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 "block/coroutines.h"
33 #include "block/dirty-bitmap.h"
34 #include "block/write-threshold.h"
35 #include "qemu/cutils.h"
36 #include "qemu/memalign.h"
37 #include "qapi/error.h"
38 #include "qemu/error-report.h"
39 #include "qemu/main-loop.h"
40 #include "sysemu/replay.h"
42 /* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */
43 #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS)
45 static void bdrv_parent_cb_resize(BlockDriverState
*bs
);
46 static int coroutine_fn
bdrv_co_do_pwrite_zeroes(BlockDriverState
*bs
,
47 int64_t offset
, int64_t bytes
, BdrvRequestFlags flags
);
49 static void bdrv_parent_drained_begin(BlockDriverState
*bs
, BdrvChild
*ignore
)
53 QLIST_FOREACH_SAFE(c
, &bs
->parents
, next_parent
, next
) {
57 bdrv_parent_drained_begin_single(c
);
61 void bdrv_parent_drained_end_single(BdrvChild
*c
)
65 assert(c
->quiesced_parent
);
66 c
->quiesced_parent
= false;
68 if (c
->klass
->drained_end
) {
69 c
->klass
->drained_end(c
);
73 static void bdrv_parent_drained_end(BlockDriverState
*bs
, BdrvChild
*ignore
)
77 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
81 bdrv_parent_drained_end_single(c
);
85 bool bdrv_parent_drained_poll_single(BdrvChild
*c
)
87 if (c
->klass
->drained_poll
) {
88 return c
->klass
->drained_poll(c
);
93 static bool bdrv_parent_drained_poll(BlockDriverState
*bs
, BdrvChild
*ignore
,
94 bool ignore_bds_parents
)
99 QLIST_FOREACH_SAFE(c
, &bs
->parents
, next_parent
, next
) {
100 if (c
== ignore
|| (ignore_bds_parents
&& c
->klass
->parent_is_bds
)) {
103 busy
|= bdrv_parent_drained_poll_single(c
);
109 void bdrv_parent_drained_begin_single(BdrvChild
*c
)
113 assert(!c
->quiesced_parent
);
114 c
->quiesced_parent
= true;
116 if (c
->klass
->drained_begin
) {
117 c
->klass
->drained_begin(c
);
121 static void bdrv_merge_limits(BlockLimits
*dst
, const BlockLimits
*src
)
123 dst
->pdiscard_alignment
= MAX(dst
->pdiscard_alignment
,
124 src
->pdiscard_alignment
);
125 dst
->opt_transfer
= MAX(dst
->opt_transfer
, src
->opt_transfer
);
126 dst
->max_transfer
= MIN_NON_ZERO(dst
->max_transfer
, src
->max_transfer
);
127 dst
->max_hw_transfer
= MIN_NON_ZERO(dst
->max_hw_transfer
,
128 src
->max_hw_transfer
);
129 dst
->opt_mem_alignment
= MAX(dst
->opt_mem_alignment
,
130 src
->opt_mem_alignment
);
131 dst
->min_mem_alignment
= MAX(dst
->min_mem_alignment
,
132 src
->min_mem_alignment
);
133 dst
->max_iov
= MIN_NON_ZERO(dst
->max_iov
, src
->max_iov
);
134 dst
->max_hw_iov
= MIN_NON_ZERO(dst
->max_hw_iov
, src
->max_hw_iov
);
137 typedef struct BdrvRefreshLimitsState
{
138 BlockDriverState
*bs
;
140 } BdrvRefreshLimitsState
;
142 static void bdrv_refresh_limits_abort(void *opaque
)
144 BdrvRefreshLimitsState
*s
= opaque
;
146 s
->bs
->bl
= s
->old_bl
;
149 static TransactionActionDrv bdrv_refresh_limits_drv
= {
150 .abort
= bdrv_refresh_limits_abort
,
154 /* @tran is allowed to be NULL, in this case no rollback is possible. */
155 void bdrv_refresh_limits(BlockDriverState
*bs
, Transaction
*tran
, Error
**errp
)
158 BlockDriver
*drv
= bs
->drv
;
163 assume_graph_lock(); /* FIXME */
166 BdrvRefreshLimitsState
*s
= g_new(BdrvRefreshLimitsState
, 1);
167 *s
= (BdrvRefreshLimitsState
) {
171 tran_add(tran
, &bdrv_refresh_limits_drv
, s
);
174 memset(&bs
->bl
, 0, sizeof(bs
->bl
));
180 /* Default alignment based on whether driver has byte interface */
181 bs
->bl
.request_alignment
= (drv
->bdrv_co_preadv
||
182 drv
->bdrv_aio_preadv
||
183 drv
->bdrv_co_preadv_part
) ? 1 : 512;
185 /* Take some limits from the children as a default */
187 QLIST_FOREACH(c
, &bs
->children
, next
) {
188 if (c
->role
& (BDRV_CHILD_DATA
| BDRV_CHILD_FILTERED
| BDRV_CHILD_COW
))
190 bdrv_merge_limits(&bs
->bl
, &c
->bs
->bl
);
196 bs
->bl
.min_mem_alignment
= 512;
197 bs
->bl
.opt_mem_alignment
= qemu_real_host_page_size();
199 /* Safe default since most protocols use readv()/writev()/etc */
200 bs
->bl
.max_iov
= IOV_MAX
;
203 /* Then let the driver override it */
204 if (drv
->bdrv_refresh_limits
) {
205 drv
->bdrv_refresh_limits(bs
, errp
);
211 if (bs
->bl
.request_alignment
> BDRV_MAX_ALIGNMENT
) {
212 error_setg(errp
, "Driver requires too large request alignment");
217 * The copy-on-read flag is actually a reference count so multiple users may
218 * use the feature without worrying about clobbering its previous state.
219 * Copy-on-read stays enabled until all users have called to disable it.
221 void bdrv_enable_copy_on_read(BlockDriverState
*bs
)
224 qatomic_inc(&bs
->copy_on_read
);
227 void bdrv_disable_copy_on_read(BlockDriverState
*bs
)
229 int old
= qatomic_fetch_dec(&bs
->copy_on_read
);
236 BlockDriverState
*bs
;
243 /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
244 bool bdrv_drain_poll(BlockDriverState
*bs
, BdrvChild
*ignore_parent
,
245 bool ignore_bds_parents
)
249 if (bdrv_parent_drained_poll(bs
, ignore_parent
, ignore_bds_parents
)) {
253 if (qatomic_read(&bs
->in_flight
)) {
260 static bool bdrv_drain_poll_top_level(BlockDriverState
*bs
,
261 BdrvChild
*ignore_parent
)
263 return bdrv_drain_poll(bs
, ignore_parent
, false);
266 static void bdrv_do_drained_begin(BlockDriverState
*bs
, BdrvChild
*parent
,
268 static void bdrv_do_drained_end(BlockDriverState
*bs
, BdrvChild
*parent
);
270 static void bdrv_co_drain_bh_cb(void *opaque
)
272 BdrvCoDrainData
*data
= opaque
;
273 Coroutine
*co
= data
->co
;
274 BlockDriverState
*bs
= data
->bs
;
277 AioContext
*ctx
= bdrv_get_aio_context(bs
);
278 aio_context_acquire(ctx
);
279 bdrv_dec_in_flight(bs
);
281 bdrv_do_drained_begin(bs
, data
->parent
, data
->poll
);
284 bdrv_do_drained_end(bs
, data
->parent
);
286 aio_context_release(ctx
);
289 bdrv_drain_all_begin();
296 static void coroutine_fn
bdrv_co_yield_to_drain(BlockDriverState
*bs
,
301 BdrvCoDrainData data
;
302 Coroutine
*self
= qemu_coroutine_self();
303 AioContext
*ctx
= bdrv_get_aio_context(bs
);
304 AioContext
*co_ctx
= qemu_coroutine_get_aio_context(self
);
306 /* Calling bdrv_drain() from a BH ensures the current coroutine yields and
307 * other coroutines run if they were queued by aio_co_enter(). */
309 assert(qemu_in_coroutine());
310 data
= (BdrvCoDrainData
) {
320 bdrv_inc_in_flight(bs
);
324 * Temporarily drop the lock across yield or we would get deadlocks.
325 * bdrv_co_drain_bh_cb() reaquires the lock as needed.
327 * When we yield below, the lock for the current context will be
328 * released, so if this is actually the lock that protects bs, don't drop
332 aio_context_release(ctx
);
334 replay_bh_schedule_oneshot_event(ctx
, bdrv_co_drain_bh_cb
, &data
);
336 qemu_coroutine_yield();
337 /* If we are resumed from some other event (such as an aio completion or a
338 * timer callback), it is a bug in the caller that should be fixed. */
341 /* Reaquire the AioContext of bs if we dropped it */
343 aio_context_acquire(ctx
);
347 static void bdrv_do_drained_begin(BlockDriverState
*bs
, BdrvChild
*parent
,
352 if (qemu_in_coroutine()) {
353 bdrv_co_yield_to_drain(bs
, true, parent
, poll
);
357 /* Stop things in parent-to-child order */
358 if (qatomic_fetch_inc(&bs
->quiesce_counter
) == 0) {
359 aio_disable_external(bdrv_get_aio_context(bs
));
360 bdrv_parent_drained_begin(bs
, parent
);
361 if (bs
->drv
&& bs
->drv
->bdrv_drain_begin
) {
362 bs
->drv
->bdrv_drain_begin(bs
);
367 * Wait for drained requests to finish.
369 * Calling BDRV_POLL_WHILE() only once for the top-level node is okay: The
370 * call is needed so things in this AioContext can make progress even
371 * though we don't return to the main AioContext loop - this automatically
372 * includes other nodes in the same AioContext and therefore all child
376 BDRV_POLL_WHILE(bs
, bdrv_drain_poll_top_level(bs
, parent
));
380 void bdrv_do_drained_begin_quiesce(BlockDriverState
*bs
, BdrvChild
*parent
)
382 bdrv_do_drained_begin(bs
, parent
, false);
385 void bdrv_drained_begin(BlockDriverState
*bs
)
388 bdrv_do_drained_begin(bs
, NULL
, true);
392 * This function does not poll, nor must any of its recursively called
395 static void bdrv_do_drained_end(BlockDriverState
*bs
, BdrvChild
*parent
)
397 int old_quiesce_counter
;
399 if (qemu_in_coroutine()) {
400 bdrv_co_yield_to_drain(bs
, false, parent
, false);
403 assert(bs
->quiesce_counter
> 0);
405 /* Re-enable things in child-to-parent order */
406 old_quiesce_counter
= qatomic_fetch_dec(&bs
->quiesce_counter
);
407 if (old_quiesce_counter
== 1) {
408 if (bs
->drv
&& bs
->drv
->bdrv_drain_end
) {
409 bs
->drv
->bdrv_drain_end(bs
);
411 bdrv_parent_drained_end(bs
, parent
);
412 aio_enable_external(bdrv_get_aio_context(bs
));
416 void bdrv_drained_end(BlockDriverState
*bs
)
419 bdrv_do_drained_end(bs
, NULL
);
422 void bdrv_drain(BlockDriverState
*bs
)
425 bdrv_drained_begin(bs
);
426 bdrv_drained_end(bs
);
429 static void bdrv_drain_assert_idle(BlockDriverState
*bs
)
431 BdrvChild
*child
, *next
;
433 assert(qatomic_read(&bs
->in_flight
) == 0);
434 QLIST_FOREACH_SAFE(child
, &bs
->children
, next
, next
) {
435 bdrv_drain_assert_idle(child
->bs
);
439 unsigned int bdrv_drain_all_count
= 0;
441 static bool bdrv_drain_all_poll(void)
443 BlockDriverState
*bs
= NULL
;
447 /* bdrv_drain_poll() can't make changes to the graph and we are holding the
448 * main AioContext lock, so iterating bdrv_next_all_states() is safe. */
449 while ((bs
= bdrv_next_all_states(bs
))) {
450 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
451 aio_context_acquire(aio_context
);
452 result
|= bdrv_drain_poll(bs
, NULL
, true);
453 aio_context_release(aio_context
);
460 * Wait for pending requests to complete across all BlockDriverStates
462 * This function does not flush data to disk, use bdrv_flush_all() for that
463 * after calling this function.
465 * This pauses all block jobs and disables external clients. It must
466 * be paired with bdrv_drain_all_end().
468 * NOTE: no new block jobs or BlockDriverStates can be created between
469 * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls.
