2 * Block layer I/O functions
4 * Copyright (c) 2003 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 #include "qemu/osdep.h"
27 #include "sysemu/block-backend.h"
28 #include "block/aio-wait.h"
29 #include "block/blockjob.h"
30 #include "block/blockjob_int.h"
31 #include "block/block_int.h"
32 #include "qemu/cutils.h"
33 #include "qapi/error.h"
34 #include "qemu/error-report.h"
35 #include "qemu/main-loop.h"
36 #include "sysemu/replay.h"
38 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
40 /* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */
41 #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS)
43 static void bdrv_parent_cb_resize(BlockDriverState
*bs
);
44 static int coroutine_fn
bdrv_co_do_pwrite_zeroes(BlockDriverState
*bs
,
45 int64_t offset
, int bytes
, BdrvRequestFlags flags
);
47 static void bdrv_parent_drained_begin(BlockDriverState
*bs
, BdrvChild
*ignore
,
48 bool ignore_bds_parents
)
52 QLIST_FOREACH_SAFE(c
, &bs
->parents
, next_parent
, next
) {
53 if (c
== ignore
|| (ignore_bds_parents
&& c
->role
->parent_is_bds
)) {
56 bdrv_parent_drained_begin_single(c
, false);
60 static void bdrv_parent_drained_end_single_no_poll(BdrvChild
*c
,
61 int *drained_end_counter
)
63 assert(c
->parent_quiesce_counter
> 0);
64 c
->parent_quiesce_counter
--;
65 if (c
->role
->drained_end
) {
66 c
->role
->drained_end(c
, drained_end_counter
);
70 void bdrv_parent_drained_end_single(BdrvChild
*c
)
72 int drained_end_counter
= 0;
73 bdrv_parent_drained_end_single_no_poll(c
, &drained_end_counter
);
74 BDRV_POLL_WHILE(c
->bs
, atomic_read(&drained_end_counter
) > 0);
77 static void bdrv_parent_drained_end(BlockDriverState
*bs
, BdrvChild
*ignore
,
78 bool ignore_bds_parents
,
79 int *drained_end_counter
)
83 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
84 if (c
== ignore
|| (ignore_bds_parents
&& c
->role
->parent_is_bds
)) {
87 bdrv_parent_drained_end_single_no_poll(c
, drained_end_counter
);
91 static bool bdrv_parent_drained_poll_single(BdrvChild
*c
)
93 if (c
->role
->drained_poll
) {
94 return c
->role
->drained_poll(c
);
99 static bool bdrv_parent_drained_poll(BlockDriverState
*bs
, BdrvChild
*ignore
,
100 bool ignore_bds_parents
)
105 QLIST_FOREACH_SAFE(c
, &bs
->parents
, next_parent
, next
) {
106 if (c
== ignore
|| (ignore_bds_parents
&& c
->role
->parent_is_bds
)) {
109 busy
|= bdrv_parent_drained_poll_single(c
);
115 void bdrv_parent_drained_begin_single(BdrvChild
*c
, bool poll
)
117 c
->parent_quiesce_counter
++;
118 if (c
->role
->drained_begin
) {
119 c
->role
->drained_begin(c
);
122 BDRV_POLL_WHILE(c
->bs
, bdrv_parent_drained_poll_single(c
));
126 static void bdrv_merge_limits(BlockLimits
*dst
, const BlockLimits
*src
)
128 dst
->opt_transfer
= MAX(dst
->opt_transfer
, src
->opt_transfer
);
129 dst
->max_transfer
= MIN_NON_ZERO(dst
->max_transfer
, src
->max_transfer
);
130 dst
->opt_mem_alignment
= MAX(dst
->opt_mem_alignment
,
131 src
->opt_mem_alignment
);
132 dst
->min_mem_alignment
= MAX(dst
->min_mem_alignment
,
133 src
->min_mem_alignment
);
134 dst
->max_iov
= MIN_NON_ZERO(dst
->max_iov
, src
->max_iov
);
137 void bdrv_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
139 BlockDriver
*drv
= bs
->drv
;
140 Error
*local_err
= NULL
;
142 memset(&bs
->bl
, 0, sizeof(bs
->bl
));
148 /* Default alignment based on whether driver has byte interface */
149 bs
->bl
.request_alignment
= (drv
->bdrv_co_preadv
||
150 drv
->bdrv_aio_preadv
||
151 drv
->bdrv_co_preadv_part
) ? 1 : 512;
153 /* Take some limits from the children as a default */
155 bdrv_refresh_limits(bs
->file
->bs
, &local_err
);
157 error_propagate(errp
, local_err
);
160 bdrv_merge_limits(&bs
->bl
, &bs
->file
->bs
->bl
);
162 bs
->bl
.min_mem_alignment
= 512;
163 bs
->bl
.opt_mem_alignment
= qemu_real_host_page_size
;
165 /* Safe default since most protocols use readv()/writev()/etc */
166 bs
->bl
.max_iov
= IOV_MAX
;
170 bdrv_refresh_limits(bs
->backing
->bs
, &local_err
);
172 error_propagate(errp
, local_err
);
175 bdrv_merge_limits(&bs
->bl
, &bs
->backing
->bs
->bl
);
178 /* Then let the driver override it */
179 if (drv
->bdrv_refresh_limits
) {
180 drv
->bdrv_refresh_limits(bs
, errp
);
185 * The copy-on-read flag is actually a reference count so multiple users may
186 * use the feature without worrying about clobbering its previous state.
187 * Copy-on-read stays enabled until all users have called to disable it.
189 void bdrv_enable_copy_on_read(BlockDriverState
*bs
)
191 atomic_inc(&bs
->copy_on_read
);
194 void bdrv_disable_copy_on_read(BlockDriverState
*bs
)
196 int old
= atomic_fetch_dec(&bs
->copy_on_read
);
202 BlockDriverState
*bs
;
208 bool ignore_bds_parents
;
209 int *drained_end_counter
;
212 static void coroutine_fn
bdrv_drain_invoke_entry(void *opaque
)
214 BdrvCoDrainData
*data
= opaque
;
215 BlockDriverState
*bs
= data
->bs
;
218 bs
->drv
->bdrv_co_drain_begin(bs
);
220 bs
->drv
->bdrv_co_drain_end(bs
);
223 /* Set data->done and decrement drained_end_counter before bdrv_wakeup() */
224 atomic_mb_set(&data
->done
, true);
226 atomic_dec(data
->drained_end_counter
);
228 bdrv_dec_in_flight(bs
);
233 /* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */
234 static void bdrv_drain_invoke(BlockDriverState
*bs
, bool begin
,
235 int *drained_end_counter
)
237 BdrvCoDrainData
*data
;
239 if (!bs
->drv
|| (begin
&& !bs
->drv
->bdrv_co_drain_begin
) ||
240 (!begin
&& !bs
->drv
->bdrv_co_drain_end
)) {
244 data
= g_new(BdrvCoDrainData
, 1);
245 *data
= (BdrvCoDrainData
) {
249 .drained_end_counter
= drained_end_counter
,
253 atomic_inc(drained_end_counter
);
256 /* Make sure the driver callback completes during the polling phase for
258 bdrv_inc_in_flight(bs
);
259 data
->co
= qemu_coroutine_create(bdrv_drain_invoke_entry
, data
);
260 aio_co_schedule(bdrv_get_aio_context(bs
), data
->co
);
263 /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
264 bool bdrv_drain_poll(BlockDriverState
*bs
, bool recursive
,
265 BdrvChild
*ignore_parent
, bool ignore_bds_parents
)
267 BdrvChild
*child
, *next
;
269 if (bdrv_parent_drained_poll(bs
, ignore_parent
, ignore_bds_parents
)) {
273 if (atomic_read(&bs
->in_flight
)) {
278 assert(!ignore_bds_parents
);
279 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
280 if (bdrv_drain_poll(child
->bs
, recursive
, child
, false)) {
289 static bool bdrv_drain_poll_top_level(BlockDriverState
*bs
, bool recursive
,
290 BdrvChild
*ignore_parent
)
292 return bdrv_drain_poll(bs
, recursive
, ignore_parent
, false);
295 static void bdrv_do_drained_begin(BlockDriverState
*bs
, bool recursive
,
296 BdrvChild
*parent
, bool ignore_bds_parents
,
298 static void bdrv_do_drained_end(BlockDriverState
*bs
, bool recursive
,
299 BdrvChild
*parent
, bool ignore_bds_parents
,
300 int *drained_end_counter
);
302 static void bdrv_co_drain_bh_cb(void *opaque
)
304 BdrvCoDrainData
*data
= opaque
;
305 Coroutine
*co
= data
->co
;
306 BlockDriverState
*bs
= data
->bs
;
309 AioContext
*ctx
= bdrv_get_aio_context(bs
);
310 AioContext
*co_ctx
= qemu_coroutine_get_aio_context(co
);
313 * When the coroutine yielded, the lock for its home context was
314 * released, so we need to re-acquire it here. If it explicitly
315 * acquired a different context, the lock is still held and we don't
316 * want to lock it a second time (or AIO_WAIT_WHILE() would hang).
319 aio_context_acquire(ctx
);
321 bdrv_dec_in_flight(bs
);
323 assert(!data
->drained_end_counter
);
324 bdrv_do_drained_begin(bs
, data
->recursive
, data
->parent
,
325 data
->ignore_bds_parents
, data
->poll
);
328 bdrv_do_drained_end(bs
, data
->recursive
, data
->parent
,
329 data
->ignore_bds_parents
,
330 data
->drained_end_counter
);
333 aio_context_release(ctx
);
337 bdrv_drain_all_begin();
344 static void coroutine_fn
bdrv_co_yield_to_drain(BlockDriverState
*bs
,
345 bool begin
, bool recursive
,
347 bool ignore_bds_parents
,
349 int *drained_end_counter
)
351 BdrvCoDrainData data
;
353 /* Calling bdrv_drain() from a BH ensures the current coroutine yields and
354 * other coroutines run if they were queued by aio_co_enter(). */
356 assert(qemu_in_coroutine());
357 data
= (BdrvCoDrainData
) {
358 .co
= qemu_coroutine_self(),
362 .recursive
= recursive
,
364 .ignore_bds_parents
= ignore_bds_parents
,
366 .drained_end_counter
= drained_end_counter
,
370 bdrv_inc_in_flight(bs
);
372 replay_bh_schedule_oneshot_event(bdrv_get_aio_context(bs
),
373 bdrv_co_drain_bh_cb
, &data
);
375 qemu_coroutine_yield();
376 /* If we are resumed from some other event (such as an aio completion or a
377 * timer callback), it is a bug in the caller that should be fixed. */
381 void bdrv_do_drained_begin_quiesce(BlockDriverState
*bs
,
382 BdrvChild
*parent
, bool ignore_bds_parents
)
384 assert(!qemu_in_coroutine());
386 /* Stop things in parent-to-child order */
387 if (atomic_fetch_inc(&bs
->quiesce_counter
) == 0) {
388 aio_disable_external(bdrv_get_aio_context(bs
));
391 bdrv_parent_drained_begin(bs
, parent
, ignore_bds_parents
);
392 bdrv_drain_invoke(bs
, true, NULL
);
395 static void bdrv_do_drained_begin(BlockDriverState
*bs
, bool recursive
,
396 BdrvChild
*parent
, bool ignore_bds_parents
,
399 BdrvChild
*child
, *next
;
401 if (qemu_in_coroutine()) {
402 bdrv_co_yield_to_drain(bs
, true, recursive
, parent
, ignore_bds_parents
,
407 bdrv_do_drained_begin_quiesce(bs
, parent
, ignore_bds_parents
);
410 assert(!ignore_bds_parents
);
411 bs
->recursive_quiesce_counter
++;
412 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
413 bdrv_do_drained_begin(child
->bs
, true, child
, ignore_bds_parents
,
419 * Wait for drained requests to finish.
421 * Calling BDRV_POLL_WHILE() only once for the top-level node is okay: The
422 * call is needed so things in this AioContext can make progress even
423 * though we don't return to the main AioContext loop - this automatically
424 * includes other nodes in the same AioContext and therefore all child
428 assert(!ignore_bds_parents
);
429 BDRV_POLL_WHILE(bs
, bdrv_drain_poll_top_level(bs
, recursive
, parent
));
433 void bdrv_drained_begin(BlockDriverState
*bs
)
435 bdrv_do_drained_begin(bs
, false, NULL
, false, true);
438 void bdrv_subtree_drained_begin(BlockDriverState
*bs
)
440 bdrv_do_drained_begin(bs
, true, NULL
, false, true);
444 * This function does not poll, nor must any of its recursively called
445 * functions. The *drained_end_counter pointee will be incremented
446 * once for every background operation scheduled, and decremented once
447 * the operation settles. Therefore, the pointer must remain valid
448 * until the pointee reaches 0. That implies that whoever sets up the
449 * pointee has to poll until it is 0.
