Revert "gdbstub: Do not kill target in system emulation mode"
[qemu/qmp-unstable.git] / block / mirror.c
blob58f391a6d626d4b4cca9567c3feedff2fd8482de
1 /*
2 * Image mirroring
4 * Copyright Red Hat, Inc. 2012
6 * Authors:
7 * Paolo Bonzini <pbonzini@redhat.com>
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
14 #include "trace.h"
15 #include "block/blockjob.h"
16 #include "block/block_int.h"
17 #include "qemu/ratelimit.h"
18 #include "qemu/bitmap.h"
20 #define SLICE_TIME 100000000ULL /* ns */
21 #define MAX_IN_FLIGHT 16
23 /* The mirroring buffer is a list of granularity-sized chunks.
24 * Free chunks are organized in a list.
26 typedef struct MirrorBuffer {
27 QSIMPLEQ_ENTRY(MirrorBuffer) next;
28 } MirrorBuffer;
30 typedef struct MirrorBlockJob {
31 BlockJob common;
32 RateLimit limit;
33 BlockDriverState *target;
34 BlockDriverState *base;
35 /* The name of the graph node to replace */
36 char *replaces;
37 /* The BDS to replace */
38 BlockDriverState *to_replace;
39 /* Used to block operations on the drive-mirror-replace target */
40 Error *replace_blocker;
41 bool is_none_mode;
42 BlockdevOnError on_source_error, on_target_error;
43 bool synced;
44 bool should_complete;
45 int64_t sector_num;
46 int64_t granularity;
47 size_t buf_size;
48 int64_t bdev_length;
49 unsigned long *cow_bitmap;
50 BdrvDirtyBitmap *dirty_bitmap;
51 HBitmapIter hbi;
52 uint8_t *buf;
53 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
54 int buf_free_count;
56 unsigned long *in_flight_bitmap;
57 int in_flight;
58 int sectors_in_flight;
59 int ret;
60 } MirrorBlockJob;
62 typedef struct MirrorOp {
63 MirrorBlockJob *s;
64 QEMUIOVector qiov;
65 int64_t sector_num;
66 int nb_sectors;
67 } MirrorOp;
69 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
70 int error)
72 s->synced = false;
73 if (read) {
74 return block_job_error_action(&s->common, s->common.bs,
75 s->on_source_error, true, error);
76 } else {
77 return block_job_error_action(&s->common, s->target,
78 s->on_target_error, false, error);
82 static void mirror_iteration_done(MirrorOp *op, int ret)
84 MirrorBlockJob *s = op->s;
85 struct iovec *iov;
86 int64_t chunk_num;
87 int i, nb_chunks, sectors_per_chunk;
89 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret);
91 s->in_flight--;
92 s->sectors_in_flight -= op->nb_sectors;
93 iov = op->qiov.iov;
94 for (i = 0; i < op->qiov.niov; i++) {
95 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
96 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
97 s->buf_free_count++;
100 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
101 chunk_num = op->sector_num / sectors_per_chunk;
102 nb_chunks = op->nb_sectors / sectors_per_chunk;
103 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
104 if (ret >= 0) {
105 if (s->cow_bitmap) {
106 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
108 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE;
111 qemu_iovec_destroy(&op->qiov);
112 g_slice_free(MirrorOp, op);
114 /* Enter coroutine when it is not sleeping. The coroutine sleeps to
115 * rate-limit itself. The coroutine will eventually resume since there is
116 * a sleep timeout so don't wake it early.
118 if (s->common.busy) {
119 qemu_coroutine_enter(s->common.co, NULL);
123 static void mirror_write_complete(void *opaque, int ret)
125 MirrorOp *op = opaque;
126 MirrorBlockJob *s = op->s;
127 if (ret < 0) {
128 BlockErrorAction action;
130 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
131 action = mirror_error_action(s, false, -ret);
132 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
133 s->ret = ret;
136 mirror_iteration_done(op, ret);
139 static void mirror_read_complete(void *opaque, int ret)
141 MirrorOp *op = opaque;
142 MirrorBlockJob *s = op->s;
143 if (ret < 0) {
144 BlockErrorAction action;
146 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
147 action = mirror_error_action(s, true, -ret);
148 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
149 s->ret = ret;
152 mirror_iteration_done(op, ret);
153 return;
155 bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors,
156 mirror_write_complete, op);
159 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
161 BlockDriverState *source = s->common.bs;
162 int nb_sectors, sectors_per_chunk, nb_chunks;
163 int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector;
164 uint64_t delay_ns = 0;
165 MirrorOp *op;
167 s->sector_num = hbitmap_iter_next(&s->hbi);
168 if (s->sector_num < 0) {
169 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
170 s->sector_num = hbitmap_iter_next(&s->hbi);
171 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
172 assert(s->sector_num >= 0);
175 hbitmap_next_sector = s->sector_num;
176 sector_num = s->sector_num;
177 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
178 end = s->bdev_length / BDRV_SECTOR_SIZE;
180 /* Extend the QEMUIOVector to include all adjacent blocks that will
181 * be copied in this operation.
