curses: use the bit mask constants provided by curses
[qemu/ar7.git] / block / mirror.c
blobfe984efb90b824e07c242732fae68476e36317b8
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 "qemu/osdep.h"
15 #include "qemu/cutils.h"
16 #include "qemu/coroutine.h"
17 #include "qemu/range.h"
18 #include "trace.h"
19 #include "block/blockjob_int.h"
20 #include "block/block_int.h"
21 #include "sysemu/block-backend.h"
22 #include "qapi/error.h"
23 #include "qapi/qmp/qerror.h"
24 #include "qemu/ratelimit.h"
25 #include "qemu/bitmap.h"
27 #define MAX_IN_FLIGHT 16
28 #define MAX_IO_BYTES (1 << 20) /* 1 Mb */
29 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES)
31 /* The mirroring buffer is a list of granularity-sized chunks.
32 * Free chunks are organized in a list.
34 typedef struct MirrorBuffer {
35 QSIMPLEQ_ENTRY(MirrorBuffer) next;
36 } MirrorBuffer;
38 typedef struct MirrorOp MirrorOp;
40 typedef struct MirrorBlockJob {
41 BlockJob common;
42 BlockBackend *target;
43 BlockDriverState *mirror_top_bs;
44 BlockDriverState *base;
46 /* The name of the graph node to replace */
47 char *replaces;
48 /* The BDS to replace */
49 BlockDriverState *to_replace;
50 /* Used to block operations on the drive-mirror-replace target */
51 Error *replace_blocker;
52 bool is_none_mode;
53 BlockMirrorBackingMode backing_mode;
54 /* Whether the target image requires explicit zero-initialization */
55 bool zero_target;
56 MirrorCopyMode copy_mode;
57 BlockdevOnError on_source_error, on_target_error;
58 bool synced;
59 /* Set when the target is synced (dirty bitmap is clean, nothing
60 * in flight) and the job is running in active mode */
61 bool actively_synced;
62 bool should_complete;
63 int64_t granularity;
64 size_t buf_size;
65 int64_t bdev_length;
66 unsigned long *cow_bitmap;
67 BdrvDirtyBitmap *dirty_bitmap;
68 BdrvDirtyBitmapIter *dbi;
69 uint8_t *buf;
70 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
71 int buf_free_count;
73 uint64_t last_pause_ns;
74 unsigned long *in_flight_bitmap;
75 int in_flight;
76 int64_t bytes_in_flight;
77 QTAILQ_HEAD(, MirrorOp) ops_in_flight;
78 int ret;
79 bool unmap;
80 int target_cluster_size;
81 int max_iov;
82 bool initial_zeroing_ongoing;
83 int in_active_write_counter;
84 bool prepared;
85 bool in_drain;
86 } MirrorBlockJob;
88 typedef struct MirrorBDSOpaque {
89 MirrorBlockJob *job;
90 bool stop;
91 } MirrorBDSOpaque;
93 struct MirrorOp {
94 MirrorBlockJob *s;
95 QEMUIOVector qiov;
96 int64_t offset;
97 uint64_t bytes;
99 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and
100 * mirror_co_discard() before yielding for the first time */
101 int64_t *bytes_handled;
103 bool is_pseudo_op;
104 bool is_active_write;
105 CoQueue waiting_requests;
107 QTAILQ_ENTRY(MirrorOp) next;
110 typedef enum MirrorMethod {
111 MIRROR_METHOD_COPY,
112 MIRROR_METHOD_ZERO,
113 MIRROR_METHOD_DISCARD,
114 } MirrorMethod;
116 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
117 int error)
119 s->synced = false;
120 s->actively_synced = false;
121 if (read) {
122 return block_job_error_action(&s->common, s->on_source_error,
123 true, error);
124 } else {
125 return block_job_error_action(&s->common, s->on_target_error,
126 false, error);
130 static void coroutine_fn mirror_wait_on_conflicts(MirrorOp *self,
131 MirrorBlockJob *s,
132 uint64_t offset,
133 uint64_t bytes)
135 uint64_t self_start_chunk = offset / s->granularity;
136 uint64_t self_end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity);
137 uint64_t self_nb_chunks = self_end_chunk - self_start_chunk;
139 while (find_next_bit(s->in_flight_bitmap, self_end_chunk,
140 self_start_chunk) < self_end_chunk &&
141 s->ret >= 0)
143 MirrorOp *op;
145 QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
146 uint64_t op_start_chunk = op->offset / s->granularity;
147 uint64_t op_nb_chunks = DIV_ROUND_UP(op->offset + op->bytes,
148 s->granularity) -
149 op_start_chunk;
151 if (op == self) {
152 continue;
155 if (ranges_overlap(self_start_chunk, self_nb_chunks,
156 op_start_chunk, op_nb_chunks))
158 qemu_co_queue_wait(&op->waiting_requests, NULL);
159 break;
165 static void coroutine_fn mirror_iteration_done(MirrorOp *op, int ret)
167 MirrorBlockJob *s = op->s;
168 struct iovec *iov;
169 int64_t chunk_num;
170 int i, nb_chunks;
172 trace_mirror_iteration_done(s, op->offset, op->bytes, ret);
174 s->in_flight--;
175 s->bytes_in_flight -= op->bytes;
176 iov = op->qiov.iov;
177 for (i = 0; i < op->qiov.niov; i++) {
178 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
179 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
180 s->buf_free_count++;
183 chunk_num = op->offset / s->granularity;
184 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);
186 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
187 QTAILQ_REMOVE(&s->ops_in_flight, op, next);
188 if (ret >= 0) {
189 if (s->cow_bitmap) {
190 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
192 if (!s->initial_zeroing_ongoing) {
193 job_progress_update(&s->common.job, op->bytes);
196 qemu_iovec_destroy(&op->qiov);
198 qemu_co_queue_restart_all(&op->waiting_requests);
199 g_free(op);
202 static void coroutine_fn mirror_write_complete(MirrorOp *op, int ret)
204 MirrorBlockJob *s = op->s;
206 if (ret < 0) {
207 BlockErrorAction action;
209 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
210 action = mirror_error_action(s, false, -ret);
211 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
212 s->ret = ret;
216 mirror_iteration_done(op, ret);
219 static void coroutine_fn mirror_read_complete(MirrorOp *op, int ret)
221 MirrorBlockJob *s = op->s;
223 if (ret < 0) {
224 BlockErrorAction action;
226 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
227 action = mirror_error_action(s, true, -ret);
228 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
229 s->ret = ret;
232 mirror_iteration_done(op, ret);
233 return;
236 ret = blk_co_pwritev(s->target, op->offset, op->qiov.size, &op->qiov, 0);
237 mirror_write_complete(op, ret);
240 /* Clip bytes relative to offset to not exceed end-of-file */
241 static inline int64_t mirror_clip_bytes(MirrorBlockJob *s,
242 int64_t offset,
243 int64_t bytes)
245 return MIN(bytes, s->bdev_length - offset);
248 /* Round offset and/or bytes to target cluster if COW is needed, and
249 * return the offset of the adjusted tail against original. */
250 static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
251 uint64_t *bytes)
253 bool need_cow;
254 int ret = 0;
255 int64_t align_offset = *offset;
256 int64_t align_bytes = *bytes;
257 int max_bytes = s->granularity * s->max_iov;
259 need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap);
260 need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity,
261 s->cow_bitmap);
262 if (need_cow) {
263 bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes,
264 &align_offset, &align_bytes);
267 if (align_bytes > max_bytes) {
268 align_bytes = max_bytes;
269 if (need_cow) {
270 align_bytes = QEMU_ALIGN_DOWN(align_bytes, s->target_cluster_size);
273 /* Clipping may result in align_bytes unaligned to chunk boundary, but
274 * that doesn't matter because it's already the end of source image. */
275 align_bytes = mirror_clip_bytes(s, align_offset, align_bytes);
277 ret = align_offset + align_bytes - (*offset + *bytes);
278 *offset = align_offset;
279 *bytes = align_bytes;
280 assert(ret >= 0);
281 return ret;
284 static inline void coroutine_fn
285 mirror_wait_for_any_operation(MirrorBlockJob *s, bool active)
287 MirrorOp *op;
289 QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
290 /* Do not wait on pseudo ops, because it may in turn wait on
291 * some other operation to start, which may in fact be the
292 * caller of this function. Since there is only one pseudo op
293 * at any given time, we will always find some real operation
294 * to wait on. */
295 if (!op->is_pseudo_op && op->is_active_write == active) {
296 qemu_co_queue_wait(&op->waiting_requests, NULL);
297 return;
300 abort();
303 static inline void coroutine_fn
304 mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
306 /* Only non-active operations use up in-flight slots */
307 mirror_wait_for_any_operation(s, false);
310 /* Perform a mirror copy operation.