451 * We use atomic operations to access *drained_end_counter, because
452 * (1) when called from bdrv_set_aio_context_ignore(), the subgraph of
453 * @bs may contain nodes in different AioContexts,
454 * (2) bdrv_drain_all_end() uses the same counter for all nodes,
455 * regardless of which AioContext they are in.
457 static void bdrv_do_drained_end(BlockDriverState
*bs
, bool recursive
,
458 BdrvChild
*parent
, bool ignore_bds_parents
,
459 int *drained_end_counter
)
462 int old_quiesce_counter
;
464 assert(drained_end_counter
!= NULL
);
466 if (qemu_in_coroutine()) {
467 bdrv_co_yield_to_drain(bs
, false, recursive
, parent
, ignore_bds_parents
,
468 false, drained_end_counter
);
471 assert(bs
->quiesce_counter
> 0);
473 /* Re-enable things in child-to-parent order */
474 bdrv_drain_invoke(bs
, false, drained_end_counter
);
475 bdrv_parent_drained_end(bs
, parent
, ignore_bds_parents
,
476 drained_end_counter
);
478 old_quiesce_counter
= atomic_fetch_dec(&bs
->quiesce_counter
);
479 if (old_quiesce_counter
== 1) {
480 aio_enable_external(bdrv_get_aio_context(bs
));
484 assert(!ignore_bds_parents
);
485 bs
->recursive_quiesce_counter
--;
486 QLIST_FOREACH(child
, &bs
->children
, next
) {
487 bdrv_do_drained_end(child
->bs
, true, child
, ignore_bds_parents
,
488 drained_end_counter
);
493 void bdrv_drained_end(BlockDriverState
*bs
)
495 int drained_end_counter
= 0;
496 bdrv_do_drained_end(bs
, false, NULL
, false, &drained_end_counter
);
497 BDRV_POLL_WHILE(bs
, atomic_read(&drained_end_counter
) > 0);
500 void bdrv_drained_end_no_poll(BlockDriverState
*bs
, int *drained_end_counter
)
502 bdrv_do_drained_end(bs
, false, NULL
, false, drained_end_counter
);
505 void bdrv_subtree_drained_end(BlockDriverState
*bs
)
507 int drained_end_counter
= 0;
508 bdrv_do_drained_end(bs
, true, NULL
, false, &drained_end_counter
);
509 BDRV_POLL_WHILE(bs
, atomic_read(&drained_end_counter
) > 0);
512 void bdrv_apply_subtree_drain(BdrvChild
*child
, BlockDriverState
*new_parent
)
516 for (i
= 0; i
< new_parent
->recursive_quiesce_counter
; i
++) {
517 bdrv_do_drained_begin(child
->bs
, true, child
, false, true);
521 void bdrv_unapply_subtree_drain(BdrvChild
*child
, BlockDriverState
*old_parent
)
523 int drained_end_counter
= 0;
526 for (i
= 0; i
< old_parent
->recursive_quiesce_counter
; i
++) {
527 bdrv_do_drained_end(child
->bs
, true, child
, false,
528 &drained_end_counter
);
531 BDRV_POLL_WHILE(child
->bs
, atomic_read(&drained_end_counter
) > 0);
535 * Wait for pending requests to complete on a single BlockDriverState subtree,
536 * and suspend block driver's internal I/O until next request arrives.
538 * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState
541 void coroutine_fn
bdrv_co_drain(BlockDriverState
*bs
)
543 assert(qemu_in_coroutine());
544 bdrv_drained_begin(bs
);
545 bdrv_drained_end(bs
);
548 void bdrv_drain(BlockDriverState
*bs
)
550 bdrv_drained_begin(bs
);
551 bdrv_drained_end(bs
);
554 static void bdrv_drain_assert_idle(BlockDriverState
*bs
)
556 BdrvChild
*child
, *next
;
558 assert(atomic_read(&bs
->in_flight
) == 0);
559 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
560 bdrv_drain_assert_idle(child
->bs
);
564 unsigned int bdrv_drain_all_count
= 0;
566 static bool bdrv_drain_all_poll(void)
568 BlockDriverState
*bs
= NULL
;
571 /* bdrv_drain_poll() can't make changes to the graph and we are holding the
572 * main AioContext lock, so iterating bdrv_next_all_states() is safe. */
573 while ((bs
= bdrv_next_all_states(bs
))) {
574 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
575 aio_context_acquire(aio_context
);
576 result
|= bdrv_drain_poll(bs
, false, NULL
, true);
577 aio_context_release(aio_context
);
584 * Wait for pending requests to complete across all BlockDriverStates
586 * This function does not flush data to disk, use bdrv_flush_all() for that
587 * after calling this function.
589 * This pauses all block jobs and disables external clients. It must
590 * be paired with bdrv_drain_all_end().
592 * NOTE: no new block jobs or BlockDriverStates can be created between
593 * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls.
595 void bdrv_drain_all_begin(void)
597 BlockDriverState
*bs
= NULL
;
599 if (qemu_in_coroutine()) {
600 bdrv_co_yield_to_drain(NULL
, true, false, NULL
, true, true, NULL
);
605 * bdrv queue is managed by record/replay,
606 * waiting for finishing the I/O requests may
609 if (replay_events_enabled()) {
613 /* AIO_WAIT_WHILE() with a NULL context can only be called from the main
614 * loop AioContext, so make sure we're in the main context. */
615 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
616 assert(bdrv_drain_all_count
< INT_MAX
);
617 bdrv_drain_all_count
++;
619 /* Quiesce all nodes, without polling in-flight requests yet. The graph
620 * cannot change during this loop. */
621 while ((bs
= bdrv_next_all_states(bs
))) {
622 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
624 aio_context_acquire(aio_context
);
625 bdrv_do_drained_begin(bs
, false, NULL
, true, false);
626 aio_context_release(aio_context
);
629 /* Now poll the in-flight requests */
630 AIO_WAIT_WHILE(NULL
, bdrv_drain_all_poll());
632 while ((bs
= bdrv_next_all_states(bs
))) {
633 bdrv_drain_assert_idle(bs
);
637 void bdrv_drain_all_end(void)
639 BlockDriverState
*bs
= NULL
;
640 int drained_end_counter
= 0;
643 * bdrv queue is managed by record/replay,
644 * waiting for finishing the I/O requests may
647 if (replay_events_enabled()) {
651 while ((bs
= bdrv_next_all_states(bs
))) {
652 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
654 aio_context_acquire(aio_context
);
655 bdrv_do_drained_end(bs
, false, NULL
, true, &drained_end_counter
);
656 aio_context_release(aio_context
);
659 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
660 AIO_WAIT_WHILE(NULL
, atomic_read(&drained_end_counter
) > 0);
662 assert(bdrv_drain_all_count
> 0);
663 bdrv_drain_all_count
--;
666 void bdrv_drain_all(void)
668 bdrv_drain_all_begin();
669 bdrv_drain_all_end();
673 * Remove an active request from the tracked requests list
675 * This function should be called when a tracked request is completing.
677 static void tracked_request_end(BdrvTrackedRequest
*req
)
679 if (req
->serialising
) {
680 atomic_dec(&req
->bs
->serialising_in_flight
);
683 qemu_co_mutex_lock(&req
->bs
->reqs_lock
);
684 QLIST_REMOVE(req
, list
);
685 qemu_co_queue_restart_all(&req
->wait_queue
);
686 qemu_co_mutex_unlock(&req
->bs
->reqs_lock
);
690 * Add an active request to the tracked requests list
692 static void tracked_request_begin(BdrvTrackedRequest
*req
,
693 BlockDriverState
*bs
,
696 enum BdrvTrackedRequestType type
)
698 assert(bytes
<= INT64_MAX
&& offset
<= INT64_MAX
- bytes
);
700 *req
= (BdrvTrackedRequest
){
705 .co
= qemu_coroutine_self(),
706 .serialising
= false,
707 .overlap_offset
= offset
,
708 .overlap_bytes
= bytes
,
711 qemu_co_queue_init(&req
->wait_queue
);
713 qemu_co_mutex_lock(&bs
->reqs_lock
);
714 QLIST_INSERT_HEAD(&bs
->tracked_requests
, req
, list
);
715 qemu_co_mutex_unlock(&bs
->reqs_lock
);
718 static bool tracked_request_overlaps(BdrvTrackedRequest
*req
,
719 int64_t offset
, uint64_t bytes
)
722 if (offset
>= req
->overlap_offset
+ req
->overlap_bytes
) {
726 if (req
->overlap_offset
>= offset
+ bytes
) {
732 static bool coroutine_fn
733 bdrv_wait_serialising_requests_locked(BlockDriverState
*bs
,
734 BdrvTrackedRequest
*self
)
736 BdrvTrackedRequest
*req
;
742 QLIST_FOREACH(req
, &bs
->tracked_requests
, list
) {
743 if (req
== self
|| (!req
->serialising
&& !self
->serialising
)) {
746 if (tracked_request_overlaps(req
, self
->overlap_offset
,
747 self
->overlap_bytes
))
749 /* Hitting this means there was a reentrant request, for
750 * example, a block driver issuing nested requests. This must
751 * never happen since it means deadlock.
753 assert(qemu_coroutine_self() != req
->co
);
755 /* If the request is already (indirectly) waiting for us, or
756 * will wait for us as soon as it wakes up, then just go on
757 * (instead of producing a deadlock in the former case). */
758 if (!req
->waiting_for
) {
759 self
->waiting_for
= req
;
760 qemu_co_queue_wait(&req
->wait_queue
, &bs
->reqs_lock
);
761 self
->waiting_for
= NULL
;
772 bool bdrv_mark_request_serialising(BdrvTrackedRequest
*req
, uint64_t align
)
774 BlockDriverState
*bs
= req
->bs
;
775 int64_t overlap_offset
= req
->offset
& ~(align
- 1);
776 uint64_t overlap_bytes
= ROUND_UP(req
->offset
+ req
->bytes
, align
)
780 qemu_co_mutex_lock(&bs
->reqs_lock
);
781 if (!req
->serialising
) {
782 atomic_inc(&req
->bs
->serialising_in_flight
);
783 req
->serialising
= true;
786 req
->overlap_offset
= MIN(req
->overlap_offset
, overlap_offset
);
787 req
->overlap_bytes
= MAX(req
->overlap_bytes
, overlap_bytes
);
788 waited
= bdrv_wait_serialising_requests_locked(bs
, req
);
789 qemu_co_mutex_unlock(&bs
->reqs_lock
);
794 * Return the tracked request on @bs for the current coroutine, or
795 * NULL if there is none.
797 BdrvTrackedRequest
*coroutine_fn
bdrv_co_get_self_request(BlockDriverState
*bs
)
799 BdrvTrackedRequest
*req
;
800 Coroutine
*self
= qemu_coroutine_self();
802 QLIST_FOREACH(req
, &bs
->tracked_requests
, list
) {
803 if (req
->co
== self
) {
812 * Round a region to cluster boundaries
814 void bdrv_round_to_clusters(BlockDriverState
*bs
,
815 int64_t offset
, int64_t bytes
,
816 int64_t *cluster_offset
,
817 int64_t *cluster_bytes
)
821 if (bdrv_get_info(bs
, &bdi
) < 0 || bdi
.cluster_size
== 0) {
822 *cluster_offset
= offset
;
823 *cluster_bytes
= bytes
;
825 int64_t c
= bdi
.cluster_size
;
826 *cluster_offset
= QEMU_ALIGN_DOWN(offset
, c
);
827 *cluster_bytes
= QEMU_ALIGN_UP(offset
- *cluster_offset
+ bytes
, c
);
831 static int bdrv_get_cluster_size(BlockDriverState
*bs
)
836 ret
= bdrv_get_info(bs
, &bdi
);
837 if (ret
< 0 || bdi
.cluster_size
== 0) {
838 return bs
->bl
.request_alignment
;
840 return bdi
.cluster_size
;
844 void bdrv_inc_in_flight(BlockDriverState
*bs
)
846 atomic_inc(&bs
->in_flight
);
849 void bdrv_wakeup(BlockDriverState
*bs
)
854 void bdrv_dec_in_flight(BlockDriverState
*bs
)
856 atomic_dec(&bs
->in_flight
);
860 static bool coroutine_fn
bdrv_wait_serialising_requests(BdrvTrackedRequest
*self
)
862 BlockDriverState
*bs
= self
->bs
;
865 if (!atomic_read(&bs
->serialising_in_flight
)) {
869 qemu_co_mutex_lock(&bs
->reqs_lock
);
870 waited
= bdrv_wait_serialising_requests_locked(bs
, self
);
871 qemu_co_mutex_unlock(&bs
->reqs_lock
);
876 static int bdrv_check_byte_request(BlockDriverState
*bs
, int64_t offset
,
879 if (size
> BDRV_REQUEST_MAX_BYTES
) {
883 if (!bdrv_is_inserted(bs
)) {
894 typedef struct RwCo
{
900 BdrvRequestFlags flags
;
903 static void coroutine_fn
bdrv_rw_co_entry(void *opaque
)
907 if (!rwco
->is_write
) {
908 rwco
->ret
= bdrv_co_preadv(rwco
->child
, rwco
->offset
,
909 rwco
->qiov
->size
, rwco
->qiov
,
912 rwco
->ret
= bdrv_co_pwritev(rwco
->child
, rwco
->offset
,
913 rwco
->qiov
->size
, rwco
->qiov
,
920 * Process a vectored synchronous request using coroutines
922 static int bdrv_prwv_co(BdrvChild
*child
, int64_t offset
,
923 QEMUIOVector
*qiov
, bool is_write
,
924 BdrvRequestFlags flags
)
931 .is_write
= is_write
,
936 if (qemu_in_coroutine()) {
937 /* Fast-path if already in coroutine context */
938 bdrv_rw_co_entry(&rwco
);
940 co
= qemu_coroutine_create(bdrv_rw_co_entry
, &rwco
);
941 bdrv_coroutine_enter(child
->bs
, co
);
942 BDRV_POLL_WHILE(child
->bs
, rwco
.ret
== NOT_DONE
);
947 int bdrv_pwrite_zeroes(BdrvChild
*child
, int64_t offset
,
948 int bytes
, BdrvRequestFlags flags
)
950 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, NULL
, bytes
);
952 return bdrv_prwv_co(child
, offset
, &qiov
, true,
953 BDRV_REQ_ZERO_WRITE
| flags
);
957 * Completely zero out a block device with the help of bdrv_pwrite_zeroes.
