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 "block/dirty-bitmap.h"
22 #include "sysemu/block-backend.h"
23 #include "qapi/error.h"
24 #include "qemu/ratelimit.h"
25 #include "qemu/bitmap.h"
26 #include "qemu/memalign.h"
28 #define MAX_IN_FLIGHT 16
29 #define MAX_IO_BYTES (1 << 20) /* 1 Mb */
30 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES)
32 /* The mirroring buffer is a list of granularity-sized chunks.
33 * Free chunks are organized in a list.
35 typedef struct MirrorBuffer
{
36 QSIMPLEQ_ENTRY(MirrorBuffer
) next
;
39 typedef struct MirrorOp MirrorOp
;
41 typedef struct MirrorBlockJob
{
44 BlockDriverState
*mirror_top_bs
;
45 BlockDriverState
*base
;
46 BlockDriverState
*base_overlay
;
48 /* The name of the graph node to replace */
50 /* The BDS to replace */
51 BlockDriverState
*to_replace
;
52 /* Used to block operations on the drive-mirror-replace target */
53 Error
*replace_blocker
;
55 BlockMirrorBackingMode backing_mode
;
56 /* Whether the target image requires explicit zero-initialization */
59 * To be accesssed with atomics. Written only under the BQL (required by the
60 * current implementation of mirror_change()).
62 MirrorCopyMode copy_mode
;
63 BlockdevOnError on_source_error
, on_target_error
;
65 * To be accessed with atomics.
67 * Set when the target is synced (dirty bitmap is clean, nothing in flight)
68 * and the job is running in active mode.
75 unsigned long *cow_bitmap
;
76 BdrvDirtyBitmap
*dirty_bitmap
;
77 BdrvDirtyBitmapIter
*dbi
;
79 QSIMPLEQ_HEAD(, MirrorBuffer
) buf_free
;
82 uint64_t last_pause_ns
;
83 unsigned long *in_flight_bitmap
;
85 int64_t bytes_in_flight
;
86 QTAILQ_HEAD(, MirrorOp
) ops_in_flight
;
89 int target_cluster_size
;
91 bool initial_zeroing_ongoing
;
92 int in_active_write_counter
;
93 int64_t active_write_bytes_in_flight
;
99 typedef struct MirrorBDSOpaque
{
111 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and
112 * mirror_co_discard() before yielding for the first time */
113 int64_t *bytes_handled
;
116 bool is_active_write
;
118 CoQueue waiting_requests
;
120 MirrorOp
*waiting_for_op
;
122 QTAILQ_ENTRY(MirrorOp
) next
;
125 typedef enum MirrorMethod
{
128 MIRROR_METHOD_DISCARD
,
131 static BlockErrorAction
mirror_error_action(MirrorBlockJob
*s
, bool read
,
134 qatomic_set(&s
->actively_synced
, false);
136 return block_job_error_action(&s
->common
, s
->on_source_error
,
139 return block_job_error_action(&s
->common
, s
->on_target_error
,
144 static void coroutine_fn
mirror_wait_on_conflicts(MirrorOp
*self
,
149 uint64_t self_start_chunk
= offset
/ s
->granularity
;
150 uint64_t self_end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
151 uint64_t self_nb_chunks
= self_end_chunk
- self_start_chunk
;
153 while (find_next_bit(s
->in_flight_bitmap
, self_end_chunk
,
154 self_start_chunk
) < self_end_chunk
&&
159 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
160 uint64_t op_start_chunk
= op
->offset
/ s
->granularity
;
161 uint64_t op_nb_chunks
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
169 if (ranges_overlap(self_start_chunk
, self_nb_chunks
,
170 op_start_chunk
, op_nb_chunks
))
174 * If the operation is already (indirectly) waiting for us,
175 * or will wait for us as soon as it wakes up, then just go
176 * on (instead of producing a deadlock in the former case).
178 if (op
->waiting_for_op
) {
182 self
->waiting_for_op
= op
;
185 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
188 self
->waiting_for_op
= NULL
;
197 static void coroutine_fn
mirror_iteration_done(MirrorOp
*op
, int ret
)
199 MirrorBlockJob
*s
= op
->s
;
204 trace_mirror_iteration_done(s
, op
->offset
, op
->bytes
, ret
);
207 s
->bytes_in_flight
-= op
->bytes
;
209 for (i
= 0; i
< op
->qiov
.niov
; i
++) {
210 MirrorBuffer
*buf
= (MirrorBuffer
*) iov
[i
].iov_base
;
211 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, buf
, next
);
215 chunk_num
= op
->offset
/ s
->granularity
;
216 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
218 bitmap_clear(s
->in_flight_bitmap
, chunk_num
, nb_chunks
);
219 QTAILQ_REMOVE(&s
->ops_in_flight
, op
, next
);
222 bitmap_set(s
->cow_bitmap
, chunk_num
, nb_chunks
);
224 if (!s
->initial_zeroing_ongoing
) {
225 job_progress_update(&s
->common
.job
, op
->bytes
);
228 qemu_iovec_destroy(&op
->qiov
);
230 qemu_co_queue_restart_all(&op
->waiting_requests
);
234 static void coroutine_fn
mirror_write_complete(MirrorOp
*op
, int ret
)
236 MirrorBlockJob
*s
= op
->s
;
239 BlockErrorAction action
;
241 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
242 action
= mirror_error_action(s
, false, -ret
);
243 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
248 mirror_iteration_done(op
, ret
);
251 static void coroutine_fn
mirror_read_complete(MirrorOp
*op
, int ret
)
253 MirrorBlockJob
*s
= op
->s
;
256 BlockErrorAction action
;
258 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
259 action
= mirror_error_action(s
, true, -ret
);
260 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
264 mirror_iteration_done(op
, ret
);
268 ret
= blk_co_pwritev(s
->target
, op
->offset
, op
->qiov
.size
, &op
->qiov
, 0);
269 mirror_write_complete(op
, ret
);
272 /* Clip bytes relative to offset to not exceed end-of-file */
273 static inline int64_t mirror_clip_bytes(MirrorBlockJob
*s
,
277 return MIN(bytes
, s
->bdev_length
- offset
);
280 /* Round offset and/or bytes to target cluster if COW is needed, and
281 * return the offset of the adjusted tail against original. */
282 static int coroutine_fn
mirror_cow_align(MirrorBlockJob
*s
, int64_t *offset
,
287 int64_t align_offset
= *offset
;
288 int64_t align_bytes
= *bytes
;
289 int max_bytes
= s
->granularity
* s
->max_iov
;
291 need_cow
= !test_bit(*offset
/ s
->granularity
, s
->cow_bitmap
);
292 need_cow
|= !test_bit((*offset
+ *bytes
- 1) / s
->granularity
,
295 bdrv_round_to_subclusters(blk_bs(s
->target
), *offset
, *bytes
,
296 &align_offset
, &align_bytes
);
299 if (align_bytes
> max_bytes
) {
300 align_bytes
= max_bytes
;
302 align_bytes
= QEMU_ALIGN_DOWN(align_bytes
, s
->target_cluster_size
);
305 /* Clipping may result in align_bytes unaligned to chunk boundary, but
306 * that doesn't matter because it's already the end of source image. */
307 align_bytes
= mirror_clip_bytes(s
, align_offset
, align_bytes
);
309 ret
= align_offset
+ align_bytes
- (*offset
+ *bytes
);
310 *offset
= align_offset
;
311 *bytes
= align_bytes
;
316 static inline void coroutine_fn
317 mirror_wait_for_free_in_flight_slot(MirrorBlockJob
*s
)
321 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
323 * Do not wait on pseudo ops, because it may in turn wait on
324 * some other operation to start, which may in fact be the
325 * caller of this function. Since there is only one pseudo op
326 * at any given time, we will always find some real operation
328 * Also, do not wait on active operations, because they do not
329 * use up in-flight slots.
331 if (!op
->is_pseudo_op
&& op
->is_in_flight
&& !op
->is_active_write
) {
332 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
339 /* Perform a mirror copy operation.
341 * *op->bytes_handled is set to the number of bytes copied after and
342 * including offset, excluding any bytes copied prior to offset due
343 * to alignment. This will be op->bytes if no alignment is necessary,
344 * or (new_end - op->offset) if the tail is rounded up or down due to
345 * alignment or buffer limit.