312 * *op->bytes_handled is set to the number of bytes copied after and
313 * including offset, excluding any bytes copied prior to offset due
314 * to alignment. This will be op->bytes if no alignment is necessary,
315 * or (new_end - op->offset) if the tail is rounded up or down due to
316 * alignment or buffer limit.
318 static void coroutine_fn mirror_co_read(void *opaque)
320 MirrorOp *op = opaque;
321 MirrorBlockJob *s = op->s;
322 int nb_chunks;
323 uint64_t ret;
324 uint64_t max_bytes;
326 max_bytes = s->granularity * s->max_iov;
328 /* We can only handle as much as buf_size at a time. */
329 op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes));
330 assert(op->bytes);
331 assert(op->bytes < BDRV_REQUEST_MAX_BYTES);
332 *op->bytes_handled = op->bytes;
334 if (s->cow_bitmap) {
335 *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes);
337 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
338 assert(*op->bytes_handled <= UINT_MAX);
339 assert(op->bytes <= s->buf_size);
340 /* The offset is granularity-aligned because:
341 * 1) Caller passes in aligned values;
342 * 2) mirror_cow_align is used only when target cluster is larger. */
343 assert(QEMU_IS_ALIGNED(op->offset, s->granularity));
344 /* The range is sector-aligned, since bdrv_getlength() rounds up. */
345 assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE));
346 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);
348 while (s->buf_free_count < nb_chunks) {
349 trace_mirror_yield_in_flight(s, op->offset, s->in_flight);
350 mirror_wait_for_free_in_flight_slot(s);
353 /* Now make a QEMUIOVector taking enough granularity-sized chunks
354 * from s->buf_free.
356 qemu_iovec_init(&op->qiov, nb_chunks);
357 while (nb_chunks-- > 0) {
358 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
359 size_t remaining = op->bytes - op->qiov.size;
361 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
362 s->buf_free_count--;
363 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
366 /* Copy the dirty cluster. */
367 s->in_flight++;
368 s->bytes_in_flight += op->bytes;
369 trace_mirror_one_iteration(s, op->offset, op->bytes);
371 ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes,
372 &op->qiov, 0);
373 mirror_read_complete(op, ret);
376 static void coroutine_fn mirror_co_zero(void *opaque)
378 MirrorOp *op = opaque;
379 int ret;
381 op->s->in_flight++;
382 op->s->bytes_in_flight += op->bytes;
383 *op->bytes_handled = op->bytes;
385 ret = blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes,
386 op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0);
387 mirror_write_complete(op, ret);
390 static void coroutine_fn mirror_co_discard(void *opaque)
392 MirrorOp *op = opaque;
393 int ret;
395 op->s->in_flight++;
396 op->s->bytes_in_flight += op->bytes;
397 *op->bytes_handled = op->bytes;
399 ret = blk_co_pdiscard(op->s->target, op->offset, op->bytes);
400 mirror_write_complete(op, ret);
403 static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset,
404 unsigned bytes, MirrorMethod mirror_method)
406 MirrorOp *op;
407 Coroutine *co;
408 int64_t bytes_handled = -1;
410 op = g_new(MirrorOp, 1);
411 *op = (MirrorOp){
412 .s = s,
413 .offset = offset,
414 .bytes = bytes,
415 .bytes_handled = &bytes_handled,
417 qemu_co_queue_init(&op->waiting_requests);
419 switch (mirror_method) {
420 case MIRROR_METHOD_COPY:
421 co = qemu_coroutine_create(mirror_co_read, op);
422 break;
423 case MIRROR_METHOD_ZERO:
424 co = qemu_coroutine_create(mirror_co_zero, op);
425 break;
426 case MIRROR_METHOD_DISCARD:
427 co = qemu_coroutine_create(mirror_co_discard, op);
428 break;
429 default:
430 abort();
433 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next);
434 qemu_coroutine_enter(co);
435 /* At this point, ownership of op has been moved to the coroutine
436 * and the object may already be freed */
438 /* Assert that this value has been set */
439 assert(bytes_handled >= 0);
441 /* Same assertion as in mirror_co_read() (and for mirror_co_read()
442 * and mirror_co_discard(), bytes_handled == op->bytes, which
443 * is the @bytes parameter given to this function) */
444 assert(bytes_handled <= UINT_MAX);
445 return bytes_handled;
448 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
450 BlockDriverState *source = s->mirror_top_bs->backing->bs;
451 MirrorOp *pseudo_op;
452 int64_t offset;
453 uint64_t delay_ns = 0, ret = 0;
454 /* At least the first dirty chunk is mirrored in one iteration. */
455 int nb_chunks = 1;
456 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
457 int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
459 bdrv_dirty_bitmap_lock(s->dirty_bitmap);
460 offset = bdrv_dirty_iter_next(s->dbi);
461 if (offset < 0) {
462 bdrv_set_dirty_iter(s->dbi, 0);
463 offset = bdrv_dirty_iter_next(s->dbi);
464 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
465 assert(offset >= 0);
467 bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
469 mirror_wait_on_conflicts(NULL, s, offset, 1);
471 job_pause_point(&s->common.job);
473 /* Find the number of consective dirty chunks following the first dirty
474 * one, and wait for in flight requests in them. */
475 bdrv_dirty_bitmap_lock(s->dirty_bitmap);
476 while (nb_chunks * s->granularity < s->buf_size) {
477 int64_t next_dirty;
478 int64_t next_offset = offset + nb_chunks * s->granularity;
479 int64_t next_chunk = next_offset / s->granularity;
480 if (next_offset >= s->bdev_length ||
481 !bdrv_dirty_bitmap_get_locked(s->dirty_bitmap, next_offset)) {
482 break;
484 if (test_bit(next_chunk, s->in_flight_bitmap)) {
485 break;
488 next_dirty = bdrv_dirty_iter_next(s->dbi);
489 if (next_dirty > next_offset || next_dirty < 0) {
490 /* The bitmap iterator's cache is stale, refresh it */
491 bdrv_set_dirty_iter(s->dbi, next_offset);
492 next_dirty = bdrv_dirty_iter_next(s->dbi);
494 assert(next_dirty == next_offset);
495 nb_chunks++;
498 /* Clear dirty bits before querying the block status, because
499 * calling bdrv_block_status_above could yield - if some blocks are
500 * marked dirty in this window, we need to know.