958 * The operation is sped up by checking the block status and only writing
959 * zeroes to the device if they currently do not return zeroes. Optional
960 * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP,
963 * Returns < 0 on error, 0 on success. For error codes see bdrv_write().
965 int bdrv_make_zero(BdrvChild
*child
, BdrvRequestFlags flags
)
968 int64_t target_size
, bytes
, offset
= 0;
969 BlockDriverState
*bs
= child
->bs
;
971 target_size
= bdrv_getlength(bs
);
972 if (target_size
< 0) {
977 bytes
= MIN(target_size
- offset
, BDRV_REQUEST_MAX_BYTES
);
981 ret
= bdrv_block_status(bs
, offset
, bytes
, &bytes
, NULL
, NULL
);
985 if (ret
& BDRV_BLOCK_ZERO
) {
989 ret
= bdrv_pwrite_zeroes(child
, offset
, bytes
, flags
);
997 int bdrv_preadv(BdrvChild
*child
, int64_t offset
, QEMUIOVector
*qiov
)
1001 ret
= bdrv_prwv_co(child
, offset
, qiov
, false, 0);
1009 /* See bdrv_pwrite() for the return codes */
1010 int bdrv_pread(BdrvChild
*child
, int64_t offset
, void *buf
, int bytes
)
1012 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, bytes
);
1018 return bdrv_preadv(child
, offset
, &qiov
);
1021 int bdrv_pwritev(BdrvChild
*child
, int64_t offset
, QEMUIOVector
*qiov
)
1025 ret
= bdrv_prwv_co(child
, offset
, qiov
, true, 0);
1033 /* Return no. of bytes on success or < 0 on error. Important errors are:
1034 -EIO generic I/O error (may happen for all errors)
1035 -ENOMEDIUM No media inserted.
1036 -EINVAL Invalid offset or number of bytes
1037 -EACCES Trying to write a read-only device
1039 int bdrv_pwrite(BdrvChild
*child
, int64_t offset
, const void *buf
, int bytes
)
1041 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, bytes
);
1047 return bdrv_pwritev(child
, offset
, &qiov
);
1051 * Writes to the file and ensures that no writes are reordered across this
1052 * request (acts as a barrier)
1054 * Returns 0 on success, -errno in error cases.
1056 int bdrv_pwrite_sync(BdrvChild
*child
, int64_t offset
,
1057 const void *buf
, int count
)
1061 ret
= bdrv_pwrite(child
, offset
, buf
, count
);
1066 ret
= bdrv_flush(child
->bs
);
1074 typedef struct CoroutineIOCompletion
{
1075 Coroutine
*coroutine
;
1077 } CoroutineIOCompletion
;
1079 static void bdrv_co_io_em_complete(void *opaque
, int ret
)
1081 CoroutineIOCompletion
*co
= opaque
;
1084 aio_co_wake(co
->coroutine
);
1087 static int coroutine_fn
bdrv_driver_preadv(BlockDriverState
*bs
,
1088 uint64_t offset
, uint64_t bytes
,
1090 size_t qiov_offset
, int flags
)
1092 BlockDriver
*drv
= bs
->drv
;
1094 unsigned int nb_sectors
;
1095 QEMUIOVector local_qiov
;
1098 assert(!(flags
& ~BDRV_REQ_MASK
));
1099 assert(!(flags
& BDRV_REQ_NO_FALLBACK
));
1105 if (drv
->bdrv_co_preadv_part
) {
1106 return drv
->bdrv_co_preadv_part(bs
, offset
, bytes
, qiov
, qiov_offset
,
1110 if (qiov_offset
> 0 || bytes
!= qiov
->size
) {
1111 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
1115 if (drv
->bdrv_co_preadv
) {
1116 ret
= drv
->bdrv_co_preadv(bs
, offset
, bytes
, qiov
, flags
);
1120 if (drv
->bdrv_aio_preadv
) {
1122 CoroutineIOCompletion co
= {
1123 .coroutine
= qemu_coroutine_self(),
1126 acb
= drv
->bdrv_aio_preadv(bs
, offset
, bytes
, qiov
, flags
,
1127 bdrv_co_io_em_complete
, &co
);
1132 qemu_coroutine_yield();
1138 sector_num
= offset
>> BDRV_SECTOR_BITS
;
1139 nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
1141 assert(QEMU_IS_ALIGNED(offset
, BDRV_SECTOR_SIZE
));
1142 assert(QEMU_IS_ALIGNED(bytes
, BDRV_SECTOR_SIZE
));
1143 assert(bytes
<= BDRV_REQUEST_MAX_BYTES
);
1144 assert(drv
->bdrv_co_readv
);
1146 ret
= drv
->bdrv_co_readv(bs
, sector_num
, nb_sectors
, qiov
);
1149 if (qiov
== &local_qiov
) {
1150 qemu_iovec_destroy(&local_qiov
);
1156 static int coroutine_fn
bdrv_driver_pwritev(BlockDriverState
*bs
,
1157 uint64_t offset
, uint64_t bytes
,
1159 size_t qiov_offset
, int flags
)
1161 BlockDriver
*drv
= bs
->drv
;
1163 unsigned int nb_sectors
;
1164 QEMUIOVector local_qiov
;
1167 assert(!(flags
& ~BDRV_REQ_MASK
));
1168 assert(!(flags
& BDRV_REQ_NO_FALLBACK
));
1174 if (drv
->bdrv_co_pwritev_part
) {
1175 ret
= drv
->bdrv_co_pwritev_part(bs
, offset
, bytes
, qiov
, qiov_offset
,
1176 flags
& bs
->supported_write_flags
);
1177 flags
&= ~bs
->supported_write_flags
;
1181 if (qiov_offset
> 0 || bytes
!= qiov
->size
) {
1182 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
1186 if (drv
->bdrv_co_pwritev
) {
1187 ret
= drv
->bdrv_co_pwritev(bs
, offset
, bytes
, qiov
,
1188 flags
& bs
->supported_write_flags
);
1189 flags
&= ~bs
->supported_write_flags
;
1193 if (drv
->bdrv_aio_pwritev
) {
1195 CoroutineIOCompletion co
= {
1196 .coroutine
= qemu_coroutine_self(),
1199 acb
= drv
->bdrv_aio_pwritev(bs
, offset
, bytes
, qiov
,
1200 flags
& bs
->supported_write_flags
,
1201 bdrv_co_io_em_complete
, &co
);
1202 flags
&= ~bs
->supported_write_flags
;
1206 qemu_coroutine_yield();
1212 sector_num
= offset
>> BDRV_SECTOR_BITS
;
1213 nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
1215 assert(QEMU_IS_ALIGNED(offset
, BDRV_SECTOR_SIZE
));
1216 assert(QEMU_IS_ALIGNED(bytes
, BDRV_SECTOR_SIZE
));
1217 assert(bytes
<= BDRV_REQUEST_MAX_BYTES
);
1219 assert(drv
->bdrv_co_writev
);
1220 ret
= drv
->bdrv_co_writev(bs
, sector_num
, nb_sectors
, qiov
,
1221 flags
& bs
->supported_write_flags
);
1222 flags
&= ~bs
->supported_write_flags
;
1225 if (ret
== 0 && (flags
& BDRV_REQ_FUA
)) {
1226 ret
= bdrv_co_flush(bs
);
1229 if (qiov
== &local_qiov
) {
1230 qemu_iovec_destroy(&local_qiov
);
1236 static int coroutine_fn
1237 bdrv_driver_pwritev_compressed(BlockDriverState
*bs
, uint64_t offset
,
1238 uint64_t bytes
, QEMUIOVector
*qiov
,
1241 BlockDriver
*drv
= bs
->drv
;
1242 QEMUIOVector local_qiov
;
1249 if (!block_driver_can_compress(drv
)) {
1253 if (drv
->bdrv_co_pwritev_compressed_part
) {
1254 return drv
->bdrv_co_pwritev_compressed_part(bs
, offset
, bytes
,
1258 if (qiov_offset
== 0) {
1259 return drv
->bdrv_co_pwritev_compressed(bs
, offset
, bytes
, qiov
);
1262 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
1263 ret
= drv
->bdrv_co_pwritev_compressed(bs
, offset
, bytes
, &local_qiov
);
1264 qemu_iovec_destroy(&local_qiov
);
1269 static int coroutine_fn
bdrv_co_do_copy_on_readv(BdrvChild
*child
,
1270 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
1271 size_t qiov_offset
, int flags
)
1273 BlockDriverState
*bs
= child
->bs
;
1275 /* Perform I/O through a temporary buffer so that users who scribble over
1276 * their read buffer while the operation is in progress do not end up
1277 * modifying the image file. This is critical for zero-copy guest I/O
1278 * where anything might happen inside guest memory.
1280 void *bounce_buffer
= NULL
;
1282 BlockDriver
*drv
= bs
->drv
;
1283 int64_t cluster_offset
;
1284 int64_t cluster_bytes
;
1287 int max_transfer
= MIN_NON_ZERO(bs
->bl
.max_transfer
,
1288 BDRV_REQUEST_MAX_BYTES
);
1289 unsigned int progress
= 0;
1297 * Do not write anything when the BDS is inactive. That is not
1298 * allowed, and it would not help.
1300 skip_write
= (bs
->open_flags
& BDRV_O_INACTIVE
);
1302 /* FIXME We cannot require callers to have write permissions when all they
1303 * are doing is a read request. If we did things right, write permissions
1304 * would be obtained anyway, but internally by the copy-on-read code. As
1305 * long as it is implemented here rather than in a separate filter driver,
1306 * the copy-on-read code doesn't have its own BdrvChild, however, for which
1307 * it could request permissions. Therefore we have to bypass the permission
1308 * system for the moment. */
1309 // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
1311 /* Cover entire cluster so no additional backing file I/O is required when
1312 * allocating cluster in the image file. Note that this value may exceed
1313 * BDRV_REQUEST_MAX_BYTES (even when the original read did not), which
1314 * is one reason we loop rather than doing it all at once.
1316 bdrv_round_to_clusters(bs
, offset
, bytes
, &cluster_offset
, &cluster_bytes
);
1317 skip_bytes
= offset
- cluster_offset
;
1319 trace_bdrv_co_do_copy_on_readv(bs
, offset
, bytes
,
1320 cluster_offset
, cluster_bytes
);
1322 while (cluster_bytes
) {
1326 ret
= 1; /* "already allocated", so nothing will be copied */
1327 pnum
= MIN(cluster_bytes
, max_transfer
);
1329 ret
= bdrv_is_allocated(bs
, cluster_offset
,
1330 MIN(cluster_bytes
, max_transfer
), &pnum
);
1333 * Safe to treat errors in querying allocation as if
1334 * unallocated; we'll probably fail again soon on the
1335 * read, but at least that will set a decent errno.