471 void bdrv_drain_all_begin_nopoll(void)
473 BlockDriverState
*bs
= NULL
;
477 * bdrv queue is managed by record/replay,
478 * waiting for finishing the I/O requests may
481 if (replay_events_enabled()) {
485 /* AIO_WAIT_WHILE() with a NULL context can only be called from the main
486 * loop AioContext, so make sure we're in the main context. */
487 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
488 assert(bdrv_drain_all_count
< INT_MAX
);
489 bdrv_drain_all_count
++;
491 /* Quiesce all nodes, without polling in-flight requests yet. The graph
492 * cannot change during this loop. */
493 while ((bs
= bdrv_next_all_states(bs
))) {
494 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
496 aio_context_acquire(aio_context
);
497 bdrv_do_drained_begin(bs
, NULL
, false);
498 aio_context_release(aio_context
);
502 void bdrv_drain_all_begin(void)
504 BlockDriverState
*bs
= NULL
;
506 if (qemu_in_coroutine()) {
507 bdrv_co_yield_to_drain(NULL
, true, NULL
, true);
512 * bdrv queue is managed by record/replay,
513 * waiting for finishing the I/O requests may
516 if (replay_events_enabled()) {
520 bdrv_drain_all_begin_nopoll();
522 /* Now poll the in-flight requests */
523 AIO_WAIT_WHILE(NULL
, bdrv_drain_all_poll());
525 while ((bs
= bdrv_next_all_states(bs
))) {
526 bdrv_drain_assert_idle(bs
);
530 void bdrv_drain_all_end_quiesce(BlockDriverState
*bs
)
534 g_assert(bs
->quiesce_counter
> 0);
535 g_assert(!bs
->refcnt
);
537 while (bs
->quiesce_counter
) {
538 bdrv_do_drained_end(bs
, NULL
);
542 void bdrv_drain_all_end(void)
544 BlockDriverState
*bs
= NULL
;
548 * bdrv queue is managed by record/replay,
549 * waiting for finishing the I/O requests may
552 if (replay_events_enabled()) {
556 while ((bs
= bdrv_next_all_states(bs
))) {
557 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
559 aio_context_acquire(aio_context
);
560 bdrv_do_drained_end(bs
, NULL
);
561 aio_context_release(aio_context
);
564 assert(qemu_get_current_aio_context() == qemu_get_aio_context());
565 assert(bdrv_drain_all_count
> 0);
566 bdrv_drain_all_count
--;
569 void bdrv_drain_all(void)
572 bdrv_drain_all_begin();
573 bdrv_drain_all_end();
577 * Remove an active request from the tracked requests list
579 * This function should be called when a tracked request is completing.
581 static void coroutine_fn
tracked_request_end(BdrvTrackedRequest
*req
)
583 if (req
->serialising
) {
584 qatomic_dec(&req
->bs
->serialising_in_flight
);
587 qemu_co_mutex_lock(&req
->bs
->reqs_lock
);
588 QLIST_REMOVE(req
, list
);
589 qemu_co_queue_restart_all(&req
->wait_queue
);
590 qemu_co_mutex_unlock(&req
->bs
->reqs_lock
);
594 * Add an active request to the tracked requests list
596 static void coroutine_fn
tracked_request_begin(BdrvTrackedRequest
*req
,
597 BlockDriverState
*bs
,
600 enum BdrvTrackedRequestType type
)
602 bdrv_check_request(offset
, bytes
, &error_abort
);
604 *req
= (BdrvTrackedRequest
){
609 .co
= qemu_coroutine_self(),
610 .serialising
= false,
611 .overlap_offset
= offset
,
612 .overlap_bytes
= bytes
,
615 qemu_co_queue_init(&req
->wait_queue
);
617 qemu_co_mutex_lock(&bs
->reqs_lock
);
618 QLIST_INSERT_HEAD(&bs
->tracked_requests
, req
, list
);
619 qemu_co_mutex_unlock(&bs
->reqs_lock
);
622 static bool tracked_request_overlaps(BdrvTrackedRequest
*req
,
623 int64_t offset
, int64_t bytes
)
625 bdrv_check_request(offset
, bytes
, &error_abort
);
628 if (offset
>= req
->overlap_offset
+ req
->overlap_bytes
) {
632 if (req
->overlap_offset
>= offset
+ bytes
) {
638 /* Called with self->bs->reqs_lock held */
639 static coroutine_fn BdrvTrackedRequest
*
640 bdrv_find_conflicting_request(BdrvTrackedRequest
*self
)
642 BdrvTrackedRequest
*req
;
644 QLIST_FOREACH(req
, &self
->bs
->tracked_requests
, list
) {
645 if (req
== self
|| (!req
->serialising
&& !self
->serialising
)) {
648 if (tracked_request_overlaps(req
, self
->overlap_offset
,
649 self
->overlap_bytes
))
652 * Hitting this means there was a reentrant request, for
653 * example, a block driver issuing nested requests. This must
654 * never happen since it means deadlock.
656 assert(qemu_coroutine_self() != req
->co
);
659 * If the request is already (indirectly) waiting for us, or
660 * will wait for us as soon as it wakes up, then just go on
661 * (instead of producing a deadlock in the former case).
663 if (!req
->waiting_for
) {
672 /* Called with self->bs->reqs_lock held */
673 static void coroutine_fn
674 bdrv_wait_serialising_requests_locked(BdrvTrackedRequest
*self
)
676 BdrvTrackedRequest
*req
;
678 while ((req
= bdrv_find_conflicting_request(self
))) {
679 self
->waiting_for
= req
;
680 qemu_co_queue_wait(&req
->wait_queue
, &self
->bs
->reqs_lock
);
681 self
->waiting_for
= NULL
;
685 /* Called with req->bs->reqs_lock held */
686 static void tracked_request_set_serialising(BdrvTrackedRequest
*req
,
689 int64_t overlap_offset
= req
->offset
& ~(align
- 1);
690 int64_t overlap_bytes
=
691 ROUND_UP(req
->offset
+ req
->bytes
, align
) - overlap_offset
;
693 bdrv_check_request(req
->offset
, req
->bytes
, &error_abort
);
695 if (!req
->serialising
) {
696 qatomic_inc(&req
->bs
->serialising_in_flight
);
697 req
->serialising
= true;
700 req
->overlap_offset
= MIN(req
->overlap_offset
, overlap_offset
);
701 req
->overlap_bytes
= MAX(req
->overlap_bytes
, overlap_bytes
);
705 * Return the tracked request on @bs for the current coroutine, or
706 * NULL if there is none.
708 BdrvTrackedRequest
*coroutine_fn
bdrv_co_get_self_request(BlockDriverState
*bs
)
710 BdrvTrackedRequest
*req
;
711 Coroutine
*self
= qemu_coroutine_self();
714 QLIST_FOREACH(req
, &bs
->tracked_requests
, list
) {
715 if (req
->co
== self
) {
724 * Round a region to cluster boundaries
726 void coroutine_fn
bdrv_round_to_clusters(BlockDriverState
*bs
,
727 int64_t offset
, int64_t bytes
,
728 int64_t *cluster_offset
,
729 int64_t *cluster_bytes
)
733 if (bdrv_co_get_info(bs
, &bdi
) < 0 || bdi
.cluster_size
== 0) {
734 *cluster_offset
= offset
;
735 *cluster_bytes
= bytes
;
737 int64_t c
= bdi
.cluster_size
;
738 *cluster_offset
= QEMU_ALIGN_DOWN(offset
, c
);
739 *cluster_bytes
= QEMU_ALIGN_UP(offset
- *cluster_offset
+ bytes
, c
);
743 static coroutine_fn
int bdrv_get_cluster_size(BlockDriverState
*bs
)
748 ret
= bdrv_co_get_info(bs
, &bdi
);
749 if (ret
< 0 || bdi
.cluster_size
== 0) {
750 return bs
->bl
.request_alignment
;
752 return bdi
.cluster_size
;
756 void bdrv_inc_in_flight(BlockDriverState
*bs
)
759 qatomic_inc(&bs
->in_flight
);
762 void bdrv_wakeup(BlockDriverState
*bs
)
768 void bdrv_dec_in_flight(BlockDriverState
*bs
)
771 qatomic_dec(&bs
->in_flight
);
775 static void coroutine_fn
776 bdrv_wait_serialising_requests(BdrvTrackedRequest
*self
)
778 BlockDriverState
*bs
= self
->bs
;
780 if (!qatomic_read(&bs
->serialising_in_flight
)) {
784 qemu_co_mutex_lock(&bs
->reqs_lock
);
785 bdrv_wait_serialising_requests_locked(self
);
786 qemu_co_mutex_unlock(&bs
->reqs_lock
);
789 void coroutine_fn
bdrv_make_request_serialising(BdrvTrackedRequest
*req
,
794 qemu_co_mutex_lock(&req
->bs
->reqs_lock
);
796 tracked_request_set_serialising(req
, align
);
797 bdrv_wait_serialising_requests_locked(req
);
799 qemu_co_mutex_unlock(&req
->bs
->reqs_lock
);
802 int bdrv_check_qiov_request(int64_t offset
, int64_t bytes
,
803 QEMUIOVector
*qiov
, size_t qiov_offset
,
807 * Check generic offset/bytes correctness
811 error_setg(errp
, "offset is negative: %" PRIi64
, offset
);
816 error_setg(errp
, "bytes is negative: %" PRIi64
, bytes
);
820 if (bytes
> BDRV_MAX_LENGTH
) {
821 error_setg(errp
, "bytes(%" PRIi64
") exceeds maximum(%" PRIi64
")",
822 bytes
, BDRV_MAX_LENGTH
);
826 if (offset
> BDRV_MAX_LENGTH
) {
827 error_setg(errp
, "offset(%" PRIi64
") exceeds maximum(%" PRIi64
")",
828 offset
, BDRV_MAX_LENGTH
);
832 if (offset
> BDRV_MAX_LENGTH
- bytes
) {
833 error_setg(errp
, "sum of offset(%" PRIi64
") and bytes(%" PRIi64
") "
834 "exceeds maximum(%" PRIi64
")", offset
, bytes
,
844 * Check qiov and qiov_offset
847 if (qiov_offset
> qiov
->size
) {
848 error_setg(errp
, "qiov_offset(%zu) overflow io vector size(%zu)",
849 qiov_offset
, qiov
->size
);
853 if (bytes
> qiov
->size
- qiov_offset
) {
854 error_setg(errp
, "bytes(%" PRIi64
") + qiov_offset(%zu) overflow io "
855 "vector size(%zu)", bytes
, qiov_offset
, qiov
->size
);
862 int bdrv_check_request(int64_t offset
, int64_t bytes
, Error
**errp
)
864 return bdrv_check_qiov_request(offset
, bytes
, NULL
, 0, errp
);
867 static int bdrv_check_request32(int64_t offset
, int64_t bytes
,
868 QEMUIOVector
*qiov
, size_t qiov_offset
)
870 int ret
= bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, NULL
);
875 if (bytes
> BDRV_REQUEST_MAX_BYTES
) {
883 * Completely zero out a block device with the help of bdrv_pwrite_zeroes.
884 * The operation is sped up by checking the block status and only writing
885 * zeroes to the device if they currently do not return zeroes. Optional
886 * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP,
889 * Returns < 0 on error, 0 on success. For error codes see bdrv_pwrite().
891 int bdrv_make_zero(BdrvChild
*child
, BdrvRequestFlags flags
)
894 int64_t target_size
, bytes
, offset
= 0;
895 BlockDriverState
*bs
= child
->bs
;
898 target_size
= bdrv_getlength(bs
);
899 if (target_size
< 0) {
904 bytes
= MIN(target_size
- offset
, BDRV_REQUEST_MAX_BYTES
);
908 ret
= bdrv_block_status(bs
, offset
, bytes
, &bytes
, NULL
, NULL
);
912 if (ret
& BDRV_BLOCK_ZERO
) {
916 ret
= bdrv_pwrite_zeroes(child
, offset
, bytes
, flags
);
925 * Writes to the file and ensures that no writes are reordered across this
926 * request (acts as a barrier)
928 * Returns 0 on success, -errno in error cases.