347 static void coroutine_fn
mirror_co_read(void *opaque
)
349 MirrorOp
*op
= opaque
;
350 MirrorBlockJob
*s
= op
->s
;
355 max_bytes
= s
->granularity
* s
->max_iov
;
357 /* We can only handle as much as buf_size at a time. */
358 op
->bytes
= MIN(s
->buf_size
, MIN(max_bytes
, op
->bytes
));
360 assert(op
->bytes
< BDRV_REQUEST_MAX_BYTES
);
361 *op
->bytes_handled
= op
->bytes
;
364 *op
->bytes_handled
+= mirror_cow_align(s
, &op
->offset
, &op
->bytes
);
366 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
367 assert(*op
->bytes_handled
<= UINT_MAX
);
368 assert(op
->bytes
<= s
->buf_size
);
369 /* The offset is granularity-aligned because:
370 * 1) Caller passes in aligned values;
371 * 2) mirror_cow_align is used only when target cluster is larger. */
372 assert(QEMU_IS_ALIGNED(op
->offset
, s
->granularity
));
373 /* The range is sector-aligned, since bdrv_getlength() rounds up. */
374 assert(QEMU_IS_ALIGNED(op
->bytes
, BDRV_SECTOR_SIZE
));
375 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
377 while (s
->buf_free_count
< nb_chunks
) {
378 trace_mirror_yield_in_flight(s
, op
->offset
, s
->in_flight
);
379 mirror_wait_for_free_in_flight_slot(s
);
382 /* Now make a QEMUIOVector taking enough granularity-sized chunks
385 qemu_iovec_init(&op
->qiov
, nb_chunks
);
386 while (nb_chunks
-- > 0) {
387 MirrorBuffer
*buf
= QSIMPLEQ_FIRST(&s
->buf_free
);
388 size_t remaining
= op
->bytes
- op
->qiov
.size
;
390 QSIMPLEQ_REMOVE_HEAD(&s
->buf_free
, next
);
392 qemu_iovec_add(&op
->qiov
, buf
, MIN(s
->granularity
, remaining
));
395 /* Copy the dirty cluster. */
397 s
->bytes_in_flight
+= op
->bytes
;
398 op
->is_in_flight
= true;
399 trace_mirror_one_iteration(s
, op
->offset
, op
->bytes
);
401 WITH_GRAPH_RDLOCK_GUARD() {
402 ret
= bdrv_co_preadv(s
->mirror_top_bs
->backing
, op
->offset
, op
->bytes
,
405 mirror_read_complete(op
, ret
);
408 static void coroutine_fn
mirror_co_zero(void *opaque
)
410 MirrorOp
*op
= opaque
;
414 op
->s
->bytes_in_flight
+= op
->bytes
;
415 *op
->bytes_handled
= op
->bytes
;
416 op
->is_in_flight
= true;
418 ret
= blk_co_pwrite_zeroes(op
->s
->target
, op
->offset
, op
->bytes
,
419 op
->s
->unmap
? BDRV_REQ_MAY_UNMAP
: 0);
420 mirror_write_complete(op
, ret
);
423 static void coroutine_fn
mirror_co_discard(void *opaque
)
425 MirrorOp
*op
= opaque
;
429 op
->s
->bytes_in_flight
+= op
->bytes
;
430 *op
->bytes_handled
= op
->bytes
;
431 op
->is_in_flight
= true;
433 ret
= blk_co_pdiscard(op
->s
->target
, op
->offset
, op
->bytes
);
434 mirror_write_complete(op
, ret
);
437 static unsigned mirror_perform(MirrorBlockJob
*s
, int64_t offset
,
438 unsigned bytes
, MirrorMethod mirror_method
)
442 int64_t bytes_handled
= -1;
444 op
= g_new(MirrorOp
, 1);
449 .bytes_handled
= &bytes_handled
,
451 qemu_co_queue_init(&op
->waiting_requests
);
453 switch (mirror_method
) {
454 case MIRROR_METHOD_COPY
:
455 co
= qemu_coroutine_create(mirror_co_read
, op
);
457 case MIRROR_METHOD_ZERO
:
458 co
= qemu_coroutine_create(mirror_co_zero
, op
);
460 case MIRROR_METHOD_DISCARD
:
461 co
= qemu_coroutine_create(mirror_co_discard
, op
);
468 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
469 qemu_coroutine_enter(co
);
470 /* At this point, ownership of op has been moved to the coroutine
471 * and the object may already be freed */
473 /* Assert that this value has been set */
474 assert(bytes_handled
>= 0);
476 /* Same assertion as in mirror_co_read() (and for mirror_co_read()
477 * and mirror_co_discard(), bytes_handled == op->bytes, which
478 * is the @bytes parameter given to this function) */
479 assert(bytes_handled
<= UINT_MAX
);
480 return bytes_handled
;
483 static void coroutine_fn GRAPH_UNLOCKED
mirror_iteration(MirrorBlockJob
*s
)
485 BlockDriverState
*source
;
488 /* At least the first dirty chunk is mirrored in one iteration. */
490 bool write_zeroes_ok
= bdrv_can_write_zeroes_with_unmap(blk_bs(s
->target
));
491 int max_io_bytes
= MAX(s
->buf_size
/ MAX_IN_FLIGHT
, MAX_IO_BYTES
);
493 bdrv_graph_co_rdlock();
494 source
= s
->mirror_top_bs
->backing
->bs
;
495 bdrv_graph_co_rdunlock();
497 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
498 offset
= bdrv_dirty_iter_next(s
->dbi
);
500 bdrv_set_dirty_iter(s
->dbi
, 0);
501 offset
= bdrv_dirty_iter_next(s
->dbi
);
502 trace_mirror_restart_iter(s
, bdrv_get_dirty_count(s
->dirty_bitmap
));
505 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
508 * Wait for concurrent requests to @offset. The next loop will limit the
509 * copied area based on in_flight_bitmap so we only copy an area that does
510 * not overlap with concurrent in-flight requests. Still, we would like to
511 * copy something, so wait until there are at least no more requests to the
512 * very beginning of the area.
514 mirror_wait_on_conflicts(NULL
, s
, offset
, 1);
516 job_pause_point(&s
->common
.job
);
518 /* Find the number of consecutive dirty chunks following the first dirty
519 * one, and wait for in flight requests in them. */
520 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
521 while (nb_chunks
* s
->granularity
< s
->buf_size
) {
523 int64_t next_offset
= offset
+ nb_chunks
* s
->granularity
;
524 int64_t next_chunk
= next_offset
/ s
->granularity
;
525 if (next_offset
>= s
->bdev_length
||
526 !bdrv_dirty_bitmap_get_locked(s
->dirty_bitmap
, next_offset
)) {
529 if (test_bit(next_chunk
, s
->in_flight_bitmap
)) {
533 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
534 if (next_dirty
> next_offset
|| next_dirty
< 0) {
535 /* The bitmap iterator's cache is stale, refresh it */
536 bdrv_set_dirty_iter(s
->dbi
, next_offset
);
537 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
539 assert(next_dirty
== next_offset
);
543 /* Clear dirty bits before querying the block status, because
544 * calling bdrv_block_status_above could yield - if some blocks are
545 * marked dirty in this window, we need to know.
547 bdrv_reset_dirty_bitmap_locked(s
->dirty_bitmap
, offset
,
548 nb_chunks
* s
->granularity
);
549 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
551 /* Before claiming an area in the in-flight bitmap, we have to
552 * create a MirrorOp for it so that conflicting requests can wait
553 * for it. mirror_perform() will create the real MirrorOps later,
554 * for now we just create a pseudo operation that will wake up all
555 * conflicting requests once all real operations have been
557 pseudo_op
= g_new(MirrorOp
, 1);
558 *pseudo_op
= (MirrorOp
){
560 .bytes
= nb_chunks
* s
->granularity
,
561 .is_pseudo_op
= true,
563 qemu_co_queue_init(&pseudo_op
->waiting_requests
);
564 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, pseudo_op
, next
);
566 bitmap_set(s
->in_flight_bitmap
, offset
/ s
->granularity
, nb_chunks
);
567 while (nb_chunks
> 0 && offset
< s
->bdev_length
) {
570 int64_t io_bytes_acct
;
571 MirrorMethod mirror_method
= MIRROR_METHOD_COPY
;
573 assert(!(offset
% s
->granularity
));
574 WITH_GRAPH_RDLOCK_GUARD() {
575 ret
= bdrv_co_block_status_above(source
, NULL
, offset
,
576 nb_chunks
* s
->granularity
,
577 &io_bytes
, NULL
, NULL
);
580 io_bytes
= MIN(nb_chunks
* s
->granularity
, max_io_bytes
);
581 } else if (ret
& BDRV_BLOCK_DATA
) {
582 io_bytes
= MIN(io_bytes
, max_io_bytes
);
585 io_bytes
-= io_bytes
% s
->granularity
;
586 if (io_bytes
< s
->granularity
) {
587 io_bytes
= s
->granularity
;
588 } else if (ret
>= 0 && !(ret
& BDRV_BLOCK_DATA
)) {
589 int64_t target_offset
;
590 int64_t target_bytes
;
591 WITH_GRAPH_RDLOCK_GUARD() {
592 bdrv_round_to_subclusters(blk_bs(s
->target
), offset
, io_bytes
,
593 &target_offset
, &target_bytes
);
595 if (target_offset
== offset
&&
596 target_bytes
== io_bytes
) {
597 mirror_method
= ret
& BDRV_BLOCK_ZERO
?