1337 pnum
= MIN(cluster_bytes
, max_transfer
);
1340 /* Stop at EOF if the image ends in the middle of the cluster */
1341 if (ret
== 0 && pnum
== 0) {
1342 assert(progress
>= bytes
);
1346 assert(skip_bytes
< pnum
);
1350 QEMUIOVector local_qiov
;
1352 /* Must copy-on-read; use the bounce buffer */
1353 pnum
= MIN(pnum
, MAX_BOUNCE_BUFFER
);
1354 if (!bounce_buffer
) {
1355 int64_t max_we_need
= MAX(pnum
, cluster_bytes
- pnum
);
1356 int64_t max_allowed
= MIN(max_transfer
, MAX_BOUNCE_BUFFER
);
1357 int64_t bounce_buffer_len
= MIN(max_we_need
, max_allowed
);
1359 bounce_buffer
= qemu_try_blockalign(bs
, bounce_buffer_len
);
1360 if (!bounce_buffer
) {
1365 qemu_iovec_init_buf(&local_qiov
, bounce_buffer
, pnum
);
1367 ret
= bdrv_driver_preadv(bs
, cluster_offset
, pnum
,
1373 bdrv_debug_event(bs
, BLKDBG_COR_WRITE
);
1374 if (drv
->bdrv_co_pwrite_zeroes
&&
1375 buffer_is_zero(bounce_buffer
, pnum
)) {
1376 /* FIXME: Should we (perhaps conditionally) be setting
1377 * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
1378 * that still correctly reads as zero? */
1379 ret
= bdrv_co_do_pwrite_zeroes(bs
, cluster_offset
, pnum
,
1380 BDRV_REQ_WRITE_UNCHANGED
);
1382 /* This does not change the data on the disk, it is not
1383 * necessary to flush even in cache=writethrough mode.
1385 ret
= bdrv_driver_pwritev(bs
, cluster_offset
, pnum
,
1387 BDRV_REQ_WRITE_UNCHANGED
);
1391 /* It might be okay to ignore write errors for guest
1392 * requests. If this is a deliberate copy-on-read
1393 * then we don't want to ignore the error. Simply
1394 * report it in all cases.
1399 if (!(flags
& BDRV_REQ_PREFETCH
)) {
1400 qemu_iovec_from_buf(qiov
, qiov_offset
+ progress
,
1401 bounce_buffer
+ skip_bytes
,
1402 MIN(pnum
- skip_bytes
, bytes
- progress
));
1404 } else if (!(flags
& BDRV_REQ_PREFETCH
)) {
1405 /* Read directly into the destination */
1406 ret
= bdrv_driver_preadv(bs
, offset
+ progress
,
1407 MIN(pnum
- skip_bytes
, bytes
- progress
),
1408 qiov
, qiov_offset
+ progress
, 0);
1414 cluster_offset
+= pnum
;
1415 cluster_bytes
-= pnum
;
1416 progress
+= pnum
- skip_bytes
;
1422 qemu_vfree(bounce_buffer
);
1427 * Forwards an already correctly aligned request to the BlockDriver. This
1428 * handles copy on read, zeroing after EOF, and fragmentation of large
1429 * reads; any other features must be implemented by the caller.
1431 static int coroutine_fn
bdrv_aligned_preadv(BdrvChild
*child
,
1432 BdrvTrackedRequest
*req
, int64_t offset
, unsigned int bytes
,
1433 int64_t align
, QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
1435 BlockDriverState
*bs
= child
->bs
;
1436 int64_t total_bytes
, max_bytes
;
1438 uint64_t bytes_remaining
= bytes
;
1441 assert(is_power_of_2(align
));
1442 assert((offset
& (align
- 1)) == 0);
1443 assert((bytes
& (align
- 1)) == 0);
1444 assert((bs
->open_flags
& BDRV_O_NO_IO
) == 0);
1445 max_transfer
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_transfer
, INT_MAX
),
1448 /* TODO: We would need a per-BDS .supported_read_flags and
1449 * potential fallback support, if we ever implement any read flags
1450 * to pass through to drivers. For now, there aren't any
1451 * passthrough flags. */
1452 assert(!(flags
& ~(BDRV_REQ_COPY_ON_READ
| BDRV_REQ_PREFETCH
)));
1454 /* Handle Copy on Read and associated serialisation */
1455 if (flags
& BDRV_REQ_COPY_ON_READ
) {
1456 /* If we touch the same cluster it counts as an overlap. This
1457 * guarantees that allocating writes will be serialized and not race
1458 * with each other for the same cluster. For example, in copy-on-read
1459 * it ensures that the CoR read and write operations are atomic and
1460 * guest writes cannot interleave between them. */
1461 bdrv_mark_request_serialising(req
, bdrv_get_cluster_size(bs
));
1463 bdrv_wait_serialising_requests(req
);
1466 if (flags
& BDRV_REQ_COPY_ON_READ
) {
1469 ret
= bdrv_is_allocated(bs
, offset
, bytes
, &pnum
);
1474 if (!ret
|| pnum
!= bytes
) {
1475 ret
= bdrv_co_do_copy_on_readv(child
, offset
, bytes
,
1476 qiov
, qiov_offset
, flags
);
1478 } else if (flags
& BDRV_REQ_PREFETCH
) {
1483 /* Forward the request to the BlockDriver, possibly fragmenting it */
1484 total_bytes
= bdrv_getlength(bs
);
1485 if (total_bytes
< 0) {
1490 max_bytes
= ROUND_UP(MAX(0, total_bytes
- offset
), align
);
1491 if (bytes
<= max_bytes
&& bytes
<= max_transfer
) {
1492 ret
= bdrv_driver_preadv(bs
, offset
, bytes
, qiov
, qiov_offset
, 0);
1496 while (bytes_remaining
) {
1500 num
= MIN(bytes_remaining
, MIN(max_bytes
, max_transfer
));
1503 ret
= bdrv_driver_preadv(bs
, offset
+ bytes
- bytes_remaining
,
1504 num
, qiov
, bytes
- bytes_remaining
, 0);
1507 num
= bytes_remaining
;
1508 ret
= qemu_iovec_memset(qiov
, bytes
- bytes_remaining
, 0,
1514 bytes_remaining
-= num
;
1518 return ret
< 0 ? ret
: 0;
1524 * |<---- align ----->| |<----- align ---->|
1525 * |<- head ->|<------------- bytes ------------->|<-- tail -->|
1527 * -*----------$-------*-------- ... --------*-----$------------*---
1529 * | offset | | end |
1530 * ALIGN_DOWN(offset) ALIGN_UP(offset) ALIGN_DOWN(end) ALIGN_UP(end)
1531 * [buf ... ) [tail_buf )
1533 * @buf is an aligned allocation needed to store @head and @tail paddings. @head
1534 * is placed at the beginning of @buf and @tail at the @end.
1536 * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk
1537 * around tail, if tail exists.
1539 * @merge_reads is true for small requests,
1540 * if @buf_len == @head + bytes + @tail. In this case it is possible that both
1541 * head and tail exist but @buf_len == align and @tail_buf == @buf.
1543 typedef struct BdrvRequestPadding
{
1550 QEMUIOVector local_qiov
;
1551 } BdrvRequestPadding
;
1553 static bool bdrv_init_padding(BlockDriverState
*bs
,
1554 int64_t offset
, int64_t bytes
,
1555 BdrvRequestPadding
*pad
)
1557 uint64_t align
= bs
->bl
.request_alignment
;
1560 memset(pad
, 0, sizeof(*pad
));
1562 pad
->head
= offset
& (align
- 1);
1563 pad
->tail
= ((offset
+ bytes
) & (align
- 1));
1565 pad
->tail
= align
- pad
->tail
;
1568 if (!pad
->head
&& !pad
->tail
) {
1572 assert(bytes
); /* Nothing good in aligning zero-length requests */
1574 sum
= pad
->head
+ bytes
+ pad
->tail
;
1575 pad
->buf_len
= (sum
> align
&& pad
->head
&& pad
->tail
) ? 2 * align
: align
;
1576 pad
->buf
= qemu_blockalign(bs
, pad
->buf_len
);
1577 pad
->merge_reads
= sum
== pad
->buf_len
;
1579 pad
->tail_buf
= pad
->buf
+ pad
->buf_len
- align
;
1585 static int bdrv_padding_rmw_read(BdrvChild
*child
,
1586 BdrvTrackedRequest
*req
,
1587 BdrvRequestPadding
*pad
,
1590 QEMUIOVector local_qiov
;
1591 BlockDriverState
*bs
= child
->bs
;
1592 uint64_t align
= bs
->bl
.request_alignment
;
1595 assert(req
->serialising
&& pad
->buf
);
1597 if (pad
->head
|| pad
->merge_reads
) {
1598 uint64_t bytes
= pad
->merge_reads
? pad
->buf_len
: align
;
1600 qemu_iovec_init_buf(&local_qiov
, pad
->buf
, bytes
);
1603 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_HEAD
);
1605 if (pad
->merge_reads
&& pad
->tail
) {
1606 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1608 ret
= bdrv_aligned_preadv(child
, req
, req
->overlap_offset
, bytes
,
1609 align
, &local_qiov
, 0, 0);
1614 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_HEAD
);
1616 if (pad
->merge_reads
&& pad
->tail
) {
1617 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1620 if (pad
->merge_reads
) {
1626 qemu_iovec_init_buf(&local_qiov
, pad
->tail_buf
, align
);
1628 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1629 ret
= bdrv_aligned_preadv(
1631 req
->overlap_offset
+ req
->overlap_bytes
- align
,
1632 align
, align
, &local_qiov
, 0, 0);
1636 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1641 memset(pad
->buf
+ pad
->head
, 0, pad
->buf_len
- pad
->head
- pad
->tail
);
1647 static void bdrv_padding_destroy(BdrvRequestPadding
*pad
)
1650 qemu_vfree(pad
->buf
);
1651 qemu_iovec_destroy(&pad
->local_qiov
);
1658 * Exchange request parameters with padded request if needed. Don't include RMW
1659 * read of padding, bdrv_padding_rmw_read() should be called separately if
1662 * All parameters except @bs are in-out: they represent original request at
1663 * function call and padded (if padding needed) at function finish.
1665 * Function always succeeds.
1667 static bool bdrv_pad_request(BlockDriverState
*bs
,
1668 QEMUIOVector
**qiov
, size_t *qiov_offset
,
1669 int64_t *offset
, unsigned int *bytes
,
1670 BdrvRequestPadding
*pad
)
1672 if (!bdrv_init_padding(bs
, *offset
, *bytes
, pad
)) {
1676 qemu_iovec_init_extended(&pad
->local_qiov
, pad
->buf
, pad
->head
,
1677 *qiov
, *qiov_offset
, *bytes
,
1678 pad
->buf
+ pad
->buf_len
- pad
->tail
, pad
->tail
);
1679 *bytes
+= pad
->head
+ pad
->tail
;
1680 *offset
-= pad
->head
;
1681 *qiov
= &pad
->local_qiov
;
1687 int coroutine_fn
bdrv_co_preadv(BdrvChild
*child
,
1688 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
1689 BdrvRequestFlags flags
)
1691 return bdrv_co_preadv_part(child
, offset
, bytes
, qiov
, 0, flags
);
1694 int coroutine_fn
bdrv_co_preadv_part(BdrvChild
*child
,
1695 int64_t offset
, unsigned int bytes
,
1696 QEMUIOVector
*qiov
, size_t qiov_offset
,
1697 BdrvRequestFlags flags
)
1699 BlockDriverState
*bs
= child
->bs
;
1700 BdrvTrackedRequest req
;
1701 BdrvRequestPadding pad
;
1704 trace_bdrv_co_preadv(bs
, offset
, bytes
, flags
);
1706 ret
= bdrv_check_byte_request(bs
, offset
, bytes
);
1711 if (bytes
== 0 && !QEMU_IS_ALIGNED(offset
, bs
->bl
.request_alignment
)) {
1713 * Aligning zero request is nonsense. Even if driver has special meaning
1714 * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
1715 * it to driver due to request_alignment.
1717 * Still, no reason to return an error if someone do unaligned
1718 * zero-length read occasionally.