930 int coroutine_fn
bdrv_co_pwrite_sync(BdrvChild
*child
, int64_t offset
,
931 int64_t bytes
, const void *buf
,
932 BdrvRequestFlags flags
)
937 assume_graph_lock(); /* FIXME */
939 ret
= bdrv_co_pwrite(child
, offset
, bytes
, buf
, flags
);
944 ret
= bdrv_co_flush(child
->bs
);
952 typedef struct CoroutineIOCompletion
{
953 Coroutine
*coroutine
;
955 } CoroutineIOCompletion
;
957 static void bdrv_co_io_em_complete(void *opaque
, int ret
)
959 CoroutineIOCompletion
*co
= opaque
;
962 aio_co_wake(co
->coroutine
);
965 static int coroutine_fn GRAPH_RDLOCK
966 bdrv_driver_preadv(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
967 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
969 BlockDriver
*drv
= bs
->drv
;
971 unsigned int nb_sectors
;
972 QEMUIOVector local_qiov
;
975 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
976 assert(!(flags
& ~bs
->supported_read_flags
));
982 if (drv
->bdrv_co_preadv_part
) {
983 return drv
->bdrv_co_preadv_part(bs
, offset
, bytes
, qiov
, qiov_offset
,
987 if (qiov_offset
> 0 || bytes
!= qiov
->size
) {
988 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
992 if (drv
->bdrv_co_preadv
) {
993 ret
= drv
->bdrv_co_preadv(bs
, offset
, bytes
, qiov
, flags
);
997 if (drv
->bdrv_aio_preadv
) {
999 CoroutineIOCompletion co
= {
1000 .coroutine
= qemu_coroutine_self(),
1003 acb
= drv
->bdrv_aio_preadv(bs
, offset
, bytes
, qiov
, flags
,
1004 bdrv_co_io_em_complete
, &co
);
1009 qemu_coroutine_yield();
1015 sector_num
= offset
>> BDRV_SECTOR_BITS
;
1016 nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
1018 assert(QEMU_IS_ALIGNED(offset
, BDRV_SECTOR_SIZE
));
1019 assert(QEMU_IS_ALIGNED(bytes
, BDRV_SECTOR_SIZE
));
1020 assert(bytes
<= BDRV_REQUEST_MAX_BYTES
);
1021 assert(drv
->bdrv_co_readv
);
1023 ret
= drv
->bdrv_co_readv(bs
, sector_num
, nb_sectors
, qiov
);
1026 if (qiov
== &local_qiov
) {
1027 qemu_iovec_destroy(&local_qiov
);
1033 static int coroutine_fn GRAPH_RDLOCK
1034 bdrv_driver_pwritev(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
1035 QEMUIOVector
*qiov
, size_t qiov_offset
,
1036 BdrvRequestFlags flags
)
1038 BlockDriver
*drv
= bs
->drv
;
1039 bool emulate_fua
= false;
1041 unsigned int nb_sectors
;
1042 QEMUIOVector local_qiov
;
1045 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
1051 if ((flags
& BDRV_REQ_FUA
) &&
1052 (~bs
->supported_write_flags
& BDRV_REQ_FUA
)) {
1053 flags
&= ~BDRV_REQ_FUA
;
1057 flags
&= bs
->supported_write_flags
;
1059 if (drv
->bdrv_co_pwritev_part
) {
1060 ret
= drv
->bdrv_co_pwritev_part(bs
, offset
, bytes
, qiov
, qiov_offset
,
1065 if (qiov_offset
> 0 || bytes
!= qiov
->size
) {
1066 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
1070 if (drv
->bdrv_co_pwritev
) {
1071 ret
= drv
->bdrv_co_pwritev(bs
, offset
, bytes
, qiov
, flags
);
1075 if (drv
->bdrv_aio_pwritev
) {
1077 CoroutineIOCompletion co
= {
1078 .coroutine
= qemu_coroutine_self(),
1081 acb
= drv
->bdrv_aio_pwritev(bs
, offset
, bytes
, qiov
, flags
,
1082 bdrv_co_io_em_complete
, &co
);
1086 qemu_coroutine_yield();
1092 sector_num
= offset
>> BDRV_SECTOR_BITS
;
1093 nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
1095 assert(QEMU_IS_ALIGNED(offset
, BDRV_SECTOR_SIZE
));
1096 assert(QEMU_IS_ALIGNED(bytes
, BDRV_SECTOR_SIZE
));
1097 assert(bytes
<= BDRV_REQUEST_MAX_BYTES
);
1099 assert(drv
->bdrv_co_writev
);
1100 ret
= drv
->bdrv_co_writev(bs
, sector_num
, nb_sectors
, qiov
, flags
);
1103 if (ret
== 0 && emulate_fua
) {
1104 ret
= bdrv_co_flush(bs
);
1107 if (qiov
== &local_qiov
) {
1108 qemu_iovec_destroy(&local_qiov
);
1114 static int coroutine_fn GRAPH_RDLOCK
1115 bdrv_driver_pwritev_compressed(BlockDriverState
*bs
, int64_t offset
,
1116 int64_t bytes
, QEMUIOVector
*qiov
,
1119 BlockDriver
*drv
= bs
->drv
;
1120 QEMUIOVector local_qiov
;
1123 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
1129 if (!block_driver_can_compress(drv
)) {
1133 if (drv
->bdrv_co_pwritev_compressed_part
) {
1134 return drv
->bdrv_co_pwritev_compressed_part(bs
, offset
, bytes
,
1138 if (qiov_offset
== 0) {
1139 return drv
->bdrv_co_pwritev_compressed(bs
, offset
, bytes
, qiov
);
1142 qemu_iovec_init_slice(&local_qiov
, qiov
, qiov_offset
, bytes
);
1143 ret
= drv
->bdrv_co_pwritev_compressed(bs
, offset
, bytes
, &local_qiov
);
1144 qemu_iovec_destroy(&local_qiov
);
1149 static int coroutine_fn GRAPH_RDLOCK
1150 bdrv_co_do_copy_on_readv(BdrvChild
*child
, int64_t offset
, int64_t bytes
,
1151 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
1153 BlockDriverState
*bs
= child
->bs
;
1155 /* Perform I/O through a temporary buffer so that users who scribble over
1156 * their read buffer while the operation is in progress do not end up
1157 * modifying the image file. This is critical for zero-copy guest I/O
1158 * where anything might happen inside guest memory.
1160 void *bounce_buffer
= NULL
;
1162 BlockDriver
*drv
= bs
->drv
;
1163 int64_t cluster_offset
;
1164 int64_t cluster_bytes
;
1167 int max_transfer
= MIN_NON_ZERO(bs
->bl
.max_transfer
,
1168 BDRV_REQUEST_MAX_BYTES
);
1169 int64_t progress
= 0;
1172 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
1179 * Do not write anything when the BDS is inactive. That is not
1180 * allowed, and it would not help.
1182 skip_write
= (bs
->open_flags
& BDRV_O_INACTIVE
);
1184 /* FIXME We cannot require callers to have write permissions when all they
1185 * are doing is a read request. If we did things right, write permissions
1186 * would be obtained anyway, but internally by the copy-on-read code. As
1187 * long as it is implemented here rather than in a separate filter driver,
1188 * the copy-on-read code doesn't have its own BdrvChild, however, for which
1189 * it could request permissions. Therefore we have to bypass the permission
1190 * system for the moment. */
1191 // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
1193 /* Cover entire cluster so no additional backing file I/O is required when
1194 * allocating cluster in the image file. Note that this value may exceed
1195 * BDRV_REQUEST_MAX_BYTES (even when the original read did not), which
1196 * is one reason we loop rather than doing it all at once.
1198 bdrv_round_to_clusters(bs
, offset
, bytes
, &cluster_offset
, &cluster_bytes
);
1199 skip_bytes
= offset
- cluster_offset
;
1201 trace_bdrv_co_do_copy_on_readv(bs
, offset
, bytes
,
1202 cluster_offset
, cluster_bytes
);
1204 while (cluster_bytes
) {
1208 ret
= 1; /* "already allocated", so nothing will be copied */
1209 pnum
= MIN(cluster_bytes
, max_transfer
);
1211 ret
= bdrv_is_allocated(bs
, cluster_offset
,
1212 MIN(cluster_bytes
, max_transfer
), &pnum
);
1215 * Safe to treat errors in querying allocation as if
1216 * unallocated; we'll probably fail again soon on the
1217 * read, but at least that will set a decent errno.
1219 pnum
= MIN(cluster_bytes
, max_transfer
);
1222 /* Stop at EOF if the image ends in the middle of the cluster */
1223 if (ret
== 0 && pnum
== 0) {
1224 assert(progress
>= bytes
);
1228 assert(skip_bytes
< pnum
);
1232 QEMUIOVector local_qiov
;
1234 /* Must copy-on-read; use the bounce buffer */
1235 pnum
= MIN(pnum
, MAX_BOUNCE_BUFFER
);
1236 if (!bounce_buffer
) {
1237 int64_t max_we_need
= MAX(pnum
, cluster_bytes
- pnum
);
1238 int64_t max_allowed
= MIN(max_transfer
, MAX_BOUNCE_BUFFER
);
1239 int64_t bounce_buffer_len
= MIN(max_we_need
, max_allowed
);
1241 bounce_buffer
= qemu_try_blockalign(bs
, bounce_buffer_len
);
1242 if (!bounce_buffer
) {
1247 qemu_iovec_init_buf(&local_qiov
, bounce_buffer
, pnum
);
1249 ret
= bdrv_driver_preadv(bs
, cluster_offset
, pnum
,
1255 bdrv_co_debug_event(bs
, BLKDBG_COR_WRITE
);
1256 if (drv
->bdrv_co_pwrite_zeroes
&&
1257 buffer_is_zero(bounce_buffer
, pnum
)) {
1258 /* FIXME: Should we (perhaps conditionally) be setting
1259 * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
1260 * that still correctly reads as zero? */
1261 ret
= bdrv_co_do_pwrite_zeroes(bs
, cluster_offset
, pnum
,
1262 BDRV_REQ_WRITE_UNCHANGED
);
1264 /* This does not change the data on the disk, it is not
1265 * necessary to flush even in cache=writethrough mode.
1267 ret
= bdrv_driver_pwritev(bs
, cluster_offset
, pnum
,
1269 BDRV_REQ_WRITE_UNCHANGED
);
1273 /* It might be okay to ignore write errors for guest
1274 * requests. If this is a deliberate copy-on-read
1275 * then we don't want to ignore the error. Simply
1276 * report it in all cases.
1281 if (!(flags
& BDRV_REQ_PREFETCH
)) {
1282 qemu_iovec_from_buf(qiov
, qiov_offset
+ progress
,
1283 bounce_buffer
+ skip_bytes
,
1284 MIN(pnum
- skip_bytes
, bytes
- progress
));
1286 } else if (!(flags
& BDRV_REQ_PREFETCH
)) {
1287 /* Read directly into the destination */
1288 ret
= bdrv_driver_preadv(bs
, offset
+ progress
,
1289 MIN(pnum
- skip_bytes
, bytes
- progress
),
1290 qiov
, qiov_offset
+ progress
, 0);
1296 cluster_offset
+= pnum
;
1297 cluster_bytes
-= pnum
;
1298 progress
+= pnum
- skip_bytes
;
1304 qemu_vfree(bounce_buffer
);
1309 * Forwards an already correctly aligned request to the BlockDriver. This
1310 * handles copy on read, zeroing after EOF, and fragmentation of large
1311 * reads; any other features must be implemented by the caller.
1313 static int coroutine_fn GRAPH_RDLOCK
1314 bdrv_aligned_preadv(BdrvChild
*child
, BdrvTrackedRequest
*req
,
1315 int64_t offset
, int64_t bytes
, int64_t align
,
1316 QEMUIOVector
*qiov
, size_t qiov_offset
, int flags
)
1318 BlockDriverState
*bs
= child
->bs
;
1319 int64_t total_bytes
, max_bytes
;
1321 int64_t bytes_remaining
= bytes
;
1324 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
1325 assert(is_power_of_2(align
));
1326 assert((offset
& (align
- 1)) == 0);
1327 assert((bytes
& (align
- 1)) == 0);
1328 assert((bs
->open_flags
& BDRV_O_NO_IO
) == 0);
1329 max_transfer
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_transfer
, INT_MAX
),
1333 * TODO: We would need a per-BDS .supported_read_flags and
1334 * potential fallback support, if we ever implement any read flags
1335 * to pass through to drivers. For now, there aren't any
1336 * passthrough flags except the BDRV_REQ_REGISTERED_BUF optimization hint.
1338 assert(!(flags
& ~(BDRV_REQ_COPY_ON_READ
| BDRV_REQ_PREFETCH
|
1339 BDRV_REQ_REGISTERED_BUF
)));
1341 /* Handle Copy on Read and associated serialisation */
1342 if (flags
& BDRV_REQ_COPY_ON_READ
) {
1343 /* If we touch the same cluster it counts as an overlap. This
1344 * guarantees that allocating writes will be serialized and not race
1345 * with each other for the same cluster. For example, in copy-on-read
1346 * it ensures that the CoR read and write operations are atomic and
1347 * guest writes cannot interleave between them. */
1348 bdrv_make_request_serialising(req
, bdrv_get_cluster_size(bs
));
1350 bdrv_wait_serialising_requests(req
);
1353 if (flags
& BDRV_REQ_COPY_ON_READ
) {
1356 /* The flag BDRV_REQ_COPY_ON_READ has reached its addressee */
1357 flags
&= ~BDRV_REQ_COPY_ON_READ
;
1359 ret
= bdrv_is_allocated(bs
, offset
, bytes
, &pnum
);
1364 if (!ret
|| pnum
!= bytes
) {
1365 ret
= bdrv_co_do_copy_on_readv(child
, offset
, bytes
,
1366 qiov
, qiov_offset
, flags
);
1368 } else if (flags
& BDRV_REQ_PREFETCH
) {
1373 /* Forward the request to the BlockDriver, possibly fragmenting it */
1374 total_bytes
= bdrv_getlength(bs
);
1375 if (total_bytes
< 0) {
1380 assert(!(flags
& ~(bs
->supported_read_flags
| BDRV_REQ_REGISTERED_BUF
)));
1382 max_bytes
= ROUND_UP(MAX(0, total_bytes
- offset
), align
);
1383 if (bytes
<= max_bytes
&& bytes
<= max_transfer
) {
1384 ret
= bdrv_driver_preadv(bs
, offset
, bytes
, qiov
, qiov_offset
, flags
);
1388 while (bytes_remaining
) {
1392 num
= MIN(bytes_remaining
, MIN(max_bytes
, max_transfer
));
1395 ret
= bdrv_driver_preadv(bs
, offset
+ bytes
- bytes_remaining
,
1397 qiov_offset
+ bytes
- bytes_remaining
,
1401 num
= bytes_remaining
;
1402 ret
= qemu_iovec_memset(qiov
, qiov_offset
+ bytes
- bytes_remaining
,
1403 0, bytes_remaining
);
1408 bytes_remaining
-= num
;
1412 return ret
< 0 ? ret
: 0;
1418 * |<---- align ----->| |<----- align ---->|
1419 * |<- head ->|<------------- bytes ------------->|<-- tail -->|
1421 * -*----------$-------*-------- ... --------*-----$------------*---
1423 * | offset | | end |
1424 * ALIGN_DOWN(offset) ALIGN_UP(offset) ALIGN_DOWN(end) ALIGN_UP(end)
1425 * [buf ... ) [tail_buf )
1427 * @buf is an aligned allocation needed to store @head and @tail paddings. @head
1428 * is placed at the beginning of @buf and @tail at the @end.