502 bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
503 nb_chunks * s->granularity);
504 bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
506 /* Before claiming an area in the in-flight bitmap, we have to
507 * create a MirrorOp for it so that conflicting requests can wait
508 * for it. mirror_perform() will create the real MirrorOps later,
509 * for now we just create a pseudo operation that will wake up all
510 * conflicting requests once all real operations have been
511 * launched. */
512 pseudo_op = g_new(MirrorOp, 1);
513 *pseudo_op = (MirrorOp){
514 .offset = offset,
515 .bytes = nb_chunks * s->granularity,
516 .is_pseudo_op = true,
518 qemu_co_queue_init(&pseudo_op->waiting_requests);
519 QTAILQ_INSERT_TAIL(&s->ops_in_flight, pseudo_op, next);
521 bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
522 while (nb_chunks > 0 && offset < s->bdev_length) {
523 int ret;
524 int64_t io_bytes;
525 int64_t io_bytes_acct;
526 MirrorMethod mirror_method = MIRROR_METHOD_COPY;
528 assert(!(offset % s->granularity));
529 ret = bdrv_block_status_above(source, NULL, offset,
530 nb_chunks * s->granularity,
531 &io_bytes, NULL, NULL);
532 if (ret < 0) {
533 io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
534 } else if (ret & BDRV_BLOCK_DATA) {
535 io_bytes = MIN(io_bytes, max_io_bytes);
538 io_bytes -= io_bytes % s->granularity;
539 if (io_bytes < s->granularity) {
540 io_bytes = s->granularity;
541 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
542 int64_t target_offset;
543 int64_t target_bytes;
544 bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
545 &target_offset, &target_bytes);
546 if (target_offset == offset &&
547 target_bytes == io_bytes) {
548 mirror_method = ret & BDRV_BLOCK_ZERO ?
549 MIRROR_METHOD_ZERO :
550 MIRROR_METHOD_DISCARD;
554 while (s->in_flight >= MAX_IN_FLIGHT) {
555 trace_mirror_yield_in_flight(s, offset, s->in_flight);
556 mirror_wait_for_free_in_flight_slot(s);
559 if (s->ret < 0) {
560 ret = 0;
561 goto fail;
564 io_bytes = mirror_clip_bytes(s, offset, io_bytes);
565 io_bytes = mirror_perform(s, offset, io_bytes, mirror_method);
566 if (mirror_method != MIRROR_METHOD_COPY && write_zeroes_ok) {
567 io_bytes_acct = 0;
568 } else {
569 io_bytes_acct = io_bytes;
571 assert(io_bytes);
572 offset += io_bytes;
573 nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity);
574 delay_ns = block_job_ratelimit_get_delay(&s->common, io_bytes_acct);
577 ret = delay_ns;
578 fail:
579 QTAILQ_REMOVE(&s->ops_in_flight, pseudo_op, next);
580 qemu_co_queue_restart_all(&pseudo_op->waiting_requests);
581 g_free(pseudo_op);
583 return ret;
586 static void mirror_free_init(MirrorBlockJob *s)
588 int granularity = s->granularity;
589 size_t buf_size = s->buf_size;
590 uint8_t *buf = s->buf;
592 assert(s->buf_free_count == 0);
593 QSIMPLEQ_INIT(&s->buf_free);
594 while (buf_size != 0) {
595 MirrorBuffer *cur = (MirrorBuffer *)buf;
596 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
597 s->buf_free_count++;
598 buf_size -= granularity;
599 buf += granularity;
603 /* This is also used for the .pause callback. There is no matching
604 * mirror_resume() because mirror_run() will begin iterating again
605 * when the job is resumed.
607 static void coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s)
609 while (s->in_flight > 0) {
610 mirror_wait_for_free_in_flight_slot(s);
615 * mirror_exit_common: handle both abort() and prepare() cases.
616 * for .prepare, returns 0 on success and -errno on failure.
617 * for .abort cases, denoted by abort = true, MUST return 0.
619 static int mirror_exit_common(Job *job)
621 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
622 BlockJob *bjob = &s->common;
623 MirrorBDSOpaque *bs_opaque = s->mirror_top_bs->opaque;
624 AioContext *replace_aio_context = NULL;
625 BlockDriverState *src = s->mirror_top_bs->backing->bs;
626 BlockDriverState *target_bs = blk_bs(s->target);
627 BlockDriverState *mirror_top_bs = s->mirror_top_bs;
628 Error *local_err = NULL;
629 bool abort = job->ret < 0;
630 int ret = 0;
632 if (s->prepared) {
633 return 0;
635 s->prepared = true;
637 if (bdrv_chain_contains(src, target_bs)) {
638 bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs);
641 bdrv_release_dirty_bitmap(src, s->dirty_bitmap);
643 /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
644 * before we can call bdrv_drained_end */
645 bdrv_ref(src);
646 bdrv_ref(mirror_top_bs);
647 bdrv_ref(target_bs);
650 * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
651 * inserting target_bs at s->to_replace, where we might not be able to get
652 * these permissions.
