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 /* Whether the target image requires explicit zero-initialization */
56 MirrorCopyMode copy_mode
;
57 BlockdevOnError on_source_error
, on_target_error
;
59 /* Set when the target is synced (dirty bitmap is clean, nothing
60 * in flight) and the job is running in active mode */
66 unsigned long *cow_bitmap
;
67 BdrvDirtyBitmap
*dirty_bitmap
;
68 BdrvDirtyBitmapIter
*dbi
;
70 QSIMPLEQ_HEAD(, MirrorBuffer
) buf_free
;
73 uint64_t last_pause_ns
;
74 unsigned long *in_flight_bitmap
;
76 int64_t bytes_in_flight
;
77 QTAILQ_HEAD(, MirrorOp
) ops_in_flight
;
80 int target_cluster_size
;
82 bool initial_zeroing_ongoing
;
83 int in_active_write_counter
;
88 typedef struct MirrorBDSOpaque
{
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
;
104 bool is_active_write
;
105 CoQueue waiting_requests
;
107 QTAILQ_ENTRY(MirrorOp
) next
;
110 typedef enum MirrorMethod
{
113 MIRROR_METHOD_DISCARD
,
116 static BlockErrorAction
mirror_error_action(MirrorBlockJob
*s
, bool read
,
120 s
->actively_synced
= false;
122 return block_job_error_action(&s
->common
, s
->on_source_error
,
125 return block_job_error_action(&s
->common
, s
->on_target_error
,
130 static void coroutine_fn
mirror_wait_on_conflicts(MirrorOp
*self
,
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
&&
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
,
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
);
165 static void coroutine_fn
mirror_iteration_done(MirrorOp
*op
, int ret
)
167 MirrorBlockJob
*s
= op
->s
;
172 trace_mirror_iteration_done(s
, op
->offset
, op
->bytes
, ret
);
175 s
->bytes_in_flight
-= op
->bytes
;
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
);
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
);
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
);
202 static void coroutine_fn
mirror_write_complete(MirrorOp
*op
, int ret
)
204 MirrorBlockJob
*s
= op
->s
;
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) {
216 mirror_iteration_done(op
, ret
);
219 static void coroutine_fn
mirror_read_complete(MirrorOp
*op
, int ret
)
221 MirrorBlockJob
*s
= op
->s
;
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) {
232 mirror_iteration_done(op
, ret
);
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
,
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
,
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
,
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
;
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
;
284 static inline void coroutine_fn
285 mirror_wait_for_any_operation(MirrorBlockJob
*s
, bool active
)
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
295 if (!op
->is_pseudo_op
&& op
->is_active_write
== active
) {
296 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
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
;
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
));
331 assert(op
->bytes
< BDRV_REQUEST_MAX_BYTES
);
332 *op
->bytes_handled
= op
->bytes
;
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
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
);
363 qemu_iovec_add(&op
->qiov
, buf
, MIN(s
->granularity
, remaining
));
366 /* Copy the dirty cluster. */
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
,
373 mirror_read_complete(op
, ret
);
376 static void coroutine_fn
mirror_co_zero(void *opaque
)
378 MirrorOp
*op
= opaque
;
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
;
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
)
408 int64_t bytes_handled
= -1;
410 op
= g_new(MirrorOp
, 1);
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
);
423 case MIRROR_METHOD_ZERO
:
424 co
= qemu_coroutine_create(mirror_co_zero
, op
);
426 case MIRROR_METHOD_DISCARD
:
427 co
= qemu_coroutine_create(mirror_co_discard
, op
);
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
;
453 uint64_t delay_ns
= 0, ret
= 0;
454 /* At least the first dirty chunk is mirrored in one iteration. */
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
);
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
));
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
) {
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
)) {
484 if (test_bit(next_chunk
, s
->in_flight_bitmap
)) {
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
);
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
512 pseudo_op
= g_new(MirrorOp
, 1);
513 *pseudo_op
= (MirrorOp
){
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
) {
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
);
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
?