183 * We have to do this if we have no backing file yet in the destination,
184 * and the cluster size is very large. Then we need to do COW ourselves.
185 * The first time a cluster is copied, copy it entirely. Note that,
186 * because both the granularity and the cluster size are powers of two,
187 * the number of sectors to copy cannot exceed one cluster.
189 * We also want to extend the QEMUIOVector to include more adjacent
190 * dirty blocks if possible, to limit the number of I/O operations and
191 * run efficiently even with a small granularity.
193 nb_chunks = 0;
194 nb_sectors = 0;
195 next_sector = sector_num;
196 next_chunk = sector_num / sectors_per_chunk;
198 /* Wait for I/O to this cluster (from a previous iteration) to be done. */
199 while (test_bit(next_chunk, s->in_flight_bitmap)) {
200 trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
201 qemu_coroutine_yield();
204 do {
205 int added_sectors, added_chunks;
207 if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) ||
208 test_bit(next_chunk, s->in_flight_bitmap)) {
209 assert(nb_sectors > 0);
210 break;
213 added_sectors = sectors_per_chunk;
214 if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) {
215 bdrv_round_to_clusters(s->target,
216 next_sector, added_sectors,
217 &next_sector, &added_sectors);
219 /* On the first iteration, the rounding may make us copy
220 * sectors before the first dirty one.
222 if (next_sector < sector_num) {
223 assert(nb_sectors == 0);
224 sector_num = next_sector;
225 next_chunk = next_sector / sectors_per_chunk;
229 added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors));
230 added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk;
232 /* When doing COW, it may happen that there is not enough space for
233 * a full cluster. Wait if that is the case.
235 while (nb_chunks == 0 && s->buf_free_count < added_chunks) {
236 trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight);
237 qemu_coroutine_yield();
239 if (s->buf_free_count < nb_chunks + added_chunks) {
240 trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight);
241 break;
244 /* We have enough free space to copy these sectors. */
245 bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks);
247 nb_sectors += added_sectors;
248 nb_chunks += added_chunks;
249 next_sector += added_sectors;
250 next_chunk += added_chunks;
251 if (!s->synced && s->common.speed) {
252 delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors);
254 } while (delay_ns == 0 && next_sector < end);
256 /* Allocate a MirrorOp that is used as an AIO callback. */
257 op = g_slice_new(MirrorOp);
258 op->s = s;
259 op->sector_num = sector_num;
260 op->nb_sectors = nb_sectors;
262 /* Now make a QEMUIOVector taking enough granularity-sized chunks
263 * from s->buf_free.
265 qemu_iovec_init(&op->qiov, nb_chunks);
266 next_sector = sector_num;
267 while (nb_chunks-- > 0) {
268 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
269 size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size;
271 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
272 s->buf_free_count--;
273 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
275 /* Advance the HBitmapIter in parallel, so that we do not examine
276 * the same sector twice.