599 MIRROR_METHOD_DISCARD
;
603 while (s
->in_flight
>= MAX_IN_FLIGHT
) {
604 trace_mirror_yield_in_flight(s
, offset
, s
->in_flight
);
605 mirror_wait_for_free_in_flight_slot(s
);
613 io_bytes
= mirror_clip_bytes(s
, offset
, io_bytes
);
614 io_bytes
= mirror_perform(s
, offset
, io_bytes
, mirror_method
);
615 if (mirror_method
!= MIRROR_METHOD_COPY
&& write_zeroes_ok
) {
618 io_bytes_acct
= io_bytes
;
622 nb_chunks
-= DIV_ROUND_UP(io_bytes
, s
->granularity
);
623 block_job_ratelimit_processed_bytes(&s
->common
, io_bytes_acct
);
627 QTAILQ_REMOVE(&s
->ops_in_flight
, pseudo_op
, next
);
628 qemu_co_queue_restart_all(&pseudo_op
->waiting_requests
);
632 static void mirror_free_init(MirrorBlockJob
*s
)
634 int granularity
= s
->granularity
;
635 size_t buf_size
= s
->buf_size
;
636 uint8_t *buf
= s
->buf
;
638 assert(s
->buf_free_count
== 0);
639 QSIMPLEQ_INIT(&s
->buf_free
);
640 while (buf_size
!= 0) {
641 MirrorBuffer
*cur
= (MirrorBuffer
*)buf
;
642 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, cur
, next
);
644 buf_size
-= granularity
;
649 /* This is also used for the .pause callback. There is no matching
650 * mirror_resume() because mirror_run() will begin iterating again
651 * when the job is resumed.
653 static void coroutine_fn
mirror_wait_for_all_io(MirrorBlockJob
*s
)
655 while (s
->in_flight
> 0) {
656 mirror_wait_for_free_in_flight_slot(s
);
661 * mirror_exit_common: handle both abort() and prepare() cases.
662 * for .prepare, returns 0 on success and -errno on failure.
663 * for .abort cases, denoted by abort = true, MUST return 0.
665 static int mirror_exit_common(Job
*job
)
667 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
668 BlockJob
*bjob
= &s
->common
;
669 MirrorBDSOpaque
*bs_opaque
;
670 BlockDriverState
*src
;
671 BlockDriverState
*target_bs
;
672 BlockDriverState
*mirror_top_bs
;
673 Error
*local_err
= NULL
;
674 bool abort
= job
->ret
< 0;
684 bdrv_graph_rdlock_main_loop();
686 mirror_top_bs
= s
->mirror_top_bs
;
687 bs_opaque
= mirror_top_bs
->opaque
;
688 src
= mirror_top_bs
->backing
->bs
;
689 target_bs
= blk_bs(s
->target
);
691 if (bdrv_chain_contains(src
, target_bs
)) {
692 bdrv_unfreeze_backing_chain(mirror_top_bs
, target_bs
);
695 bdrv_release_dirty_bitmap(s
->dirty_bitmap
);
697 /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
698 * before we can call bdrv_drained_end */
700 bdrv_ref(mirror_top_bs
);
703 bdrv_graph_rdunlock_main_loop();
706 * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
707 * inserting target_bs at s->to_replace, where we might not be able to get
710 blk_unref(s
->target
);
713 /* We don't access the source any more. Dropping any WRITE/RESIZE is
714 * required before it could become a backing file of target_bs. Not having
715 * these permissions any more means that we can't allow any new requests on
716 * mirror_top_bs from now on, so keep it drained. */
717 bdrv_drained_begin(mirror_top_bs
);
718 bdrv_drained_begin(target_bs
);
719 bs_opaque
->stop
= true;
721 bdrv_graph_rdlock_main_loop();
722 bdrv_child_refresh_perms(mirror_top_bs
, mirror_top_bs
->backing
,
725 if (!abort
&& s
->backing_mode
== MIRROR_SOURCE_BACKING_CHAIN
) {
726 BlockDriverState
*backing
= s
->is_none_mode
? src
: s
->base
;
727 BlockDriverState
*unfiltered_target
= bdrv_skip_filters(target_bs
);
729 if (bdrv_cow_bs(unfiltered_target
) != backing
) {
730 bdrv_set_backing_hd(unfiltered_target
, backing
, &local_err
);
732 error_report_err(local_err
);
737 } else if (!abort
&& s
->backing_mode
== MIRROR_OPEN_BACKING_CHAIN
) {
738 assert(!bdrv_backing_chain_next(target_bs
));
739 ret
= bdrv_open_backing_file(bdrv_skip_filters(target_bs
), NULL
,
740 "backing", &local_err
);
742 error_report_err(local_err
);
746 bdrv_graph_rdunlock_main_loop();
748 if (s
->should_complete
&& !abort
) {
749 BlockDriverState
*to_replace
= s
->to_replace
?: src
;
750 bool ro
= bdrv_is_read_only(to_replace
);
752 if (ro
!= bdrv_is_read_only(target_bs
)) {
753 bdrv_reopen_set_read_only(target_bs
, ro
, NULL
);
756 /* The mirror job has no requests in flight any more, but we need to
757 * drain potential other users of the BDS before changing the graph. */
759 bdrv_drained_begin(to_replace
);
761 * Cannot use check_to_replace_node() here, because that would
762 * check for an op blocker on @to_replace, and we have our own
766 if (bdrv_recurse_can_replace(src
, to_replace
)) {
767 bdrv_replace_node(to_replace
, target_bs
, &local_err
);
769 error_setg(&local_err
, "Can no longer replace '%s' by '%s', "
770 "because it can no longer be guaranteed that doing so "
771 "would not lead to an abrupt change of visible data",
772 to_replace
->node_name
, target_bs
->node_name
);
774 bdrv_graph_wrunlock();
775 bdrv_drained_end(to_replace
);
777 error_report_err(local_err
);
782 bdrv_op_unblock_all(s
->to_replace
, s
->replace_blocker
);
783 error_free(s
->replace_blocker
);
784 bdrv_unref(s
->to_replace
);
789 * Remove the mirror filter driver from the graph. Before this, get rid of
790 * the blockers on the intermediate nodes so that the resulting state is
793 block_job_remove_all_bdrv(bjob
);
795 bdrv_replace_node(mirror_top_bs
, mirror_top_bs
->backing
->bs
, &error_abort
);
796 bdrv_graph_wrunlock();
798 if (abort
&& s
->base_ro
&& !bdrv_is_read_only(target_bs
)) {
799 bdrv_reopen_set_read_only(target_bs
, true, NULL
);
802 bdrv_drained_end(target_bs
);
803 bdrv_unref(target_bs
);
805 bs_opaque
->job
= NULL
;
807 bdrv_drained_end(src
);
808 bdrv_drained_end(mirror_top_bs
);
810 bdrv_unref(mirror_top_bs
);
816 static int mirror_prepare(Job
*job
)
818 return mirror_exit_common(job
);
821 static void mirror_abort(Job
*job
)
823 int ret
= mirror_exit_common(job
);
827 static void coroutine_fn
mirror_throttle(MirrorBlockJob
*s
)
829 int64_t now
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
831 if (now
- s
->last_pause_ns
> BLOCK_JOB_SLICE_TIME
) {
832 s
->last_pause_ns
= now
;
833 job_sleep_ns(&s
->common
.job
, 0);
835 job_pause_point(&s
->common
.job
);
839 static int coroutine_fn GRAPH_UNLOCKED
mirror_dirty_init(MirrorBlockJob
*s
)
842 BlockDriverState
*bs
;
843 BlockDriverState
*target_bs
= blk_bs(s
->target
);
847 bdrv_graph_co_rdlock();
848 bs
= s
->mirror_top_bs
->backing
->bs
;
849 bdrv_graph_co_rdunlock();
851 if (s
->zero_target
) {
852 if (!bdrv_can_write_zeroes_with_unmap(target_bs
)) {
853 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, 0, s
->bdev_length
);
857 s
->initial_zeroing_ongoing
= true;
858 for (offset
= 0; offset
< s
->bdev_length
; ) {
859 int bytes
= MIN(s
->bdev_length
- offset
,
860 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
864 if (job_is_cancelled(&s
->common
.job
)) {
865 s
->initial_zeroing_ongoing
= false;
869 if (s
->in_flight
>= MAX_IN_FLIGHT
) {
870 trace_mirror_yield(s
, UINT64_MAX
, s
->buf_free_count
,
872 mirror_wait_for_free_in_flight_slot(s
);
876 mirror_perform(s
, offset
, bytes
, MIRROR_METHOD_ZERO
);
880 mirror_wait_for_all_io(s
);
881 s
->initial_zeroing_ongoing
= false;
884 /* First part, loop on the sectors and initialize the dirty bitmap. */
885 for (offset
= 0; offset
< s
->bdev_length
; ) {
886 /* Just to make sure we are not exceeding int limit. */
887 int bytes
= MIN(s
->bdev_length
- offset
,
888 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
892 if (job_is_cancelled(&s
->common
.job
)) {
896 WITH_GRAPH_RDLOCK_GUARD() {
897 ret
= bdrv_co_is_allocated_above(bs
, s
->base_overlay
, true, offset
,
906 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, offset
, count
);
913 /* Called when going out of the streaming phase to flush the bulk of the
914 * data to the medium, or just before completing.
