4 * Copyright Red Hat, Inc. 2012
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"
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
;
38 typedef struct MirrorOp MirrorOp
;
40 typedef struct MirrorBlockJob
{
43 BlockDriverState
*mirror_top_bs
;
44 BlockDriverState
*base
;
46 /* The name of the graph node to replace */
48 /* The BDS to replace */
49 BlockDriverState
*to_replace
;
50 /* Used to block operations on the drive-mirror-replace target */
51 Error
*replace_blocker
;
53 BlockMirrorBackingMode backing_mode
;
54 MirrorCopyMode copy_mode
;
55 BlockdevOnError on_source_error
, on_target_error
;
57 /* Set when the target is synced (dirty bitmap is clean, nothing
58 * in flight) and the job is running in active mode */
64 unsigned long *cow_bitmap
;
65 BdrvDirtyBitmap
*dirty_bitmap
;
66 BdrvDirtyBitmapIter
*dbi
;
68 QSIMPLEQ_HEAD(, MirrorBuffer
) buf_free
;
71 uint64_t last_pause_ns
;
72 unsigned long *in_flight_bitmap
;
74 int64_t bytes_in_flight
;
75 QTAILQ_HEAD(MirrorOpList
, MirrorOp
) ops_in_flight
;
78 int target_cluster_size
;
80 bool initial_zeroing_ongoing
;
81 int in_active_write_counter
;
84 typedef struct MirrorBDSOpaque
{
94 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and
95 * mirror_co_discard() before yielding for the first time */
96 int64_t *bytes_handled
;
100 CoQueue waiting_requests
;
102 QTAILQ_ENTRY(MirrorOp
) next
;
105 typedef enum MirrorMethod
{
108 MIRROR_METHOD_DISCARD
,
111 static BlockErrorAction
mirror_error_action(MirrorBlockJob
*s
, bool read
,
115 s
->actively_synced
= false;
117 return block_job_error_action(&s
->common
, s
->on_source_error
,
120 return block_job_error_action(&s
->common
, s
->on_target_error
,
125 static void coroutine_fn
mirror_wait_on_conflicts(MirrorOp
*self
,
130 uint64_t self_start_chunk
= offset
/ s
->granularity
;
131 uint64_t self_end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
132 uint64_t self_nb_chunks
= self_end_chunk
- self_start_chunk
;
134 while (find_next_bit(s
->in_flight_bitmap
, self_end_chunk
,
135 self_start_chunk
) < self_end_chunk
&&
140 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
141 uint64_t op_start_chunk
= op
->offset
/ s
->granularity
;
142 uint64_t op_nb_chunks
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
150 if (ranges_overlap(self_start_chunk
, self_nb_chunks
,
151 op_start_chunk
, op_nb_chunks
))
153 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
160 static void coroutine_fn
mirror_iteration_done(MirrorOp
*op
, int ret
)
162 MirrorBlockJob
*s
= op
->s
;
167 trace_mirror_iteration_done(s
, op
->offset
, op
->bytes
, ret
);
170 s
->bytes_in_flight
-= op
->bytes
;
172 for (i
= 0; i
< op
->qiov
.niov
; i
++) {
173 MirrorBuffer
*buf
= (MirrorBuffer
*) iov
[i
].iov_base
;
174 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, buf
, next
);
178 chunk_num
= op
->offset
/ s
->granularity
;
179 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
181 bitmap_clear(s
->in_flight_bitmap
, chunk_num
, nb_chunks
);
182 QTAILQ_REMOVE(&s
->ops_in_flight
, op
, next
);
185 bitmap_set(s
->cow_bitmap
, chunk_num
, nb_chunks
);
187 if (!s
->initial_zeroing_ongoing
) {
188 job_progress_update(&s
->common
.job
, op
->bytes
);
191 qemu_iovec_destroy(&op
->qiov
);
193 qemu_co_queue_restart_all(&op
->waiting_requests
);
197 static void coroutine_fn
mirror_write_complete(MirrorOp
*op
, int ret
)
199 MirrorBlockJob
*s
= op
->s
;
201 aio_context_acquire(blk_get_aio_context(s
->common
.blk
));
203 BlockErrorAction action
;
205 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
206 action
= mirror_error_action(s
, false, -ret
);
207 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
211 mirror_iteration_done(op
, ret
);
212 aio_context_release(blk_get_aio_context(s
->common
.blk
));
215 static void coroutine_fn
mirror_read_complete(MirrorOp
*op
, int ret
)
217 MirrorBlockJob
*s
= op
->s
;
219 aio_context_acquire(blk_get_aio_context(s
->common
.blk
));
221 BlockErrorAction action
;
223 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
224 action
= mirror_error_action(s
, true, -ret
);
225 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
229 mirror_iteration_done(op
, ret
);
231 ret
= blk_co_pwritev(s
->target
, op
->offset
,
232 op
->qiov
.size
, &op
->qiov
, 0);
233 mirror_write_complete(op
, ret
);
235 aio_context_release(blk_get_aio_context(s
->common
.blk
));
238 /* Clip bytes relative to offset to not exceed end-of-file */
239 static inline int64_t mirror_clip_bytes(MirrorBlockJob
*s
,
243 return MIN(bytes
, s
->bdev_length
- offset
);
246 /* Round offset and/or bytes to target cluster if COW is needed, and
247 * return the offset of the adjusted tail against original. */
248 static int mirror_cow_align(MirrorBlockJob
*s
, int64_t *offset
,
253 int64_t align_offset
= *offset
;
254 int64_t align_bytes
= *bytes
;
255 int max_bytes
= s
->granularity
* s
->max_iov
;
257 need_cow
= !test_bit(*offset
/ s
->granularity
, s
->cow_bitmap
);
258 need_cow
|= !test_bit((*offset
+ *bytes
- 1) / s
->granularity
,
261 bdrv_round_to_clusters(blk_bs(s
->target
), *offset
, *bytes
,
262 &align_offset
, &align_bytes
);
265 if (align_bytes
> max_bytes
) {
266 align_bytes
= max_bytes
;
268 align_bytes
= QEMU_ALIGN_DOWN(align_bytes
, s
->target_cluster_size
);
271 /* Clipping may result in align_bytes unaligned to chunk boundary, but
272 * that doesn't matter because it's already the end of source image. */
273 align_bytes
= mirror_clip_bytes(s
, align_offset
, align_bytes
);
275 ret
= align_offset
+ align_bytes
- (*offset
+ *bytes
);
276 *offset
= align_offset
;
277 *bytes
= align_bytes
;
282 static inline void mirror_wait_for_any_operation(MirrorBlockJob
*s
, bool active
)
286 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
287 /* Do not wait on pseudo ops, because it may in turn wait on
288 * some other operation to start, which may in fact be the
289 * caller of this function. Since there is only one pseudo op
290 * at any given time, we will always find some real operation
292 if (!op
->is_pseudo_op
&& op
->is_active_write
== active
) {
293 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
300 static inline void mirror_wait_for_free_in_flight_slot(MirrorBlockJob
*s
)
302 /* Only non-active operations use up in-flight slots */
303 mirror_wait_for_any_operation(s
, false);
306 /* Perform a mirror copy operation.