278 if (next_sector > hbitmap_next_sector
279 && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) {
280 hbitmap_next_sector = hbitmap_iter_next(&s->hbi);
283 next_sector += sectors_per_chunk;
286 bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors);
288 /* Copy the dirty cluster. */
289 s->in_flight++;
290 s->sectors_in_flight += nb_sectors;
291 trace_mirror_one_iteration(s, sector_num, nb_sectors);
292 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors,
293 mirror_read_complete, op);
294 return delay_ns;
297 static void mirror_free_init(MirrorBlockJob *s)
299 int granularity = s->granularity;
300 size_t buf_size = s->buf_size;
301 uint8_t *buf = s->buf;
303 assert(s->buf_free_count == 0);
304 QSIMPLEQ_INIT(&s->buf_free);
305 while (buf_size != 0) {
306 MirrorBuffer *cur = (MirrorBuffer *)buf;
307 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
308 s->buf_free_count++;
309 buf_size -= granularity;
310 buf += granularity;
314 static void mirror_drain(MirrorBlockJob *s)
316 while (s->in_flight > 0) {
317 qemu_coroutine_yield();
321 typedef struct {
322 int ret;
323 } MirrorExitData;
325 static void mirror_exit(BlockJob *job, void *opaque)
327 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
328 MirrorExitData *data = opaque;
329 AioContext *replace_aio_context = NULL;
331 if (s->to_replace) {
332 replace_aio_context = bdrv_get_aio_context(s->to_replace);
333 aio_context_acquire(replace_aio_context);
336 if (s->should_complete && data->ret == 0) {
337 BlockDriverState *to_replace = s->common.bs;
338 if (s->to_replace) {
339 to_replace = s->to_replace;
341 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) {
342 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL);
344 bdrv_swap(s->target, to_replace);
345 if (s->common.driver->job_type == BLOCK_JOB_TYPE_COMMIT) {
346 /* drop the bs loop chain formed by the swap: break the loop then
347 * trigger the unref from the top one */
348 BlockDriverState *p = s->base->backing_hd;
349 bdrv_set_backing_hd(s->base, NULL);
350 bdrv_unref(p);
353 if (s->to_replace) {
354 bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
355 error_free(s->replace_blocker);
356 bdrv_unref(s->to_replace);
358 if (replace_aio_context) {
359 aio_context_release(replace_aio_context);
361 g_free(s->replaces);
362 bdrv_unref(s->target);
363 block_job_completed(&s->common, data->ret);
364 g_free(data);
367 static void coroutine_fn mirror_run(void *opaque)
369 MirrorBlockJob *s = opaque;
370 MirrorExitData *data;
371 BlockDriverState *bs = s->common.bs;
372 int64_t sector_num, end, sectors_per_chunk, length;
373 uint64_t last_pause_ns;
374 BlockDriverInfo bdi;
375 char backing_filename[2]; /* we only need 2 characters because we are only
376 checking for a NULL string */
377 int ret = 0;
378 int n;
380 if (block_job_is_cancelled(&s->common)) {
381 goto immediate_exit;
384 s->bdev_length = bdrv_getlength(bs);
385 if (s->bdev_length < 0) {
386 ret = s->bdev_length;
387 goto immediate_exit;
388 } else if (s->bdev_length == 0) {
389 /* Report BLOCK_JOB_READY and wait for complete. */
390 block_job_event_ready(&s->common);
391 s->synced = true;
392 while (!block_job_is_cancelled(&s->common) && !s->should_complete) {
393 block_job_yield(&s->common);
395 s->common.cancelled = false;
396 goto immediate_exit;
399 length = DIV_ROUND_UP(s->bdev_length, s->granularity);
400 s->in_flight_bitmap = bitmap_new(length);
402 /* If we have no backing file yet in the destination, we cannot let
403 * the destination do COW. Instead, we copy sectors around the
404 * dirty data if needed. We need a bitmap to do that.
406 bdrv_get_backing_filename(s->target, backing_filename,
407 sizeof(backing_filename));
408 if (backing_filename[0] && !s->target->backing_hd) {
409 ret = bdrv_get_info(s->target, &bdi);
410 if (ret < 0) {
411 goto immediate_exit;
413 if (s->granularity < bdi.cluster_size) {
414 s->buf_size = MAX(s->buf_size, bdi.cluster_size);
415 s->cow_bitmap = bitmap_new(length);
419 end = s->bdev_length / BDRV_SECTOR_SIZE;
420 s->buf = qemu_try_blockalign(bs, s->buf_size);
421 if (s->buf == NULL) {
422 ret = -ENOMEM;
423 goto immediate_exit;
426 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
427 mirror_free_init(s);
429 if (!s->is_none_mode) {
430 /* First part, loop on the sectors and initialize the dirty bitmap. */
431 BlockDriverState *base = s->base;
432 for (sector_num = 0; sector_num < end; ) {
433 int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
434 ret = bdrv_is_allocated_above(bs, base,
435 sector_num, next - sector_num, &n);
437 if (ret < 0) {
438 goto immediate_exit;
441 assert(n > 0);
442 if (ret == 1) {
443 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
444 sector_num = next;
445 } else {
446 sector_num += n;
451 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
452 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
453 for (;;) {
454 uint64_t delay_ns = 0;
455 int64_t cnt;
456 bool should_complete;
458 if (s->ret < 0) {
459 ret = s->ret;
460 goto immediate_exit;
463 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
464 /* s->common.offset contains the number of bytes already processed so
465 * far, cnt is the number of dirty sectors remaining and
466 * s->sectors_in_flight is the number of sectors currently being
467 * processed; together those are the current total operation length */
468 s->common.len = s->common.offset +
469 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE;
471 /* Note that even when no rate limit is applied we need to yield
472 * periodically with no pending I/O so that bdrv_drain_all() returns.