916 static int coroutine_fn
mirror_flush(MirrorBlockJob
*s
)
918 int ret
= blk_co_flush(s
->target
);
920 if (mirror_error_action(s
, false, -ret
) == BLOCK_ERROR_ACTION_REPORT
) {
927 static int coroutine_fn
mirror_run(Job
*job
, Error
**errp
)
929 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
930 BlockDriverState
*bs
;
931 MirrorBDSOpaque
*mirror_top_opaque
= s
->mirror_top_bs
->opaque
;
932 BlockDriverState
*target_bs
= blk_bs(s
->target
);
933 bool need_drain
= true;
934 BlockDeviceIoStatus iostatus
;
936 int64_t target_length
;
938 char backing_filename
[2]; /* we only need 2 characters because we are only
939 checking for a NULL string */
942 bdrv_graph_co_rdlock();
943 bs
= bdrv_filter_bs(s
->mirror_top_bs
);
944 bdrv_graph_co_rdunlock();
946 if (job_is_cancelled(&s
->common
.job
)) {
950 bdrv_graph_co_rdlock();
951 s
->bdev_length
= bdrv_co_getlength(bs
);
952 bdrv_graph_co_rdunlock();
954 if (s
->bdev_length
< 0) {
955 ret
= s
->bdev_length
;
959 target_length
= blk_co_getlength(s
->target
);
960 if (target_length
< 0) {
965 /* Active commit must resize the base image if its size differs from the
967 if (s
->base
== blk_bs(s
->target
)) {
968 if (s
->bdev_length
> target_length
) {
969 ret
= blk_co_truncate(s
->target
, s
->bdev_length
, false,
970 PREALLOC_MODE_OFF
, 0, NULL
);
975 } else if (s
->bdev_length
!= target_length
) {
976 error_setg(errp
, "Source and target image have different sizes");
981 if (s
->bdev_length
== 0) {
982 /* Transition to the READY state and wait for complete. */
983 job_transition_to_ready(&s
->common
.job
);
984 qatomic_set(&s
->actively_synced
, true);
985 while (!job_cancel_requested(&s
->common
.job
) && !s
->should_complete
) {
986 job_yield(&s
->common
.job
);
991 length
= DIV_ROUND_UP(s
->bdev_length
, s
->granularity
);
992 s
->in_flight_bitmap
= bitmap_new(length
);
994 /* If we have no backing file yet in the destination, we cannot let
995 * the destination do COW. Instead, we copy sectors around the
996 * dirty data if needed. We need a bitmap to do that.
998 bdrv_get_backing_filename(target_bs
, backing_filename
,
999 sizeof(backing_filename
));
1000 bdrv_graph_co_rdlock();
1001 if (!bdrv_co_get_info(target_bs
, &bdi
) && bdi
.cluster_size
) {
1002 s
->target_cluster_size
= bdi
.cluster_size
;
1004 s
->target_cluster_size
= BDRV_SECTOR_SIZE
;
1006 if (backing_filename
[0] && !bdrv_backing_chain_next(target_bs
) &&
1007 s
->granularity
< s
->target_cluster_size
) {
1008 s
->buf_size
= MAX(s
->buf_size
, s
->target_cluster_size
);
1009 s
->cow_bitmap
= bitmap_new(length
);
1011 s
->max_iov
= MIN(bs
->bl
.max_iov
, target_bs
->bl
.max_iov
);
1012 bdrv_graph_co_rdunlock();
1014 s
->buf
= qemu_try_blockalign(bs
, s
->buf_size
);
1015 if (s
->buf
== NULL
) {
1017 goto immediate_exit
;
1020 mirror_free_init(s
);
1022 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
1023 if (!s
->is_none_mode
) {
1024 ret
= mirror_dirty_init(s
);
1025 if (ret
< 0 || job_is_cancelled(&s
->common
.job
)) {
1026 goto immediate_exit
;
1031 * Only now the job is fully initialised and mirror_top_bs should start
1034 mirror_top_opaque
->job
= s
;
1037 s
->dbi
= bdrv_dirty_iter_new(s
->dirty_bitmap
);
1040 bool should_complete
;
1044 goto immediate_exit
;
1047 job_pause_point(&s
->common
.job
);
1049 if (job_is_cancelled(&s
->common
.job
)) {
1051 goto immediate_exit
;
1054 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1055 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
1056 * the number of bytes currently being processed; together those are
1057 * the current remaining operation length */
1058 job_progress_set_remaining(&s
->common
.job
,
1059 s
->bytes_in_flight
+ cnt
+
1060 s
->active_write_bytes_in_flight
);
1062 /* Note that even when no rate limit is applied we need to yield
1063 * periodically with no pending I/O so that bdrv_drain_all() returns.
1064 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
1065 * an error, or when the source is clean, whichever comes first. */
1066 delta
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
) - s
->last_pause_ns
;
1067 WITH_JOB_LOCK_GUARD() {
1068 iostatus
= s
->common
.iostatus
;
1070 if (delta
< BLOCK_JOB_SLICE_TIME
&&
1071 iostatus
== BLOCK_DEVICE_IO_STATUS_OK
) {
1072 if (s
->in_flight
>= MAX_IN_FLIGHT
|| s
->buf_free_count
== 0 ||
1073 (cnt
== 0 && s
->in_flight
> 0)) {
1074 trace_mirror_yield(s
, cnt
, s
->buf_free_count
, s
->in_flight
);
1075 mirror_wait_for_free_in_flight_slot(s
);
1077 } else if (cnt
!= 0) {
1078 mirror_iteration(s
);
1082 should_complete
= false;
1083 if (s
->in_flight
== 0 && cnt
== 0) {
1084 trace_mirror_before_flush(s
);
1085 if (!job_is_ready(&s
->common
.job
)) {
1086 if (mirror_flush(s
) < 0) {
1087 /* Go check s->ret. */
1090 /* We're out of the streaming phase. From now on, if the job
1091 * is cancelled we will actually complete all pending I/O and
1092 * report completion. This way, block-job-cancel will leave
1093 * the target in a consistent state.