308 * *op->bytes_handled is set to the number of bytes copied after and
309 * including offset, excluding any bytes copied prior to offset due
310 * to alignment. This will be op->bytes if no alignment is necessary,
311 * or (new_end - op->offset) if the tail is rounded up or down due to
312 * alignment or buffer limit.
314 static void coroutine_fn
mirror_co_read(void *opaque
)
316 MirrorOp
*op
= opaque
;
317 MirrorBlockJob
*s
= op
->s
;
322 max_bytes
= s
->granularity
* s
->max_iov
;
324 /* We can only handle as much as buf_size at a time. */
325 op
->bytes
= MIN(s
->buf_size
, MIN(max_bytes
, op
->bytes
));
327 assert(op
->bytes
< BDRV_REQUEST_MAX_BYTES
);
328 *op
->bytes_handled
= op
->bytes
;
331 *op
->bytes_handled
+= mirror_cow_align(s
, &op
->offset
, &op
->bytes
);
333 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
334 assert(*op
->bytes_handled
<= UINT_MAX
);
335 assert(op
->bytes
<= s
->buf_size
);
336 /* The offset is granularity-aligned because:
337 * 1) Caller passes in aligned values;
338 * 2) mirror_cow_align is used only when target cluster is larger. */
339 assert(QEMU_IS_ALIGNED(op
->offset
, s
->granularity
));
340 /* The range is sector-aligned, since bdrv_getlength() rounds up. */
341 assert(QEMU_IS_ALIGNED(op
->bytes
, BDRV_SECTOR_SIZE
));
342 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
344 while (s
->buf_free_count
< nb_chunks
) {
345 trace_mirror_yield_in_flight(s
, op
->offset
, s
->in_flight
);
346 mirror_wait_for_free_in_flight_slot(s
);
349 /* Now make a QEMUIOVector taking enough granularity-sized chunks
352 qemu_iovec_init(&op
->qiov
, nb_chunks
);
353 while (nb_chunks
-- > 0) {
354 MirrorBuffer
*buf
= QSIMPLEQ_FIRST(&s
->buf_free
);
355 size_t remaining
= op
->bytes
- op
->qiov
.size
;
357 QSIMPLEQ_REMOVE_HEAD(&s
->buf_free
, next
);
359 qemu_iovec_add(&op
->qiov
, buf
, MIN(s
->granularity
, remaining
));
362 /* Copy the dirty cluster. */
364 s
->bytes_in_flight
+= op
->bytes
;
365 trace_mirror_one_iteration(s
, op
->offset
, op
->bytes
);
367 ret
= bdrv_co_preadv(s
->mirror_top_bs
->backing
, op
->offset
, op
->bytes
,
369 mirror_read_complete(op
, ret
);
372 static void coroutine_fn
mirror_co_zero(void *opaque
)
374 MirrorOp
*op
= opaque
;
378 op
->s
->bytes_in_flight
+= op
->bytes
;
379 *op
->bytes_handled
= op
->bytes
;
381 ret
= blk_co_pwrite_zeroes(op
->s
->target
, op
->offset
, op
->bytes
,
382 op
->s
->unmap
? BDRV_REQ_MAY_UNMAP
: 0);
383 mirror_write_complete(op
, ret
);
386 static void coroutine_fn
mirror_co_discard(void *opaque
)
388 MirrorOp
*op
= opaque
;
392 op
->s
->bytes_in_flight
+= op
->bytes
;
393 *op
->bytes_handled
= op
->bytes
;
395 ret
= blk_co_pdiscard(op
->s
->target
, op
->offset
, op
->bytes
);
396 mirror_write_complete(op
, ret
);
399 static unsigned mirror_perform(MirrorBlockJob
*s
, int64_t offset
,
400 unsigned bytes
, MirrorMethod mirror_method
)
404 int64_t bytes_handled
= -1;
406 op
= g_new(MirrorOp
, 1);
411 .bytes_handled
= &bytes_handled
,
413 qemu_co_queue_init(&op
->waiting_requests
);
415 switch (mirror_method
) {
416 case MIRROR_METHOD_COPY
:
417 co
= qemu_coroutine_create(mirror_co_read
, op
);
419 case MIRROR_METHOD_ZERO
:
420 co
= qemu_coroutine_create(mirror_co_zero
, op
);
422 case MIRROR_METHOD_DISCARD
:
423 co
= qemu_coroutine_create(mirror_co_discard
, op
);
429 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
430 qemu_coroutine_enter(co
);
431 /* At this point, ownership of op has been moved to the coroutine
432 * and the object may already be freed */
434 /* Assert that this value has been set */
435 assert(bytes_handled
>= 0);
437 /* Same assertion as in mirror_co_read() (and for mirror_co_read()
438 * and mirror_co_discard(), bytes_handled == op->bytes, which
439 * is the @bytes parameter given to this function) */
440 assert(bytes_handled
<= UINT_MAX
);
441 return bytes_handled
;
444 static uint64_t coroutine_fn
mirror_iteration(MirrorBlockJob
*s
)
446 BlockDriverState
*source
= s
->mirror_top_bs
->backing
->bs
;
449 uint64_t delay_ns
= 0, ret
= 0;
450 /* At least the first dirty chunk is mirrored in one iteration. */
452 bool write_zeroes_ok
= bdrv_can_write_zeroes_with_unmap(blk_bs(s
->target
));
453 int max_io_bytes
= MAX(s
->buf_size
/ MAX_IN_FLIGHT
, MAX_IO_BYTES
);
455 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
456 offset
= bdrv_dirty_iter_next(s
->dbi
);
458 bdrv_set_dirty_iter(s
->dbi
, 0);
459 offset
= bdrv_dirty_iter_next(s
->dbi
);
460 trace_mirror_restart_iter(s
, bdrv_get_dirty_count(s
->dirty_bitmap
));
463 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
465 mirror_wait_on_conflicts(NULL
, s
, offset
, 1);
467 job_pause_point(&s
->common
.job
);
469 /* Find the number of consective dirty chunks following the first dirty
470 * one, and wait for in flight requests in them. */
471 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
472 while (nb_chunks
* s
->granularity
< s
->buf_size
) {
474 int64_t next_offset
= offset
+ nb_chunks
* s
->granularity
;
475 int64_t next_chunk
= next_offset
/ s
->granularity
;
476 if (next_offset
>= s
->bdev_length
||
477 !bdrv_get_dirty_locked(source
, s
->dirty_bitmap
, next_offset
)) {
480 if (test_bit(next_chunk
, s
->in_flight_bitmap
)) {
484 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
485 if (next_dirty
> next_offset
|| next_dirty
< 0) {
486 /* The bitmap iterator's cache is stale, refresh it */
487 bdrv_set_dirty_iter(s
->dbi
, next_offset
);
488 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
490 assert(next_dirty
== next_offset
);
494 /* Clear dirty bits before querying the block status, because
495 * calling bdrv_block_status_above could yield - if some blocks are
496 * marked dirty in this window, we need to know.