473 * We do so every SLICE_TIME nanoseconds, or when there is an error,
474 * or when the source is clean, whichever comes first.
476 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME &&
477 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
478 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
479 (cnt == 0 && s->in_flight > 0)) {
480 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
481 qemu_coroutine_yield();
482 continue;
483 } else if (cnt != 0) {
484 delay_ns = mirror_iteration(s);
488 should_complete = false;
489 if (s->in_flight == 0 && cnt == 0) {
490 trace_mirror_before_flush(s);
491 ret = bdrv_flush(s->target);
492 if (ret < 0) {
493 if (mirror_error_action(s, false, -ret) ==
494 BLOCK_ERROR_ACTION_REPORT) {
495 goto immediate_exit;
497 } else {
498 /* We're out of the streaming phase. From now on, if the job
499 * is cancelled we will actually complete all pending I/O and
500 * report completion. This way, block-job-cancel will leave
501 * the target in a consistent state.
503 if (!s->synced) {
504 block_job_event_ready(&s->common);
505 s->synced = true;
508 should_complete = s->should_complete ||
509 block_job_is_cancelled(&s->common);
510 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
514 if (cnt == 0 && should_complete) {
515 /* The dirty bitmap is not updated while operations are pending.
516 * If we're about to exit, wait for pending operations before
517 * calling bdrv_get_dirty_count(bs), or we may exit while the
518 * source has dirty data to copy!
520 * Note that I/O can be submitted by the guest while
521 * mirror_populate runs.
523 trace_mirror_before_drain(s, cnt);
524 bdrv_drain(bs);
525 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
528 ret = 0;
529 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
530 if (!s->synced) {
531 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
532 if (block_job_is_cancelled(&s->common)) {
533 break;
535 } else if (!should_complete) {
536 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
537 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
538 } else if (cnt == 0) {
539 /* The two disks are in sync. Exit and report successful
540 * completion.
542 assert(QLIST_EMPTY(&bs->tracked_requests));
543 s->common.cancelled = false;
544 break;
546 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
549 immediate_exit:
550 if (s->in_flight > 0) {
551 /* We get here only if something went wrong. Either the job failed,
552 * or it was cancelled prematurely so that we do not guarantee that
553 * the target is a copy of the source.
555 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
556 mirror_drain(s);
559 assert(s->in_flight == 0);
560 qemu_vfree(s->buf);
561 g_free(s->cow_bitmap);
562 g_free(s->in_flight_bitmap);
563 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
564 bdrv_iostatus_disable(s->target);
566 data = g_malloc(sizeof(*data));
567 data->ret = ret;
568 block_job_defer_to_main_loop(&s->common, mirror_exit, data);
571 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp)
573 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
575 if (speed < 0) {
576 error_set(errp, QERR_INVALID_PARAMETER, "speed");
577 return;
579 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
582 static void mirror_iostatus_reset(BlockJob *job)
584 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
586 bdrv_iostatus_reset(s->target);
589 static void mirror_complete(BlockJob *job, Error **errp)
591 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
592 Error *local_err = NULL;
593 int ret;
595 ret = bdrv_open_backing_file(s->target, NULL, &local_err);
596 if (ret < 0) {
597 error_propagate(errp, local_err);
598 return;
600 if (!s->synced) {
601 error_set(errp, QERR_BLOCK_JOB_NOT_READY,
602 bdrv_get_device_name(job->bs));
603 return;
606 /* check the target bs is not blocked and block all operations on it */
607 if (s->replaces) {
608 AioContext *replace_aio_context;
610 s->to_replace = check_to_replace_node(s->replaces, &local_err);
611 if (!s->to_replace) {
612 error_propagate(errp, local_err);
613 return;
616 replace_aio_context = bdrv_get_aio_context(s->to_replace);
617 aio_context_acquire(replace_aio_context);
619 error_setg(&s->replace_blocker,
620 "block device is in use by block-job-complete");
621 bdrv_op_block_all(s->to_replace, s->replace_blocker);
622 bdrv_ref(s->to_replace);
624 aio_context_release(replace_aio_context);