1095 job_transition_to_ready(&s
->common
.job
);
1097 if (qatomic_read(&s
->copy_mode
) != MIRROR_COPY_MODE_BACKGROUND
) {
1098 qatomic_set(&s
->actively_synced
, true);
1101 should_complete
= s
->should_complete
||
1102 job_cancel_requested(&s
->common
.job
);
1103 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1106 if (cnt
== 0 && should_complete
) {
1107 /* The dirty bitmap is not updated while operations are pending.
1108 * If we're about to exit, wait for pending operations before
1109 * calling bdrv_get_dirty_count(bs), or we may exit while the
1110 * source has dirty data to copy!
1112 * Note that I/O can be submitted by the guest while
1113 * mirror_populate runs, so pause it now. Before deciding
1114 * whether to switch to target check one last time if I/O has
1115 * come in the meanwhile, and if not flush the data to disk.
1117 trace_mirror_before_drain(s
, cnt
);
1120 bdrv_drained_begin(bs
);
1122 /* Must be zero because we are drained */
1123 assert(s
->in_active_write_counter
== 0);
1125 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1126 if (cnt
> 0 || mirror_flush(s
) < 0) {
1127 bdrv_drained_end(bs
);
1128 s
->in_drain
= false;
1132 /* The two disks are in sync. Exit and report successful
1135 assert(QLIST_EMPTY(&bs
->tracked_requests
));
1140 if (job_is_ready(&s
->common
.job
) && !should_complete
) {
1141 if (s
->in_flight
== 0 && cnt
== 0) {
1142 trace_mirror_before_sleep(s
, cnt
, job_is_ready(&s
->common
.job
),
1143 BLOCK_JOB_SLICE_TIME
);
1144 job_sleep_ns(&s
->common
.job
, BLOCK_JOB_SLICE_TIME
);
1147 block_job_ratelimit_sleep(&s
->common
);
1149 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
1153 if (s
->in_flight
> 0) {
1154 /* We get here only if something went wrong. Either the job failed,
1155 * or it was cancelled prematurely so that we do not guarantee that
1156 * the target is a copy of the source.
1158 assert(ret
< 0 || job_is_cancelled(&s
->common
.job
));
1160 mirror_wait_for_all_io(s
);
1163 assert(s
->in_flight
== 0);
1165 g_free(s
->cow_bitmap
);
1166 g_free(s
->in_flight_bitmap
);
1167 bdrv_dirty_iter_free(s
->dbi
);
1171 bdrv_drained_begin(bs
);
1177 static void mirror_complete(Job
*job
, Error
**errp
)
1179 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1181 if (!job_is_ready(job
)) {
1182 error_setg(errp
, "The active block job '%s' cannot be completed",
1187 /* block all operations on to_replace bs */
1189 s
->to_replace
= bdrv_find_node(s
->replaces
);
1190 if (!s
->to_replace
) {
1191 error_setg(errp
, "Node name '%s' not found", s
->replaces
);
1195 /* TODO Translate this into child freeze system. */
1196 error_setg(&s
->replace_blocker
,
1197 "block device is in use by block-job-complete");
1198 bdrv_op_block_all(s
->to_replace
, s
->replace_blocker
);
1199 bdrv_ref(s
->to_replace
);
1202 s
->should_complete
= true;
1204 /* If the job is paused, it will be re-entered when it is resumed */
1205 WITH_JOB_LOCK_GUARD() {
1207 job_enter_cond_locked(job
, NULL
);
1212 static void coroutine_fn
mirror_pause(Job
*job
)
1214 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1216 mirror_wait_for_all_io(s
);
1219 static bool mirror_drained_poll(BlockJob
*job
)
1221 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1223 /* If the job isn't paused nor cancelled, we can't be sure that it won't
1224 * issue more requests. We make an exception if we've reached this point
1225 * from one of our own drain sections, to avoid a deadlock waiting for
1228 WITH_JOB_LOCK_GUARD() {
1229 if (!s
->common
.job
.paused
&& !job_is_cancelled_locked(&job
->job
)
1235 return !!s
->in_flight
;
1238 static bool mirror_cancel(Job
*job
, bool force
)
1240 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1241 BlockDriverState
*target
= blk_bs(s
->target
);
1244 * Before the job is READY, we treat any cancellation like a
1245 * force-cancellation.
1247 force
= force
|| !job_is_ready(job
);
1250 bdrv_cancel_in_flight(target
);
1255 static bool commit_active_cancel(Job
*job
, bool force
)
1257 /* Same as above in mirror_cancel() */
1258 return force
|| !job_is_ready(job
);
1261 static void mirror_change(BlockJob
*job
, BlockJobChangeOptions
*opts
,
1264 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1265 BlockJobChangeOptionsMirror
*change_opts
= &opts
->u
.mirror
;
1266 MirrorCopyMode current
;
1269 * The implementation relies on the fact that copy_mode is only written
1270 * under the BQL. Otherwise, further synchronization would be required.
1273 GLOBAL_STATE_CODE();
1275 if (qatomic_read(&s
->copy_mode
) == change_opts
->copy_mode
) {
1279 if (change_opts
->copy_mode
!= MIRROR_COPY_MODE_WRITE_BLOCKING
) {
1280 error_setg(errp
, "Change to copy mode '%s' is not implemented",
1281 MirrorCopyMode_str(change_opts
->copy_mode
));
1285 current
= qatomic_cmpxchg(&s
->copy_mode
, MIRROR_COPY_MODE_BACKGROUND
,
1286 change_opts
->copy_mode
);
1287 if (current
!= MIRROR_COPY_MODE_BACKGROUND
) {
1288 error_setg(errp
, "Expected current copy mode '%s', got '%s'",
1289 MirrorCopyMode_str(MIRROR_COPY_MODE_BACKGROUND
),
1290 MirrorCopyMode_str(current
));
1294 static void mirror_query(BlockJob
*job
, BlockJobInfo
*info
)
1296 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1298 info
->u
.mirror
= (BlockJobInfoMirror
) {
1299 .actively_synced
= qatomic_read(&s
->actively_synced
),
1303 static const BlockJobDriver mirror_job_driver
= {
1305 .instance_size
= sizeof(MirrorBlockJob
),
1306 .job_type
= JOB_TYPE_MIRROR
,
1307 .free
= block_job_free
,
1308 .user_resume
= block_job_user_resume
,
1310 .prepare
= mirror_prepare
,
1311 .abort
= mirror_abort
,
1312 .pause
= mirror_pause
,
1313 .complete
= mirror_complete
,
1314 .cancel
= mirror_cancel
,
1316 .drained_poll
= mirror_drained_poll
,
1317 .change
= mirror_change
,
1318 .query
= mirror_query
,
1321 static const BlockJobDriver commit_active_job_driver
= {
1323 .instance_size
= sizeof(MirrorBlockJob
),
1324 .job_type
= JOB_TYPE_COMMIT
,
1325 .free
= block_job_free
,
1326 .user_resume
= block_job_user_resume
,
1328 .prepare
= mirror_prepare
,
1329 .abort
= mirror_abort
,
1330 .pause
= mirror_pause
,
1331 .complete
= mirror_complete
,
1332 .cancel
= commit_active_cancel
,
1334 .drained_poll
= mirror_drained_poll
,
1337 static void coroutine_fn
1338 do_sync_target_write(MirrorBlockJob
*job
, MirrorMethod method
,
1339 uint64_t offset
, uint64_t bytes
,
1340 QEMUIOVector
*qiov
, int flags
)
1343 size_t qiov_offset
= 0;
1344 int64_t bitmap_offset
, bitmap_end
;
1346 if (!QEMU_IS_ALIGNED(offset
, job
->granularity
) &&
1347 bdrv_dirty_bitmap_get(job
->dirty_bitmap
, offset
))
1350 * Dirty unaligned padding: ignore it.
1353 * 1. If we copy it, we can't reset corresponding bit in
1354 * dirty_bitmap as there may be some "dirty" bytes still not
1356 * 2. It's already dirty, so skipping it we don't diverge mirror
1359 * Note, that because of this, guest write may have no contribution
1360 * into mirror converge, but that's not bad, as we have background
1361 * process of mirroring. If under some bad circumstances (high guest
1362 * IO load) background process starve, we will not converge anyway,
1363 * even if each write will contribute, as guest is not guaranteed to
1364 * rewrite the whole disk.