1723 bdrv_inc_in_flight(bs
);
1725 /* Don't do copy-on-read if we read data before write operation */
1726 if (atomic_read(&bs
->copy_on_read
)) {
1727 flags
|= BDRV_REQ_COPY_ON_READ
;
1730 bdrv_pad_request(bs
, &qiov
, &qiov_offset
, &offset
, &bytes
, &pad
);
1732 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_READ
);
1733 ret
= bdrv_aligned_preadv(child
, &req
, offset
, bytes
,
1734 bs
->bl
.request_alignment
,
1735 qiov
, qiov_offset
, flags
);
1736 tracked_request_end(&req
);
1737 bdrv_dec_in_flight(bs
);
1739 bdrv_padding_destroy(&pad
);
1744 static int coroutine_fn
bdrv_co_do_pwrite_zeroes(BlockDriverState
*bs
,
1745 int64_t offset
, int bytes
, BdrvRequestFlags flags
)
1747 BlockDriver
*drv
= bs
->drv
;
1751 bool need_flush
= false;
1755 int max_write_zeroes
= MIN_NON_ZERO(bs
->bl
.max_pwrite_zeroes
, INT_MAX
);
1756 int alignment
= MAX(bs
->bl
.pwrite_zeroes_alignment
,
1757 bs
->bl
.request_alignment
);
1758 int max_transfer
= MIN_NON_ZERO(bs
->bl
.max_transfer
, MAX_BOUNCE_BUFFER
);
1764 if ((flags
& ~bs
->supported_zero_flags
) & BDRV_REQ_NO_FALLBACK
) {
1768 assert(alignment
% bs
->bl
.request_alignment
== 0);
1769 head
= offset
% alignment
;
1770 tail
= (offset
+ bytes
) % alignment
;
1771 max_write_zeroes
= QEMU_ALIGN_DOWN(max_write_zeroes
, alignment
);
1772 assert(max_write_zeroes
>= bs
->bl
.request_alignment
);
1774 while (bytes
> 0 && !ret
) {
1777 /* Align request. Block drivers can expect the "bulk" of the request
1778 * to be aligned, and that unaligned requests do not cross cluster
1782 /* Make a small request up to the first aligned sector. For
1783 * convenience, limit this request to max_transfer even if
1784 * we don't need to fall back to writes. */
1785 num
= MIN(MIN(bytes
, max_transfer
), alignment
- head
);
1786 head
= (head
+ num
) % alignment
;
1787 assert(num
< max_write_zeroes
);
1788 } else if (tail
&& num
> alignment
) {
1789 /* Shorten the request to the last aligned sector. */
1793 /* limit request size */
1794 if (num
> max_write_zeroes
) {
1795 num
= max_write_zeroes
;
1799 /* First try the efficient write zeroes operation */
1800 if (drv
->bdrv_co_pwrite_zeroes
) {
1801 ret
= drv
->bdrv_co_pwrite_zeroes(bs
, offset
, num
,
1802 flags
& bs
->supported_zero_flags
);
1803 if (ret
!= -ENOTSUP
&& (flags
& BDRV_REQ_FUA
) &&
1804 !(bs
->supported_zero_flags
& BDRV_REQ_FUA
)) {
1808 assert(!bs
->supported_zero_flags
);
1811 if (ret
== -ENOTSUP
&& !(flags
& BDRV_REQ_NO_FALLBACK
)) {
1812 /* Fall back to bounce buffer if write zeroes is unsupported */
1813 BdrvRequestFlags write_flags
= flags
& ~BDRV_REQ_ZERO_WRITE
;
1815 if ((flags
& BDRV_REQ_FUA
) &&
1816 !(bs
->supported_write_flags
& BDRV_REQ_FUA
)) {
1817 /* No need for bdrv_driver_pwrite() to do a fallback
1818 * flush on each chunk; use just one at the end */
1819 write_flags
&= ~BDRV_REQ_FUA
;
1822 num
= MIN(num
, max_transfer
);
1824 buf
= qemu_try_blockalign0(bs
, num
);
1830 qemu_iovec_init_buf(&qiov
, buf
, num
);
1832 ret
= bdrv_driver_pwritev(bs
, offset
, num
, &qiov
, 0, write_flags
);
1834 /* Keep bounce buffer around if it is big enough for all
1835 * all future requests.
1837 if (num
< max_transfer
) {
1848 if (ret
== 0 && need_flush
) {
1849 ret
= bdrv_co_flush(bs
);
1855 static inline int coroutine_fn
1856 bdrv_co_write_req_prepare(BdrvChild
*child
, int64_t offset
, uint64_t bytes
,
1857 BdrvTrackedRequest
*req
, int flags
)
1859 BlockDriverState
*bs
= child
->bs
;
1861 int64_t end_sector
= DIV_ROUND_UP(offset
+ bytes
, BDRV_SECTOR_SIZE
);
1863 if (bs
->read_only
) {
1867 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
1868 assert((bs
->open_flags
& BDRV_O_NO_IO
) == 0);
1869 assert(!(flags
& ~BDRV_REQ_MASK
));
1871 if (flags
& BDRV_REQ_SERIALISING
) {
1872 waited
= bdrv_mark_request_serialising(req
, bdrv_get_cluster_size(bs
));
1874 * For a misaligned request we should have already waited earlier,
1875 * because we come after bdrv_padding_rmw_read which must be called
1876 * with the request already marked as serialising.
1879 (req
->offset
== req
->overlap_offset
&&
1880 req
->bytes
== req
->overlap_bytes
));
1882 bdrv_wait_serialising_requests(req
);
1885 assert(req
->overlap_offset
<= offset
);
1886 assert(offset
+ bytes
<= req
->overlap_offset
+ req
->overlap_bytes
);
1887 assert(end_sector
<= bs
->total_sectors
|| child
->perm
& BLK_PERM_RESIZE
);
1889 switch (req
->type
) {
1890 case BDRV_TRACKED_WRITE
:
1891 case BDRV_TRACKED_DISCARD
:
1892 if (flags
& BDRV_REQ_WRITE_UNCHANGED
) {
1893 assert(child
->perm
& (BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
));
1895 assert(child
->perm
& BLK_PERM_WRITE
);
1897 return notifier_with_return_list_notify(&bs
->before_write_notifiers
,
1899 case BDRV_TRACKED_TRUNCATE
:
1900 assert(child
->perm
& BLK_PERM_RESIZE
);
1907 static inline void coroutine_fn
1908 bdrv_co_write_req_finish(BdrvChild
*child
, int64_t offset
, uint64_t bytes
,
1909 BdrvTrackedRequest
*req
, int ret
)
1911 int64_t end_sector
= DIV_ROUND_UP(offset
+ bytes
, BDRV_SECTOR_SIZE
);
1912 BlockDriverState
*bs
= child
->bs
;
1914 atomic_inc(&bs
->write_gen
);
1917 * Discard cannot extend the image, but in error handling cases, such as
1918 * when reverting a qcow2 cluster allocation, the discarded range can pass
1919 * the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD
1920 * here. Instead, just skip it, since semantically a discard request
1921 * beyond EOF cannot expand the image anyway.
1924 (req
->type
== BDRV_TRACKED_TRUNCATE
||
1925 end_sector
> bs
->total_sectors
) &&
1926 req
->type
!= BDRV_TRACKED_DISCARD
) {
1927 bs
->total_sectors
= end_sector
;
1928 bdrv_parent_cb_resize(bs
);
1929 bdrv_dirty_bitmap_truncate(bs
, end_sector
<< BDRV_SECTOR_BITS
);
1932 switch (req
->type
) {
1933 case BDRV_TRACKED_WRITE
:
1934 stat64_max(&bs
->wr_highest_offset
, offset
+ bytes
);
1935 /* fall through, to set dirty bits */
1936 case BDRV_TRACKED_DISCARD
:
1937 bdrv_set_dirty(bs
, offset
, bytes
);
1946 * Forwards an already correctly aligned write request to the BlockDriver,
1947 * after possibly fragmenting it.
1949 static int coroutine_fn
bdrv_aligned_pwritev(BdrvChild
*child
,
1950 BdrvTrackedRequest
*req
, int64_t offset
, unsigned int bytes
,
1951 int64_t align
, QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
1953 BlockDriverState
*bs
= child
->bs
;
1954 BlockDriver
*drv
= bs
->drv
;
1957 uint64_t bytes_remaining
= bytes
;
1964 if (bdrv_has_readonly_bitmaps(bs
)) {
1968 assert(is_power_of_2(align
));
1969 assert((offset
& (align
- 1)) == 0);
1970 assert((bytes
& (align
- 1)) == 0);
1971 assert(!qiov
|| qiov_offset
+ bytes
<= qiov
->size
);
1972 max_transfer
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_transfer
, INT_MAX
),
1975 ret
= bdrv_co_write_req_prepare(child
, offset
, bytes
, req
, flags
);
1977 if (!ret
&& bs
->detect_zeroes
!= BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
&&
1978 !(flags
& BDRV_REQ_ZERO_WRITE
) && drv
->bdrv_co_pwrite_zeroes
&&
1979 qemu_iovec_is_zero(qiov
, qiov_offset
, bytes
)) {
1980 flags
|= BDRV_REQ_ZERO_WRITE
;
1981 if (bs
->detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
) {
1982 flags
|= BDRV_REQ_MAY_UNMAP
;
1987 /* Do nothing, write notifier decided to fail this request */
1988 } else if (flags
& BDRV_REQ_ZERO_WRITE
) {
1989 bdrv_debug_event(bs
, BLKDBG_PWRITEV_ZERO
);
1990 ret
= bdrv_co_do_pwrite_zeroes(bs
, offset
, bytes
, flags
);
1991 } else if (flags
& BDRV_REQ_WRITE_COMPRESSED
) {
1992 ret
= bdrv_driver_pwritev_compressed(bs
, offset
, bytes
,
1994 } else if (bytes
<= max_transfer
) {
1995 bdrv_debug_event(bs
, BLKDBG_PWRITEV
);
1996 ret
= bdrv_driver_pwritev(bs
, offset
, bytes
, qiov
, qiov_offset
, flags
);
1998 bdrv_debug_event(bs
, BLKDBG_PWRITEV
);
1999 while (bytes_remaining
) {
2000 int num
= MIN(bytes_remaining
, max_transfer
);
2001 int local_flags
= flags
;
2004 if (num
< bytes_remaining
&& (flags
& BDRV_REQ_FUA
) &&
2005 !(bs
->supported_write_flags
& BDRV_REQ_FUA
)) {
2006 /* If FUA is going to be emulated by flush, we only
2007 * need to flush on the last iteration */
2008 local_flags
&= ~BDRV_REQ_FUA
;
2011 ret
= bdrv_driver_pwritev(bs
, offset
+ bytes
- bytes_remaining
,
2012 num
, qiov
, bytes
- bytes_remaining
,
2017 bytes_remaining
-= num
;
2020 bdrv_debug_event(bs
, BLKDBG_PWRITEV_DONE
);
2025 bdrv_co_write_req_finish(child
, offset
, bytes
, req
, ret
);
2030 static int coroutine_fn
bdrv_co_do_zero_pwritev(BdrvChild
*child
,
2033 BdrvRequestFlags flags
,
2034 BdrvTrackedRequest
*req
)
2036 BlockDriverState
*bs
= child
->bs
;
2037 QEMUIOVector local_qiov
;
2038 uint64_t align
= bs
->bl
.request_alignment
;
2041 BdrvRequestPadding pad
;
2043 padding
= bdrv_init_padding(bs
, offset
, bytes
, &pad
);
2045 bdrv_mark_request_serialising(req
, align
);
2047 bdrv_padding_rmw_read(child
, req
, &pad
, true);
2049 if (pad
.head
|| pad
.merge_reads
) {
2050 int64_t aligned_offset
= offset
& ~(align
- 1);
2051 int64_t write_bytes
= pad
.merge_reads
? pad
.buf_len
: align
;
2053 qemu_iovec_init_buf(&local_qiov
, pad
.buf
, write_bytes
);
2054 ret
= bdrv_aligned_pwritev(child
, req
, aligned_offset
, write_bytes
,
2055 align
, &local_qiov
, 0,
2056 flags
& ~BDRV_REQ_ZERO_WRITE
);
2057 if (ret
< 0 || pad
.merge_reads
) {
2058 /* Error or all work is done */
2061 offset
+= write_bytes
- pad
.head
;
2062 bytes
-= write_bytes
- pad
.head
;
2066 assert(!bytes
|| (offset
& (align
- 1)) == 0);
2067 if (bytes
>= align
) {
2068 /* Write the aligned part in the middle. */
2069 uint64_t aligned_bytes
= bytes
& ~(align
- 1);
2070 ret
= bdrv_aligned_pwritev(child
, req
, offset
, aligned_bytes
, align
,
2075 bytes
-= aligned_bytes
;
2076 offset
+= aligned_bytes
;
2079 assert(!bytes
|| (offset
& (align
- 1)) == 0);
2081 assert(align
== pad
.tail
+ bytes
);
2083 qemu_iovec_init_buf(&local_qiov
, pad
.tail_buf
, align
);
2084 ret
= bdrv_aligned_pwritev(child
, req
, offset
, align
, align
,
2086 flags
& ~BDRV_REQ_ZERO_WRITE
);
2090 bdrv_padding_destroy(&pad
);
2096 * Handle a write request in coroutine context
2098 int coroutine_fn
bdrv_co_pwritev(BdrvChild
*child
,
2099 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
2100 BdrvRequestFlags flags
)
2102 return bdrv_co_pwritev_part(child
, offset
, bytes
, qiov
, 0, flags
);
2105 int coroutine_fn
bdrv_co_pwritev_part(BdrvChild
*child
,
2106 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
, size_t qiov_offset
,
2107 BdrvRequestFlags flags
)
2109 BlockDriverState
*bs
= child
->bs
;
2110 BdrvTrackedRequest req
;
2111 uint64_t align
= bs
->bl
.request_alignment
;
2112 BdrvRequestPadding pad
;
2115 trace_bdrv_co_pwritev(child
->bs
, offset
, bytes
, flags
);
2121 ret
= bdrv_check_byte_request(bs
, offset
, bytes
);
2126 /* If the request is misaligned then we can't make it efficient */
2127 if ((flags
& BDRV_REQ_NO_FALLBACK
) &&
2128 !QEMU_IS_ALIGNED(offset
| bytes
, align
))
2133 if (bytes
== 0 && !QEMU_IS_ALIGNED(offset
, bs
->bl
.request_alignment
)) {
2135 * Aligning zero request is nonsense. Even if driver has special meaning
2136 * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
2137 * it to driver due to request_alignment.