1430 * @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk
1431 * around tail, if tail exists.
1433 * @merge_reads is true for small requests,
1434 * if @buf_len == @head + bytes + @tail. In this case it is possible that both
1435 * head and tail exist but @buf_len == align and @tail_buf == @buf.
1437 typedef struct BdrvRequestPadding
{
1444 QEMUIOVector local_qiov
;
1445 } BdrvRequestPadding
;
1447 static bool bdrv_init_padding(BlockDriverState
*bs
,
1448 int64_t offset
, int64_t bytes
,
1449 BdrvRequestPadding
*pad
)
1451 int64_t align
= bs
->bl
.request_alignment
;
1454 bdrv_check_request(offset
, bytes
, &error_abort
);
1455 assert(align
<= INT_MAX
); /* documented in block/block_int.h */
1456 assert(align
<= SIZE_MAX
/ 2); /* so we can allocate the buffer */
1458 memset(pad
, 0, sizeof(*pad
));
1460 pad
->head
= offset
& (align
- 1);
1461 pad
->tail
= ((offset
+ bytes
) & (align
- 1));
1463 pad
->tail
= align
- pad
->tail
;
1466 if (!pad
->head
&& !pad
->tail
) {
1470 assert(bytes
); /* Nothing good in aligning zero-length requests */
1472 sum
= pad
->head
+ bytes
+ pad
->tail
;
1473 pad
->buf_len
= (sum
> align
&& pad
->head
&& pad
->tail
) ? 2 * align
: align
;
1474 pad
->buf
= qemu_blockalign(bs
, pad
->buf_len
);
1475 pad
->merge_reads
= sum
== pad
->buf_len
;
1477 pad
->tail_buf
= pad
->buf
+ pad
->buf_len
- align
;
1483 static int coroutine_fn GRAPH_RDLOCK
1484 bdrv_padding_rmw_read(BdrvChild
*child
, BdrvTrackedRequest
*req
,
1485 BdrvRequestPadding
*pad
, bool zero_middle
)
1487 QEMUIOVector local_qiov
;
1488 BlockDriverState
*bs
= child
->bs
;
1489 uint64_t align
= bs
->bl
.request_alignment
;
1492 assert(req
->serialising
&& pad
->buf
);
1494 if (pad
->head
|| pad
->merge_reads
) {
1495 int64_t bytes
= pad
->merge_reads
? pad
->buf_len
: align
;
1497 qemu_iovec_init_buf(&local_qiov
, pad
->buf
, bytes
);
1500 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_HEAD
);
1502 if (pad
->merge_reads
&& pad
->tail
) {
1503 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1505 ret
= bdrv_aligned_preadv(child
, req
, req
->overlap_offset
, bytes
,
1506 align
, &local_qiov
, 0, 0);
1511 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_HEAD
);
1513 if (pad
->merge_reads
&& pad
->tail
) {
1514 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1517 if (pad
->merge_reads
) {
1523 qemu_iovec_init_buf(&local_qiov
, pad
->tail_buf
, align
);
1525 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1526 ret
= bdrv_aligned_preadv(
1528 req
->overlap_offset
+ req
->overlap_bytes
- align
,
1529 align
, align
, &local_qiov
, 0, 0);
1533 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1538 memset(pad
->buf
+ pad
->head
, 0, pad
->buf_len
- pad
->head
- pad
->tail
);
1544 static void bdrv_padding_destroy(BdrvRequestPadding
*pad
)
1547 qemu_vfree(pad
->buf
);
1548 qemu_iovec_destroy(&pad
->local_qiov
);
1550 memset(pad
, 0, sizeof(*pad
));
1556 * Exchange request parameters with padded request if needed. Don't include RMW
1557 * read of padding, bdrv_padding_rmw_read() should be called separately if
1560 * Request parameters (@qiov, &qiov_offset, &offset, &bytes) are in-out:
1561 * - on function start they represent original request
1562 * - on failure or when padding is not needed they are unchanged
1563 * - on success when padding is needed they represent padded request
1565 static int bdrv_pad_request(BlockDriverState
*bs
,
1566 QEMUIOVector
**qiov
, size_t *qiov_offset
,
1567 int64_t *offset
, int64_t *bytes
,
1568 BdrvRequestPadding
*pad
, bool *padded
,
1569 BdrvRequestFlags
*flags
)
1573 bdrv_check_qiov_request(*offset
, *bytes
, *qiov
, *qiov_offset
, &error_abort
);
1575 if (!bdrv_init_padding(bs
, *offset
, *bytes
, pad
)) {
1582 ret
= qemu_iovec_init_extended(&pad
->local_qiov
, pad
->buf
, pad
->head
,
1583 *qiov
, *qiov_offset
, *bytes
,
1584 pad
->buf
+ pad
->buf_len
- pad
->tail
,
1587 bdrv_padding_destroy(pad
);
1590 *bytes
+= pad
->head
+ pad
->tail
;
1591 *offset
-= pad
->head
;
1592 *qiov
= &pad
->local_qiov
;
1598 /* Can't use optimization hint with bounce buffer */
1599 *flags
&= ~BDRV_REQ_REGISTERED_BUF
;
1605 int coroutine_fn
bdrv_co_preadv(BdrvChild
*child
,
1606 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
,
1607 BdrvRequestFlags flags
)
1610 return bdrv_co_preadv_part(child
, offset
, bytes
, qiov
, 0, flags
);
1613 int coroutine_fn
bdrv_co_preadv_part(BdrvChild
*child
,
1614 int64_t offset
, int64_t bytes
,
1615 QEMUIOVector
*qiov
, size_t qiov_offset
,
1616 BdrvRequestFlags flags
)
1618 BlockDriverState
*bs
= child
->bs
;
1619 BdrvTrackedRequest req
;
1620 BdrvRequestPadding pad
;
1624 assume_graph_lock(); /* FIXME */
1626 trace_bdrv_co_preadv_part(bs
, offset
, bytes
, flags
);
1628 if (!bdrv_co_is_inserted(bs
)) {
1632 ret
= bdrv_check_request32(offset
, bytes
, qiov
, qiov_offset
);
1637 if (bytes
== 0 && !QEMU_IS_ALIGNED(offset
, bs
->bl
.request_alignment
)) {
1639 * Aligning zero request is nonsense. Even if driver has special meaning
1640 * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
1641 * it to driver due to request_alignment.
1643 * Still, no reason to return an error if someone do unaligned
1644 * zero-length read occasionally.
1649 bdrv_inc_in_flight(bs
);
1651 /* Don't do copy-on-read if we read data before write operation */
1652 if (qatomic_read(&bs
->copy_on_read
)) {
1653 flags
|= BDRV_REQ_COPY_ON_READ
;
1656 ret
= bdrv_pad_request(bs
, &qiov
, &qiov_offset
, &offset
, &bytes
, &pad
,
1662 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_READ
);
1663 ret
= bdrv_aligned_preadv(child
, &req
, offset
, bytes
,
1664 bs
->bl
.request_alignment
,
1665 qiov
, qiov_offset
, flags
);
1666 tracked_request_end(&req
);
1667 bdrv_padding_destroy(&pad
);
1670 bdrv_dec_in_flight(bs
);
1675 static int coroutine_fn
bdrv_co_do_pwrite_zeroes(BlockDriverState
*bs
,
1676 int64_t offset
, int64_t bytes
, BdrvRequestFlags flags
)
1678 BlockDriver
*drv
= bs
->drv
;
1682 bool need_flush
= false;
1686 assume_graph_lock(); /* FIXME */
1688 int64_t max_write_zeroes
= MIN_NON_ZERO(bs
->bl
.max_pwrite_zeroes
,
1690 int alignment
= MAX(bs
->bl
.pwrite_zeroes_alignment
,
1691 bs
->bl
.request_alignment
);
1692 int max_transfer
= MIN_NON_ZERO(bs
->bl
.max_transfer
, MAX_BOUNCE_BUFFER
);
1694 assert_bdrv_graph_readable();
1695 bdrv_check_request(offset
, bytes
, &error_abort
);
1701 if ((flags
& ~bs
->supported_zero_flags
) & BDRV_REQ_NO_FALLBACK
) {
1705 /* By definition there is no user buffer so this flag doesn't make sense */
1706 if (flags
& BDRV_REQ_REGISTERED_BUF
) {
1710 /* Invalidate the cached block-status data range if this write overlaps */
1711 bdrv_bsc_invalidate_range(bs
, offset
, bytes
);
1713 assert(alignment
% bs
->bl
.request_alignment
== 0);
1714 head
= offset
% alignment
;
1715 tail
= (offset
+ bytes
) % alignment
;
1716 max_write_zeroes
= QEMU_ALIGN_DOWN(max_write_zeroes
, alignment
);
1717 assert(max_write_zeroes
>= bs
->bl
.request_alignment
);
1719 while (bytes
> 0 && !ret
) {
1720 int64_t num
= bytes
;
1722 /* Align request. Block drivers can expect the "bulk" of the request
1723 * to be aligned, and that unaligned requests do not cross cluster
1727 /* Make a small request up to the first aligned sector. For
1728 * convenience, limit this request to max_transfer even if
1729 * we don't need to fall back to writes. */
1730 num
= MIN(MIN(bytes
, max_transfer
), alignment
- head
);
1731 head
= (head
+ num
) % alignment
;
1732 assert(num
< max_write_zeroes
);
1733 } else if (tail
&& num
> alignment
) {
1734 /* Shorten the request to the last aligned sector. */
1738 /* limit request size */
1739 if (num
> max_write_zeroes
) {
1740 num
= max_write_zeroes
;
1744 /* First try the efficient write zeroes operation */
1745 if (drv
->bdrv_co_pwrite_zeroes
) {
1746 ret
= drv
->bdrv_co_pwrite_zeroes(bs
, offset
, num
,
1747 flags
& bs
->supported_zero_flags
);
1748 if (ret
!= -ENOTSUP
&& (flags
& BDRV_REQ_FUA
) &&
1749 !(bs
->supported_zero_flags
& BDRV_REQ_FUA
)) {
1753 assert(!bs
->supported_zero_flags
);
1756 if (ret
== -ENOTSUP
&& !(flags
& BDRV_REQ_NO_FALLBACK
)) {
1757 /* Fall back to bounce buffer if write zeroes is unsupported */
1758 BdrvRequestFlags write_flags
= flags
& ~BDRV_REQ_ZERO_WRITE
;
1760 if ((flags
& BDRV_REQ_FUA
) &&
1761 !(bs
->supported_write_flags
& BDRV_REQ_FUA
)) {
1762 /* No need for bdrv_driver_pwrite() to do a fallback
1763 * flush on each chunk; use just one at the end */
1764 write_flags
&= ~BDRV_REQ_FUA
;
1767 num
= MIN(num
, max_transfer
);
1769 buf
= qemu_try_blockalign0(bs
, num
);
1775 qemu_iovec_init_buf(&qiov
, buf
, num
);
1777 ret
= bdrv_driver_pwritev(bs
, offset
, num
, &qiov
, 0, write_flags
);
1779 /* Keep bounce buffer around if it is big enough for all
1780 * all future requests.
1782 if (num
< max_transfer
) {
1793 if (ret
== 0 && need_flush
) {
1794 ret
= bdrv_co_flush(bs
);
1800 static inline int coroutine_fn
1801 bdrv_co_write_req_prepare(BdrvChild
*child
, int64_t offset
, int64_t bytes
,
1802 BdrvTrackedRequest
*req
, int flags
)
1804 BlockDriverState
*bs
= child
->bs
;
1806 bdrv_check_request(offset
, bytes
, &error_abort
);
1808 if (bdrv_is_read_only(bs
)) {
1812 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
1813 assert((bs
->open_flags
& BDRV_O_NO_IO
) == 0);
1814 assert(!(flags
& ~BDRV_REQ_MASK
));
1815 assert(!((flags
& BDRV_REQ_NO_WAIT
) && !(flags
& BDRV_REQ_SERIALISING
)));
1817 if (flags
& BDRV_REQ_SERIALISING
) {
1818 QEMU_LOCK_GUARD(&bs
->reqs_lock
);
1820 tracked_request_set_serialising(req
, bdrv_get_cluster_size(bs
));
1822 if ((flags
& BDRV_REQ_NO_WAIT
) && bdrv_find_conflicting_request(req
)) {
1826 bdrv_wait_serialising_requests_locked(req
);
1828 bdrv_wait_serialising_requests(req
);
1831 assert(req
->overlap_offset
<= offset
);
1832 assert(offset
+ bytes
<= req
->overlap_offset
+ req
->overlap_bytes
);
1833 assert(offset
+ bytes
<= bs
->total_sectors
* BDRV_SECTOR_SIZE
||
1834 child
->perm
& BLK_PERM_RESIZE
);
1836 switch (req
->type
) {
1837 case BDRV_TRACKED_WRITE
:
1838 case BDRV_TRACKED_DISCARD
:
1839 if (flags
& BDRV_REQ_WRITE_UNCHANGED
) {
1840 assert(child
->perm
& (BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
));
1842 assert(child
->perm
& BLK_PERM_WRITE
);
1844 bdrv_write_threshold_check_write(bs
, offset
, bytes
);
1846 case BDRV_TRACKED_TRUNCATE
:
1847 assert(child
->perm
& BLK_PERM_RESIZE
);
1854 static inline void coroutine_fn
1855 bdrv_co_write_req_finish(BdrvChild
*child
, int64_t offset
, int64_t bytes
,
1856 BdrvTrackedRequest
*req
, int ret
)
1858 int64_t end_sector
= DIV_ROUND_UP(offset
+ bytes
, BDRV_SECTOR_SIZE
);
1859 BlockDriverState
*bs
= child
->bs
;
1861 bdrv_check_request(offset
, bytes
, &error_abort
);
1863 qatomic_inc(&bs
->write_gen
);
1866 * Discard cannot extend the image, but in error handling cases, such as
1867 * when reverting a qcow2 cluster allocation, the discarded range can pass
1868 * the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD
1869 * here. Instead, just skip it, since semantically a discard request
1870 * beyond EOF cannot expand the image anyway.
