv_get_device_name(bs));
374 return NULL;
377 if (!bdrv_is_inserted(target)) {
378 error_setg(errp, "Device is not inserted: %s",
379 bdrv_get_device_name(target));
380 return NULL;
383 if (compress && !block_driver_can_compress(target->drv)) {
384 error_setg(errp, "Compression is not supported for this drive %s",
385 bdrv_get_device_name(target));
386 return NULL;
389 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
390 return NULL;
393 if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
394 return NULL;
397 if (sync_bitmap) {
398 /* If we need to write to this bitmap, check that we can: */
399 if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
400 bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) {
401 return NULL;
404 /* Create a new bitmap, and freeze/disable this one. */
405 if (bdrv_dirty_bitmap_create_successor(sync_bitmap, errp) < 0) {
406 return NULL;
410 len = bdrv_getlength(bs);
411 if (len < 0) {
412 error_setg_errno(errp, -len, "unable to get length for '%s'",
413 bdrv_get_device_name(bs));
414 goto error;
417 cluster_size = backup_calculate_cluster_size(target, errp);
418 if (cluster_size < 0) {
419 goto error;
423 * If source is in backing chain of target assume that target is going to be
424 * used for "image fleecing", i.e. it should represent a kind of snapshot of
425 * source at backup-start point in time. And target is going to be read by
426 * somebody (for example, used as NBD export) during backup job.
428 * In this case, we need to add BDRV_REQ_SERIALISING write flag to avoid
429 * intersection of backup writes and third party reads from target,
430 * otherwise reading from target we may occasionally read already updated by
431 * guest data.
433 * For more information see commit f8d59dfb40bb and test
434 * tests/qemu-iotests/222
436 write_flags = (bdrv_chain_contains(target, bs) ? BDRV_REQ_SERIALISING : 0) |
437 (compress ? BDRV_REQ_WRITE_COMPRESSED : 0),
439 backup_top = bdrv_backup_top_append(bs, target, filter_node_name,
440 cluster_size, write_flags, &bcs, errp);
441 if (!backup_top) {
442 goto error;
445 /* job->len is fixed, so we can't allow resize */
446 job = block_job_create(job_id, &backup_job_driver, txn, backup_top,
447 0, BLK_PERM_ALL,
448 speed, creation_flags, cb, opaque, errp);
449 if (!job) {
450 goto error;
453 job->backup_top = backup_top;
454 job->source_bs = bs;
455 job->on_source_error = on_source_error;
456 job->on_target_error = on_target_error;
457 job->sync_mode = sync_mode;
458 job->sync_bitmap = sync_bitmap;
459 job->bitmap_mode = bitmap_mode;
460 job->bcs = bcs;
461 job->cluster_size = cluster_size;
462 job->len = len;
464 block_copy_set_callbacks(bcs, backup_progress_bytes_callback,
465 backup_progress_reset_callback, job);
467 /* Required permissions are already taken by backup-top target */
468 block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
469 &error_abort);
471 return &job->common;
473 error:
474 if (sync_bitmap) {
475 bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL);
477 if (job) {
478 backup_clean(&job->common.job);
479 job_early_fail(&job->common.job);
480 } else if (backup_top) {
481 bdrv_backup_top_drop(backup_top);
484 return NULL;