654 blk_unref(s->target);
655 s->target = NULL;
657 /* We don't access the source any more. Dropping any WRITE/RESIZE is
658 * required before it could become a backing file of target_bs. Not having
659 * these permissions any more means that we can't allow any new requests on
660 * mirror_top_bs from now on, so keep it drained. */
661 bdrv_drained_begin(mirror_top_bs);
662 bs_opaque->stop = true;
663 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
664 &error_abort);
665 if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
666 BlockDriverState *backing = s->is_none_mode ? src : s->base;
667 if (backing_bs(target_bs) != backing) {
668 bdrv_set_backing_hd(target_bs, backing, &local_err);
669 if (local_err) {
670 error_report_err(local_err);
671 ret = -EPERM;
676 if (s->to_replace) {
677 replace_aio_context = bdrv_get_aio_context(s->to_replace);
678 aio_context_acquire(replace_aio_context);
681 if (s->should_complete && !abort) {
682 BlockDriverState *to_replace = s->to_replace ?: src;
683 bool ro = bdrv_is_read_only(to_replace);
685 if (ro != bdrv_is_read_only(target_bs)) {
686 bdrv_reopen_set_read_only(target_bs, ro, NULL);
689 /* The mirror job has no requests in flight any more, but we need to
690 * drain potential other users of the BDS before changing the graph. */
691 assert(s->in_drain);
692 bdrv_drained_begin(target_bs);
693 bdrv_replace_node(to_replace, target_bs, &local_err);
694 bdrv_drained_end(target_bs);
695 if (local_err) {
696 error_report_err(local_err);
697 ret = -EPERM;
700 if (s->to_replace) {
701 bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
702 error_free(s->replace_blocker);
703 bdrv_unref(s->to_replace);
705 if (replace_aio_context) {
706 aio_context_release(replace_aio_context);
708 g_free(s->replaces);
709 bdrv_unref(target_bs);
712 * Remove the mirror filter driver from the graph. Before this, get rid of
713 * the blockers on the intermediate nodes so that the resulting state is
714 * valid.
716 block_job_remove_all_bdrv(bjob);
717 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);
719 /* We just changed the BDS the job BB refers to (with either or both of the
720 * bdrv_replace_node() calls), so switch the BB back so the cleanup does
721 * the right thing. We don't need any permissions any more now. */
722 blk_remove_bs(bjob->blk);
723 blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
724 blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
726 bs_opaque->job = NULL;
728 bdrv_drained_end(src);
729 bdrv_drained_end(mirror_top_bs);
730 s->in_drain = false;
731 bdrv_unref(mirror_top_bs);
732 bdrv_unref(src);
734 return ret;
737 static int mirror_prepare(Job *job)
739 return mirror_exit_common(job);
742 static void mirror_abort(Job *job)
744 int ret = mirror_exit_common(job);
745 assert(ret == 0);
748 static void coroutine_fn mirror_throttle(MirrorBlockJob *s)
750 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
752 if (now - s->last_pause_ns > BLOCK_JOB_SLICE_TIME) {
753 s->last_pause_ns = now;
754 job_sleep_ns(&s->common.job, 0);
755 } else {
756 job_pause_point(&s->common.job);
760 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
762 int64_t offset;
763 BlockDriverState *base = s->base;
764 BlockDriverState *bs = s->mirror_top_bs->backing->bs;
765 BlockDriverState *target_bs = blk_bs(s->target);
766 int ret;
767 int64_t count;
769 if (s->zero_target) {
770 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
771 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length);
772 return 0;
775 s->initial_zeroing_ongoing = true;
776 for (offset = 0; offset < s->bdev_length; ) {
777 int bytes = MIN(s->bdev_length - offset,
778 QEMU_ALIGN_DOWN(INT_MAX, s->granularity));
780 mirror_throttle(s);
782 if (job_is_cancelled(&s->common.job)) {
783 s->initial_zeroing_ongoing = false;
784 return 0;
787 if (s->in_flight >= MAX_IN_FLIGHT) {
788 trace_mirror_yield(s, UINT64_MAX, s->buf_free_count,
789 s->in_flight);
790 mirror_wait_for_free_in_flight_slot(s);
791 continue;
794 mirror_perform(s, offset, bytes, MIRROR_METHOD_ZERO);
795 offset += bytes;
798 mirror_wait_for_all_io(s);
799 s->initial_zeroing_ongoing = false;
802 /* First part, loop on the sectors and initialize the dirty bitmap. */
803 for (offset = 0; offset < s->bdev_length; ) {
804 /* Just to make sure we are not exceeding int limit. */
805 int bytes = MIN(s->bdev_length - offset,
806 QEMU_ALIGN_DOWN(INT_MAX, s->granularity));
808 mirror_throttle(s);
810 if (job_is_cancelled(&s->common.job)) {
811 return 0;
814 ret = bdrv_is_allocated_above(bs, base, false, offset, bytes, &count);
815 if (ret < 0) {
816 return ret;
819 assert(count);
820 if (ret == 1) {
821 bdrv_set_dirty_bitmap(s->dirty_bitmap, offset, count);
823 offset += count;
825 return 0;
828 /* Called when going out of the streaming phase to flush the bulk of the
829 * data to the medium, or just before completing.
831 static int mirror_flush(MirrorBlockJob *s)
833 int ret = blk_flush(s->target);
834 if (ret < 0) {
835 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) {
836 s->ret = ret;
839 return ret;
842 static int coroutine_fn mirror_run(Job *job, Error **errp)
844 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
845 BlockDriverState *bs = s->mirror_top_bs->backing->bs;
846 BlockDriverState *target_bs = blk_bs(s->target);
847 bool need_drain = true;
848 int64_t length;
849 BlockDriverInfo bdi;
850 char backing_filename[2]; /* we only need 2 characters because we are only
851 checking for a NULL string */
852 int ret = 0;
854 if (job_is_cancelled(&s->common.job)) {
855 goto immediate_exit;
858 s->bdev_length = bdrv_getlength(bs);
859 if (s->bdev_length < 0) {
860 ret = s->bdev_length;
861 goto immediate_exit;
864 /* Active commit must resize the base image if its size differs from the
865 * active layer. */
866 if (s->base == blk_bs(s->target)) {
867 int64_t base_length;
869 base_length = blk_getlength(s->target);
870 if (base_length < 0) {
871 ret = base_length;
872 goto immediate_exit;
875 if (s->bdev_length > base_length) {
876 ret = blk_truncate(s->target, s->bdev_length, PREALLOC_MODE_OFF,
877 NULL);
878 if (ret < 0) {
879 goto immediate_exit;
884 if (s->bdev_length == 0) {
885 /* Transition to the READY state and wait for complete. */
886 job_transition_to_ready(&s->common.job);
887 s->synced = true;
888 s->actively_synced = true;
889 while (!job_is_cancelled(&s->common.job) && !s->should_complete) {
890 job_yield(&s->common.job);
892 s->common.job.cancelled = false;
893 goto immediate_exit;
896 length = DIV_ROUND_UP(s->bdev_length, s->granularity);
897 s->in_flight_bitmap = bitmap_new(length);
899 /* If we have no backing file yet in the destination, we cannot let
900 * the destination do COW. Instead, we copy sectors around the
901 * dirty data if needed. We need a bitmap to do that.