498 bdrv_reset_dirty_bitmap_locked(s
->dirty_bitmap
, offset
,
499 nb_chunks
* s
->granularity
);
500 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
502 /* Before claiming an area in the in-flight bitmap, we have to
503 * create a MirrorOp for it so that conflicting requests can wait
504 * for it. mirror_perform() will create the real MirrorOps later,
505 * for now we just create a pseudo operation that will wake up all
506 * conflicting requests once all real operations have been
508 pseudo_op
= g_new(MirrorOp
, 1);
509 *pseudo_op
= (MirrorOp
){
511 .bytes
= nb_chunks
* s
->granularity
,
512 .is_pseudo_op
= true,
514 qemu_co_queue_init(&pseudo_op
->waiting_requests
);
515 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, pseudo_op
, next
);
517 bitmap_set(s
->in_flight_bitmap
, offset
/ s
->granularity
, nb_chunks
);
518 while (nb_chunks
> 0 && offset
< s
->bdev_length
) {
521 int64_t io_bytes_acct
;
522 MirrorMethod mirror_method
= MIRROR_METHOD_COPY
;
524 assert(!(offset
% s
->granularity
));
525 ret
= bdrv_block_status_above(source
, NULL
, offset
,
526 nb_chunks
* s
->granularity
,
527 &io_bytes
, NULL
, NULL
);
529 io_bytes
= MIN(nb_chunks
* s
->granularity
, max_io_bytes
);
530 } else if (ret
& BDRV_BLOCK_DATA
) {
531 io_bytes
= MIN(io_bytes
, max_io_bytes
);
534 io_bytes
-= io_bytes
% s
->granularity
;
535 if (io_bytes
< s
->granularity
) {
536 io_bytes
= s
->granularity
;
537 } else if (ret
>= 0 && !(ret
& BDRV_BLOCK_DATA
)) {
538 int64_t target_offset
;
539 int64_t target_bytes
;
540 bdrv_round_to_clusters(blk_bs(s
->target
), offset
, io_bytes
,
541 &target_offset
, &target_bytes
);
542 if (target_offset
== offset
&&
543 target_bytes
== io_bytes
) {
544 mirror_method
= ret
& BDRV_BLOCK_ZERO
?
546 MIRROR_METHOD_DISCARD
;
550 while (s
->in_flight
>= MAX_IN_FLIGHT
) {
551 trace_mirror_yield_in_flight(s
, offset
, s
->in_flight
);
552 mirror_wait_for_free_in_flight_slot(s
);
560 io_bytes
= mirror_clip_bytes(s
, offset
, io_bytes
);
561 io_bytes
= mirror_perform(s
, offset
, io_bytes
, mirror_method
);
562 if (mirror_method
!= MIRROR_METHOD_COPY
&& write_zeroes_ok
) {
565 io_bytes_acct
= io_bytes
;
569 nb_chunks
-= DIV_ROUND_UP(io_bytes
, s
->granularity
);
570 delay_ns
= block_job_ratelimit_get_delay(&s
->common
, io_bytes_acct
);
575 QTAILQ_REMOVE(&s
->ops_in_flight
, pseudo_op
, next
);
576 qemu_co_queue_restart_all(&pseudo_op
->waiting_requests
);
582 static void mirror_free_init(MirrorBlockJob
*s
)
584 int granularity
= s
->granularity
;
585 size_t buf_size
= s
->buf_size
;
586 uint8_t *buf
= s
->buf
;
588 assert(s
->buf_free_count
== 0);
589 QSIMPLEQ_INIT(&s
->buf_free
);
590 while (buf_size
!= 0) {
591 MirrorBuffer
*cur
= (MirrorBuffer
*)buf
;
592 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, cur
, next
);
594 buf_size
-= granularity
;
599 /* This is also used for the .pause callback. There is no matching
600 * mirror_resume() because mirror_run() will begin iterating again
601 * when the job is resumed.
603 static void mirror_wait_for_all_io(MirrorBlockJob
*s
)
605 while (s
->in_flight
> 0) {
606 mirror_wait_for_free_in_flight_slot(s
);
610 static void mirror_exit(Job
*job
)
612 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
613 BlockJob
*bjob
= &s
->common
;
614 MirrorBDSOpaque
*bs_opaque
= s
->mirror_top_bs
->opaque
;
615 AioContext
*replace_aio_context
= NULL
;
616 BlockDriverState
*src
= s
->mirror_top_bs
->backing
->bs
;
617 BlockDriverState
*target_bs
= blk_bs(s
->target
);
618 BlockDriverState
*mirror_top_bs
= s
->mirror_top_bs
;
619 Error
*local_err
= NULL
;
622 bdrv_release_dirty_bitmap(src
, s
->dirty_bitmap
);
624 /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
625 * before we can call bdrv_drained_end */
627 bdrv_ref(mirror_top_bs
);
630 /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
631 * inserting target_bs at s->to_replace, where we might not be able to get
634 * Note that blk_unref() alone doesn't necessarily drop permissions because
635 * we might be running nested inside mirror_drain(), which takes an extra
636 * reference, so use an explicit blk_set_perm() first. */
637 blk_set_perm(s
->target
, 0, BLK_PERM_ALL
, &error_abort
);
638 blk_unref(s
->target
);
641 /* We don't access the source any more. Dropping any WRITE/RESIZE is
642 * required before it could become a backing file of target_bs. */
643 bdrv_child_try_set_perm(mirror_top_bs
->backing
, 0, BLK_PERM_ALL
,
645 if (s
->backing_mode
== MIRROR_SOURCE_BACKING_CHAIN
) {
646 BlockDriverState
*backing
= s
->is_none_mode
? src
: s
->base
;
647 if (backing_bs(target_bs
) != backing
) {
648 bdrv_set_backing_hd(target_bs
, backing
, &local_err
);
650 error_report_err(local_err
);
657 replace_aio_context
= bdrv_get_aio_context(s
->to_replace
);
658 aio_context_acquire(replace_aio_context
);
661 if (s
->should_complete
&& ret
== 0) {
662 BlockDriverState
*to_replace
= src
;
664 to_replace
= s
->to_replace
;
667 if (bdrv_get_flags(target_bs
) != bdrv_get_flags(to_replace
)) {
668 bdrv_reopen(target_bs
, bdrv_get_flags(to_replace