2139 * Still, no reason to return an error if someone do unaligned
2140 * zero-length write occasionally.
2145 bdrv_inc_in_flight(bs
);
2147 * Align write if necessary by performing a read-modify-write cycle.
2148 * Pad qiov with the read parts and be sure to have a tracked request not
2149 * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle.
2151 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_WRITE
);
2153 if (flags
& BDRV_REQ_ZERO_WRITE
) {
2154 ret
= bdrv_co_do_zero_pwritev(child
, offset
, bytes
, flags
, &req
);
2158 if (bdrv_pad_request(bs
, &qiov
, &qiov_offset
, &offset
, &bytes
, &pad
)) {
2159 bdrv_mark_request_serialising(&req
, align
);
2160 bdrv_padding_rmw_read(child
, &req
, &pad
, false);
2163 ret
= bdrv_aligned_pwritev(child
, &req
, offset
, bytes
, align
,
2164 qiov
, qiov_offset
, flags
);
2166 bdrv_padding_destroy(&pad
);
2169 tracked_request_end(&req
);
2170 bdrv_dec_in_flight(bs
);
2175 int coroutine_fn
bdrv_co_pwrite_zeroes(BdrvChild
*child
, int64_t offset
,
2176 int bytes
, BdrvRequestFlags flags
)
2178 trace_bdrv_co_pwrite_zeroes(child
->bs
, offset
, bytes
, flags
);
2180 if (!(child
->bs
->open_flags
& BDRV_O_UNMAP
)) {
2181 flags
&= ~BDRV_REQ_MAY_UNMAP
;
2184 return bdrv_co_pwritev(child
, offset
, bytes
, NULL
,
2185 BDRV_REQ_ZERO_WRITE
| flags
);
2189 * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not.
2191 int bdrv_flush_all(void)
2193 BdrvNextIterator it
;
2194 BlockDriverState
*bs
= NULL
;
2198 * bdrv queue is managed by record/replay,
2199 * creating new flush request for stopping
2200 * the VM may break the determinism
2202 if (replay_events_enabled()) {
2206 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
2207 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
2210 aio_context_acquire(aio_context
);
2211 ret
= bdrv_flush(bs
);
2212 if (ret
< 0 && !result
) {
2215 aio_context_release(aio_context
);
2222 typedef struct BdrvCoBlockStatusData
{
2223 BlockDriverState
*bs
;
2224 BlockDriverState
*base
;
2230 BlockDriverState
**file
;
2233 } BdrvCoBlockStatusData
;
2235 int coroutine_fn
bdrv_co_block_status_from_file(BlockDriverState
*bs
,
2241 BlockDriverState
**file
)
2243 assert(bs
->file
&& bs
->file
->bs
);
2246 *file
= bs
->file
->bs
;
2247 return BDRV_BLOCK_RAW
| BDRV_BLOCK_OFFSET_VALID
;
2250 int coroutine_fn
bdrv_co_block_status_from_backing(BlockDriverState
*bs
,
2256 BlockDriverState
**file
)
2258 assert(bs
->backing
&& bs
->backing
->bs
);
2261 *file
= bs
->backing
->bs
;
2262 return BDRV_BLOCK_RAW
| BDRV_BLOCK_OFFSET_VALID
;
2266 * Returns the allocation status of the specified sectors.
2267 * Drivers not implementing the functionality are assumed to not support
2268 * backing files, hence all their sectors are reported as allocated.
2270 * If 'want_zero' is true, the caller is querying for mapping
2271 * purposes, with a focus on valid BDRV_BLOCK_OFFSET_VALID, _DATA, and
2272 * _ZERO where possible; otherwise, the result favors larger 'pnum',
2273 * with a focus on accurate BDRV_BLOCK_ALLOCATED.
2275 * If 'offset' is beyond the end of the disk image the return value is
2276 * BDRV_BLOCK_EOF and 'pnum' is set to 0.
2278 * 'bytes' is the max value 'pnum' should be set to. If bytes goes
2279 * beyond the end of the disk image it will be clamped; if 'pnum' is set to
2280 * the end of the image, then the returned value will include BDRV_BLOCK_EOF.
2282 * 'pnum' is set to the number of bytes (including and immediately
2283 * following the specified offset) that are easily known to be in the
2284 * same allocated/unallocated state. Note that a second call starting
2285 * at the original offset plus returned pnum may have the same status.
2286 * The returned value is non-zero on success except at end-of-file.
2288 * Returns negative errno on failure. Otherwise, if the
2289 * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are
2290 * set to the host mapping and BDS corresponding to the guest offset.
2292 static int coroutine_fn
bdrv_co_block_status(BlockDriverState
*bs
,
2294 int64_t offset
, int64_t bytes
,
2295 int64_t *pnum
, int64_t *map
,
2296 BlockDriverState
**file
)
2299 int64_t n
; /* bytes */
2301 int64_t local_map
= 0;
2302 BlockDriverState
*local_file
= NULL
;
2303 int64_t aligned_offset
, aligned_bytes
;
2308 total_size
= bdrv_getlength(bs
);
2309 if (total_size
< 0) {
2314 if (offset
>= total_size
) {
2315 ret
= BDRV_BLOCK_EOF
;
2323 n
= total_size
- offset
;
2328 /* Must be non-NULL or bdrv_getlength() would have failed */
2330 if (!bs
->drv
->bdrv_co_block_status
) {
2332 ret
= BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
;
2333 if (offset
+ bytes
== total_size
) {
2334 ret
|= BDRV_BLOCK_EOF
;
2336 if (bs
->drv
->protocol_name
) {
2337 ret
|= BDRV_BLOCK_OFFSET_VALID
;
2344 bdrv_inc_in_flight(bs
);
2346 /* Round out to request_alignment boundaries */
2347 align
= bs
->bl
.request_alignment
;
2348 aligned_offset
= QEMU_ALIGN_DOWN(offset
, align
);
2349 aligned_bytes
= ROUND_UP(offset
+ bytes
, align
) - aligned_offset
;
2351 ret
= bs
->drv
->bdrv_co_block_status(bs
, want_zero
, aligned_offset
,
2352 aligned_bytes
, pnum
, &local_map
,
2360 * The driver's result must be a non-zero multiple of request_alignment.
2361 * Clamp pnum and adjust map to original request.
2363 assert(*pnum
&& QEMU_IS_ALIGNED(*pnum
, align
) &&
2364 align
> offset
- aligned_offset
);
2365 if (ret
& BDRV_BLOCK_RECURSE
) {
2366 assert(ret
& BDRV_BLOCK_DATA
);
2367 assert(ret
& BDRV_BLOCK_OFFSET_VALID
);
2368 assert(!(ret
& BDRV_BLOCK_ZERO
));
2371 *pnum
-= offset
- aligned_offset
;
2372 if (*pnum
> bytes
) {
2375 if (ret
& BDRV_BLOCK_OFFSET_VALID
) {
2376 local_map
+= offset
- aligned_offset
;
2379 if (ret
& BDRV_BLOCK_RAW
) {
2380 assert(ret
& BDRV_BLOCK_OFFSET_VALID
&& local_file
);
2381 ret
= bdrv_co_block_status(local_file
, want_zero
, local_map
,
2382 *pnum
, pnum
, &local_map
, &local_file
);
2386 if (ret
& (BDRV_BLOCK_DATA
| BDRV_BLOCK_ZERO
)) {
2387 ret
|= BDRV_BLOCK_ALLOCATED
;
2388 } else if (want_zero
) {
2389 if (bdrv_unallocated_blocks_are_zero(bs
)) {
2390 ret
|= BDRV_BLOCK_ZERO
;
2391 } else if (bs
->backing
) {
2392 BlockDriverState
*bs2
= bs
->backing
->bs
;
2393 int64_t size2
= bdrv_getlength(bs2
);
2395 if (size2
>= 0 && offset
>= size2
) {
2396 ret
|= BDRV_BLOCK_ZERO
;
2401 if (want_zero
&& ret
& BDRV_BLOCK_RECURSE
&&
2402 local_file
&& local_file
!= bs
&&
2403 (ret
& BDRV_BLOCK_DATA
) && !(ret
& BDRV_BLOCK_ZERO
) &&
2404 (ret
& BDRV_BLOCK_OFFSET_VALID
)) {
2408 ret2
= bdrv_co_block_status(local_file
, want_zero
, local_map
,
2409 *pnum
, &file_pnum
, NULL
, NULL
);
2411 /* Ignore errors. This is just providing extra information, it
2412 * is useful but not necessary.
2414 if (ret2
& BDRV_BLOCK_EOF
&&
2415 (!file_pnum
|| ret2
& BDRV_BLOCK_ZERO
)) {
2417 * It is valid for the format block driver to read
2418 * beyond the end of the underlying file's current
2419 * size; such areas read as zero.
2421 ret
|= BDRV_BLOCK_ZERO
;
2423 /* Limit request to the range reported by the protocol driver */
2425 ret
|= (ret2
& BDRV_BLOCK_ZERO
);
2431 bdrv_dec_in_flight(bs
);
2432 if (ret
>= 0 && offset
+ *pnum
== total_size
) {
2433 ret
|= BDRV_BLOCK_EOF
;
2445 static int coroutine_fn
bdrv_co_block_status_above(BlockDriverState
*bs
,
2446 BlockDriverState
*base
,
2452 BlockDriverState
**file
)
2454 BlockDriverState
*p
;
2459 for (p
= bs
; p
!= base
; p
= backing_bs(p
)) {
2460 ret
= bdrv_co_block_status(p
, want_zero
, offset
, bytes
, pnum
, map
,
2465 if (ret
& BDRV_BLOCK_ZERO
&& ret
& BDRV_BLOCK_EOF
&& !first
) {
2467 * Reading beyond the end of the file continues to read
2468 * zeroes, but we can only widen the result to the
2469 * unallocated length we learned from an earlier
2474 if (ret
& (BDRV_BLOCK_ZERO
| BDRV_BLOCK_DATA
)) {
2477 /* [offset, pnum] unallocated on this layer, which could be only
2478 * the first part of [offset, bytes]. */
2479 bytes
= MIN(bytes
, *pnum
);
2485 /* Coroutine wrapper for bdrv_block_status_above() */
2486 static void coroutine_fn
bdrv_block_status_above_co_entry(void *opaque
)
2488 BdrvCoBlockStatusData
*data
= opaque
;
2490 data
->ret
= bdrv_co_block_status_above(data
->bs
, data
->base
,
2492 data
->offset
, data
->bytes
,
2493 data
->pnum
, data
->map
, data
->file
);
2499 * Synchronous wrapper around bdrv_co_block_status_above().
2501 * See bdrv_co_block_status_above() for details.
2503 static int bdrv_common_block_status_above(BlockDriverState
*bs
,
2504 BlockDriverState
*base
,
2505 bool want_zero
, int64_t offset
,
2506 int64_t bytes
, int64_t *pnum
,
2508 BlockDriverState
**file
)
2511 BdrvCoBlockStatusData data
= {
2514 .want_zero
= want_zero
,
2523 if (qemu_in_coroutine()) {
2524 /* Fast-path if already in coroutine context */
2525 bdrv_block_status_above_co_entry(&data
);
2527 co
= qemu_coroutine_create(bdrv_block_status_above_co_entry
, &data
);
2528 bdrv_coroutine_enter(bs
, co
);
2529 BDRV_POLL_WHILE(bs
, !data
.done
);
2534 int bdrv_block_status_above(BlockDriverState
*bs
, BlockDriverState
*base
,
2535 int64_t offset
, int64_t bytes
, int64_t *pnum
,
2536 int64_t *map
, BlockDriverState
**file
)
2538 return bdrv_common_block_status_above(bs
, base
, true, offset
, bytes
,
2542 int bdrv_block_status(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
2543 int64_t *pnum
, int64_t *map
, BlockDriverState
**file
)
2545 return bdrv_block_status_above(bs
, backing_bs(bs
),
2546 offset
, bytes
, pnum
, map
, file
);
2549 int coroutine_fn
bdrv_is_allocated(BlockDriverState
*bs
, int64_t offset
,
2550 int64_t bytes
, int64_t *pnum
)
2555 ret
= bdrv_common_block_status_above(bs
, backing_bs(bs
), false, offset
,
2556 bytes
, pnum
? pnum
: &dummy
, NULL
,
2561 return !!(ret
& BDRV_BLOCK_ALLOCATED
);
2565 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
2567 * Return 1 if (a prefix of) the given range is allocated in any image
2568 * between BASE and TOP (BASE is only included if include_base is set).