903 bdrv_get_backing_filename(target_bs, backing_filename,
904 sizeof(backing_filename));
905 if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) {
906 s->target_cluster_size = bdi.cluster_size;
907 } else {
908 s->target_cluster_size = BDRV_SECTOR_SIZE;
910 if (backing_filename[0] && !target_bs->backing &&
911 s->granularity < s->target_cluster_size) {
912 s->buf_size = MAX(s->buf_size, s->target_cluster_size);
913 s->cow_bitmap = bitmap_new(length);
915 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov);
917 s->buf = qemu_try_blockalign(bs, s->buf_size);
918 if (s->buf == NULL) {
919 ret = -ENOMEM;
920 goto immediate_exit;
923 mirror_free_init(s);
925 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
926 if (!s->is_none_mode) {
927 ret = mirror_dirty_init(s);
928 if (ret < 0 || job_is_cancelled(&s->common.job)) {
929 goto immediate_exit;
933 assert(!s->dbi);
934 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap);
935 for (;;) {
936 uint64_t delay_ns = 0;
937 int64_t cnt, delta;
938 bool should_complete;
940 /* Do not start passive operations while there are active
941 * writes in progress */
942 while (s->in_active_write_counter) {
943 mirror_wait_for_any_operation(s, true);
946 if (s->ret < 0) {
947 ret = s->ret;
948 goto immediate_exit;
951 job_pause_point(&s->common.job);
953 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
954 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
955 * the number of bytes currently being processed; together those are
956 * the current remaining operation length */
957 job_progress_set_remaining(&s->common.job, s->bytes_in_flight + cnt);
959 /* Note that even when no rate limit is applied we need to yield
960 * periodically with no pending I/O so that bdrv_drain_all() returns.
961 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
962 * an error, or when the source is clean, whichever comes first. */
963 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
964 if (delta < BLOCK_JOB_SLICE_TIME &&
965 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
966 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
967 (cnt == 0 && s->in_flight > 0)) {
968 trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
969 mirror_wait_for_free_in_flight_slot(s);
970 continue;
971 } else if (cnt != 0) {
972 delay_ns = mirror_iteration(s);
976 should_complete = false;
977 if (s->in_flight == 0 && cnt == 0) {
978 trace_mirror_before_flush(s);
979 if (!s->synced) {
980 if (mirror_flush(s) < 0) {
981 /* Go check s->ret. */
982 continue;
984 /* We're out of the streaming phase. From now on, if the job
985 * is cancelled we will actually complete all pending I/O and
986 * report completion. This way, block-job-cancel will leave
987 * the target in a consistent state.
989 job_transition_to_ready(&s->common.job);
990 s->synced = true;
991 if (s->copy_mode != MIRROR_COPY_MODE_BACKGROUND) {
992 s->actively_synced = true;
996 should_complete = s->should_complete ||
997 job_is_cancelled(&s->common.job);
998 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
1001 if (cnt == 0 && should_complete) {
1002 /* The dirty bitmap is not updated while operations are pending.
1003 * If we're about to exit, wait for pending operations before
1004 * calling bdrv_get_dirty_count(bs), or we may exit while the
1005 * source has dirty data to copy!
1007 * Note that I/O can be submitted by the guest while
1008 * mirror_populate runs, so pause it now. Before deciding
1009 * whether to switch to target check one last time if I/O has
1010 * come in the meanwhile, and if not flush the data to disk.
1012 trace_mirror_before_drain(s, cnt);
1014 s->in_drain = true;
1015 bdrv_drained_begin(bs);
1016 cnt = bdrv_get_dirty_count(s->dirty_bitmap);
1017 if (cnt > 0 || mirror_flush(s) < 0) {
1018 bdrv_drained_end(bs);
1019 s->in_drain = false;
1020 continue;
1023 /* The two disks are in sync. Exit and report successful
1024 * completion.
1026 assert(QLIST_EMPTY(&bs->tracked_requests));
1027 s->common.job.cancelled = false;
1028 need_drain = false;
1029 break;
1032 ret = 0;
1034 if (s->synced && !should_complete) {
1035 delay_ns = (s->in_flight == 0 &&
1036 cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0);
1038 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
1039 job_sleep_ns(&s->common.job, delay_ns);
1040 if (job_is_cancelled(&s->common.job) &&
1041 (!s->synced || s->common.job.force_cancel))
1043 break;
1045 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
1048 immediate_exit:
1049 if (s->in_flight > 0) {
1050 /* We get here only if something went wrong. Either the job failed,
1051 * or it was cancelled prematurely so that we do not guarantee that
1052 * the target is a copy of the source.
1054 assert(ret < 0 || ((s->common.job.force_cancel || !s->synced) &&
1055 job_is_cancelled(&s->common.job)));
1056 assert(need_drain);
1057 mirror_wait_for_all_io(s);
1060 assert(s->in_flight == 0);
1061 qemu_vfree(s->buf);
1062 g_free(s->cow_bitmap);
1063 g_free(s->in_flight_bitmap);
1064 bdrv_dirty_iter_free(s->dbi);
1066 if (need_drain) {
1067 s->in_drain = true;
1068 bdrv_drained_begin(bs);
1071 return ret;
1074 static void mirror_complete(Job *job, Error **errp)
1076 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
1077 BlockDriverState *target;
1079 target = blk_bs(s->target);
1081 if (!s->synced) {
1082 error_setg(errp, "The active block job '%s' cannot be completed",
1083 job->id);
1084 return;
1087 if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) {
1088 int ret;
1090 assert(!target->backing);
1091 ret = bdrv_open_backing_file(target, NULL, "backing", errp);
1092 if (ret < 0) {
1093 return;
1097 /* block all operations on to_replace bs */
1098 if (s->replaces) {
1099 AioContext *replace_aio_context;
1101 s->to_replace = bdrv_find_node(s->replaces);
1102 if (!s->to_replace) {
1103 error_setg(errp, "Node name '%s' not found", s->replaces);
1104 return;
1107 replace_aio_context = bdrv_get_aio_context(s->to_replace);
1108 aio_context_acquire(replace_aio_context);
1110 /* TODO Translate this into permission system. Current definition of
1111 * GRAPH_MOD would require to request it for the parents; they might
1112 * not even be BlockDriverStates, however, so a BdrvChild can't address
1113 * them. May need redefinition of GRAPH_MOD. */
1114 error_setg(&s->replace_blocker,
1115 "block device is in use by block-job-complete");
1116 bdrv_op_block_all(s->to_replace, s->replace_blocker);
1117 bdrv_ref(s->to_replace);
1119 aio_context_release(replace_aio_context);
1122 s->should_complete = true;
1123 job_enter(job);
1126 static void coroutine_fn mirror_pause(Job *job)
1128 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
1130 mirror_wait_for_all_io(s);
1133 static bool mirror_drained_poll(BlockJob *job)
1135 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
1137 /* If the job isn't paused nor cancelled, we can't be sure that it won't
1138 * issue more requests. We make an exception if we've reached this point
1139 * from one of our own drain sections, to avoid a deadlock waiting for
1140 * ourselves.