), NULL
);
671 /* The mirror job has no requests in flight any more, but we need to
672 * drain potential other users of the BDS before changing the graph. */
673 bdrv_drained_begin(target_bs
);
674 bdrv_replace_node(to_replace
, target_bs
, &local_err
);
675 bdrv_drained_end(target_bs
);
677 error_report_err(local_err
);
682 bdrv_op_unblock_all(s
->to_replace
, s
->replace_blocker
);
683 error_free(s
->replace_blocker
);
684 bdrv_unref(s
->to_replace
);
686 if (replace_aio_context
) {
687 aio_context_release(replace_aio_context
);
690 bdrv_unref(target_bs
);
692 /* Remove the mirror filter driver from the graph. Before this, get rid of
693 * the blockers on the intermediate nodes so that the resulting state is
694 * valid. Also give up permissions on mirror_top_bs->backing, which might
695 * block the removal. */
696 block_job_remove_all_bdrv(bjob
);
697 bdrv_child_try_set_perm(mirror_top_bs
->backing
, 0, BLK_PERM_ALL
,
699 bdrv_replace_node(mirror_top_bs
, backing_bs(mirror_top_bs
), &error_abort
);
701 /* We just changed the BDS the job BB refers to (with either or both of the
702 * bdrv_replace_node() calls), so switch the BB back so the cleanup does
703 * the right thing. We don't need any permissions any more now. */
704 blk_remove_bs(bjob
->blk
);
705 blk_set_perm(bjob
->blk
, 0, BLK_PERM_ALL
, &error_abort
);
706 blk_insert_bs(bjob
->blk
, mirror_top_bs
, &error_abort
);
708 bs_opaque
->job
= NULL
;
710 bdrv_drained_end(src
);
711 bdrv_unref(mirror_top_bs
);
717 static void mirror_throttle(MirrorBlockJob
*s
)
719 int64_t now
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
721 if (now
- s
->last_pause_ns
> BLOCK_JOB_SLICE_TIME
) {
722 s
->last_pause_ns
= now
;
723 job_sleep_ns(&s
->common
.job
, 0);
725 job_pause_point(&s
->common
.job
);
729 static int coroutine_fn
mirror_dirty_init(MirrorBlockJob
*s
)
732 BlockDriverState
*base
= s
->base
;
733 BlockDriverState
*bs
= s
->mirror_top_bs
->backing
->bs
;
734 BlockDriverState
*target_bs
= blk_bs(s
->target
);
738 if (base
== NULL
&& !bdrv_has_zero_init(target_bs
)) {
739 if (!bdrv_can_write_zeroes_with_unmap(target_bs
)) {
740 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, 0, s
->bdev_length
);
744 s
->initial_zeroing_ongoing
= true;
745 for (offset
= 0; offset
< s
->bdev_length
; ) {
746 int bytes
= MIN(s
->bdev_length
- offset
,
747 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
751 if (job_is_cancelled(&s
->common
.job
)) {
752 s
->initial_zeroing_ongoing
= false;
756 if (s
->in_flight
>= MAX_IN_FLIGHT
) {
757 trace_mirror_yield(s
, UINT64_MAX
, s
->buf_free_count
,
759 mirror_wait_for_free_in_flight_slot(s
);
763 mirror_perform(s
, offset
, bytes
, MIRROR_METHOD_ZERO
);
767 mirror_wait_for_all_io(s
);
768 s
->initial_zeroing_ongoing
= false;
771 /* First part, loop on the sectors and initialize the dirty bitmap. */
772 for (offset
= 0; offset
< s
->bdev_length
; ) {
773 /* Just to make sure we are not exceeding int limit. */
774 int bytes
= MIN(s
->bdev_length
- offset
,
775 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
779 if (job_is_cancelled(&s
->common
.job
)) {
783 ret
= bdrv_is_allocated_above(bs
, base
, offset
, bytes
, &count
);
790 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, offset
, count
);
797 /* Called when going out of the streaming phase to flush the bulk of the
798 * data to the medium, or just before completing.
800 static int mirror_flush(MirrorBlockJob
*s
)
802 int ret
= blk_flush(s
->target
);
804 if (mirror_error_action(s
, false, -ret
) == BLOCK_ERROR_ACTION_REPORT
) {
811 static int coroutine_fn
mirror_run(Job
*job
, Error
**errp
)
813 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
814 BlockDriverState
*bs
= s
->mirror_top_bs
->backing
->bs
;
815 BlockDriverState
*target_bs
= blk_bs(s
->target
);
816 bool need_drain
= true;
819 char backing_filename
[2]; /* we only need 2 characters because we are only
820 checking for a NULL string */
823 if (job_is_cancelled(&s
->common
.job
)) {
827 s
->bdev_length
= bdrv_getlength(bs
);
828 if (s
->bdev_length
< 0) {
829 ret
= s
->bdev_length
;
833 /* Active commit must resize the base image if its size differs from the
835 if (s
->base
== blk_bs(s
->target
)) {
838 base_length
= blk_getlength(s
->target
);
839 if (base_length
< 0) {
844 if (s
->bdev_length
> base_length
) {
845 ret
= blk_truncate(s
->target
, s
->bdev_length
, PREALLOC_MODE_OFF
,
853 if (s
->bdev_length
== 0) {
854 /* Transition to the READY state and wait for complete. */
855 job_transition_to_ready(&s
->common
.job
);
857 s
->actively_synced
= true;
858 while (!job_is_cancelled(&s
->common
.job
) && !s
->should_complete
) {
859 job_yield(&s
->common
.job
);
861 s
->common
.job
.cancelled
= false;
865 length
= DIV_ROUND_UP(s
->bdev_length
, s
->granularity
);
866 s
->in_flight_bitmap
= bitmap_new(length
);
868 /* If we have no backing file yet in the destination, we cannot let
869 * the destination do COW. Instead, we copy sectors around the
870 * dirty data if needed. We need a bitmap to do that.