1873 (req
->type
== BDRV_TRACKED_TRUNCATE
||
1874 end_sector
> bs
->total_sectors
) &&
1875 req
->type
!= BDRV_TRACKED_DISCARD
) {
1876 bs
->total_sectors
= end_sector
;
1877 bdrv_parent_cb_resize(bs
);
1878 bdrv_dirty_bitmap_truncate(bs
, end_sector
<< BDRV_SECTOR_BITS
);
1881 switch (req
->type
) {
1882 case BDRV_TRACKED_WRITE
:
1883 stat64_max(&bs
->wr_highest_offset
, offset
+ bytes
);
1884 /* fall through, to set dirty bits */
1885 case BDRV_TRACKED_DISCARD
:
1886 bdrv_set_dirty(bs
, offset
, bytes
);
1895 * Forwards an already correctly aligned write request to the BlockDriver,
1896 * after possibly fragmenting it.
1898 static int coroutine_fn GRAPH_RDLOCK
1899 bdrv_aligned_pwritev(BdrvChild
*child
, BdrvTrackedRequest
*req
,
1900 int64_t offset
, int64_t bytes
, int64_t align
,
1901 QEMUIOVector
*qiov
, size_t qiov_offset
,
1902 BdrvRequestFlags flags
)
1904 BlockDriverState
*bs
= child
->bs
;
1905 BlockDriver
*drv
= bs
->drv
;
1908 int64_t bytes_remaining
= bytes
;
1911 bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, &error_abort
);
1917 if (bdrv_has_readonly_bitmaps(bs
)) {
1921 assert(is_power_of_2(align
));
1922 assert((offset
& (align
- 1)) == 0);
1923 assert((bytes
& (align
- 1)) == 0);
1924 max_transfer
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_transfer
, INT_MAX
),
1927 ret
= bdrv_co_write_req_prepare(child
, offset
, bytes
, req
, flags
);
1929 if (!ret
&& bs
->detect_zeroes
!= BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
&&
1930 !(flags
& BDRV_REQ_ZERO_WRITE
) && drv
->bdrv_co_pwrite_zeroes
&&
1931 qemu_iovec_is_zero(qiov
, qiov_offset
, bytes
)) {
1932 flags
|= BDRV_REQ_ZERO_WRITE
;
1933 if (bs
->detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
) {
1934 flags
|= BDRV_REQ_MAY_UNMAP
;
1937 /* Can't use optimization hint with bufferless zero write */
1938 flags
&= ~BDRV_REQ_REGISTERED_BUF
;
1942 /* Do nothing, write notifier decided to fail this request */
1943 } else if (flags
& BDRV_REQ_ZERO_WRITE
) {
1944 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_ZERO
);
1945 ret
= bdrv_co_do_pwrite_zeroes(bs
, offset
, bytes
, flags
);
1946 } else if (flags
& BDRV_REQ_WRITE_COMPRESSED
) {
1947 ret
= bdrv_driver_pwritev_compressed(bs
, offset
, bytes
,
1949 } else if (bytes
<= max_transfer
) {
1950 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV
);
1951 ret
= bdrv_driver_pwritev(bs
, offset
, bytes
, qiov
, qiov_offset
, flags
);
1953 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV
);
1954 while (bytes_remaining
) {
1955 int num
= MIN(bytes_remaining
, max_transfer
);
1956 int local_flags
= flags
;
1959 if (num
< bytes_remaining
&& (flags
& BDRV_REQ_FUA
) &&
1960 !(bs
->supported_write_flags
& BDRV_REQ_FUA
)) {
1961 /* If FUA is going to be emulated by flush, we only
1962 * need to flush on the last iteration */
1963 local_flags
&= ~BDRV_REQ_FUA
;
1966 ret
= bdrv_driver_pwritev(bs
, offset
+ bytes
- bytes_remaining
,
1968 qiov_offset
+ bytes
- bytes_remaining
,
1973 bytes_remaining
-= num
;
1976 bdrv_co_debug_event(bs
, BLKDBG_PWRITEV_DONE
);
1981 bdrv_co_write_req_finish(child
, offset
, bytes
, req
, ret
);
1986 static int coroutine_fn GRAPH_RDLOCK
1987 bdrv_co_do_zero_pwritev(BdrvChild
*child
, int64_t offset
, int64_t bytes
,
1988 BdrvRequestFlags flags
, BdrvTrackedRequest
*req
)
1990 BlockDriverState
*bs
= child
->bs
;
1991 QEMUIOVector local_qiov
;
1992 uint64_t align
= bs
->bl
.request_alignment
;
1995 BdrvRequestPadding pad
;
1997 /* This flag doesn't make sense for padding or zero writes */
1998 flags
&= ~BDRV_REQ_REGISTERED_BUF
;
2000 padding
= bdrv_init_padding(bs
, offset
, bytes
, &pad
);
2002 assert(!(flags
& BDRV_REQ_NO_WAIT
));
2003 bdrv_make_request_serialising(req
, align
);
2005 bdrv_padding_rmw_read(child
, req
, &pad
, true);
2007 if (pad
.head
|| pad
.merge_reads
) {
2008 int64_t aligned_offset
= offset
& ~(align
- 1);
2009 int64_t write_bytes
= pad
.merge_reads
? pad
.buf_len
: align
;
2011 qemu_iovec_init_buf(&local_qiov
, pad
.buf
, write_bytes
);
2012 ret
= bdrv_aligned_pwritev(child
, req
, aligned_offset
, write_bytes
,
2013 align
, &local_qiov
, 0,
2014 flags
& ~BDRV_REQ_ZERO_WRITE
);
2015 if (ret
< 0 || pad
.merge_reads
) {
2016 /* Error or all work is done */
2019 offset
+= write_bytes
- pad
.head
;
2020 bytes
-= write_bytes
- pad
.head
;
2024 assert(!bytes
|| (offset
& (align
- 1)) == 0);
2025 if (bytes
>= align
) {
2026 /* Write the aligned part in the middle. */
2027 int64_t aligned_bytes
= bytes
& ~(align
- 1);
2028 ret
= bdrv_aligned_pwritev(child
, req
, offset
, aligned_bytes
, align
,
2033 bytes
-= aligned_bytes
;
2034 offset
+= aligned_bytes
;
2037 assert(!bytes
|| (offset
& (align
- 1)) == 0);
2039 assert(align
== pad
.tail
+ bytes
);
2041 qemu_iovec_init_buf(&local_qiov
, pad
.tail_buf
, align
);
2042 ret
= bdrv_aligned_pwritev(child
, req
, offset
, align
, align
,
2044 flags
& ~BDRV_REQ_ZERO_WRITE
);
2048 bdrv_padding_destroy(&pad
);
2054 * Handle a write request in coroutine context
2056 int coroutine_fn
bdrv_co_pwritev(BdrvChild
*child
,
2057 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
,
2058 BdrvRequestFlags flags
)
2061 return bdrv_co_pwritev_part(child
, offset
, bytes
, qiov
, 0, flags
);
2064 int coroutine_fn
bdrv_co_pwritev_part(BdrvChild
*child
,
2065 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
, size_t qiov_offset
,
2066 BdrvRequestFlags flags
)
2068 BlockDriverState
*bs
= child
->bs
;
2069 BdrvTrackedRequest req
;
2070 uint64_t align
= bs
->bl
.request_alignment
;
2071 BdrvRequestPadding pad
;
2073 bool padded
= false;
2076 assume_graph_lock(); /* FIXME */
2078 trace_bdrv_co_pwritev_part(child
->bs
, offset
, bytes
, flags
);
2080 if (!bdrv_co_is_inserted(bs
)) {
2084 if (flags
& BDRV_REQ_ZERO_WRITE
) {
2085 ret
= bdrv_check_qiov_request(offset
, bytes
, qiov
, qiov_offset
, NULL
);
2087 ret
= bdrv_check_request32(offset
, bytes
, qiov
, qiov_offset
);
2093 /* If the request is misaligned then we can't make it efficient */
2094 if ((flags
& BDRV_REQ_NO_FALLBACK
) &&
2095 !QEMU_IS_ALIGNED(offset
| bytes
, align
))
2100 if (bytes
== 0 && !QEMU_IS_ALIGNED(offset
, bs
->bl
.request_alignment
)) {
2102 * Aligning zero request is nonsense. Even if driver has special meaning
2103 * of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
2104 * it to driver due to request_alignment.
2106 * Still, no reason to return an error if someone do unaligned
2107 * zero-length write occasionally.
2112 if (!(flags
& BDRV_REQ_ZERO_WRITE
)) {
2114 * Pad request for following read-modify-write cycle.
2115 * bdrv_co_do_zero_pwritev() does aligning by itself, so, we do
2116 * alignment only if there is no ZERO flag.
2118 ret
= bdrv_pad_request(bs
, &qiov
, &qiov_offset
, &offset
, &bytes
, &pad
,
2125 bdrv_inc_in_flight(bs
);
2126 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_WRITE
);
2128 if (flags
& BDRV_REQ_ZERO_WRITE
) {
2130 ret
= bdrv_co_do_zero_pwritev(child
, offset
, bytes
, flags
, &req
);
2136 * Request was unaligned to request_alignment and therefore
2137 * padded. We are going to do read-modify-write, and must
2138 * serialize the request to prevent interactions of the
2139 * widened region with other transactions.
2141 assert(!(flags
& BDRV_REQ_NO_WAIT
));
2142 bdrv_make_request_serialising(&req
, align
);
2143 bdrv_padding_rmw_read(child
, &req
, &pad
, false);
2146 ret
= bdrv_aligned_pwritev(child
, &req
, offset
, bytes
, align
,
2147 qiov
, qiov_offset
, flags
);
2149 bdrv_padding_destroy(&pad
);
2152 tracked_request_end(&req
);
2153 bdrv_dec_in_flight(bs
);
2158 int coroutine_fn
bdrv_co_pwrite_zeroes(BdrvChild
*child
, int64_t offset
,
2159 int64_t bytes
, BdrvRequestFlags flags
)
2162 trace_bdrv_co_pwrite_zeroes(child
->bs
, offset
, bytes
, flags
);
2163 assert_bdrv_graph_readable();
2165 if (!(child
->bs
->open_flags
& BDRV_O_UNMAP
)) {
2166 flags
&= ~BDRV_REQ_MAY_UNMAP
;
2169 return bdrv_co_pwritev(child
, offset
, bytes
, NULL
,
2170 BDRV_REQ_ZERO_WRITE
| flags
);
2174 * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not.
2176 int bdrv_flush_all(void)
2178 BdrvNextIterator it
;
2179 BlockDriverState
*bs
= NULL
;
2182 GLOBAL_STATE_CODE();
2185 * bdrv queue is managed by record/replay,
2186 * creating new flush request for stopping
2187 * the VM may break the determinism
2189 if (replay_events_enabled()) {
2193 for (bs
= bdrv_first(&it
); bs
; bs
= bdrv_next(&it
)) {
2194 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
2197 aio_context_acquire(aio_context
);
2198 ret
= bdrv_flush(bs
);
2199 if (ret
< 0 && !result
) {
2202 aio_context_release(aio_context
);
2209 * Returns the allocation status of the specified sectors.
2210 * Drivers not implementing the functionality are assumed to not support
2211 * backing files, hence all their sectors are reported as allocated.
2213 * If 'want_zero' is true, the caller is querying for mapping
2214 * purposes, with a focus on valid BDRV_BLOCK_OFFSET_VALID, _DATA, and
2215 * _ZERO where possible; otherwise, the result favors larger 'pnum',
2216 * with a focus on accurate BDRV_BLOCK_ALLOCATED.
2218 * If 'offset' is beyond the end of the disk image the return value is
2219 * BDRV_BLOCK_EOF and 'pnum' is set to 0.
2221 * 'bytes' is the max value 'pnum' should be set to. If bytes goes
2222 * beyond the end of the disk image it will be clamped; if 'pnum' is set to
2223 * the end of the image, then the returned value will include BDRV_BLOCK_EOF.
2225 * 'pnum' is set to the number of bytes (including and immediately
2226 * following the specified offset) that are easily known to be in the
2227 * same allocated/unallocated state. Note that a second call starting
2228 * at the original offset plus returned pnum may have the same status.