1142 if (!s->common.job.paused && !s->common.job.cancelled && !s->in_drain) {
1143 return true;
1146 return !!s->in_flight;
1149 static const BlockJobDriver mirror_job_driver = {
1150 .job_driver = {
1151 .instance_size = sizeof(MirrorBlockJob),
1152 .job_type = JOB_TYPE_MIRROR,
1153 .free = block_job_free,
1154 .user_resume = block_job_user_resume,
1155 .run = mirror_run,
1156 .prepare = mirror_prepare,
1157 .abort = mirror_abort,
1158 .pause = mirror_pause,
1159 .complete = mirror_complete,
1161 .drained_poll = mirror_drained_poll,
1164 static const BlockJobDriver commit_active_job_driver = {
1165 .job_driver = {
1166 .instance_size = sizeof(MirrorBlockJob),
1167 .job_type = JOB_TYPE_COMMIT,
1168 .free = block_job_free,
1169 .user_resume = block_job_user_resume,
1170 .run = mirror_run,
1171 .prepare = mirror_prepare,
1172 .abort = mirror_abort,
1173 .pause = mirror_pause,
1174 .complete = mirror_complete,
1176 .drained_poll = mirror_drained_poll,
1179 static void coroutine_fn
1180 do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
1181 uint64_t offset, uint64_t bytes,
1182 QEMUIOVector *qiov, int flags)
1184 QEMUIOVector target_qiov;
1185 uint64_t dirty_offset = offset;
1186 uint64_t dirty_bytes;
1188 if (qiov) {
1189 qemu_iovec_init(&target_qiov, qiov->niov);
1192 while (true) {
1193 bool valid_area;
1194 int ret;
1196 bdrv_dirty_bitmap_lock(job->dirty_bitmap);
1197 dirty_bytes = MIN(offset + bytes - dirty_offset, INT_MAX);
1198 valid_area = bdrv_dirty_bitmap_next_dirty_area(job->dirty_bitmap,
1199 &dirty_offset,
1200 &dirty_bytes);
1201 if (!valid_area) {
1202 bdrv_dirty_bitmap_unlock(job->dirty_bitmap);
1203 break;
1206 bdrv_reset_dirty_bitmap_locked(job->dirty_bitmap,
1207 dirty_offset, dirty_bytes);
1208 bdrv_dirty_bitmap_unlock(job->dirty_bitmap);
1210 job_progress_increase_remaining(&job->common.job, dirty_bytes);
1212 assert(dirty_offset - offset <= SIZE_MAX);
1213 if (qiov) {
1214 qemu_iovec_reset(&target_qiov);
1215 qemu_iovec_concat(&target_qiov, qiov,
1216 dirty_offset - offset, dirty_bytes);
1219 switch (method) {
1220 case MIRROR_METHOD_COPY:
1221 ret = blk_co_pwritev(job->target, dirty_offset, dirty_bytes,
1222 qiov ? &target_qiov : NULL, flags);
1223 break;
1225 case MIRROR_METHOD_ZERO:
1226 assert(!qiov);
1227 ret = blk_co_pwrite_zeroes(job->target, dirty_offset, dirty_bytes,
1228 flags);
1229 break;
1231 case MIRROR_METHOD_DISCARD:
1232 assert(!qiov);
1233 ret = blk_co_pdiscard(job->target, dirty_offset, dirty_bytes);
1234 break;
1236 default:
1237 abort();
1240 if (ret >= 0) {
1241 job_progress_update(&job->common.job, dirty_bytes);
1242 } else {
1243 BlockErrorAction action;
1245 bdrv_set_dirty_bitmap(job->dirty_bitmap, dirty_offset, dirty_bytes);
1246 job->actively_synced = false;
1248 action = mirror_error_action(job, false, -ret);
1249 if (action == BLOCK_ERROR_ACTION_REPORT) {
1250 if (!job->ret) {
1251 job->ret = ret;
1253 break;
1257 dirty_offset += dirty_bytes;
1260 if (qiov) {
1261 qemu_iovec_destroy(&target_qiov);
1265 static MirrorOp *coroutine_fn active_write_prepare(MirrorBlockJob *s,
1266 uint64_t offset,
1267 uint64_t bytes)
1269 MirrorOp *op;
1270 uint64_t start_chunk = offset / s->granularity;
1271 uint64_t end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity);
1273 op = g_new(MirrorOp, 1);
1274 *op = (MirrorOp){
1275 .s = s,
1276 .offset = offset,
1277 .bytes = bytes,
1278 .is_active_write = true,
1280 qemu_co_queue_init(&op->waiting_requests);
1281 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next);
1283 s->in_active_write_counter++;
1285 mirror_wait_on_conflicts(op, s, offset, bytes);
1287 bitmap_set(s->in_flight_bitmap, start_chunk, end_chunk - start_chunk);
1289 return op;
1292 static void coroutine_fn active_write_settle(MirrorOp *op)
1294 uint64_t start_chunk = op->offset / op->s->granularity;
1295 uint64_t end_chunk = DIV_ROUND_UP(op->offset + op->bytes,
1296 op->s->granularity);
1298 if (!--op->s->in_active_write_counter && op->s->actively_synced) {
1299 BdrvChild *source = op->s->mirror_top_bs->backing;
1301 if (QLIST_FIRST(&source->bs->parents) == source &&
1302 QLIST_NEXT(source, next_parent) == NULL)
1304 /* Assert that we are back in sync once all active write
1305 * operations are settled.