872 bdrv_get_backing_filename(target_bs
, backing_filename
,
873 sizeof(backing_filename
));
874 if (!bdrv_get_info(target_bs
, &bdi
) && bdi
.cluster_size
) {
875 s
->target_cluster_size
= bdi
.cluster_size
;
877 s
->target_cluster_size
= BDRV_SECTOR_SIZE
;
879 if (backing_filename
[0] && !target_bs
->backing
&&
880 s
->granularity
< s
->target_cluster_size
) {
881 s
->buf_size
= MAX(s
->buf_size
, s
->target_cluster_size
);
882 s
->cow_bitmap
= bitmap_new(length
);
884 s
->max_iov
= MIN(bs
->bl
.max_iov
, target_bs
->bl
.max_iov
);
886 s
->buf
= qemu_try_blockalign(bs
, s
->buf_size
);
887 if (s
->buf
== NULL
) {
894 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
895 if (!s
->is_none_mode
) {
896 ret
= mirror_dirty_init(s
);
897 if (ret
< 0 || job_is_cancelled(&s
->common
.job
)) {
903 s
->dbi
= bdrv_dirty_iter_new(s
->dirty_bitmap
);
905 uint64_t delay_ns
= 0;
907 bool should_complete
;
909 /* Do not start passive operations while there are active
910 * writes in progress */
911 while (s
->in_active_write_counter
) {
912 mirror_wait_for_any_operation(s
, true);
920 job_pause_point(&s
->common
.job
);
922 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
923 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
924 * the number of bytes currently being processed; together those are
925 * the current remaining operation length */
926 job_progress_set_remaining(&s
->common
.job
, s
->bytes_in_flight
+ cnt
);
928 /* Note that even when no rate limit is applied we need to yield
929 * periodically with no pending I/O so that bdrv_drain_all() returns.
930 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
931 * an error, or when the source is clean, whichever comes first. */
932 delta
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
) - s
->last_pause_ns
;
933 if (delta
< BLOCK_JOB_SLICE_TIME
&&
934 s
->common
.iostatus
== BLOCK_DEVICE_IO_STATUS_OK
) {
935 if (s
->in_flight
>= MAX_IN_FLIGHT
|| s
->buf_free_count
== 0 ||
936 (cnt
== 0 && s
->in_flight
> 0)) {
937 trace_mirror_yield(s
, cnt
, s
->buf_free_count
, s
->in_flight
);
938 mirror_wait_for_free_in_flight_slot(s
);
940 } else if (cnt
!= 0) {
941 delay_ns
= mirror_iteration(s
);
945 should_complete
= false;
946 if (s
->in_flight
== 0 && cnt
== 0) {
947 trace_mirror_before_flush(s
);
949 if (mirror_flush(s
) < 0) {
950 /* Go check s->ret. */
953 /* We're out of the streaming phase. From now on, if the job
954 * is cancelled we will actually complete all pending I/O and
955 * report completion. This way, block-job-cancel will leave
956 * the target in a consistent state.
958 job_transition_to_ready(&s
->common
.job
);
960 if (s
->copy_mode
!= MIRROR_COPY_MODE_BACKGROUND
) {
961 s
->actively_synced
= true;
965 should_complete
= s
->should_complete
||
966 job_is_cancelled(&s
->common
.job
);
967 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
970 if (cnt
== 0 && should_complete
) {
971 /* The dirty bitmap is not updated while operations are pending.
972 * If we're about to exit, wait for pending operations before
973 * calling bdrv_get_dirty_count(bs), or we may exit while the
974 * source has dirty data to copy!
976 * Note that I/O can be submitted by the guest while
977 * mirror_populate runs, so pause it now. Before deciding
978 * whether to switch to target check one last time if I/O has
979 * come in the meanwhile, and if not flush the data to disk.
981 trace_mirror_before_drain(s
, cnt
);
983 bdrv_drained_begin(bs
);
984 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
985 if (cnt
> 0 || mirror_flush(s
) < 0) {
986 bdrv_drained_end(bs
);
990 /* The two disks are in sync. Exit and report successful
993 assert(QLIST_EMPTY(&bs
->tracked_requests
));
994 s
->common
.job
.cancelled
= false;
1001 if (s
->synced
&& !should_complete
) {
1002 delay_ns
= (s
->in_flight
== 0 &&
1003 cnt
== 0 ? BLOCK_JOB_SLICE_TIME
: 0);
1005 trace_mirror_before_sleep(s
, cnt
, s
->synced
, delay_ns
);
1006 job_sleep_ns(&s
->common
.job
, delay_ns
);
1007 if (job_is_cancelled(&s
->common
.job
) &&
1008 (!s
->synced
|| s
->common
.job
.force_cancel
))
1012 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
1016 if (s
->in_flight
> 0) {
1017 /* We get here only if something went wrong. Either the job failed,
1018 * or it was cancelled prematurely so that we do not guarantee that
1019 * the target is a copy of the source.
1021 assert(ret
< 0 || ((s
->common
.job
.force_cancel
|| !s
->synced
) &&
1022 job_is_cancelled(&s
->common
.job
)));
1024 mirror_wait_for_all_io(s
);
1027 assert(s
->in_flight
== 0);
1029 g_free(s
->cow_bitmap
);
1030 g_free(s
->in_flight_bitmap
);
1031 bdrv_dirty_iter_free(s
->dbi
);
1034 bdrv_drained_begin(bs
);
1040 static void mirror_complete(Job
*job
, Error
**errp
)
1042 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1043 BlockDriverState
*target
;
1045 target
= blk_bs(s
->target
);
1048 error_setg(errp
, "The active block job '%s' cannot be completed",
1053 if (s
->backing_mode
== MIRROR_OPEN_BACKING_CHAIN
) {
1056 assert(!target
->backing
);
1057 ret
= bdrv_open_backing_file(target
, NULL
, "backing", errp
);
1063 /* block all operations on to_replace bs */
1065 AioContext
*replace_aio_context
;
1067 s
->to_replace
= bdrv_find_node(s
->replaces
);
1068 if (!s
->to_replace
) {
1069 error_setg(errp
, "Node name '%s' not found", s
->replaces
);
1073 replace_aio_context
= bdrv_get_aio_context(s
->to_replace
);
1074 aio_context_acquire(replace_aio_context
);
1076 /* TODO Translate this into permission system. Current definition of
1077 * GRAPH_MOD would require to request it for the parents; they might
1078 * not even be BlockDriverStates, however, so a BdrvChild can't address
1079 * them. May need redefinition of GRAPH_MOD. */
1080 error_setg(&s
->replace_blocker
,
1081 "block device is in use by block-job-complete");
1082 bdrv_op_block_all(s
->to_replace
, s
->replace_blocker
);
1083 bdrv_ref(s
->to_replace
);
1085 aio_context_release(replace_aio_context
);
1088 s
->should_complete
= true;
1092 static void mirror_pause(Job
*job
)
1094 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1096 mirror_wait_for_all_io(s
);
1099 static bool mirror_drained_poll(BlockJob
*job
)
1101 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1102 return !!s
->in_flight
;
1105 static void mirror_attached_aio_context(BlockJob
*job
, AioContext
*new_context
)
1107 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1109 blk_set_aio_context(s
->target
, new_context
);
1112 static void mirror_drain(BlockJob
*job
)
1114 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1116 /* Need to keep a reference in case blk_drain triggers execution
1117 * of mirror_complete...