2229 * The returned value is non-zero on success except at end-of-file.
2231 * Returns negative errno on failure. Otherwise, if the
2232 * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are
2233 * set to the host mapping and BDS corresponding to the guest offset.
2235 static int coroutine_fn GRAPH_RDLOCK
2236 bdrv_co_block_status(BlockDriverState
*bs
, bool want_zero
,
2237 int64_t offset
, int64_t bytes
,
2238 int64_t *pnum
, int64_t *map
, BlockDriverState
**file
)
2241 int64_t n
; /* bytes */
2243 int64_t local_map
= 0;
2244 BlockDriverState
*local_file
= NULL
;
2245 int64_t aligned_offset
, aligned_bytes
;
2247 bool has_filtered_child
;
2250 assert_bdrv_graph_readable();
2252 total_size
= bdrv_getlength(bs
);
2253 if (total_size
< 0) {
2258 if (offset
>= total_size
) {
2259 ret
= BDRV_BLOCK_EOF
;
2267 n
= total_size
- offset
;
2272 /* Must be non-NULL or bdrv_getlength() would have failed */
2274 has_filtered_child
= bdrv_filter_child(bs
);
2275 if (!bs
->drv
->bdrv_co_block_status
&& !has_filtered_child
) {
2277 ret
= BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
;
2278 if (offset
+ bytes
== total_size
) {
2279 ret
|= BDRV_BLOCK_EOF
;
2281 if (bs
->drv
->protocol_name
) {
2282 ret
|= BDRV_BLOCK_OFFSET_VALID
;
2289 bdrv_inc_in_flight(bs
);
2291 /* Round out to request_alignment boundaries */
2292 align
= bs
->bl
.request_alignment
;
2293 aligned_offset
= QEMU_ALIGN_DOWN(offset
, align
);
2294 aligned_bytes
= ROUND_UP(offset
+ bytes
, align
) - aligned_offset
;
2296 if (bs
->drv
->bdrv_co_block_status
) {
2298 * Use the block-status cache only for protocol nodes: Format
2299 * drivers are generally quick to inquire the status, but protocol
2300 * drivers often need to get information from outside of qemu, so
2301 * we do not have control over the actual implementation. There
2302 * have been cases where inquiring the status took an unreasonably
2303 * long time, and we can do nothing in qemu to fix it.
2304 * This is especially problematic for images with large data areas,
2305 * because finding the few holes in them and giving them special
2306 * treatment does not gain much performance. Therefore, we try to
2307 * cache the last-identified data region.
2309 * Second, limiting ourselves to protocol nodes allows us to assume
2310 * the block status for data regions to be DATA | OFFSET_VALID, and
2311 * that the host offset is the same as the guest offset.
2313 * Note that it is possible that external writers zero parts of
2314 * the cached regions without the cache being invalidated, and so
2315 * we may report zeroes as data. This is not catastrophic,
2316 * however, because reporting zeroes as data is fine.
2318 if (QLIST_EMPTY(&bs
->children
) &&
2319 bdrv_bsc_is_data(bs
, aligned_offset
, pnum
))
2321 ret
= BDRV_BLOCK_DATA
| BDRV_BLOCK_OFFSET_VALID
;
2323 local_map
= aligned_offset
;
2325 ret
= bs
->drv
->bdrv_co_block_status(bs
, want_zero
, aligned_offset
,
2326 aligned_bytes
, pnum
, &local_map
,
2330 * Note that checking QLIST_EMPTY(&bs->children) is also done when
2331 * the cache is queried above. Technically, we do not need to check
2332 * it here; the worst that can happen is that we fill the cache for
2333 * non-protocol nodes, and then it is never used. However, filling
2334 * the cache requires an RCU update, so double check here to avoid
2335 * such an update if possible.
2337 * Check want_zero, because we only want to update the cache when we
2338 * have accurate information about what is zero and what is data.
2341 ret
== (BDRV_BLOCK_DATA
| BDRV_BLOCK_OFFSET_VALID
) &&
2342 QLIST_EMPTY(&bs
->children
))
2345 * When a protocol driver reports BLOCK_OFFSET_VALID, the
2346 * returned local_map value must be the same as the offset we
2347 * have passed (aligned_offset), and local_bs must be the node
2349 * Assert this, because we follow this rule when reading from
2350 * the cache (see the `local_file = bs` and
2351 * `local_map = aligned_offset` assignments above), and the
2352 * result the cache delivers must be the same as the driver
2355 assert(local_file
== bs
);
2356 assert(local_map
== aligned_offset
);
2357 bdrv_bsc_fill(bs
, aligned_offset
, *pnum
);
2361 /* Default code for filters */
2363 local_file
= bdrv_filter_bs(bs
);
2366 *pnum
= aligned_bytes
;
2367 local_map
= aligned_offset
;
2368 ret
= BDRV_BLOCK_RAW
| BDRV_BLOCK_OFFSET_VALID
;
2376 * The driver's result must be a non-zero multiple of request_alignment.
2377 * Clamp pnum and adjust map to original request.
2379 assert(*pnum
&& QEMU_IS_ALIGNED(*pnum
, align
) &&
2380 align
> offset
- aligned_offset
);
2381 if (ret
& BDRV_BLOCK_RECURSE
) {
2382 assert(ret
& BDRV_BLOCK_DATA
);
2383 assert(ret
& BDRV_BLOCK_OFFSET_VALID
);
2384 assert(!(ret
& BDRV_BLOCK_ZERO
));
2387 *pnum
-= offset
- aligned_offset
;
2388 if (*pnum
> bytes
) {
2391 if (ret
& BDRV_BLOCK_OFFSET_VALID
) {
2392 local_map
+= offset
- aligned_offset
;
2395 if (ret
& BDRV_BLOCK_RAW
) {
2396 assert(ret
& BDRV_BLOCK_OFFSET_VALID
&& local_file
);
2397 ret
= bdrv_co_block_status(local_file
, want_zero
, local_map
,
2398 *pnum
, pnum
, &local_map
, &local_file
);
2402 if (ret
& (BDRV_BLOCK_DATA
| BDRV_BLOCK_ZERO
)) {
2403 ret
|= BDRV_BLOCK_ALLOCATED
;
2404 } else if (bs
->drv
->supports_backing
) {
2405 BlockDriverState
*cow_bs
= bdrv_cow_bs(bs
);
2408 ret
|= BDRV_BLOCK_ZERO
;
2409 } else if (want_zero
) {
2410 int64_t size2
= bdrv_getlength(cow_bs
);
2412 if (size2
>= 0 && offset
>= size2
) {
2413 ret
|= BDRV_BLOCK_ZERO
;
2418 if (want_zero
&& ret
& BDRV_BLOCK_RECURSE
&&
2419 local_file
&& local_file
!= bs
&&
2420 (ret
& BDRV_BLOCK_DATA
) && !(ret
& BDRV_BLOCK_ZERO
) &&
2421 (ret
& BDRV_BLOCK_OFFSET_VALID
)) {
2425 ret2
= bdrv_co_block_status(local_file
, want_zero
, local_map
,
2426 *pnum
, &file_pnum
, NULL
, NULL
);
2428 /* Ignore errors. This is just providing extra information, it
2429 * is useful but not necessary.
2431 if (ret2
& BDRV_BLOCK_EOF
&&
2432 (!file_pnum
|| ret2
& BDRV_BLOCK_ZERO
)) {
2434 * It is valid for the format block driver to read
2435 * beyond the end of the underlying file's current
2436 * size; such areas read as zero.
2438 ret
|= BDRV_BLOCK_ZERO
;
2440 /* Limit request to the range reported by the protocol driver */
2442 ret
|= (ret2
& BDRV_BLOCK_ZERO
);
2448 bdrv_dec_in_flight(bs
);
2449 if (ret
>= 0 && offset
+ *pnum
== total_size
) {
2450 ret
|= BDRV_BLOCK_EOF
;
2463 bdrv_co_common_block_status_above(BlockDriverState
*bs
,
2464 BlockDriverState
*base
,
2471 BlockDriverState
**file
,
2475 BlockDriverState
*p
;
2480 assert(!include_base
|| base
); /* Can't include NULL base */
2481 assert_bdrv_graph_readable();
2488 if (!include_base
&& bs
== base
) {
2493 ret
= bdrv_co_block_status(bs
, want_zero
, offset
, bytes
, pnum
, map
, file
);
2495 if (ret
< 0 || *pnum
== 0 || ret
& BDRV_BLOCK_ALLOCATED
|| bs
== base
) {
2499 if (ret
& BDRV_BLOCK_EOF
) {
2500 eof
= offset
+ *pnum
;
2503 assert(*pnum
<= bytes
);
2506 for (p
= bdrv_filter_or_cow_bs(bs
); include_base
|| p
!= base
;
2507 p
= bdrv_filter_or_cow_bs(p
))
2509 ret
= bdrv_co_block_status(p
, want_zero
, offset
, bytes
, pnum
, map
,
2517 * The top layer deferred to this layer, and because this layer is
2518 * short, any zeroes that we synthesize beyond EOF behave as if they
2519 * were allocated at this layer.
2521 * We don't include BDRV_BLOCK_EOF into ret, as upper layer may be
2522 * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
2525 assert(ret
& BDRV_BLOCK_EOF
);
2530 ret
= BDRV_BLOCK_ZERO
| BDRV_BLOCK_ALLOCATED
;
2533 if (ret
& BDRV_BLOCK_ALLOCATED
) {
2535 * We've found the node and the status, we must break.
2537 * Drop BDRV_BLOCK_EOF, as it's not for upper layer, which may be
2538 * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
2541 ret
&= ~BDRV_BLOCK_EOF
;
2546 assert(include_base
);
2551 * OK, [offset, offset + *pnum) region is unallocated on this layer,
2552 * let's continue the diving.
2554 assert(*pnum
<= bytes
);
2558 if (offset
+ *pnum
== eof
) {
2559 ret
|= BDRV_BLOCK_EOF
;
2565 int coroutine_fn
bdrv_co_block_status_above(BlockDriverState
*bs
,
2566 BlockDriverState
*base
,
2567 int64_t offset
, int64_t bytes
,
2568 int64_t *pnum
, int64_t *map
,
2569 BlockDriverState
**file
)
2572 return bdrv_co_common_block_status_above(bs
, base
, false, true, offset
,
2573 bytes
, pnum
, map
, file
, NULL
);
2576 int bdrv_block_status_above(BlockDriverState
*bs
, BlockDriverState
*base
,
2577 int64_t offset
, int64_t bytes
, int64_t *pnum
,
2578 int64_t *map
, BlockDriverState
**file
)
2581 return bdrv_common_block_status_above(bs
, base
, false, true, offset
, bytes
,
2582 pnum
, map
, file
, NULL
);
2585 int bdrv_block_status(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
2586 int64_t *pnum
, int64_t *map
, BlockDriverState
**file
)
2589 return bdrv_block_status_above(bs
, bdrv_filter_or_cow_bs(bs
),
2590 offset
, bytes
, pnum
, map
, file
);
2594 * Check @bs (and its backing chain) to see if the range defined
2595 * by @offset and @bytes is known to read as zeroes.
2596 * Return 1 if that is the case, 0 otherwise and -errno on error.
2597 * This test is meant to be fast rather than accurate so returning 0
2598 * does not guarantee non-zero data.
2600 int coroutine_fn
bdrv_co_is_zero_fast(BlockDriverState
*bs
, int64_t offset
,
2604 int64_t pnum
= bytes
;
2611 ret
= bdrv_co_common_block_status_above(bs
, NULL
, false, false, offset
,
2612 bytes
, &pnum
, NULL
, NULL
, NULL
);
2618 return (pnum
== bytes
) && (ret
& BDRV_BLOCK_ZERO
);
2621 int coroutine_fn
bdrv_co_is_allocated(BlockDriverState
*bs
, int64_t offset
,
2622 int64_t bytes
, int64_t *pnum
)
2628 ret
= bdrv_co_common_block_status_above(bs
, bs
, true, false, offset
,
2629 bytes
, pnum
? pnum
: &dummy
, NULL
,
2634 return !!(ret
& BDRV_BLOCK_ALLOCATED
);
2637 int bdrv_is_allocated(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
,
2644 ret
= bdrv_common_block_status_above(bs
, bs
, true, false, offset
,
2645 bytes
, pnum
? pnum
: &dummy
, NULL
,
2650 return !!(ret
& BDRV_BLOCK_ALLOCATED
);
2653 /* See bdrv_is_allocated_above for documentation */
2654 int coroutine_fn
bdrv_co_is_allocated_above(BlockDriverState
*top
,
2655 BlockDriverState
*base
,
2656 bool include_base
, int64_t offset
,
2657 int64_t bytes
, int64_t *pnum
)
2663 ret
= bdrv_co_common_block_status_above(top
, base
, include_base
, false,
2664 offset
, bytes
, pnum
, NULL
, NULL
,
2670 if (ret
& BDRV_BLOCK_ALLOCATED
) {
2677 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
2679 * Return a positive depth if (a prefix of) the given range is allocated
2680 * in any image between BASE and TOP (BASE is only included if include_base
2681 * is set). Depth 1 is TOP, 2 is the first backing layer, and so forth.