2569 * BASE can be NULL to check if the given offset is allocated in any
2570 * image of the chain. Return 0 otherwise, or negative errno on
2573 * 'pnum' is set to the number of bytes (including and immediately
2574 * following the specified offset) that are known to be in the same
2575 * allocated/unallocated state. Note that a subsequent call starting
2576 * at 'offset + *pnum' may return the same allocation status (in other
2577 * words, the result is not necessarily the maximum possible range);
2578 * but 'pnum' will only be 0 when end of file is reached.
2581 int bdrv_is_allocated_above(BlockDriverState
*top
,
2582 BlockDriverState
*base
,
2583 bool include_base
, int64_t offset
,
2584 int64_t bytes
, int64_t *pnum
)
2586 BlockDriverState
*intermediate
;
2590 assert(base
|| !include_base
);
2593 while (include_base
|| intermediate
!= base
) {
2597 assert(intermediate
);
2598 ret
= bdrv_is_allocated(intermediate
, offset
, bytes
, &pnum_inter
);
2607 size_inter
= bdrv_getlength(intermediate
);
2608 if (size_inter
< 0) {
2611 if (n
> pnum_inter
&&
2612 (intermediate
== top
|| offset
+ pnum_inter
< size_inter
)) {
2616 if (intermediate
== base
) {
2620 intermediate
= backing_bs(intermediate
);
2627 typedef struct BdrvVmstateCo
{
2628 BlockDriverState
*bs
;
2635 static int coroutine_fn
2636 bdrv_co_rw_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
,
2639 BlockDriver
*drv
= bs
->drv
;
2642 bdrv_inc_in_flight(bs
);
2646 } else if (drv
->bdrv_load_vmstate
) {
2648 ret
= drv
->bdrv_load_vmstate(bs
, qiov
, pos
);
2650 ret
= drv
->bdrv_save_vmstate(bs
, qiov
, pos
);
2652 } else if (bs
->file
) {
2653 ret
= bdrv_co_rw_vmstate(bs
->file
->bs
, qiov
, pos
, is_read
);
2656 bdrv_dec_in_flight(bs
);
2660 static void coroutine_fn
bdrv_co_rw_vmstate_entry(void *opaque
)
2662 BdrvVmstateCo
*co
= opaque
;
2663 co
->ret
= bdrv_co_rw_vmstate(co
->bs
, co
->qiov
, co
->pos
, co
->is_read
);
2668 bdrv_rw_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
,
2671 if (qemu_in_coroutine()) {
2672 return bdrv_co_rw_vmstate(bs
, qiov
, pos
, is_read
);
2674 BdrvVmstateCo data
= {
2679 .ret
= -EINPROGRESS
,
2681 Coroutine
*co
= qemu_coroutine_create(bdrv_co_rw_vmstate_entry
, &data
);
2683 bdrv_coroutine_enter(bs
, co
);
2684 BDRV_POLL_WHILE(bs
, data
.ret
== -EINPROGRESS
);
2689 int bdrv_save_vmstate(BlockDriverState
*bs
, const uint8_t *buf
,
2690 int64_t pos
, int size
)
2692 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, size
);
2695 ret
= bdrv_writev_vmstate(bs
, &qiov
, pos
);
2703 int bdrv_writev_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
)
2705 return bdrv_rw_vmstate(bs
, qiov
, pos
, false);
2708 int bdrv_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
2709 int64_t pos
, int size
)
2711 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, size
);
2714 ret
= bdrv_readv_vmstate(bs
, &qiov
, pos
);
2722 int bdrv_readv_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
)
2724 return bdrv_rw_vmstate(bs
, qiov
, pos
, true);
2727 /**************************************************************/
2730 void bdrv_aio_cancel(BlockAIOCB
*acb
)
2733 bdrv_aio_cancel_async(acb
);
2734 while (acb
->refcnt
> 1) {
2735 if (acb
->aiocb_info
->get_aio_context
) {
2736 aio_poll(acb
->aiocb_info
->get_aio_context(acb
), true);
2737 } else if (acb
->bs
) {
2738 /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
2739 * assert that we're not using an I/O thread. Thread-safe
2740 * code should use bdrv_aio_cancel_async exclusively.
2742 assert(bdrv_get_aio_context(acb
->bs
) == qemu_get_aio_context());
2743 aio_poll(bdrv_get_aio_context(acb
->bs
), true);
2748 qemu_aio_unref(acb
);
2751 /* Async version of aio cancel. The caller is not blocked if the acb implements
2752 * cancel_async, otherwise we do nothing and let the request normally complete.
2753 * In either case the completion callback must be called. */
2754 void bdrv_aio_cancel_async(BlockAIOCB
*acb
)
2756 if (acb
->aiocb_info
->cancel_async
) {
2757 acb
->aiocb_info
->cancel_async(acb
);
2761 /**************************************************************/
2762 /* Coroutine block device emulation */
2764 typedef struct FlushCo
{
2765 BlockDriverState
*bs
;
2770 static void coroutine_fn
bdrv_flush_co_entry(void *opaque
)
2772 FlushCo
*rwco
= opaque
;
2774 rwco
->ret
= bdrv_co_flush(rwco
->bs
);
2778 int coroutine_fn
bdrv_co_flush(BlockDriverState
*bs
)
2783 bdrv_inc_in_flight(bs
);
2785 if (!bdrv_is_inserted(bs
) || bdrv_is_read_only(bs
) ||
2790 qemu_co_mutex_lock(&bs
->reqs_lock
);
2791 current_gen
= atomic_read(&bs
->write_gen
);
2793 /* Wait until any previous flushes are completed */
2794 while (bs
->active_flush_req
) {
2795 qemu_co_queue_wait(&bs
->flush_queue
, &bs
->reqs_lock
);
2798 /* Flushes reach this point in nondecreasing current_gen order. */
2799 bs
->active_flush_req
= true;
2800 qemu_co_mutex_unlock(&bs
->reqs_lock
);
2802 /* Write back all layers by calling one driver function */
2803 if (bs
->drv
->bdrv_co_flush
) {
2804 ret
= bs
->drv
->bdrv_co_flush(bs
);
2808 /* Write back cached data to the OS even with cache=unsafe */
2809 BLKDBG_EVENT(bs
->file
, BLKDBG_FLUSH_TO_OS
);
2810 if (bs
->drv
->bdrv_co_flush_to_os
) {
2811 ret
= bs
->drv
->bdrv_co_flush_to_os(bs
);
2817 /* But don't actually force it to the disk with cache=unsafe */
2818 if (bs
->open_flags
& BDRV_O_NO_FLUSH
) {
2822 /* Check if we really need to flush anything */
2823 if (bs
->flushed_gen
== current_gen
) {
2827 BLKDBG_EVENT(bs
->file
, BLKDBG_FLUSH_TO_DISK
);
2829 /* bs->drv->bdrv_co_flush() might have ejected the BDS
2830 * (even in case of apparent success) */
2834 if (bs
->drv
->bdrv_co_flush_to_disk
) {
2835 ret
= bs
->drv
->bdrv_co_flush_to_disk(bs
);
2836 } else if (bs
->drv
->bdrv_aio_flush
) {
2838 CoroutineIOCompletion co
= {
2839 .coroutine
= qemu_coroutine_self(),
2842 acb
= bs
->drv
->bdrv_aio_flush(bs
, bdrv_co_io_em_complete
, &co
);
2846 qemu_coroutine_yield();
2851 * Some block drivers always operate in either writethrough or unsafe
2852 * mode and don't support bdrv_flush therefore. Usually qemu doesn't
2853 * know how the server works (because the behaviour is hardcoded or
2854 * depends on server-side configuration), so we can't ensure that
2855 * everything is safe on disk. Returning an error doesn't work because
2856 * that would break guests even if the server operates in writethrough
2859 * Let's hope the user knows what he's doing.
2868 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH
2869 * in the case of cache=unsafe, so there are no useless flushes.
2872 ret
= bs
->file
? bdrv_co_flush(bs
->file
->bs
) : 0;
2874 /* Notify any pending flushes that we have completed */
2876 bs
->flushed_gen
= current_gen
;
2879 qemu_co_mutex_lock(&bs
->reqs_lock
);
2880 bs
->active_flush_req
= false;
2881 /* Return value is ignored - it's ok if wait queue is empty */
2882 qemu_co_queue_next(&bs
->flush_queue
);
2883 qemu_co_mutex_unlock(&bs
->reqs_lock
);
2886 bdrv_dec_in_flight(bs
);
2890 int bdrv_flush(BlockDriverState
*bs
)
2893 FlushCo flush_co
= {
2898 if (qemu_in_coroutine()) {
2899 /* Fast-path if already in coroutine context */
2900 bdrv_flush_co_entry(&flush_co
);
2902 co
= qemu_coroutine_create(bdrv_flush_co_entry
, &flush_co
);
2903 bdrv_coroutine_enter(bs
, co
);
2904 BDRV_POLL_WHILE(bs
, flush_co
.ret
== NOT_DONE
);
2907 return flush_co
.ret
;
2910 typedef struct DiscardCo
{
2916 static void coroutine_fn
bdrv_pdiscard_co_entry(void *opaque
)
2918 DiscardCo
*rwco
= opaque
;
2920 rwco
->ret
= bdrv_co_pdiscard(rwco
->child
, rwco
->offset
, rwco
->bytes
);
2924 int coroutine_fn
bdrv_co_pdiscard(BdrvChild
*child
, int64_t offset
,
2927 BdrvTrackedRequest req
;
2928 int max_pdiscard
, ret
;
2929 int head
, tail
, align
;
2930 BlockDriverState
*bs
= child
->bs
;
2932 if (!bs
|| !bs
->drv
|| !bdrv_is_inserted(bs
)) {
2936 if (bdrv_has_readonly_bitmaps(bs
)) {
2940 if (offset
< 0 || bytes
< 0 || bytes
> INT64_MAX
- offset
) {
2944 /* Do nothing if disabled. */
2945 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
2949 if (!bs
->drv
->bdrv_co_pdiscard
&& !bs
->drv
->bdrv_aio_pdiscard
) {
2953 /* Discard is advisory, but some devices track and coalesce
2954 * unaligned requests, so we must pass everything down rather than
2955 * round here. Still, most devices will just silently ignore
2956 * unaligned requests (by returning -ENOTSUP), so we must fragment
2957 * the request accordingly. */
2958 align
= MAX(bs
->bl
.pdiscard_alignment
, bs
->bl
.request_alignment
);
2959 assert(align
% bs
->bl
.request_alignment
== 0);
2960 head
= offset
% align
;
2961 tail
= (offset
+ bytes
) % align
;
2963 bdrv_inc_in_flight(bs
);
2964 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_DISCARD
);
2966 ret
= bdrv_co_write_req_prepare(child
, offset
, bytes
, &req
, 0);
2971 max_pdiscard
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_pdiscard
, INT_MAX
),
2973 assert(max_pdiscard
>= bs
->bl
.request_alignment
);
2976 int64_t num
= bytes
;
2979 /* Make small requests to get to alignment boundaries. */
2980 num
= MIN(bytes
, align
- head
);
2981 if (!QEMU_IS_ALIGNED(num
, bs
->bl
.request_alignment
)) {
2982 num
%= bs
->bl
.request_alignment
;
2984 head
= (head
+ num
) % align
;
2985 assert(num
< max_pdiscard
);
2988 /* Shorten the request to the last aligned cluster. */
2990 } else if (!QEMU_IS_ALIGNED(tail
, bs
->bl
.request_alignment
) &&
2991 tail
> bs
->bl
.request_alignment
) {
2992 tail
%= bs
->bl
.request_alignment
;
2996 /* limit request size */
2997 if (num
> max_pdiscard
) {
3005 if (bs
->drv
->bdrv_co_pdiscard
) {
3006 ret
= bs
->drv
->bdrv_co_pdiscard(bs
, offset
, num
);
3009 CoroutineIOCompletion co
= {
3010 .coroutine
= qemu_coroutine_self(),
3013 acb
= bs
->drv
->bdrv_aio_pdiscard(bs
, offset
, num
,
3014 bdrv_co_io_em_complete
, &co
);
3019 qemu_coroutine_yield();
3023 if (ret
&& ret
!= -ENOTSUP
) {
3032 bdrv_co_write_req_finish(child
, req
.offset
, req
.bytes
, &req
, ret
);
3033 tracked_request_end(&req
);
3034 bdrv_dec_in_flight(bs
);
3038 int bdrv_pdiscard(BdrvChild
*child
, int64_t offset
, int64_t bytes
)
3048 if (qemu_in_coroutine()) {
3049 /* Fast-path if already in coroutine context */
3050 bdrv_pdiscard_co_entry(&rwco
);
3052 co
= qemu_coroutine_create(bdrv_pdiscard_co_entry
, &rwco
);
3053 bdrv_coroutine_enter(child
->bs
, co
);
3054 BDRV_POLL_WHILE(child
->bs
, rwco
.ret
== NOT_DONE
);
3060 int bdrv_co_ioctl(BlockDriverState
*bs
, int req
, void *buf
)
3062 BlockDriver
*drv
= bs
->drv
;
3063 CoroutineIOCompletion co
= {
3064 .coroutine
= qemu_coroutine_self(),
3068 bdrv_inc_in_flight(bs
);
3069 if (!drv
|| (!drv
->bdrv_aio_ioctl
&& !drv
->bdrv_co_ioctl
)) {
3074 if (drv
->bdrv_co_ioctl
) {
3075 co
.ret
= drv
->bdrv_co_ioctl(bs
, req
, buf
);
3077 acb
= drv
->bdrv_aio_ioctl(bs
, req
, buf
, bdrv_co_io_em_complete
, &co
);
3082 qemu_coroutine_yield();
3085 bdrv_dec_in_flight(bs
);
3089 void *qemu_blockalign(BlockDriverState
*bs
, size_t size
)
3091 return qemu_memalign(bdrv_opt_mem_align(bs
), size
);
3094 void *qemu_blockalign0(BlockDriverState
*bs
, size_t size
)
3096 return memset(qemu_blockalign(bs
, size
), 0, size
);
3099 void *qemu_try_blockalign(BlockDriverState
*bs
, size_t size
)
3101 size_t align
= bdrv_opt_mem_align(bs
);
3103 /* Ensure that NULL is never returned on success */
3109 return qemu_try_memalign(align
, size
);
3112 void *qemu_try_blockalign0(BlockDriverState
*bs
, size_t size
)
3114 void *mem
= qemu_try_blockalign(bs
, size
);
3117 memset(mem
, 0, size
);
3124 * Check if all memory in this vector is sector aligned.