1120 BlockBackend
*target
= s
->target
;
1127 static const BlockJobDriver mirror_job_driver
= {
1129 .instance_size
= sizeof(MirrorBlockJob
),
1130 .job_type
= JOB_TYPE_MIRROR
,
1131 .free
= block_job_free
,
1132 .user_resume
= block_job_user_resume
,
1133 .drain
= block_job_drain
,
1135 .exit
= mirror_exit
,
1136 .pause
= mirror_pause
,
1137 .complete
= mirror_complete
,
1139 .drained_poll
= mirror_drained_poll
,
1140 .attached_aio_context
= mirror_attached_aio_context
,
1141 .drain
= mirror_drain
,
1144 static const BlockJobDriver commit_active_job_driver
= {
1146 .instance_size
= sizeof(MirrorBlockJob
),
1147 .job_type
= JOB_TYPE_COMMIT
,
1148 .free
= block_job_free
,
1149 .user_resume
= block_job_user_resume
,
1150 .drain
= block_job_drain
,
1152 .exit
= mirror_exit
,
1153 .pause
= mirror_pause
,
1154 .complete
= mirror_complete
,
1156 .drained_poll
= mirror_drained_poll
,
1157 .attached_aio_context
= mirror_attached_aio_context
,
1158 .drain
= mirror_drain
,
1161 static void do_sync_target_write(MirrorBlockJob
*job
, MirrorMethod method
,
1162 uint64_t offset
, uint64_t bytes
,
1163 QEMUIOVector
*qiov
, int flags
)
1165 BdrvDirtyBitmapIter
*iter
;
1166 QEMUIOVector target_qiov
;
1167 uint64_t dirty_offset
;
1171 qemu_iovec_init(&target_qiov
, qiov
->niov
);
1174 iter
= bdrv_dirty_iter_new(job
->dirty_bitmap
);
1175 bdrv_set_dirty_iter(iter
, offset
);
1181 bdrv_dirty_bitmap_lock(job
->dirty_bitmap
);
1182 valid_area
= bdrv_dirty_iter_next_area(iter
, offset
+ bytes
,
1183 &dirty_offset
, &dirty_bytes
);
1185 bdrv_dirty_bitmap_unlock(job
->dirty_bitmap
);
1189 bdrv_reset_dirty_bitmap_locked(job
->dirty_bitmap
,
1190 dirty_offset
, dirty_bytes
);
1191 bdrv_dirty_bitmap_unlock(job
->dirty_bitmap
);
1193 job_progress_increase_remaining(&job
->common
.job
, dirty_bytes
);
1195 assert(dirty_offset
- offset
<= SIZE_MAX
);
1197 qemu_iovec_reset(&target_qiov
);
1198 qemu_iovec_concat(&target_qiov
, qiov
,
1199 dirty_offset
- offset
, dirty_bytes
);
1203 case MIRROR_METHOD_COPY
:
1204 ret
= blk_co_pwritev(job
->target
, dirty_offset
, dirty_bytes
,
1205 qiov
? &target_qiov
: NULL
, flags
);
1208 case MIRROR_METHOD_ZERO
:
1210 ret
= blk_co_pwrite_zeroes(job
->target
, dirty_offset
, dirty_bytes
,
1214 case MIRROR_METHOD_DISCARD
:
1216 ret
= blk_co_pdiscard(job
->target
, dirty_offset
, dirty_bytes
);
1224 job_progress_update(&job
->common
.job
, dirty_bytes
);
1226 BlockErrorAction action
;
1228 bdrv_set_dirty_bitmap(job
->dirty_bitmap
, dirty_offset
, dirty_bytes
);
1229 job
->actively_synced
= false;
1231 action
= mirror_error_action(job
, false, -ret
);
1232 if (action
== BLOCK_ERROR_ACTION_REPORT
) {
1241 bdrv_dirty_iter_free(iter
);
1243 qemu_iovec_destroy(&target_qiov
);
1247 static MirrorOp
*coroutine_fn
active_write_prepare(MirrorBlockJob
*s
,
1252 uint64_t start_chunk
= offset
/ s
->granularity
;
1253 uint64_t end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
1255 op
= g_new(MirrorOp
, 1);
1260 .is_active_write
= true,
1262 qemu_co_queue_init(&op
->waiting_requests
);
1263 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
1265 s
->in_active_write_counter
++;
1267 mirror_wait_on_conflicts(op
, s
, offset
, bytes
);
1269 bitmap_set(s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1274 static void coroutine_fn
active_write_settle(MirrorOp
*op
)
1276 uint64_t start_chunk
= op
->offset
/ op
->s
->granularity
;
1277 uint64_t end_chunk
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
1278 op
->s
->granularity
);
1280 if (!--op
->s
->in_active_write_counter
&& op
->s
->actively_synced
) {
1281 BdrvChild
*source
= op
->s
->mirror_top_bs
->backing
;
1283 if (QLIST_FIRST(&source
->bs
->parents
) == source
&&
1284 QLIST_NEXT(source
, next_parent
) == NULL
)
1286 /* Assert that we are back in sync once all active write
1287 * operations are settled.