2682 * BASE can be NULL to check if the given offset is allocated in any
2683 * image of the chain. Return 0 otherwise, or negative errno on
2686 * 'pnum' is set to the number of bytes (including and immediately
2687 * following the specified offset) that are known to be in the same
2688 * allocated/unallocated state. Note that a subsequent call starting
2689 * at 'offset + *pnum' may return the same allocation status (in other
2690 * words, the result is not necessarily the maximum possible range);
2691 * but 'pnum' will only be 0 when end of file is reached.
2693 int bdrv_is_allocated_above(BlockDriverState
*top
,
2694 BlockDriverState
*base
,
2695 bool include_base
, int64_t offset
,
2696 int64_t bytes
, int64_t *pnum
)
2702 ret
= bdrv_common_block_status_above(top
, base
, include_base
, false,
2703 offset
, bytes
, pnum
, NULL
, NULL
,
2709 if (ret
& BDRV_BLOCK_ALLOCATED
) {
2716 bdrv_co_readv_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
)
2718 BlockDriver
*drv
= bs
->drv
;
2719 BlockDriverState
*child_bs
= bdrv_primary_bs(bs
);
2722 assert_bdrv_graph_readable();
2724 ret
= bdrv_check_qiov_request(pos
, qiov
->size
, qiov
, 0, NULL
);
2733 bdrv_inc_in_flight(bs
);
2735 if (drv
->bdrv_co_load_vmstate
) {
2736 ret
= drv
->bdrv_co_load_vmstate(bs
, qiov
, pos
);
2737 } else if (child_bs
) {
2738 ret
= bdrv_co_readv_vmstate(child_bs
, qiov
, pos
);
2743 bdrv_dec_in_flight(bs
);
2749 bdrv_co_writev_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
)
2751 BlockDriver
*drv
= bs
->drv
;
2752 BlockDriverState
*child_bs
= bdrv_primary_bs(bs
);
2755 assert_bdrv_graph_readable();
2757 ret
= bdrv_check_qiov_request(pos
, qiov
->size
, qiov
, 0, NULL
);
2766 bdrv_inc_in_flight(bs
);
2768 if (drv
->bdrv_co_save_vmstate
) {
2769 ret
= drv
->bdrv_co_save_vmstate(bs
, qiov
, pos
);
2770 } else if (child_bs
) {
2771 ret
= bdrv_co_writev_vmstate(child_bs
, qiov
, pos
);
2776 bdrv_dec_in_flight(bs
);
2781 int bdrv_save_vmstate(BlockDriverState
*bs
, const uint8_t *buf
,
2782 int64_t pos
, int size
)
2784 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, size
);
2785 int ret
= bdrv_writev_vmstate(bs
, &qiov
, pos
);
2788 return ret
< 0 ? ret
: size
;
2791 int bdrv_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
2792 int64_t pos
, int size
)
2794 QEMUIOVector qiov
= QEMU_IOVEC_INIT_BUF(qiov
, buf
, size
);
2795 int ret
= bdrv_readv_vmstate(bs
, &qiov
, pos
);
2798 return ret
< 0 ? ret
: size
;
2801 /**************************************************************/
2804 void bdrv_aio_cancel(BlockAIOCB
*acb
)
2808 bdrv_aio_cancel_async(acb
);
2809 while (acb
->refcnt
> 1) {
2810 if (acb
->aiocb_info
->get_aio_context
) {
2811 aio_poll(acb
->aiocb_info
->get_aio_context(acb
), true);
2812 } else if (acb
->bs
) {
2813 /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
2814 * assert that we're not using an I/O thread. Thread-safe
2815 * code should use bdrv_aio_cancel_async exclusively.
2817 assert(bdrv_get_aio_context(acb
->bs
) == qemu_get_aio_context());
2818 aio_poll(bdrv_get_aio_context(acb
->bs
), true);
2823 qemu_aio_unref(acb
);
2826 /* Async version of aio cancel. The caller is not blocked if the acb implements
2827 * cancel_async, otherwise we do nothing and let the request normally complete.
2828 * In either case the completion callback must be called. */
2829 void bdrv_aio_cancel_async(BlockAIOCB
*acb
)
2832 if (acb
->aiocb_info
->cancel_async
) {
2833 acb
->aiocb_info
->cancel_async(acb
);
2837 /**************************************************************/
2838 /* Coroutine block device emulation */
2840 int coroutine_fn
bdrv_co_flush(BlockDriverState
*bs
)
2842 BdrvChild
*primary_child
= bdrv_primary_child(bs
);
2848 assert_bdrv_graph_readable();
2849 bdrv_inc_in_flight(bs
);
2851 if (!bdrv_co_is_inserted(bs
) || bdrv_is_read_only(bs
) ||
2856 qemu_co_mutex_lock(&bs
->reqs_lock
);
2857 current_gen
= qatomic_read(&bs
->write_gen
);
2859 /* Wait until any previous flushes are completed */
2860 while (bs
->active_flush_req
) {
2861 qemu_co_queue_wait(&bs
->flush_queue
, &bs
->reqs_lock
);
2864 /* Flushes reach this point in nondecreasing current_gen order. */
2865 bs
->active_flush_req
= true;
2866 qemu_co_mutex_unlock(&bs
->reqs_lock
);
2868 /* Write back all layers by calling one driver function */
2869 if (bs
->drv
->bdrv_co_flush
) {
2870 ret
= bs
->drv
->bdrv_co_flush(bs
);
2874 /* Write back cached data to the OS even with cache=unsafe */
2875 BLKDBG_EVENT(primary_child
, BLKDBG_FLUSH_TO_OS
);
2876 if (bs
->drv
->bdrv_co_flush_to_os
) {
2877 ret
= bs
->drv
->bdrv_co_flush_to_os(bs
);
2883 /* But don't actually force it to the disk with cache=unsafe */
2884 if (bs
->open_flags
& BDRV_O_NO_FLUSH
) {
2885 goto flush_children
;
2888 /* Check if we really need to flush anything */
2889 if (bs
->flushed_gen
== current_gen
) {
2890 goto flush_children
;
2893 BLKDBG_EVENT(primary_child
, BLKDBG_FLUSH_TO_DISK
);
2895 /* bs->drv->bdrv_co_flush() might have ejected the BDS
2896 * (even in case of apparent success) */
2900 if (bs
->drv
->bdrv_co_flush_to_disk
) {
2901 ret
= bs
->drv
->bdrv_co_flush_to_disk(bs
);
2902 } else if (bs
->drv
->bdrv_aio_flush
) {
2904 CoroutineIOCompletion co
= {
2905 .coroutine
= qemu_coroutine_self(),
2908 acb
= bs
->drv
->bdrv_aio_flush(bs
, bdrv_co_io_em_complete
, &co
);
2912 qemu_coroutine_yield();
2917 * Some block drivers always operate in either writethrough or unsafe
2918 * mode and don't support bdrv_flush therefore. Usually qemu doesn't
2919 * know how the server works (because the behaviour is hardcoded or
2920 * depends on server-side configuration), so we can't ensure that
2921 * everything is safe on disk. Returning an error doesn't work because
2922 * that would break guests even if the server operates in writethrough
2925 * Let's hope the user knows what he's doing.
2934 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH
2935 * in the case of cache=unsafe, so there are no useless flushes.
2939 QLIST_FOREACH(child
, &bs
->children
, next
) {
2940 if (child
->perm
& (BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
)) {
2941 int this_child_ret
= bdrv_co_flush(child
->bs
);
2943 ret
= this_child_ret
;
2949 /* Notify any pending flushes that we have completed */
2951 bs
->flushed_gen
= current_gen
;
2954 qemu_co_mutex_lock(&bs
->reqs_lock
);
2955 bs
->active_flush_req
= false;
2956 /* Return value is ignored - it's ok if wait queue is empty */
2957 qemu_co_queue_next(&bs
->flush_queue
);
2958 qemu_co_mutex_unlock(&bs
->reqs_lock
);
2961 bdrv_dec_in_flight(bs
);
2965 int coroutine_fn
bdrv_co_pdiscard(BdrvChild
*child
, int64_t offset
,
2968 BdrvTrackedRequest req
;
2970 int64_t max_pdiscard
;
2971 int head
, tail
, align
;
2972 BlockDriverState
*bs
= child
->bs
;
2974 assert_bdrv_graph_readable();
2976 if (!bs
|| !bs
->drv
|| !bdrv_co_is_inserted(bs
)) {
2980 if (bdrv_has_readonly_bitmaps(bs
)) {
2984 ret
= bdrv_check_request(offset
, bytes
, NULL
);
2989 /* Do nothing if disabled. */
2990 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
2994 if (!bs
->drv
->bdrv_co_pdiscard
&& !bs
->drv
->bdrv_aio_pdiscard
) {
2998 /* Invalidate the cached block-status data range if this discard overlaps */
2999 bdrv_bsc_invalidate_range(bs
, offset
, bytes
);
3001 /* Discard is advisory, but some devices track and coalesce
3002 * unaligned requests, so we must pass everything down rather than
3003 * round here. Still, most devices will just silently ignore
3004 * unaligned requests (by returning -ENOTSUP), so we must fragment
3005 * the request accordingly. */
3006 align
= MAX(bs
->bl
.pdiscard_alignment
, bs
->bl
.request_alignment
);
3007 assert(align
% bs
->bl
.request_alignment
== 0);
3008 head
= offset
% align
;
3009 tail
= (offset
+ bytes
) % align
;
3011 bdrv_inc_in_flight(bs
);
3012 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_DISCARD
);
3014 ret
= bdrv_co_write_req_prepare(child
, offset
, bytes
, &req
, 0);
3019 max_pdiscard
= QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs
->bl
.max_pdiscard
, INT64_MAX
),
3021 assert(max_pdiscard
>= bs
->bl
.request_alignment
);
3024 int64_t num
= bytes
;
3027 /* Make small requests to get to alignment boundaries. */
3028 num
= MIN(bytes
, align
- head
);
3029 if (!QEMU_IS_ALIGNED(num
, bs
->bl
.request_alignment
)) {
3030 num
%= bs
->bl
.request_alignment
;
3032 head
= (head
+ num
) % align
;
3033 assert(num
< max_pdiscard
);
3036 /* Shorten the request to the last aligned cluster. */
3038 } else if (!QEMU_IS_ALIGNED(tail
, bs
->bl
.request_alignment
) &&
3039 tail
> bs
->bl
.request_alignment
) {
3040 tail
%= bs
->bl
.request_alignment
;
3044 /* limit request size */
3045 if (num
> max_pdiscard
) {
3053 if (bs
->drv
->bdrv_co_pdiscard
) {
3054 ret
= bs
->drv
->bdrv_co_pdiscard(bs
, offset
, num
);
3057 CoroutineIOCompletion co
= {
3058 .coroutine
= qemu_coroutine_self(),
3061 acb
= bs
->drv
->bdrv_aio_pdiscard(bs
, offset
, num
,
3062 bdrv_co_io_em_complete
, &co
);
3067 qemu_coroutine_yield();
3071 if (ret
&& ret
!= -ENOTSUP
) {
3080 bdrv_co_write_req_finish(child
, req
.offset
, req
.bytes
, &req
, ret
);
3081 tracked_request_end(&req
);
3082 bdrv_dec_in_flight(bs
);
3086 int coroutine_fn
bdrv_co_ioctl(BlockDriverState
*bs
, int req
, void *buf
)
3088 BlockDriver
*drv
= bs
->drv
;
3089 CoroutineIOCompletion co
= {
3090 .coroutine
= qemu_coroutine_self(),
3094 assert_bdrv_graph_readable();
3096 bdrv_inc_in_flight(bs
);
3097 if (!drv
|| (!drv
->bdrv_aio_ioctl
&& !drv
->bdrv_co_ioctl
)) {
3102 if (drv
->bdrv_co_ioctl
) {
3103 co
.ret
= drv
->bdrv_co_ioctl(bs
, req
, buf
);
3105 acb
= drv
->bdrv_aio_ioctl(bs
, req
, buf
, bdrv_co_io_em_complete
, &co
);
3110 qemu_coroutine_yield();
3113 bdrv_dec_in_flight(bs
);
3117 void *qemu_blockalign(BlockDriverState
*bs
, size_t size
)
3120 return qemu_memalign(bdrv_opt_mem_align(bs
), size
);
3123 void *qemu_blockalign0(BlockDriverState
*bs
, size_t size
)
3126 return memset(qemu_blockalign(bs
, size
), 0, size
);
3129 void *qemu_try_blockalign(BlockDriverState
*bs
, size_t size
)
3131 size_t align
= bdrv_opt_mem_align(bs
);
3134 /* Ensure that NULL is never returned on success */
3140 return qemu_try_memalign(align
, size
);
3143 void *qemu_try_blockalign0(BlockDriverState
*bs
, size_t size
)
3145 void *mem