1366 qiov_offset
= QEMU_ALIGN_UP(offset
, job
->granularity
) - offset
;
1367 if (bytes
<= qiov_offset
) {
1368 /* nothing to do after shrink */
1371 offset
+= qiov_offset
;
1372 bytes
-= qiov_offset
;
1375 if (!QEMU_IS_ALIGNED(offset
+ bytes
, job
->granularity
) &&
1376 bdrv_dirty_bitmap_get(job
->dirty_bitmap
, offset
+ bytes
- 1))
1378 uint64_t tail
= (offset
+ bytes
) % job
->granularity
;
1380 if (bytes
<= tail
) {
1381 /* nothing to do after shrink */
1388 * Tails are either clean or shrunk, so for bitmap resetting
1389 * we safely align the range down.
1391 bitmap_offset
= QEMU_ALIGN_UP(offset
, job
->granularity
);
1392 bitmap_end
= QEMU_ALIGN_DOWN(offset
+ bytes
, job
->granularity
);
1393 if (bitmap_offset
< bitmap_end
) {
1394 bdrv_reset_dirty_bitmap(job
->dirty_bitmap
, bitmap_offset
,
1395 bitmap_end
- bitmap_offset
);
1398 job_progress_increase_remaining(&job
->common
.job
, bytes
);
1399 job
->active_write_bytes_in_flight
+= bytes
;
1402 case MIRROR_METHOD_COPY
:
1403 ret
= blk_co_pwritev_part(job
->target
, offset
, bytes
,
1404 qiov
, qiov_offset
, flags
);
1407 case MIRROR_METHOD_ZERO
:
1409 ret
= blk_co_pwrite_zeroes(job
->target
, offset
, bytes
, flags
);
1412 case MIRROR_METHOD_DISCARD
:
1414 ret
= blk_co_pdiscard(job
->target
, offset
, bytes
);
1421 job
->active_write_bytes_in_flight
-= bytes
;
1423 job_progress_update(&job
->common
.job
, bytes
);
1425 BlockErrorAction action
;
1428 * We failed, so we should mark dirty the whole area, aligned up.
1429 * Note that we don't care about shrunk tails if any: they were dirty
1430 * at function start, and they must be still dirty, as we've locked
1431 * the region for in-flight op.
1433 bitmap_offset
= QEMU_ALIGN_DOWN(offset
, job
->granularity
);
1434 bitmap_end
= QEMU_ALIGN_UP(offset
+ bytes
, job
->granularity
);
1435 bdrv_set_dirty_bitmap(job
->dirty_bitmap
, bitmap_offset
,
1436 bitmap_end
- bitmap_offset
);
1437 qatomic_set(&job
->actively_synced
, false);
1439 action
= mirror_error_action(job
, false, -ret
);
1440 if (action
== BLOCK_ERROR_ACTION_REPORT
) {
1448 static MirrorOp
*coroutine_fn
active_write_prepare(MirrorBlockJob
*s
,
1453 uint64_t start_chunk
= offset
/ s
->granularity
;
1454 uint64_t end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
1456 op
= g_new(MirrorOp
, 1);
1461 .is_active_write
= true,
1462 .is_in_flight
= true,
1463 .co
= qemu_coroutine_self(),
1465 qemu_co_queue_init(&op
->waiting_requests
);
1466 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
1468 s
->in_active_write_counter
++;
1471 * Wait for concurrent requests affecting the area. If there are already
1472 * running requests that are copying off now-to-be stale data in the area,
1473 * we must wait for them to finish before we begin writing fresh data to the
1474 * target so that the write operations appear in the correct order.
1475 * Note that background requests (see mirror_iteration()) in contrast only
1476 * wait for conflicting requests at the start of the dirty area, and then
1477 * (based on the in_flight_bitmap) truncate the area to copy so it will not
1478 * conflict with any requests beyond that. For active writes, however, we
1479 * cannot truncate that area. The request from our parent must be blocked
1480 * until the area is copied in full. Therefore, we must wait for the whole
1481 * area to become free of concurrent requests.
1483 mirror_wait_on_conflicts(op
, s
, offset
, bytes
);
1485 bitmap_set(s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1490 static void coroutine_fn GRAPH_RDLOCK
active_write_settle(MirrorOp
*op
)
1492 uint64_t start_chunk
= op
->offset
/ op
->s
->granularity
;
1493 uint64_t end_chunk
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
1494 op
->s
->granularity
);
1496 if (!--op
->s
->in_active_write_counter
&&
1497 qatomic_read(&op
->s
->actively_synced
)) {
1498 BdrvChild
*source
= op
->s
->mirror_top_bs
->backing
;
1500 if (QLIST_FIRST(&source
->bs
->parents
) == source
&&
1501 QLIST_NEXT(source
, next_parent
) == NULL
)
1503 /* Assert that we are back in sync once all active write
1504 * operations are settled.
1505 * Note that we can only assert this if the mirror node
1506 * is the source node's only parent. */
1507 assert(!bdrv_get_dirty_count(op
->s
->dirty_bitmap
));
1510 bitmap_clear(op
->s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1511 QTAILQ_REMOVE(&op
->s
->ops_in_flight
, op
, next
);
1512 qemu_co_queue_restart_all(&op
->waiting_requests
);
1516 static int coroutine_fn GRAPH_RDLOCK
1517 bdrv_mirror_top_preadv(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
1518 QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
1520 return bdrv_co_preadv(bs
->backing
, offset
, bytes
, qiov
, flags
);
1523 static bool should_copy_to_target(MirrorBDSOpaque
*s
)
1525 return s
->job
&& s
->job
->ret
>= 0 &&
1526 !job_is_cancelled(&s
->job
->common
.job
) &&
1527 qatomic_read(&s
->job
->copy_mode
) == MIRROR_COPY_MODE_WRITE_BLOCKING
;
1530 static int coroutine_fn GRAPH_RDLOCK
1531 bdrv_mirror_top_do_write(BlockDriverState
*bs
, MirrorMethod method
,
1532 bool copy_to_target
, uint64_t offset
, uint64_t bytes
,
1533 QEMUIOVector
*qiov
, int flags
)
1535 MirrorOp
*op
= NULL
;
1536 MirrorBDSOpaque
*s
= bs
->opaque
;
1539 if (copy_to_target
) {
1540 op
= active_write_prepare(s
->job
, offset
, bytes
);
1544 case MIRROR_METHOD_COPY
:
1545 ret
= bdrv_co_pwritev(bs
->backing
, offset
, bytes
, qiov
, flags
);
1548 case MIRROR_METHOD_ZERO
:
1549 ret
= bdrv_co_pwrite_zeroes(bs
->backing
, offset
, bytes
, flags
);
1552 case MIRROR_METHOD_DISCARD
:
1553 ret
= bdrv_co_pdiscard(bs
->backing
, offset
, bytes
);
1560 if (!copy_to_target
&& s
->job
&& s
->job
->dirty_bitmap
) {
1561 qatomic_set(&s
->job
->actively_synced
, false);
1562 bdrv_set_dirty_bitmap(s
->job
->dirty_bitmap
, offset
, bytes
);
1569 if (copy_to_target
) {
1570 do_sync_target_write(s
->job
, method
, offset
, bytes
, qiov
, flags
);
1574 if (copy_to_target
) {
1575 active_write_settle(op
);
1580 static int coroutine_fn GRAPH_RDLOCK
1581 bdrv_mirror_top_pwritev(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
1582 QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
1584 QEMUIOVector bounce_qiov
;
1587 bool copy_to_target
= should_copy_to_target(bs
->opaque
);
1589 if (copy_to_target
) {
1590 /* The guest might concurrently modify the data to write; but
1591 * the data on source and destination must match, so we have
1592 * to use a bounce buffer if we are going to write to the
1594 bounce_buf
= qemu_blockalign(bs
, bytes
);
1595 iov_to_buf_full(qiov
->iov
, qiov
->niov
, 0, bounce_buf
, bytes
);
1597 qemu_iovec_init(&bounce_qiov
, 1);
1598 qemu_iovec_add(&bounce_qiov
, bounce_buf
, bytes
);
1599 qiov
= &bounce_qiov
;
1601 flags
&= ~BDRV_REQ_REGISTERED_BUF
;
1604 ret
= bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_COPY
, copy_to_target
,
1605 offset
, bytes
, qiov
, flags
);
1607 if (copy_to_target
) {
1608 qemu_iovec_destroy(&bounce_qiov
);
1609 qemu_vfree(bounce_buf
);
1615 static int coroutine_fn GRAPH_RDLOCK
bdrv_mirror_top_flush(BlockDriverState
*bs
)
1617 if (bs
->backing
== NULL
) {
1618 /* we can be here after failed bdrv_append in mirror_start_job */
1621 return bdrv_co_flush(bs
->backing
->bs
);
1624 static int coroutine_fn GRAPH_RDLOCK
1625 bdrv_mirror_top_pwrite_zeroes(BlockDriverState
*bs
, int64_t offset
,
1626 int64_t bytes
, BdrvRequestFlags flags
)
1628 bool copy_to_target
= should_copy_to_target(bs
->opaque
);
1629 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_ZERO
, copy_to_target
,
1630 offset
, bytes
, NULL
, flags
);
1633 static int coroutine_fn GRAPH_RDLOCK
1634 bdrv_mirror_top_pdiscard(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
1636 bool copy_to_target
= should_copy_to_target(bs
->opaque
);
1637 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_DISCARD
, copy_to_target
,
1638 offset
, bytes
, NULL
, 0);
1641 static void GRAPH_RDLOCK
bdrv_mirror_top_refresh_filename(BlockDriverState
*bs
)
1643 if (bs
->backing
== NULL
) {
1644 /* we can be here after failed bdrv_attach_child in
1645 * bdrv_set_backing_hd */
1648 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
1649 bs
->backing
->bs
->filename
);
1652 static void bdrv_mirror_top_child_perm(BlockDriverState
*bs
, BdrvChild
*c
,
1654 BlockReopenQueue
*reopen_queue
,
1655 uint64_t perm
, uint64_t shared
,
1656 uint64_t *nperm
, uint64_t *nshared
)
1658 MirrorBDSOpaque
*s
= bs
->opaque
;
1662 * If the job is to be stopped, we do not need to forward
1663 * anything to the real image.