1288 * Note that we can only assert this if the mirror node
1289 * is the source node's only parent. */
1290 assert(!bdrv_get_dirty_count(op
->s
->dirty_bitmap
));
1293 bitmap_clear(op
->s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1294 QTAILQ_REMOVE(&op
->s
->ops_in_flight
, op
, next
);
1295 qemu_co_queue_restart_all(&op
->waiting_requests
);
1299 static int coroutine_fn
bdrv_mirror_top_preadv(BlockDriverState
*bs
,
1300 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
)
1302 return bdrv_co_preadv(bs
->backing
, offset
, bytes
, qiov
, flags
);
1305 static int coroutine_fn
bdrv_mirror_top_do_write(BlockDriverState
*bs
,
1306 MirrorMethod method
, uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
,
1309 MirrorOp
*op
= NULL
;
1310 MirrorBDSOpaque
*s
= bs
->opaque
;
1312 bool copy_to_target
;
1314 copy_to_target
= s
->job
->ret
>= 0 &&
1315 s
->job
->copy_mode
== MIRROR_COPY_MODE_WRITE_BLOCKING
;
1317 if (copy_to_target
) {
1318 op
= active_write_prepare(s
->job
, offset
, bytes
);
1322 case MIRROR_METHOD_COPY
:
1323 ret
= bdrv_co_pwritev(bs
->backing
, offset
, bytes
, qiov
, flags
);
1326 case MIRROR_METHOD_ZERO
:
1327 ret
= bdrv_co_pwrite_zeroes(bs
->backing
, offset
, bytes
, flags
);
1330 case MIRROR_METHOD_DISCARD
:
1331 ret
= bdrv_co_pdiscard(bs
->backing
, offset
, bytes
);
1342 if (copy_to_target
) {
1343 do_sync_target_write(s
->job
, method
, offset
, bytes
, qiov
, flags
);
1347 if (copy_to_target
) {
1348 active_write_settle(op
);
1353 static int coroutine_fn
bdrv_mirror_top_pwritev(BlockDriverState
*bs
,
1354 uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
, int flags
)
1356 MirrorBDSOpaque
*s
= bs
->opaque
;
1357 QEMUIOVector bounce_qiov
;
1360 bool copy_to_target
;
1362 copy_to_target
= s
->job
->ret
>= 0 &&
1363 s
->job
->copy_mode
== MIRROR_COPY_MODE_WRITE_BLOCKING
;
1365 if (copy_to_target
) {
1366 /* The guest might concurrently modify the data to write; but
1367 * the data on source and destination must match, so we have
1368 * to use a bounce buffer if we are going to write to the
1370 bounce_buf
= qemu_blockalign(bs
, bytes
);
1371 iov_to_buf_full(qiov
->iov
, qiov
->niov
, 0, bounce_buf
, bytes
);
1373 qemu_iovec_init(&bounce_qiov
, 1);
1374 qemu_iovec_add(&bounce_qiov
, bounce_buf
, bytes
);
1375 qiov
= &bounce_qiov
;
1378 ret
= bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_COPY
, offset
, bytes
, qiov
,
1381 if (copy_to_target
) {
1382 qemu_iovec_destroy(&bounce_qiov
);
1383 qemu_vfree(bounce_buf
);
1389 static int coroutine_fn
bdrv_mirror_top_flush(BlockDriverState
*bs
)
1391 if (bs
->backing
== NULL
) {
1392 /* we can be here after failed bdrv_append in mirror_start_job */
1395 return bdrv_co_flush(bs
->backing
->bs
);
1398 static int coroutine_fn
bdrv_mirror_top_pwrite_zeroes(BlockDriverState
*bs
,
1399 int64_t offset
, int bytes
, BdrvRequestFlags flags
)
1401 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_ZERO
, offset
, bytes
, NULL
,
1405 static int coroutine_fn
bdrv_mirror_top_pdiscard(BlockDriverState
*bs
,
1406 int64_t offset
, int bytes
)
1408 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_DISCARD
, offset
, bytes
,
1412 static void bdrv_mirror_top_refresh_filename(BlockDriverState
*bs
, QDict
*opts
)
1414 if (bs
->backing
== NULL
) {
1415 /* we can be here after failed bdrv_attach_child in
1416 * bdrv_set_backing_hd */
1419 bdrv_refresh_filename(bs
->backing
->bs
);
1420 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
1421 bs
->backing
->bs
->filename
);
1424 static void bdrv_mirror_top_child_perm(BlockDriverState
*bs
, BdrvChild
*c
,
1425 const BdrvChildRole
*role
,
1426 BlockReopenQueue
*reopen_queue
,
1427 uint64_t perm
, uint64_t shared
,
1428 uint64_t *nperm
, uint64_t *nshared
)
1430 /* Must be able to forward guest writes to the real image */
1432 if (perm
& BLK_PERM_WRITE
) {
1433 *nperm
|= BLK_PERM_WRITE
;
1436 *nshared
= BLK_PERM_ALL
;
1439 /* Dummy node that provides consistent read to its users without requiring it
1440 * from its backing file and that allows writes on the backing file chain. */
1441 static BlockDriver bdrv_mirror_top
= {
1442 .format_name
= "mirror_top",
1443 .bdrv_co_preadv
= bdrv_mirror_top_preadv
,
1444 .bdrv_co_pwritev
= bdrv_mirror_top_pwritev
,
1445 .bdrv_co_pwrite_zeroes
= bdrv_mirror_top_pwrite_zeroes
,
1446 .bdrv_co_pdiscard
= bdrv_mirror_top_pdiscard
,
1447 .bdrv_co_flush
= bdrv_mirror_top_flush
,
1448 .bdrv_co_block_status
= bdrv_co_block_status_from_backing
,
1449 .bdrv_refresh_filename
= bdrv_mirror_top_refresh_filename
,
1450 .bdrv_child_perm
= bdrv_mirror_top_child_perm
,
1453 static void mirror_start_job(const char *job_id
, BlockDriverState
*bs
,
1454 int creation_flags
, BlockDriverState
*target
,
1455 const char *replaces
, int64_t speed
,
1456 uint32_t granularity
, int64_t buf_size
,
1457 BlockMirrorBackingMode backing_mode
,
1458 BlockdevOnError on_source_error
,
1459 BlockdevOnError on_target_error
,
1461 BlockCompletionFunc
*cb
,
1463 const BlockJobDriver
*driver
,
1464 bool is_none_mode
, BlockDriverState
*base
,
1465 bool auto_complete
, const char *filter_node_name
,
1466 bool is_mirror
, MirrorCopyMode copy_mode
,
1470 MirrorBDSOpaque
*bs_opaque
;
1471 BlockDriverState
*mirror_top_bs
;
1472 bool target_graph_mod
;
1473 bool target_is_backing
;
1474 Error
*local_err
= NULL
;
1477 if (granularity
== 0) {
1478 granularity
= bdrv_get_default_bitmap_granularity(target
);
1481 assert(is_power_of_2(granularity
));
1484 error_setg(errp
, "Invalid parameter 'buf-size'");
1488 if (buf_size
== 0) {
1489 buf_size
= DEFAULT_MIRROR_BUF_SIZE
;
1493 error_setg(errp
, "Can't mirror node into itself");
1497 /* In the case of active commit, add dummy driver to provide consistent
1498 * reads on the top, while disabling it in the intermediate nodes, and make
1499 * the backing chain writable. */
1500 mirror_top_bs
= bdrv_new_open_driver(&bdrv_mirror_top
, filter_node_name
,
1502 if (mirror_top_bs
== NULL
) {
1505 if (!filter_node_name
) {
1506 mirror_top_bs
->implicit
= true;
1508 mirror_top_bs
->total_sectors
= bs
->total_sectors
;
1509 mirror_top_bs
->supported_write_flags
= BDRV_REQ_WRITE_UNCHANGED
;
1510 mirror_top_bs
->supported_zero_flags
= BDRV_REQ_WRITE_UNCHANGED
;
1511 bs_opaque
= g_new0(MirrorBDSOpaque
, 1);
1512 mirror_top_bs
->opaque
= bs_opaque
;
1513 bdrv_set_aio_context(mirror_top_bs
, bdrv_get_aio_context(bs
));
1515 /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep
1516 * it alive until block_job_create() succeeds even if bs has no parent. */
1517 bdrv_ref(mirror_top_bs
);
1518 bdrv_drained_begin(bs
);
1519 bdrv_append(mirror_top_bs
, bs
, &local_err
);
1520 bdrv_drained_end(bs
);
1523 bdrv_unref(mirror_top_bs
);
1524 error_propagate(errp
, local_err
);
1528 /* Make sure that the source is not resized while the job is running */
1529 s
= block_job_create(job_id
, driver
, NULL
, mirror_top_bs
,
1530 BLK_PERM_CONSISTENT_READ
,
1531 BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
|
1532 BLK_PERM_WRITE
| BLK_PERM_GRAPH_MOD
, speed
,
1533 creation_flags
, cb
, opaque
, errp
);
1539 /* The block job now has a reference to this node */
1540 bdrv_unref(mirror_top_bs
);
1542 s
->mirror_top_bs
= mirror_top_bs
;
1544 /* No resize for the target either; while the mirror is still running, a
1545 * consistent read isn't necessarily possible. We could possibly allow
1546 * writes and graph modifications, though it would likely defeat the
1547 * purpose of a mirror, so leave them blocked for now.