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
);
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
) {
569 io_bytes_acct
= 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
);
579 QTAILQ_REMOVE(&s
->ops_in_flight
, pseudo_op
, next
);
580 qemu_co_queue_restart_all(&pseudo_op
->waiting_requests
);
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
);
598 buf_size
-= 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;
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 */
646 bdrv_ref(mirror_top_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
654 blk_unref(s
->target
);
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
,
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
);
670 error_report_err(local_err
);
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. */
692 bdrv_drained_begin(target_bs
);
693 bdrv_replace_node(to_replace
, target_bs
, &local_err
);
694 bdrv_drained_end(target_bs
);
696 error_report_err(local_err
);
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
);
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
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
);
731 bdrv_unref(mirror_top_bs
);
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
);
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);
756 job_pause_point(&s
->common
.job
);
760 static int coroutine_fn
mirror_dirty_init(MirrorBlockJob
*s
)
763 BlockDriverState
*base
= s
->base
;
764 BlockDriverState
*bs
= s
->mirror_top_bs
->backing
->bs
;
765 BlockDriverState
*target_bs
= blk_bs(s
->target
);
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
);
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
));
782 if (job_is_cancelled(&s
->common
.job
)) {
783 s
->initial_zeroing_ongoing
= false;
787 if (s
->in_flight
>= MAX_IN_FLIGHT
) {
788 trace_mirror_yield(s
, UINT64_MAX
, s
->buf_free_count
,
790 mirror_wait_for_free_in_flight_slot(s
);
794 mirror_perform(s
, offset
, bytes
, MIRROR_METHOD_ZERO
);
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
));
810 if (job_is_cancelled(&s
->common
.job
)) {
814 ret
= bdrv_is_allocated_above(bs
, base
, false, offset
, bytes
, &count
);
821 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, offset
, count
);
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
);
835 if (mirror_error_action(s
, false, -ret
) == BLOCK_ERROR_ACTION_REPORT
) {
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;
850 char backing_filename
[2]; /* we only need 2 characters because we are only
851 checking for a NULL string */
854 if (job_is_cancelled(&s
->common
.job
)) {
858 s
->bdev_length
= bdrv_getlength(bs
);
859 if (s
->bdev_length
< 0) {
860 ret
= s
->bdev_length
;
864 /* Active commit must resize the base image if its size differs from the
866 if (s
->base
== blk_bs(s
->target
)) {
869 base_length
= blk_getlength(s
->target
);
870 if (base_length
< 0) {
875 if (s
->bdev_length
> base_length
) {
876 ret
= blk_truncate(s
->target
, s
->bdev_length
, PREALLOC_MODE_OFF
,
884 if (s
->bdev_length
== 0) {
885 /* Transition to the READY state and wait for complete. */
886 job_transition_to_ready(&s
->common
.job
);
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;
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
;
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
) {
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
)) {
934 s
->dbi
= bdrv_dirty_iter_new(s
->dirty_bitmap
);
936 uint64_t delay_ns
= 0;
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);
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
);
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
);
980 if (mirror_flush(s
) < 0) {
981 /* Go check s->ret. */
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
);
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
);
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;
1023 /* The two disks are in sync. Exit and report successful
1026 assert(QLIST_EMPTY(&bs
->tracked_requests
));
1027 s
->common
.job
.cancelled
= false;
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
))
1045 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
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
)));
1057 mirror_wait_for_all_io(s
);
1060 assert(s
->in_flight
== 0);
1062 g_free(s
->cow_bitmap
);
1063 g_free(s
->in_flight_bitmap
);
1064 bdrv_dirty_iter_free(s
->dbi
);
1068 bdrv_drained_begin(bs
);
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
);
1082 error_setg(errp
, "The active block job '%s' cannot be completed",
1087 if (s
->backing_mode
== MIRROR_OPEN_BACKING_CHAIN
) {
1090 assert(!target
->backing
);
1091 ret
= bdrv_open_backing_file(target
, NULL
, "backing", errp
);
1097 /* block all operations on to_replace bs */
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
);
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;
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
1142 if (!s
->common
.job
.paused
&& !s
->common
.job
.cancelled
&& !s
->in_drain
) {
1146 return !!s
->in_flight
;
1149 static const BlockJobDriver mirror_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
,
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
= {
1166 .instance_size
= sizeof(MirrorBlockJob
),
1167 .job_type
= JOB_TYPE_COMMIT
,
1168 .free
= block_job_free
,
1169 .user_resume
= block_job_user_resume
,
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
;
1189 qemu_iovec_init(&target_qiov
, qiov
->niov
);