1666 *nshared
= BLK_PERM_ALL
;
1670 bdrv_default_perms(bs
, c
, role
, reopen_queue
,
1671 perm
, shared
, nperm
, nshared
);
1675 * For commit jobs, we cannot take CONSISTENT_READ, because
1676 * that permission is unshared for everything above the base
1677 * node (except for filters on the base node).
1678 * We also have to force-share the WRITE permission, or
1679 * otherwise we would block ourselves at the base node (if
1680 * writes are blocked for a node, they are also blocked for
1681 * its backing file).
1682 * (We could also share RESIZE, because it may be needed for
1683 * the target if its size is less than the top node's; but
1684 * bdrv_default_perms_for_cow() automatically shares RESIZE
1685 * for backing nodes if WRITE is shared, so there is no need
1688 *nperm
&= ~BLK_PERM_CONSISTENT_READ
;
1689 *nshared
|= BLK_PERM_WRITE
;
1693 /* Dummy node that provides consistent read to its users without requiring it
1694 * from its backing file and that allows writes on the backing file chain. */
1695 static BlockDriver bdrv_mirror_top
= {
1696 .format_name
= "mirror_top",
1697 .bdrv_co_preadv
= bdrv_mirror_top_preadv
,
1698 .bdrv_co_pwritev
= bdrv_mirror_top_pwritev
,
1699 .bdrv_co_pwrite_zeroes
= bdrv_mirror_top_pwrite_zeroes
,
1700 .bdrv_co_pdiscard
= bdrv_mirror_top_pdiscard
,
1701 .bdrv_co_flush
= bdrv_mirror_top_flush
,
1702 .bdrv_refresh_filename
= bdrv_mirror_top_refresh_filename
,
1703 .bdrv_child_perm
= bdrv_mirror_top_child_perm
,
1706 .filtered_child_is_backing
= true,
1709 static BlockJob
*mirror_start_job(
1710 const char *job_id
, BlockDriverState
*bs
,
1711 int creation_flags
, BlockDriverState
*target
,
1712 const char *replaces
, int64_t speed
,
1713 uint32_t granularity
, int64_t buf_size
,
1714 BlockMirrorBackingMode backing_mode
,
1716 BlockdevOnError on_source_error
,
1717 BlockdevOnError on_target_error
,
1719 BlockCompletionFunc
*cb
,
1721 const BlockJobDriver
*driver
,
1722 bool is_none_mode
, BlockDriverState
*base
,
1723 bool auto_complete
, const char *filter_node_name
,
1724 bool is_mirror
, MirrorCopyMode copy_mode
,
1729 MirrorBDSOpaque
*bs_opaque
;
1730 BlockDriverState
*mirror_top_bs
;
1731 bool target_is_backing
;
1732 uint64_t target_perms
, target_shared_perms
;
1735 GLOBAL_STATE_CODE();
1737 if (granularity
== 0) {
1738 granularity
= bdrv_get_default_bitmap_granularity(target
);
1741 assert(is_power_of_2(granularity
));
1744 error_setg(errp
, "Invalid parameter 'buf-size'");
1748 if (buf_size
== 0) {
1749 buf_size
= DEFAULT_MIRROR_BUF_SIZE
;
1752 bdrv_graph_rdlock_main_loop();
1753 if (bdrv_skip_filters(bs
) == bdrv_skip_filters(target
)) {
1754 error_setg(errp
, "Can't mirror node into itself");
1755 bdrv_graph_rdunlock_main_loop();
1759 target_is_backing
= bdrv_chain_contains(bs
, target
);
1760 bdrv_graph_rdunlock_main_loop();
1762 /* In the case of active commit, add dummy driver to provide consistent
1763 * reads on the top, while disabling it in the intermediate nodes, and make
1764 * the backing chain writable. */
1765 mirror_top_bs
= bdrv_new_open_driver(&bdrv_mirror_top
, filter_node_name
,
1767 if (mirror_top_bs
== NULL
) {
1770 if (!filter_node_name
) {
1771 mirror_top_bs
->implicit
= true;
1774 /* So that we can always drop this node */
1775 mirror_top_bs
->never_freeze
= true;
1777 mirror_top_bs
->total_sectors
= bs
->total_sectors
;
1778 mirror_top_bs
->supported_write_flags
= BDRV_REQ_WRITE_UNCHANGED
;
1779 mirror_top_bs
->supported_zero_flags
= BDRV_REQ_WRITE_UNCHANGED
|
1780 BDRV_REQ_NO_FALLBACK
;
1781 bs_opaque
= g_new0(MirrorBDSOpaque
, 1);
1782 mirror_top_bs
->opaque
= bs_opaque
;
1784 bs_opaque
->is_commit
= target_is_backing
;
1786 bdrv_drained_begin(bs
);
1787 ret
= bdrv_append(mirror_top_bs
, bs
, errp
);
1788 bdrv_drained_end(bs
);
1791 bdrv_unref(mirror_top_bs
);
1795 /* Make sure that the source is not resized while the job is running */
1796 s
= block_job_create(job_id
, driver
, NULL
, mirror_top_bs
,
1797 BLK_PERM_CONSISTENT_READ
,
1798 BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
|
1799 BLK_PERM_WRITE
, speed
,
1800 creation_flags
, cb
, opaque
, errp
);
1805 /* The block job now has a reference to this node */
1806 bdrv_unref(mirror_top_bs
);
1808 s
->mirror_top_bs
= mirror_top_bs
;
1809 s
->base_ro
= base_ro
;
1811 /* No resize for the target either; while the mirror is still running, a
1812 * consistent read isn't necessarily possible. We could possibly allow
1813 * writes and graph modifications, though it would likely defeat the
1814 * purpose of a mirror, so leave them blocked for now.
1816 * In the case of active commit, things look a bit different, though,
1817 * because the target is an already populated backing file in active use.
1818 * We can allow anything except resize there.*/
1820 target_perms
= BLK_PERM_WRITE
;
1821 target_shared_perms
= BLK_PERM_WRITE_UNCHANGED
;
1823 if (target_is_backing
) {
1824 int64_t bs_size
, target_size
;
1825 bs_size
= bdrv_getlength(bs
);
1827 error_setg_errno(errp
, -bs_size
,
1828 "Could not inquire top image size");
1832 target_size
= bdrv_getlength(target
);
1833 if (target_size
< 0) {
1834 error_setg_errno(errp
, -target_size
,
1835 "Could not inquire base image size");
1839 if (target_size
< bs_size
) {
1840 target_perms
|= BLK_PERM_RESIZE
;
1843 target_shared_perms
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE
;
1845 bdrv_graph_rdlock_main_loop();
1846 if (bdrv_chain_contains(bs
, bdrv_skip_filters(target
))) {
1848 * We may want to allow this in the future, but it would
1849 * require taking some extra care.