1306 * Note that we can only assert this if the mirror node
1307 * is the source node's only parent. */
1308 assert(!bdrv_get_dirty_count(op->s->dirty_bitmap));
1311 bitmap_clear(op->s->in_flight_bitmap, start_chunk, end_chunk - start_chunk);
1312 QTAILQ_REMOVE(&op->s->ops_in_flight, op, next);
1313 qemu_co_queue_restart_all(&op->waiting_requests);
1314 g_free(op);
1317 static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs,
1318 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
1320 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
1323 static int coroutine_fn bdrv_mirror_top_do_write(BlockDriverState *bs,
1324 MirrorMethod method, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
1325 int flags)
1327 MirrorOp *op = NULL;
1328 MirrorBDSOpaque *s = bs->opaque;
1329 int ret = 0;
1330 bool copy_to_target;
1332 copy_to_target = s->job->ret >= 0 &&
1333 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
1335 if (copy_to_target) {
1336 op = active_write_prepare(s->job, offset, bytes);
1339 switch (method) {
1340 case MIRROR_METHOD_COPY:
1341 ret = bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
1342 break;
1344 case MIRROR_METHOD_ZERO:
1345 ret = bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags);
1346 break;
1348 case MIRROR_METHOD_DISCARD:
1349 ret = bdrv_co_pdiscard(bs->backing, offset, bytes);
1350 break;
1352 default:
1353 abort();
1356 if (ret < 0) {
1357 goto out;
1360 if (copy_to_target) {
1361 do_sync_target_write(s->job, method, offset, bytes, qiov, flags);
1364 out:
1365 if (copy_to_target) {
1366 active_write_settle(op);
1368 return ret;
1371 static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
1372 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
1374 MirrorBDSOpaque *s = bs->opaque;
1375 QEMUIOVector bounce_qiov;
1376 void *bounce_buf;
1377 int ret = 0;
1378 bool copy_to_target;
1380 copy_to_target = s->job->ret >= 0 &&
1381 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
1383 if (copy_to_target) {
1384 /* The guest might concurrently modify the data to write; but
1385 * the data on source and destination must match, so we have
1386 * to use a bounce buffer if we are going to write to the
1387 * target now. */
1388 bounce_buf = qemu_blockalign(bs, bytes);
1389 iov_to_buf_full(qiov->iov, qiov->niov, 0, bounce_buf, bytes);
1391 qemu_iovec_init(&bounce_qiov, 1);
1392 qemu_iovec_add(&bounce_qiov, bounce_buf, bytes);
1393 qiov = &bounce_qiov;
1396 ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov,
1397 flags);
1399 if (copy_to_target) {
1400 qemu_iovec_destroy(&bounce_qiov);
1401 qemu_vfree(bounce_buf);
1404 return ret;
1407 static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs)
1409 if (bs->backing == NULL) {
1410 /* we can be here after failed bdrv_append in mirror_start_job */
1411 return 0;
1413 return bdrv_co_flush(bs->backing->bs);
1416 static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs,
1417 int64_t offset, int bytes, BdrvRequestFlags flags)
1419 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, offset, bytes, NULL,
1420 flags);
1423 static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs,
1424 int64_t offset, int bytes)
1426 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, offset, bytes,
1427 NULL, 0);
1430 static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)
1432 if (bs->backing == NULL) {
1433 /* we can be here after failed bdrv_attach_child in
1434 * bdrv_set_backing_hd */
1435 return;
1437 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
1438 bs->backing->bs->filename);
1441 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
1442 const BdrvChildRole *role,
1443 BlockReopenQueue *reopen_queue,
1444 uint64_t perm, uint64_t shared,
1445 uint64_t *nperm, uint64_t *nshared)
1447 MirrorBDSOpaque *s = bs->opaque;
1449 if (s->stop) {
1451 * If the job is to be stopped, we do not need to forward
1452 * anything to the real image.
1454 *nperm = 0;
1455 *nshared = BLK_PERM_ALL;
1456 return;
1459 /* Must be able to forward guest writes to the real image */
1460 *nperm = 0;
1461 if (perm & BLK_PERM_WRITE) {
1462 *nperm |= BLK_PERM_WRITE;
1465 *nshared = BLK_PERM_ALL;
1468 static void bdrv_mirror_top_refresh_limits(BlockDriverState *bs, Error **errp)
1470 MirrorBDSOpaque *s = bs->opaque;
1472 if (s && s->job && s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING) {
1473 bs->bl.request_alignment = s->job->granularity;
1477 /* Dummy node that provides consistent read to its users without requiring it
1478 * from its backing file and that allows writes on the backing file chain. */
1479 static BlockDriver bdrv_mirror_top = {
1480 .format_name = "mirror_top",
1481 .bdrv_co_preadv = bdrv_mirror_top_preadv,
1482 .bdrv_co_pwritev = bdrv_mirror_top_pwritev,
1483 .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes,
1484 .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard,
1485 .bdrv_co_flush = bdrv_mirror_top_flush,
1486 .bdrv_co_block_status = bdrv_co_block_status_from_backing,
1487 .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename,
1488 .bdrv_child_perm = bdrv_mirror_top_child_perm,
1489 .bdrv_refresh_limits = bdrv_mirror_top_refresh_limits,
1492 static BlockJob *mirror_start_job(
1493 const char *job_id, BlockDriverState *bs,
1494 int creation_flags, BlockDriverState *target,
1495 const char *replaces, int64_t speed,
1496 uint32_t granularity, int64_t buf_size,
1497 BlockMirrorBackingMode backing_mode,
1498 bool zero_target,
1499 BlockdevOnError on_source_error,
1500 BlockdevOnError on_target_error,
1501 bool unmap,
1502 BlockCompletionFunc *cb,
1503 void *opaque,
1504 const BlockJobDriver *driver,
1505 bool is_none_mode, BlockDriverState *base,
1506 bool auto_complete, const char *filter_node_name,
1507 bool is_mirror, MirrorCopyMode copy_mode,
1508 Error **errp)
1510 MirrorBlockJob *s;
1511 MirrorBDSOpaque *bs_opaque;
1512 BlockDriverState *mirror_top_bs;
1513 bool target_graph_mod;
1514 bool target_is_backing;
1515 Error *local_err = NULL;
1516 int ret;
1518 if (granularity == 0) {
1519 granularity = bdrv_get_default_bitmap_granularity(target);
1522 assert(is_power_of_2(granularity));
1524 if (buf_size < 0) {
1525 error_setg(errp, "Invalid parameter 'buf-size'");
1526 return NULL;
1529 if (buf_size == 0) {
1530 buf_size = DEFAULT_MIRROR_BUF_SIZE;
1533 if (bs == target) {
1534 error_setg(errp, "Can't mirror node into itself");
1535 return NULL;
1538 /* In the case of active commit, add dummy driver to provide consistent
1539 * reads on the top, while disabling it in the intermediate nodes, and make
1540 * the backing chain writable. */
1541 mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name,
1542 BDRV_O_RDWR, errp);
1543 if (mirror_top_bs == NULL) {
1544 return NULL;
1546 if (!filter_node_name) {
1547 mirror_top_bs->implicit = true;
1550 /* So that we can always drop this node */
1551 mirror_top_bs->never_freeze = true;
1553 mirror_top_bs->total_sectors = bs->total_sectors;
1554 mirror_top_bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED;
1555 mirror_top_bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
1556 BDRV_REQ_NO_FALLBACK;
1557 bs_opaque = g_new0(MirrorBDSOpaque, 1);
1558 mirror_top_bs->opaque = bs_opaque;
1560 /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep
1561 * it alive until block_job_create() succeeds even if bs has no parent. */
1562 bdrv_ref(mirror_top_bs);
1563 bdrv_drained_begin(bs);
1564 bdrv_append(mirror_top_bs, bs, &local_err);
1565 bdrv_drained_end(bs);
1567 if (local_err) {
1568 bdrv_unref(mirror_top_bs);
1569 error_propagate(errp, local_err);
1570 return NULL;
1573 /* Make sure that the source is not resized while the job is running */
1574 s = block_job_create(job_id, driver, NULL, mirror_top_bs,
1575 BLK_PERM_CONSISTENT_READ,
1576 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1577 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD, speed,
1578 creation_flags, cb, opaque, errp);
1579 if (!s) {
1580 goto fail;
1582 bs_opaque->job = s;
1584 /* The block job now has a reference to this node */
1585 bdrv_unref(mirror_top_bs);
1587 s->mirror_top_bs = mirror_top_bs;
1589 /* No resize for the target either; while the mirror is still running, a
1590 * consistent read isn't necessarily possible. We could possibly allow
1591 * writes and graph modifications, though it would likely defeat the
1592 * purpose of a mirror, so leave them blocked for now.