3126 bool bdrv_qiov_is_aligned(BlockDriverState
*bs
, QEMUIOVector
*qiov
)
3129 size_t alignment
= bdrv_min_mem_align(bs
);
3131 for (i
= 0; i
< qiov
->niov
; i
++) {
3132 if ((uintptr_t) qiov
->iov
[i
].iov_base
% alignment
) {
3135 if (qiov
->iov
[i
].iov_len
% alignment
) {
3143 void bdrv_add_before_write_notifier(BlockDriverState
*bs
,
3144 NotifierWithReturn
*notifier
)
3146 notifier_with_return_list_add(&bs
->before_write_notifiers
, notifier
);
3149 void bdrv_io_plug(BlockDriverState
*bs
)
3153 QLIST_FOREACH(child
, &bs
->children
, next
) {
3154 bdrv_io_plug(child
->bs
);
3157 if (atomic_fetch_inc(&bs
->io_plugged
) == 0) {
3158 BlockDriver
*drv
= bs
->drv
;
3159 if (drv
&& drv
->bdrv_io_plug
) {
3160 drv
->bdrv_io_plug(bs
);
3165 void bdrv_io_unplug(BlockDriverState
*bs
)
3169 assert(bs
->io_plugged
);
3170 if (atomic_fetch_dec(&bs
->io_plugged
) == 1) {
3171 BlockDriver
*drv
= bs
->drv
;
3172 if (drv
&& drv
->bdrv_io_unplug
) {
3173 drv
->bdrv_io_unplug(bs
);
3177 QLIST_FOREACH(child
, &bs
->children
, next
) {
3178 bdrv_io_unplug(child
->bs
);
3182 void bdrv_register_buf(BlockDriverState
*bs
, void *host
, size_t size
)
3186 if (bs
->drv
&& bs
->drv
->bdrv_register_buf
) {
3187 bs
->drv
->bdrv_register_buf(bs
, host
, size
);
3189 QLIST_FOREACH(child
, &bs
->children
, next
) {
3190 bdrv_register_buf(child
->bs
, host
, size
);
3194 void bdrv_unregister_buf(BlockDriverState
*bs
, void *host
)
3198 if (bs
->drv
&& bs
->drv
->bdrv_unregister_buf
) {
3199 bs
->drv
->bdrv_unregister_buf(bs
, host
);
3201 QLIST_FOREACH(child
, &bs
->children
, next
) {
3202 bdrv_unregister_buf(child
->bs
, host
);
3206 static int coroutine_fn
bdrv_co_copy_range_internal(
3207 BdrvChild
*src
, uint64_t src_offset
, BdrvChild
*dst
,
3208 uint64_t dst_offset
, uint64_t bytes
,
3209 BdrvRequestFlags read_flags
, BdrvRequestFlags write_flags
,
3212 BdrvTrackedRequest req
;
3215 /* TODO We can support BDRV_REQ_NO_FALLBACK here */
3216 assert(!(read_flags
& BDRV_REQ_NO_FALLBACK
));
3217 assert(!(write_flags
& BDRV_REQ_NO_FALLBACK
));
3219 if (!dst
|| !dst
->bs
) {
3222 ret
= bdrv_check_byte_request(dst
->bs
, dst_offset
, bytes
);
3226 if (write_flags
& BDRV_REQ_ZERO_WRITE
) {
3227 return bdrv_co_pwrite_zeroes(dst
, dst_offset
, bytes
, write_flags
);
3230 if (!src
|| !src
->bs
) {
3233 ret
= bdrv_check_byte_request(src
->bs
, src_offset
, bytes
);
3238 if (!src
->bs
->drv
->bdrv_co_copy_range_from
3239 || !dst
->bs
->drv
->bdrv_co_copy_range_to
3240 || src
->bs
->encrypted
|| dst
->bs
->encrypted
) {
3245 bdrv_inc_in_flight(src
->bs
);
3246 tracked_request_begin(&req
, src
->bs
, src_offset
, bytes
,
3249 /* BDRV_REQ_SERIALISING is only for write operation */
3250 assert(!(read_flags
& BDRV_REQ_SERIALISING
));
3251 bdrv_wait_serialising_requests(&req
);
3253 ret
= src
->bs
->drv
->bdrv_co_copy_range_from(src
->bs
,
3257 read_flags
, write_flags
);
3259 tracked_request_end(&req
);
3260 bdrv_dec_in_flight(src
->bs
);
3262 bdrv_inc_in_flight(dst
->bs
);
3263 tracked_request_begin(&req
, dst
->bs
, dst_offset
, bytes
,
3264 BDRV_TRACKED_WRITE
);
3265 ret
= bdrv_co_write_req_prepare(dst
, dst_offset
, bytes
, &req
,
3268 ret
= dst
->bs
->drv
->bdrv_co_copy_range_to(dst
->bs
,
3272 read_flags
, write_flags
);
3274 bdrv_co_write_req_finish(dst
, dst_offset
, bytes
, &req
, ret
);
3275 tracked_request_end(&req
);
3276 bdrv_dec_in_flight(dst
->bs
);
3282 /* Copy range from @src to @dst.
3284 * See the comment of bdrv_co_copy_range for the parameter and return value
3286 int coroutine_fn
bdrv_co_copy_range_from(BdrvChild
*src
, uint64_t src_offset
,
3287 BdrvChild
*dst
, uint64_t dst_offset
,
3289 BdrvRequestFlags read_flags
,
3290 BdrvRequestFlags write_flags
)
3292 trace_bdrv_co_copy_range_from(src
, src_offset
, dst
, dst_offset
, bytes
,
3293 read_flags
, write_flags
);
3294 return bdrv_co_copy_range_internal(src
, src_offset
, dst
, dst_offset
,
3295 bytes
, read_flags
, write_flags
, true);
3298 /* Copy range from @src to @dst.
3300 * See the comment of bdrv_co_copy_range for the parameter and return value
3302 int coroutine_fn
bdrv_co_copy_range_to(BdrvChild
*src
, uint64_t src_offset
,
3303 BdrvChild
*dst
, uint64_t dst_offset
,
3305 BdrvRequestFlags read_flags
,
3306 BdrvRequestFlags write_flags
)
3308 trace_bdrv_co_copy_range_to(src
, src_offset
, dst
, dst_offset
, bytes
,
3309 read_flags
, write_flags
);
3310 return bdrv_co_copy_range_internal(src
, src_offset
, dst
, dst_offset
,
3311 bytes
, read_flags
, write_flags
, false);
3314 int coroutine_fn
bdrv_co_copy_range(BdrvChild
*src
, uint64_t src_offset
,
3315 BdrvChild
*dst
, uint64_t dst_offset
,
3316 uint64_t bytes
, BdrvRequestFlags read_flags
,
3317 BdrvRequestFlags write_flags
)
3319 return bdrv_co_copy_range_from(src
, src_offset
,
3321 bytes
, read_flags
, write_flags
);
3324 static void bdrv_parent_cb_resize(BlockDriverState
*bs
)
3327 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3328 if (c
->role
->resize
) {
3335 * Truncate file to 'offset' bytes (needed only for file protocols)
3337 * If 'exact' is true, the file must be resized to exactly the given
3338 * 'offset'. Otherwise, it is sufficient for the node to be at least
3339 * 'offset' bytes in length.
3341 int coroutine_fn
bdrv_co_truncate(BdrvChild
*child
, int64_t offset
, bool exact
,
3342 PreallocMode prealloc
, Error
**errp
)
3344 BlockDriverState
*bs
= child
->bs
;
3345 BlockDriver
*drv
= bs
->drv
;
3346 BdrvTrackedRequest req
;
3347 int64_t old_size
, new_bytes
;
3351 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
3353 error_setg(errp
, "No medium inserted");
3357 error_setg(errp
, "Image size cannot be negative");
3361 old_size
= bdrv_getlength(bs
);
3363 error_setg_errno(errp
, -old_size
, "Failed to get old image size");
3367 if (offset
> old_size
) {
3368 new_bytes
= offset
- old_size
;
3373 bdrv_inc_in_flight(bs
);
3374 tracked_request_begin(&req
, bs
, offset
- new_bytes
, new_bytes
,
3375 BDRV_TRACKED_TRUNCATE
);
3377 /* If we are growing the image and potentially using preallocation for the
3378 * new area, we need to make sure that no write requests are made to it
3379 * concurrently or they might be overwritten by preallocation. */
3381 bdrv_mark_request_serialising(&req
, 1);
3383 if (bs
->read_only
) {
3384 error_setg(errp
, "Image is read-only");
3388 ret
= bdrv_co_write_req_prepare(child
, offset
- new_bytes
, new_bytes
, &req
,
3391 error_setg_errno(errp
, -ret
,
3392 "Failed to prepare request for truncation");
3396 if (drv
->bdrv_co_truncate
) {
3397 ret
= drv
->bdrv_co_truncate(bs
, offset
, exact
, prealloc
, errp
);
3398 } else if (bs
->file
&& drv
->is_filter
) {
3399 ret
= bdrv_co_truncate(bs
->file
, offset
, exact
, prealloc
, errp
);
3401 error_setg(errp
, "Image format driver does not support resize");
3409 ret
= refresh_total_sectors(bs
, offset
>> BDRV_SECTOR_BITS
);
3411 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
3413 offset
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
3415 /* It's possible that truncation succeeded but refresh_total_sectors
3416 * failed, but the latter doesn't affect how we should finish the request.
3417 * Pass 0 as the last parameter so that dirty bitmaps etc. are handled. */
3418 bdrv_co_write_req_finish(child
, offset
- new_bytes
, new_bytes
, &req
, 0);
3421 tracked_request_end(&req
);
3422 bdrv_dec_in_flight(bs
);
3427 typedef struct TruncateCo
{
3431 PreallocMode prealloc
;
3436 static void coroutine_fn
bdrv_truncate_co_entry(void *opaque
)
3438 TruncateCo
*tco
= opaque
;
3439 tco
->ret
= bdrv_co_truncate(tco
->child
, tco
->offset
, tco
->exact
,
3440 tco
->prealloc
, tco
->errp
);
3444 int bdrv_truncate(BdrvChild
*child
, int64_t offset
, bool exact
,
3445 PreallocMode prealloc
, Error
**errp
)
3452 .prealloc
= prealloc
,
3457 if (qemu_in_coroutine()) {
3458 /* Fast-path if already in coroutine context */
3459 bdrv_truncate_co_entry(&tco
);
3461 co
= qemu_coroutine_create(bdrv_truncate_co_entry
, &tco
);
3462 bdrv_coroutine_enter(child
->bs
, co
);
3463 BDRV_POLL_WHILE(child
->bs
, tco
.ret
== NOT_DONE
);