627 s->should_complete = true;
628 block_job_enter(&s->common);
631 static const BlockJobDriver mirror_job_driver = {
632 .instance_size = sizeof(MirrorBlockJob),
633 .job_type = BLOCK_JOB_TYPE_MIRROR,
634 .set_speed = mirror_set_speed,
635 .iostatus_reset= mirror_iostatus_reset,
636 .complete = mirror_complete,
639 static const BlockJobDriver commit_active_job_driver = {
640 .instance_size = sizeof(MirrorBlockJob),
641 .job_type = BLOCK_JOB_TYPE_COMMIT,
642 .set_speed = mirror_set_speed,
643 .iostatus_reset
644 = mirror_iostatus_reset,
645 .complete = mirror_complete,
648 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
649 const char *replaces,
650 int64_t speed, uint32_t granularity,
651 int64_t buf_size,
652 BlockdevOnError on_source_error,
653 BlockdevOnError on_target_error,
654 BlockCompletionFunc *cb,
655 void *opaque, Error **errp,
656 const BlockJobDriver *driver,
657 bool is_none_mode, BlockDriverState *base)
659 MirrorBlockJob *s;
661 if (granularity == 0) {
662 granularity = bdrv_get_default_bitmap_granularity(target);
665 assert ((granularity & (granularity - 1)) == 0);
667 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
668 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
669 !bdrv_iostatus_is_enabled(bs)) {
670 error_set(errp, QERR_INVALID_PARAMETER, "on-source-error");
671 return;
675 s = block_job_create(driver, bs, speed, cb, opaque, errp);
676 if (!s) {
677 return;
680 s->replaces = g_strdup(replaces);
681 s->on_source_error = on_source_error;
682 s->on_target_error = on_target_error;
683 s->target = target;
684 s->is_none_mode = is_none_mode;
685 s->base = base;
686 s->granularity = granularity;
687 s->buf_size = MAX(buf_size, granularity);
689 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
690 if (!s->dirty_bitmap) {
691 return;
693 bdrv_set_enable_write_cache(s->target, true);
694 bdrv_set_on_error(s->target, on_target_error, on_target_error);
695 bdrv_iostatus_enable(s->target);
696 s->common.co = qemu_coroutine_create(mirror_run);
697 trace_mirror_start(bs, s, s->common.co, opaque);
698 qemu_coroutine_enter(s->common.co, s);
701 void mirror_start(BlockDriverState *bs, BlockDriverState *target,
702 const char *replaces,
703 int64_t speed, uint32_t granularity, int64_t buf_size,
704 MirrorSyncMode mode, BlockdevOnError on_source_error,
705 BlockdevOnError on_target_error,
706 BlockCompletionFunc *cb,
707 void *opaque, Error **errp)
709 bool is_none_mode;
710 BlockDriverState *base;
712 if (mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) {
713 error_setg(errp, "Sync mode 'dirty-bitmap' not supported");
714 return;
716 is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
717 base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL;
718 mirror_start_job(bs, target, replaces,
719 speed, granularity, buf_size,
720 on_source_error, on_target_error, cb, opaque, errp,
721 &mirror_job_driver, is_none_mode, base);
724 void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
725 int64_t speed,
726 BlockdevOnError on_error,
727 BlockCompletionFunc *cb,
728 void *opaque, Error **errp)
730 int64_t length, base_length;
731 int orig_base_flags;
732 int ret;
733 Error *local_err = NULL;
735 orig_base_flags = bdrv_get_flags(base);
737 if (bdrv_reopen(base, bs->open_flags, errp)) {
738 return;
741 length = bdrv_getlength(bs);
742 if (length < 0) {
743 error_setg_errno(errp, -length,
744 "Unable to determine length of %s", bs->filename);
745 goto error_restore_flags;
748 base_length = bdrv_getlength(base);
749 if (base_length < 0) {
750 error_setg_errno(errp, -base_length,
751 "Unable to determine length of %s", base->filename);
752 goto error_restore_flags;
755 if (length > base_length) {
756 ret = bdrv_truncate(base, length);
757 if (ret < 0) {
758 error_setg_errno(errp, -ret,
759 "Top image %s is larger than base image %s, and "
760 "resize of base image failed",
761 bs->filename, base->filename);
762 goto error_restore_flags;
766 bdrv_ref(base);
767 mirror_start_job(bs, base, NULL, speed, 0, 0,
768 on_error, on_error, cb, opaque, &local_err,
769 &commit_active_job_driver, false, base);
770 if (local_err) {
771 error_propagate(errp, local_err);
772 goto error_restore_flags;
775 return;
777 error_restore_flags:
778 /* ignore error and errp for bdrv_reopen, because we want to propagate
779 * the original error */
780 bdrv_reopen(base, orig_base_flags, NULL);
781 return;