= qemu_try_blockalign(bs
, size
);
3149 memset(mem
, 0, size
);
3155 void coroutine_fn
bdrv_co_io_plug(BlockDriverState
*bs
)
3160 QLIST_FOREACH(child
, &bs
->children
, next
) {
3161 bdrv_co_io_plug(child
->bs
);
3164 if (qatomic_fetch_inc(&bs
->io_plugged
) == 0) {
3165 BlockDriver
*drv
= bs
->drv
;
3166 if (drv
&& drv
->bdrv_co_io_plug
) {
3167 drv
->bdrv_co_io_plug(bs
);
3172 void coroutine_fn
bdrv_co_io_unplug(BlockDriverState
*bs
)
3177 assert(bs
->io_plugged
);
3178 if (qatomic_fetch_dec(&bs
->io_plugged
) == 1) {
3179 BlockDriver
*drv
= bs
->drv
;
3180 if (drv
&& drv
->bdrv_co_io_unplug
) {
3181 drv
->bdrv_co_io_unplug(bs
);
3185 QLIST_FOREACH(child
, &bs
->children
, next
) {
3186 bdrv_co_io_unplug(child
->bs
);
3190 /* Helper that undoes bdrv_register_buf() when it fails partway through */
3191 static void bdrv_register_buf_rollback(BlockDriverState
*bs
,
3194 BdrvChild
*final_child
)
3198 QLIST_FOREACH(child
, &bs
->children
, next
) {
3199 if (child
== final_child
) {
3203 bdrv_unregister_buf(child
->bs
, host
, size
);
3206 if (bs
->drv
&& bs
->drv
->bdrv_unregister_buf
) {
3207 bs
->drv
->bdrv_unregister_buf(bs
, host
, size
);
3211 bool bdrv_register_buf(BlockDriverState
*bs
, void *host
, size_t size
,
3216 GLOBAL_STATE_CODE();
3217 if (bs
->drv
&& bs
->drv
->bdrv_register_buf
) {
3218 if (!bs
->drv
->bdrv_register_buf(bs
, host
, size
, errp
)) {
3222 QLIST_FOREACH(child
, &bs
->children
, next
) {
3223 if (!bdrv_register_buf(child
->bs
, host
, size
, errp
)) {
3224 bdrv_register_buf_rollback(bs
, host
, size
, child
);
3231 void bdrv_unregister_buf(BlockDriverState
*bs
, void *host
, size_t size
)
3235 GLOBAL_STATE_CODE();
3236 if (bs
->drv
&& bs
->drv
->bdrv_unregister_buf
) {
3237 bs
->drv
->bdrv_unregister_buf(bs
, host
, size
);
3239 QLIST_FOREACH(child
, &bs
->children
, next
) {
3240 bdrv_unregister_buf(child
->bs
, host
, size
);
3244 static int coroutine_fn GRAPH_RDLOCK
bdrv_co_copy_range_internal(
3245 BdrvChild
*src
, int64_t src_offset
, BdrvChild
*dst
,
3246 int64_t dst_offset
, int64_t bytes
,
3247 BdrvRequestFlags read_flags
, BdrvRequestFlags write_flags
,
3250 BdrvTrackedRequest req
;
3253 /* TODO We can support BDRV_REQ_NO_FALLBACK here */
3254 assert(!(read_flags
& BDRV_REQ_NO_FALLBACK
));
3255 assert(!(write_flags
& BDRV_REQ_NO_FALLBACK
));
3256 assert(!(read_flags
& BDRV_REQ_NO_WAIT
));
3257 assert(!(write_flags
& BDRV_REQ_NO_WAIT
));
3259 if (!dst
|| !dst
->bs
|| !bdrv_co_is_inserted(dst
->bs
)) {
3262 ret
= bdrv_check_request32(dst_offset
, bytes
, NULL
, 0);
3266 if (write_flags
& BDRV_REQ_ZERO_WRITE
) {
3267 return bdrv_co_pwrite_zeroes(dst
, dst_offset
, bytes
, write_flags
);
3270 if (!src
|| !src
->bs
|| !bdrv_co_is_inserted(src
->bs
)) {
3273 ret
= bdrv_check_request32(src_offset
, bytes
, NULL
, 0);
3278 if (!src
->bs
->drv
->bdrv_co_copy_range_from
3279 || !dst
->bs
->drv
->bdrv_co_copy_range_to
3280 || src
->bs
->encrypted
|| dst
->bs
->encrypted
) {
3285 bdrv_inc_in_flight(src
->bs
);
3286 tracked_request_begin(&req
, src
->bs
, src_offset
, bytes
,
3289 /* BDRV_REQ_SERIALISING is only for write operation */
3290 assert(!(read_flags
& BDRV_REQ_SERIALISING
));
3291 bdrv_wait_serialising_requests(&req
);
3293 ret
= src
->bs
->drv
->bdrv_co_copy_range_from(src
->bs
,
3297 read_flags
, write_flags
);
3299 tracked_request_end(&req
);
3300 bdrv_dec_in_flight(src
->bs
);
3302 bdrv_inc_in_flight(dst
->bs
);
3303 tracked_request_begin(&req
, dst
->bs
, dst_offset
, bytes
,
3304 BDRV_TRACKED_WRITE
);
3305 ret
= bdrv_co_write_req_prepare(dst
, dst_offset
, bytes
, &req
,
3308 ret
= dst
->bs
->drv
->bdrv_co_copy_range_to(dst
->bs
,
3312 read_flags
, write_flags
);
3314 bdrv_co_write_req_finish(dst
, dst_offset
, bytes
, &req
, ret
);
3315 tracked_request_end(&req
);
3316 bdrv_dec_in_flight(dst
->bs
);
3322 /* Copy range from @src to @dst.
3324 * See the comment of bdrv_co_copy_range for the parameter and return value
3326 int coroutine_fn
bdrv_co_copy_range_from(BdrvChild
*src
, int64_t src_offset
,
3327 BdrvChild
*dst
, int64_t dst_offset
,
3329 BdrvRequestFlags read_flags
,
3330 BdrvRequestFlags write_flags
)
3333 assume_graph_lock(); /* FIXME */
3334 trace_bdrv_co_copy_range_from(src
, src_offset
, dst
, dst_offset
, bytes
,
3335 read_flags
, write_flags
);
3336 return bdrv_co_copy_range_internal(src
, src_offset
, dst
, dst_offset
,
3337 bytes
, read_flags
, write_flags
, true);
3340 /* Copy range from @src to @dst.
3342 * See the comment of bdrv_co_copy_range for the parameter and return value
3344 int coroutine_fn
bdrv_co_copy_range_to(BdrvChild
*src
, int64_t src_offset
,
3345 BdrvChild
*dst
, int64_t dst_offset
,
3347 BdrvRequestFlags read_flags
,
3348 BdrvRequestFlags write_flags
)
3351 assume_graph_lock(); /* FIXME */
3352 trace_bdrv_co_copy_range_to(src
, src_offset
, dst
, dst_offset
, bytes
,
3353 read_flags
, write_flags
);
3354 return bdrv_co_copy_range_internal(src
, src_offset
, dst
, dst_offset
,
3355 bytes
, read_flags
, write_flags
, false);
3358 int coroutine_fn
bdrv_co_copy_range(BdrvChild
*src
, int64_t src_offset
,
3359 BdrvChild
*dst
, int64_t dst_offset
,
3360 int64_t bytes
, BdrvRequestFlags read_flags
,
3361 BdrvRequestFlags write_flags
)
3364 return bdrv_co_copy_range_from(src
, src_offset
,
3366 bytes
, read_flags
, write_flags
);
3369 static void bdrv_parent_cb_resize(BlockDriverState
*bs
)
3372 QLIST_FOREACH(c
, &bs
->parents
, next_parent
) {
3373 if (c
->klass
->resize
) {
3374 c
->klass
->resize(c
);
3380 * Truncate file to 'offset' bytes (needed only for file protocols)
3382 * If 'exact' is true, the file must be resized to exactly the given
3383 * 'offset'. Otherwise, it is sufficient for the node to be at least
3384 * 'offset' bytes in length.
3386 int coroutine_fn
bdrv_co_truncate(BdrvChild
*child
, int64_t offset
, bool exact
,
3387 PreallocMode prealloc
, BdrvRequestFlags flags
,
3390 BlockDriverState
*bs
= child
->bs
;
3391 BdrvChild
*filtered
, *backing
;
3392 BlockDriver
*drv
= bs
->drv
;
3393 BdrvTrackedRequest req
;
3394 int64_t old_size
, new_bytes
;
3397 assert_bdrv_graph_readable();
3399 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
3401 error_setg(errp
, "No medium inserted");
3405 error_setg(errp
, "Image size cannot be negative");
3409 ret
= bdrv_check_request(offset
, 0, errp
);
3414 old_size
= bdrv_getlength(bs
);
3416 error_setg_errno(errp
, -old_size
, "Failed to get old image size");
3420 if (bdrv_is_read_only(bs
)) {
3421 error_setg(errp
, "Image is read-only");
3425 if (offset
> old_size
) {
3426 new_bytes
= offset
- old_size
;
3431 bdrv_inc_in_flight(bs
);
3432 tracked_request_begin(&req
, bs
, offset
- new_bytes
, new_bytes
,
3433 BDRV_TRACKED_TRUNCATE
);
3435 /* If we are growing the image and potentially using preallocation for the
3436 * new area, we need to make sure that no write requests are made to it
3437 * concurrently or they might be overwritten by preallocation. */
3439 bdrv_make_request_serialising(&req
, 1);
3441 ret
= bdrv_co_write_req_prepare(child
, offset
- new_bytes
, new_bytes
, &req
,
3444 error_setg_errno(errp
, -ret
,
3445 "Failed to prepare request for truncation");
3449 filtered
= bdrv_filter_child(bs
);
3450 backing
= bdrv_cow_child(bs
);
3453 * If the image has a backing file that is large enough that it would
3454 * provide data for the new area, we cannot leave it unallocated because
3455 * then the backing file content would become visible. Instead, zero-fill
3458 * Note that if the image has a backing file, but was opened without the
3459 * backing file, taking care of keeping things consistent with that backing
3460 * file is the user's responsibility.
3462 if (new_bytes
&& backing
) {
3463 int64_t backing_len
;
3465 backing_len
= bdrv_co_getlength(backing
->bs
);
3466 if (backing_len
< 0) {
3468 error_setg_errno(errp
, -ret
, "Could not get backing file size");
3472 if (backing_len
> old_size
) {
3473 flags
|= BDRV_REQ_ZERO_WRITE
;
3477 if (drv
->bdrv_co_truncate
) {
3478 if (flags
& ~bs
->supported_truncate_flags
) {
3479 error_setg(errp
, "Block driver does not support requested flags");
3483 ret
= drv
->bdrv_co_truncate(bs
, offset
, exact
, prealloc
, flags
, errp
);
3484 } else if (filtered
) {
3485 ret
= bdrv_co_truncate(filtered
, offset
, exact
, prealloc
, flags
, errp
);
3487 error_setg(errp
, "Image format driver does not support resize");
3495 ret
= bdrv_co_refresh_total_sectors(bs
, offset
>> BDRV_SECTOR_BITS
);
3497 error_setg_errno(errp
, -ret
, "Could not refresh total sector count");
3499 offset
= bs
->total_sectors
* BDRV_SECTOR_SIZE
;
3502 * It's possible that truncation succeeded but bdrv_refresh_total_sectors
3503 * failed, but the latter doesn't affect how we should finish the request.
3504 * Pass 0 as the last parameter so that dirty bitmaps etc. are handled.
3506 bdrv_co_write_req_finish(child
, offset
- new_bytes
, new_bytes
, &req
, 0);
3509 tracked_request_end(&req
);
3510 bdrv_dec_in_flight(bs
);
3515 void bdrv_cancel_in_flight(BlockDriverState
*bs
)
3517 GLOBAL_STATE_CODE();
3518 if (!bs
|| !bs
->drv
) {
3522 if (bs
->drv
->bdrv_cancel_in_flight
) {
3523 bs
->drv
->bdrv_cancel_in_flight(bs
);
3528 bdrv_co_preadv_snapshot(BdrvChild
*child
, int64_t offset
, int64_t bytes
,
3529 QEMUIOVector
*qiov
, size_t qiov_offset
)
3531 BlockDriverState
*bs
= child
->bs
;
3532 BlockDriver
*drv
= bs
->drv
;
3540 if (!drv
->bdrv_co_preadv_snapshot
) {
3544 bdrv_inc_in_flight(bs
);
3545 ret
= drv
->bdrv_co_preadv_snapshot(bs
, offset
, bytes
, qiov
, qiov_offset
);
3546 bdrv_dec_in_flight(bs
);
3552 bdrv_co_snapshot_block_status(BlockDriverState
*bs
,
3553 bool want_zero
, int64_t offset
, int64_t bytes
,
3554 int64_t *pnum
, int64_t *map
,
3555 BlockDriverState
**file
)
3557 BlockDriver
*drv
= bs
->drv
;
3565 if (!drv
->bdrv_co_snapshot_block_status
) {
3569 bdrv_inc_in_flight(bs
);
3570 ret
= drv
->bdrv_co_snapshot_block_status(bs
, want_zero
, offset
, bytes
,
3572 bdrv_dec_in_flight(bs
);
3578 bdrv_co_pdiscard_snapshot(BlockDriverState
*bs
, int64_t offset
, int64_t bytes
)
3580 BlockDriver
*drv
= bs
->drv
;
3583 assert_bdrv_graph_readable();
3589 if (!drv
->bdrv_co_pdiscard_snapshot
) {
3593 bdrv_inc_in_flight(bs
);
3594 ret
= drv
->bdrv_co_pdiscard_snapshot(bs
, offset
, bytes
);
3595 bdrv_dec_in_flight(bs
);