1549 * In the case of active commit, things look a bit different, though,
1550 * because the target is an already populated backing file in active use.
1551 * We can allow anything except resize there.*/
1552 target_is_backing
= bdrv_chain_contains(bs
, target
);
1553 target_graph_mod
= (backing_mode
!= MIRROR_LEAVE_BACKING_CHAIN
);
1554 s
->target
= blk_new(BLK_PERM_WRITE
| BLK_PERM_RESIZE
|
1555 (target_graph_mod
? BLK_PERM_GRAPH_MOD
: 0),
1556 BLK_PERM_WRITE_UNCHANGED
|
1557 (target_is_backing
? BLK_PERM_CONSISTENT_READ
|
1559 BLK_PERM_GRAPH_MOD
: 0));
1560 ret
= blk_insert_bs(s
->target
, target
, errp
);
1565 /* XXX: Mirror target could be a NBD server of target QEMU in the case
1566 * of non-shared block migration. To allow migration completion, we
1567 * have to allow "inactivate" of the target BB. When that happens, we
1568 * know the job is drained, and the vcpus are stopped, so no write
1569 * operation will be performed. Block layer already has assertions to
1571 blk_set_force_allow_inactivate(s
->target
);
1574 s
->replaces
= g_strdup(replaces
);
1575 s
->on_source_error
= on_source_error
;
1576 s
->on_target_error
= on_target_error
;
1577 s
->is_none_mode
= is_none_mode
;
1578 s
->backing_mode
= backing_mode
;
1579 s
->copy_mode
= copy_mode
;
1581 s
->granularity
= granularity
;
1582 s
->buf_size
= ROUND_UP(buf_size
, granularity
);
1584 if (auto_complete
) {
1585 s
->should_complete
= true;
1588 s
->dirty_bitmap
= bdrv_create_dirty_bitmap(bs
, granularity
, NULL
, errp
);
1589 if (!s
->dirty_bitmap
) {
1593 /* Required permissions are already taken with blk_new() */
1594 block_job_add_bdrv(&s
->common
, "target", target
, 0, BLK_PERM_ALL
,
1597 /* In commit_active_start() all intermediate nodes disappear, so
1598 * any jobs in them must be blocked */
1599 if (target_is_backing
) {
1600 BlockDriverState
*iter
;
1601 for (iter
= backing_bs(bs
); iter
!= target
; iter
= backing_bs(iter
)) {
1602 /* XXX BLK_PERM_WRITE needs to be allowed so we don't block
1603 * ourselves at s->base (if writes are blocked for a node, they are
1604 * also blocked for its backing file). The other options would be a
1605 * second filter driver above s->base (== target). */
1606 ret
= block_job_add_bdrv(&s
->common
, "intermediate node", iter
, 0,
1607 BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
,
1615 QTAILQ_INIT(&s
->ops_in_flight
);
1617 trace_mirror_start(bs
, s
, opaque
);
1618 job_start(&s
->common
.job
);
1623 /* Make sure this BDS does not go away until we have completed the graph
1625 bdrv_ref(mirror_top_bs
);
1627 g_free(s
->replaces
);
1628 blk_unref(s
->target
);
1629 bs_opaque
->job
= NULL
;
1630 job_early_fail(&s
->common
.job
);
1633 bdrv_child_try_set_perm(mirror_top_bs
->backing
, 0, BLK_PERM_ALL
,
1635 bdrv_replace_node(mirror_top_bs
, backing_bs(mirror_top_bs
), &error_abort
);
1637 bdrv_unref(mirror_top_bs
);
1640 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
1641 BlockDriverState
*target
, const char *replaces
,
1642 int64_t speed
, uint32_t granularity
, int64_t buf_size
,
1643 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
1644 BlockdevOnError on_source_error
,
1645 BlockdevOnError on_target_error
,
1646 bool unmap
, const char *filter_node_name
,
1647 MirrorCopyMode copy_mode
, Error
**errp
)
1650 BlockDriverState
*base
;
1652 if (mode
== MIRROR_SYNC_MODE_INCREMENTAL
) {
1653 error_setg(errp
, "Sync mode 'incremental' not supported");
1656 is_none_mode
= mode
== MIRROR_SYNC_MODE_NONE
;
1657 base
= mode
== MIRROR_SYNC_MODE_TOP
? backing_bs(bs
) : NULL
;
1658 mirror_start_job(job_id
, bs
, JOB_DEFAULT
, target
, replaces
,
1659 speed
, granularity
, buf_size
, backing_mode
,
1660 on_source_error
, on_target_error
, unmap
, NULL
, NULL
,
1661 &mirror_job_driver
, is_none_mode
, base
, false,
1662 filter_node_name
, true, copy_mode
, errp
);
1665 void commit_active_start(const char *job_id
, BlockDriverState
*bs
,
1666 BlockDriverState
*base
, int creation_flags
,
1667 int64_t speed
, BlockdevOnError on_error
,
1668 const char *filter_node_name
,
1669 BlockCompletionFunc
*cb
, void *opaque
,
1670 bool auto_complete
, Error
**errp
)
1672 int orig_base_flags
;
1673 Error
*local_err
= NULL
;
1675 orig_base_flags
= bdrv_get_flags(base
);
1677 if (bdrv_reopen(base
, bs
->open_flags
, errp
)) {
1681 mirror_start_job(job_id
, bs
, creation_flags
, base
, NULL
, speed
, 0, 0,
1682 MIRROR_LEAVE_BACKING_CHAIN
,
1683 on_error
, on_error
, true, cb
, opaque
,
1684 &commit_active_job_driver
, false, base
, auto_complete
,
1685 filter_node_name
, false, MIRROR_COPY_MODE_BACKGROUND
,
1688 error_propagate(errp
, local_err
);
1689 goto error_restore_flags
;
1694 error_restore_flags
:
1695 /* ignore error and errp for bdrv_reopen, because we want to propagate
1696 * the original error */
1697 bdrv_reopen(base
, orig_base_flags
, NULL
);