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
,
1202 bdrv_dirty_bitmap_unlock(job
->dirty_bitmap
);
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
);
1214 qemu_iovec_reset(&target_qiov
);
1215 qemu_iovec_concat(&target_qiov
, qiov
,
1216 dirty_offset
- offset
, dirty_bytes
);
1220 case MIRROR_METHOD_COPY
:
1221 ret
= blk_co_pwritev(job
->target
, dirty_offset
, dirty_bytes
,
1222 qiov
? &target_qiov
: NULL
, flags
);
1225 case MIRROR_METHOD_ZERO
:
1227 ret
= blk_co_pwrite_zeroes(job
->target
, dirty_offset
, dirty_bytes
,
1231 case MIRROR_METHOD_DISCARD
:
1233 ret
= blk_co_pdiscard(job
->target
, dirty_offset
, dirty_bytes
);
1241 job_progress_update(&job
->common
.job
, dirty_bytes
);
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
) {
1257 dirty_offset
+= dirty_bytes
;
1261 qemu_iovec_destroy(&target_qiov
);
1265 static MirrorOp
*coroutine_fn
active_write_prepare(MirrorBlockJob
*s
,
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);
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
);
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
);
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
,
1327 MirrorOp
*op
= NULL
;
1328 MirrorBDSOpaque
*s
= bs
->opaque
;
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
);
1340 case MIRROR_METHOD_COPY
:
1341 ret
= bdrv_co_pwritev(bs
->backing
, offset
, bytes
, qiov
, flags
);
1344 case MIRROR_METHOD_ZERO
:
1345 ret
= bdrv_co_pwrite_zeroes(bs
->backing
, offset
, bytes
, flags
);
1348 case MIRROR_METHOD_DISCARD
:
1349 ret
= bdrv_co_pdiscard(bs
->backing
, offset
, bytes
);
1360 if (copy_to_target
) {
1361 do_sync_target_write(s
->job
, method
, offset
, bytes
, qiov
, flags
);
1365 if (copy_to_target
) {
1366 active_write_settle(op
);
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
;
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
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
,
1399 if (copy_to_target
) {
1400 qemu_iovec_destroy(&bounce_qiov
);
1401 qemu_vfree(bounce_buf
);
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 */
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
,
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
,
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 */
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
;
1451 * If the job is to be stopped, we do not need to forward
1452 * anything to the real image.
1455 *nshared
= BLK_PERM_ALL
;
1459 /* Must be able to forward guest writes to the real image */
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
,
1499 BlockdevOnError on_source_error
,
1500 BlockdevOnError on_target_error
,
1502 BlockCompletionFunc
*cb
,
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
,
1511 MirrorBDSOpaque
*bs_opaque
;
1512 BlockDriverState
*mirror_top_bs
;
1513 bool target_graph_mod
;
1514 bool target_is_backing
;
1515 Error
*local_err
= NULL
;
1518 if (granularity
== 0) {
1519 granularity
= bdrv_get_default_bitmap_granularity(target
);
1522 assert(is_power_of_2(granularity
));
1525 error_setg(errp
, "Invalid parameter 'buf-size'");
1529 if (buf_size
== 0) {
1530 buf_size
= DEFAULT_MIRROR_BUF_SIZE
;
1534 error_setg(errp
, "Can't mirror node into itself");
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
,
1543 if (mirror_top_bs
== 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
);
1568 bdrv_unref(mirror_top_bs
);
1569 error_propagate(errp
, local_err
);
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
);
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
|
1605 BLK_PERM_GRAPH_MOD
: 0));
1606 ret
= blk_insert_bs(s
->target
, target
, errp
);
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
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
;
1630 s
->granularity
= granularity
;
1631 s
->buf_size
= ROUND_UP(buf_size
, granularity
);
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
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
);
1652 error_propagate(errp
, local_err
);
1656 s
->dirty_bitmap
= bdrv_create_dirty_bitmap(bs
, granularity
, NULL
, errp
);
1657 if (!s
->dirty_bitmap
) {
1661 ret
= block_job_add_bdrv(&s
->common
, "source", bs
, 0,
1662 BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
|
1663 BLK_PERM_CONSISTENT_READ
,
1669 /* Required permissions are already taken with blk_new() */
1670 block_job_add_bdrv(&s
->common
, "target", target
, 0, BLK_PERM_ALL
,
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
,
1690 if (bdrv_freeze_backing_chain(mirror_top_bs
, target
, errp
) < 0) {
1695 QTAILQ_INIT(&s
->ops_in_flight
);
1697 trace_mirror_start(bs
, s
, opaque
);
1698 job_start(&s
->common
.job
);
1704 /* Make sure this BDS does not go away until we have completed the graph
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
,
1720 bdrv_replace_node(mirror_top_bs
, backing_bs(mirror_top_bs
), &error_abort
);
1722 bdrv_unref(mirror_top_bs
);
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
,
1733 BlockdevOnError on_source_error
,
1734 BlockdevOnError on_target_error
,
1735 bool unmap
, const char *filter_node_name
,
1736 MirrorCopyMode copy_mode
, Error
**errp
)
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
));
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
;
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) {
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
,
1783 error_propagate(errp
, local_err
);
1784 goto error_restore_flags
;
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
);