1851 error_setg(errp
, "Cannot mirror to a filter on top of a node in "
1852 "the source's backing chain");
1853 bdrv_graph_rdunlock_main_loop();
1856 bdrv_graph_rdunlock_main_loop();
1859 s
->target
= blk_new(s
->common
.job
.aio_context
,
1860 target_perms
, target_shared_perms
);
1861 ret
= blk_insert_bs(s
->target
, target
, errp
);
1866 /* XXX: Mirror target could be a NBD server of target QEMU in the case
1867 * of non-shared block migration. To allow migration completion, we
1868 * have to allow "inactivate" of the target BB. When that happens, we
1869 * know the job is drained, and the vcpus are stopped, so no write
1870 * operation will be performed. Block layer already has assertions to
1872 blk_set_force_allow_inactivate(s
->target
);
1874 blk_set_allow_aio_context_change(s
->target
, true);
1875 blk_set_disable_request_queuing(s
->target
, true);
1877 bdrv_graph_rdlock_main_loop();
1878 s
->replaces
= g_strdup(replaces
);
1879 s
->on_source_error
= on_source_error
;
1880 s
->on_target_error
= on_target_error
;
1881 s
->is_none_mode
= is_none_mode
;
1882 s
->backing_mode
= backing_mode
;
1883 s
->zero_target
= zero_target
;
1884 qatomic_set(&s
->copy_mode
, copy_mode
);
1886 s
->base_overlay
= bdrv_find_overlay(bs
, base
);
1887 s
->granularity
= granularity
;
1888 s
->buf_size
= ROUND_UP(buf_size
, granularity
);
1890 if (auto_complete
) {
1891 s
->should_complete
= true;
1893 bdrv_graph_rdunlock_main_loop();
1895 s
->dirty_bitmap
= bdrv_create_dirty_bitmap(s
->mirror_top_bs
, granularity
,
1897 if (!s
->dirty_bitmap
) {
1902 * The dirty bitmap is set by bdrv_mirror_top_do_write() when not in active
1905 bdrv_disable_dirty_bitmap(s
->dirty_bitmap
);
1907 bdrv_graph_wrlock();
1908 ret
= block_job_add_bdrv(&s
->common
, "source", bs
, 0,
1909 BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
|
1910 BLK_PERM_CONSISTENT_READ
,
1913 bdrv_graph_wrunlock();
1917 /* Required permissions are already taken with blk_new() */
1918 block_job_add_bdrv(&s
->common
, "target", target
, 0, BLK_PERM_ALL
,
1921 /* In commit_active_start() all intermediate nodes disappear, so
1922 * any jobs in them must be blocked */
1923 if (target_is_backing
) {
1924 BlockDriverState
*iter
, *filtered_target
;
1925 uint64_t iter_shared_perms
;
1928 * The topmost node with
1929 * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target)
1931 filtered_target
= bdrv_cow_bs(bdrv_find_overlay(bs
, target
));
1933 assert(bdrv_skip_filters(filtered_target
) ==
1934 bdrv_skip_filters(target
));
1937 * XXX BLK_PERM_WRITE needs to be allowed so we don't block
1938 * ourselves at s->base (if writes are blocked for a node, they are
1939 * also blocked for its backing file). The other options would be a
1940 * second filter driver above s->base (== target).
1942 iter_shared_perms
= BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
;
1944 for (iter
= bdrv_filter_or_cow_bs(bs
); iter
!= target
;
1945 iter
= bdrv_filter_or_cow_bs(iter
))
1947 if (iter
== filtered_target
) {
1949 * From here on, all nodes are filters on the base.
1950 * This allows us to share BLK_PERM_CONSISTENT_READ.
1952 iter_shared_perms
|= BLK_PERM_CONSISTENT_READ
;
1955 ret
= block_job_add_bdrv(&s
->common
, "intermediate node", iter
, 0,
1956 iter_shared_perms
, errp
);
1958 bdrv_graph_wrunlock();
1963 if (bdrv_freeze_backing_chain(mirror_top_bs
, target
, errp
) < 0) {
1964 bdrv_graph_wrunlock();
1968 bdrv_graph_wrunlock();
1970 QTAILQ_INIT(&s
->ops_in_flight
);
1972 trace_mirror_start(bs
, s
, opaque
);
1973 job_start(&s
->common
.job
);
1979 /* Make sure this BDS does not go away until we have completed the graph
1981 bdrv_ref(mirror_top_bs
);
1983 g_free(s
->replaces
);
1984 blk_unref(s
->target
);
1985 bs_opaque
->job
= NULL
;
1986 if (s
->dirty_bitmap
) {
1987 bdrv_release_dirty_bitmap(s
->dirty_bitmap
);
1989 job_early_fail(&s
->common
.job
);
1992 bs_opaque
->stop
= true;
1993 bdrv_drained_begin(bs
);
1994 bdrv_graph_wrlock();
1995 assert(mirror_top_bs
->backing
->bs
== bs
);
1996 bdrv_child_refresh_perms(mirror_top_bs
, mirror_top_bs
->backing
,
1998 bdrv_replace_node(mirror_top_bs
, bs
, &error_abort
);
1999 bdrv_graph_wrunlock();
2000 bdrv_drained_end(bs
);
2002 bdrv_unref(mirror_top_bs
);
2007 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
2008 BlockDriverState
*target
, const char *replaces
,
2009 int creation_flags
, int64_t speed
,
2010 uint32_t granularity
, int64_t buf_size
,
2011 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
2013 BlockdevOnError on_source_error
,
2014 BlockdevOnError on_target_error
,
2015 bool unmap
, const char *filter_node_name
,
2016 MirrorCopyMode copy_mode
, Error
**errp
)
2019 BlockDriverState
*base
;
2021 GLOBAL_STATE_CODE();
2023 if ((mode
== MIRROR_SYNC_MODE_INCREMENTAL
) ||
2024 (mode
== MIRROR_SYNC_MODE_BITMAP
)) {
2025 error_setg(errp
, "Sync mode '%s' not supported",
2026 MirrorSyncMode_str(mode
));
2030 bdrv_graph_rdlock_main_loop();
2031 is_none_mode
= mode
== MIRROR_SYNC_MODE_NONE
;
2032 base
= mode
== MIRROR_SYNC_MODE_TOP
? bdrv_backing_chain_next(bs
) : NULL
;
2033 bdrv_graph_rdunlock_main_loop();
2035 mirror_start_job(job_id
, bs
, creation_flags
, target
, replaces
,
2036 speed
, granularity
, buf_size
, backing_mode
, zero_target
,
2037 on_source_error
, on_target_error
, unmap
, NULL
, NULL
,
2038 &mirror_job_driver
, is_none_mode
, base
, false,
2039 filter_node_name
, true, copy_mode
, false, errp
);
2042 BlockJob
*commit_active_start(const char *job_id
, BlockDriverState
*bs
,
2043 BlockDriverState
*base
, int creation_flags
,
2044 int64_t speed
, BlockdevOnError on_error
,
2045 const char *filter_node_name
,
2046 BlockCompletionFunc
*cb
, void *opaque
,
2047 bool auto_complete
, Error
**errp
)
2049 bool base_read_only
;
2052 GLOBAL_STATE_CODE();
2054 base_read_only
= bdrv_is_read_only(base
);
2056 if (base_read_only
) {
2057 if (bdrv_reopen_set_read_only(base
, false, errp
) < 0) {
2062 job
= mirror_start_job(
2063 job_id
, bs
, creation_flags
, base
, NULL
, speed
, 0, 0,
2064 MIRROR_LEAVE_BACKING_CHAIN
, false,
2065 on_error
, on_error
, true, cb
, opaque
,
2066 &commit_active_job_driver
, false, base
, auto_complete
,
2067 filter_node_name
, false, MIRROR_COPY_MODE_BACKGROUND
,
2068 base_read_only
, errp
);
2070 goto error_restore_flags
;
2075 error_restore_flags
:
2076 /* ignore error and errp for bdrv_reopen, because we want to propagate
2077 * the original error */
2078 if (base_read_only
) {
2079 bdrv_reopen_set_read_only(base
, true, NULL
);