1594 * In the case of active commit, things look a bit different, though,
1595 * because the target is an already populated backing file in active use.
1596 * We can allow anything except resize there.*/
1597 target_is_backing = bdrv_chain_contains(bs, target);
1598 target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN);
1599 s->target = blk_new(s->common.job.aio_context,
1600 BLK_PERM_WRITE | BLK_PERM_RESIZE |
1601 (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0),
1602 BLK_PERM_WRITE_UNCHANGED |
1603 (target_is_backing ? BLK_PERM_CONSISTENT_READ |
1604 BLK_PERM_WRITE |
1605 BLK_PERM_GRAPH_MOD : 0));
1606 ret = blk_insert_bs(s->target, target, errp);
1607 if (ret < 0) {
1608 goto fail;
1610 if (is_mirror) {
1611 /* XXX: Mirror target could be a NBD server of target QEMU in the case
1612 * of non-shared block migration. To allow migration completion, we
1613 * have to allow "inactivate" of the target BB. When that happens, we
1614 * know the job is drained, and the vcpus are stopped, so no write
1615 * operation will be performed. Block layer already has assertions to
1616 * ensure that. */
1617 blk_set_force_allow_inactivate(s->target);
1619 blk_set_allow_aio_context_change(s->target, true);
1620 blk_set_disable_request_queuing(s->target, true);
1622 s->replaces = g_strdup(replaces);
1623 s->on_source_error = on_source_error;
1624 s->on_target_error = on_target_error;
1625 s->is_none_mode = is_none_mode;
1626 s->backing_mode = backing_mode;
1627 s->zero_target = zero_target;
1628 s->copy_mode = copy_mode;
1629 s->base = base;
1630 s->granularity = granularity;
1631 s->buf_size = ROUND_UP(buf_size, granularity);
1632 s->unmap = unmap;
1633 if (auto_complete) {
1634 s->should_complete = true;
1638 * Must be called before we start tracking writes, but after
1640 * ((MirrorBlockJob *)
1641 * ((MirrorBDSOpaque *)
1642 * mirror_top_bs->opaque
1643 * )->job
1644 * )->copy_mode
1646 * has the correct value.
1647 * (We start tracking writes as of the following
1648 * bdrv_create_dirty_bitmap() call.)
1650 bdrv_refresh_limits(mirror_top_bs, &local_err);
1651 if (local_err) {
1652 error_propagate(errp, local_err);
1653 goto fail;
1656 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
1657 if (!s->dirty_bitmap) {
1658 goto fail;
1661 ret = block_job_add_bdrv(&s->common, "source", bs, 0,
1662 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE |
1663 BLK_PERM_CONSISTENT_READ,
1664 errp);
1665 if (ret < 0) {
1666 goto fail;
1669 /* Required permissions are already taken with blk_new() */
1670 block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL,
1671 &error_abort);
1673 /* In commit_active_start() all intermediate nodes disappear, so
1674 * any jobs in them must be blocked */
1675 if (target_is_backing) {
1676 BlockDriverState *iter;
1677 for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) {
1678 /* XXX BLK_PERM_WRITE needs to be allowed so we don't block
1679 * ourselves at s->base (if writes are blocked for a node, they are
1680 * also blocked for its backing file). The other options would be a
1681 * second filter driver above s->base (== target). */
1682 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
1683 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
1684 errp);
1685 if (ret < 0) {
1686 goto fail;
1690 if (bdrv_freeze_backing_chain(mirror_top_bs, target, errp) < 0) {
1691 goto fail;
1695 QTAILQ_INIT(&s->ops_in_flight);
1697 trace_mirror_start(bs, s, opaque);
1698 job_start(&s->common.job);
1700 return &s->common;
1702 fail:
1703 if (s) {
1704 /* Make sure this BDS does not go away until we have completed the graph
1705 * changes below */
1706 bdrv_ref(mirror_top_bs);
1708 g_free(s->replaces);
1709 blk_unref(s->target);
1710 bs_opaque->job = NULL;
1711 if (s->dirty_bitmap) {
1712 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
1714 job_early_fail(&s->common.job);
1717 bs_opaque->stop = true;
1718 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
1719 &error_abort);
1720 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);
1722 bdrv_unref(mirror_top_bs);
1724 return NULL;
1727 void mirror_start(const char *job_id, BlockDriverState *bs,
1728 BlockDriverState *target, const char *replaces,
1729 int creation_flags, int64_t speed,
1730 uint32_t granularity, int64_t buf_size,
1731 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
1732 bool zero_target,
1733 BlockdevOnError on_source_error,
1734 BlockdevOnError on_target_error,
1735 bool unmap, const char *filter_node_name,
1736 MirrorCopyMode copy_mode, Error **errp)
1738 bool is_none_mode;
1739 BlockDriverState *base;
1741 if ((mode == MIRROR_SYNC_MODE_INCREMENTAL) ||
1742 (mode == MIRROR_SYNC_MODE_BITMAP)) {
1743 error_setg(errp, "Sync mode '%s' not supported",
1744 MirrorSyncMode_str(mode));
1745 return;
1747 is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
1748 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL;
1749 mirror_start_job(job_id, bs, creation_flags, target, replaces,
1750 speed, granularity, buf_size, backing_mode, zero_target,
1751 on_source_error, on_target_error, unmap, NULL, NULL,
1752 &mirror_job_driver, is_none_mode, base, false,
1753 filter_node_name, true, copy_mode, errp);
1756 BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs,
1757 BlockDriverState *base, int creation_flags,
1758 int64_t speed, BlockdevOnError on_error,
1759 const char *filter_node_name,
1760 BlockCompletionFunc *cb, void *opaque,
1761 bool auto_complete, Error **errp)
1763 bool base_read_only;
1764 Error *local_err = NULL;
1765 BlockJob *ret;
1767 base_read_only = bdrv_is_read_only(base);
1769 if (base_read_only) {
1770 if (bdrv_reopen_set_read_only(base, false, errp) < 0) {
1771 return NULL;
1775 ret = mirror_start_job(
1776 job_id, bs, creation_flags, base, NULL, speed, 0, 0,
1777 MIRROR_LEAVE_BACKING_CHAIN, false,
1778 on_error, on_error, true, cb, opaque,
1779 &commit_active_job_driver, false, base, auto_complete,
1780 filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND,
1781 &local_err);
1782 if (local_err) {
1783 error_propagate(errp, local_err);
1784 goto error_restore_flags;
1787 return ret;
1789 error_restore_flags:
1790 /* ignore error and errp for bdrv_reopen, because we want to propagate
1791 * the original error */
1792 if (base_read_only) {
1793 bdrv_reopen_set_read_only(base, true, NULL);
1795 return NULL;