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/blockjob.h"
29 #include "block/block_int.h"
30 #include "block/throttle-groups.h"
31 #include "qemu/cutils.h"
32 #include "qapi/error.h"
33 #include "qemu/error-report.h"
35 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
37 static BlockAIOCB
*bdrv_aio_readv_em(BlockDriverState
*bs
,
38 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
39 BlockCompletionFunc
*cb
, void *opaque
);
40 static BlockAIOCB
*bdrv_aio_writev_em(BlockDriverState
*bs
,
41 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
42 BlockCompletionFunc
*cb
, void *opaque
);
43 static int coroutine_fn
bdrv_co_readv_em(BlockDriverState
*bs
,
44 int64_t sector_num
, int nb_sectors
,
46 static int coroutine_fn
bdrv_co_writev_em(BlockDriverState
*bs
,
47 int64_t sector_num
, int nb_sectors
,
49 static BlockAIOCB
*bdrv_co_aio_rw_vector(BlockDriverState
*bs
,
53 BdrvRequestFlags flags
,
54 BlockCompletionFunc
*cb
,
57 static void coroutine_fn
bdrv_co_do_rw(void *opaque
);
58 static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState
*bs
,
59 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
);
61 /* throttling disk I/O limits */
62 void bdrv_set_io_limits(BlockDriverState
*bs
,
67 throttle_group_config(bs
, cfg
);
69 for (i
= 0; i
< 2; i
++) {
70 qemu_co_enter_next(&bs
->throttled_reqs
[i
]);
74 /* this function drain all the throttled IOs */
75 static bool bdrv_start_throttled_reqs(BlockDriverState
*bs
)
78 bool enabled
= bs
->io_limits_enabled
;
81 bs
->io_limits_enabled
= false;
83 for (i
= 0; i
< 2; i
++) {
84 while (qemu_co_enter_next(&bs
->throttled_reqs
[i
])) {
89 bs
->io_limits_enabled
= enabled
;
94 void bdrv_io_limits_disable(BlockDriverState
*bs
)
96 bs
->io_limits_enabled
= false;
97 bdrv_start_throttled_reqs(bs
);
98 throttle_group_unregister_bs(bs
);
101 /* should be called before bdrv_set_io_limits if a limit is set */
102 void bdrv_io_limits_enable(BlockDriverState
*bs
, const char *group
)
104 assert(!bs
->io_limits_enabled
);
105 throttle_group_register_bs(bs
, group
);
106 bs
->io_limits_enabled
= true;
109 void bdrv_io_limits_update_group(BlockDriverState
*bs
, const char *group
)
111 /* this bs is not part of any group */
112 if (!bs
->throttle_state
) {
116 /* this bs is a part of the same group than the one we want */
117 if (!g_strcmp0(throttle_group_get_name(bs
), group
)) {
121 /* need to change the group this bs belong to */
122 bdrv_io_limits_disable(bs
);
123 bdrv_io_limits_enable(bs
, group
);
126 void bdrv_setup_io_funcs(BlockDriver
*bdrv
)
128 /* Block drivers without coroutine functions need emulation */
129 if (!bdrv
->bdrv_co_readv
) {
130 bdrv
->bdrv_co_readv
= bdrv_co_readv_em
;
131 bdrv
->bdrv_co_writev
= bdrv_co_writev_em
;
133 /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
134 * the block driver lacks aio we need to emulate that too.
136 if (!bdrv
->bdrv_aio_readv
) {
137 /* add AIO emulation layer */
138 bdrv
->bdrv_aio_readv
= bdrv_aio_readv_em
;
139 bdrv
->bdrv_aio_writev
= bdrv_aio_writev_em
;
144 void bdrv_refresh_limits(BlockDriverState
*bs
, Error
**errp
)
146 BlockDriver
*drv
= bs
->drv
;
147 Error
*local_err
= NULL
;
149 memset(&bs
->bl
, 0, sizeof(bs
->bl
));
155 /* Take some limits from the children as a default */
157 bdrv_refresh_limits(bs
->file
->bs
, &local_err
);
159 error_propagate(errp
, local_err
);
162 bs
->bl
.opt_transfer_length
= bs
->file
->bs
->bl
.opt_transfer_length
;
163 bs
->bl
.max_transfer_length
= bs
->file
->bs
->bl
.max_transfer_length
;
164 bs
->bl
.min_mem_alignment
= bs
->file
->bs
->bl
.min_mem_alignment
;
165 bs
->bl
.opt_mem_alignment
= bs
->file
->bs
->bl
.opt_mem_alignment
;
166 bs
->bl
.max_iov
= bs
->file
->bs
->bl
.max_iov
;
168 bs
->bl
.min_mem_alignment
= 512;
169 bs
->bl
.opt_mem_alignment
= getpagesize();
171 /* Safe default since most protocols use readv()/writev()/etc */
172 bs
->bl
.max_iov
= IOV_MAX
;
176 bdrv_refresh_limits(bs
->backing
->bs
, &local_err
);
178 error_propagate(errp
, local_err
);
181 bs
->bl
.opt_transfer_length
=
182 MAX(bs
->bl
.opt_transfer_length
,
183 bs
->backing
->bs
->bl
.opt_transfer_length
);
184 bs
->bl
.max_transfer_length
=
185 MIN_NON_ZERO(bs
->bl
.max_transfer_length
,
186 bs
->backing
->bs
->bl
.max_transfer_length
);
187 bs
->bl
.opt_mem_alignment
=
188 MAX(bs
->bl
.opt_mem_alignment
,
189 bs
->backing
->bs
->bl
.opt_mem_alignment
);
190 bs
->bl
.min_mem_alignment
=
191 MAX(bs
->bl
.min_mem_alignment
,
192 bs
->backing
->bs
->bl
.min_mem_alignment
);
195 bs
->backing
->bs
->bl
.max_iov
);
198 /* Then let the driver override it */
199 if (drv
->bdrv_refresh_limits
) {
200 drv
->bdrv_refresh_limits(bs
, errp
);
205 * The copy-on-read flag is actually a reference count so multiple users may
206 * use the feature without worrying about clobbering its previous state.
207 * Copy-on-read stays enabled until all users have called to disable it.
209 void bdrv_enable_copy_on_read(BlockDriverState
*bs
)
214 void bdrv_disable_copy_on_read(BlockDriverState
*bs
)
216 assert(bs
->copy_on_read
> 0);
220 /* Check if any requests are in-flight (including throttled requests) */
221 bool bdrv_requests_pending(BlockDriverState
*bs
)
225 if (!QLIST_EMPTY(&bs
->tracked_requests
)) {
228 if (!qemu_co_queue_empty(&bs
->throttled_reqs
[0])) {
231 if (!qemu_co_queue_empty(&bs
->throttled_reqs
[1])) {
235 QLIST_FOREACH(child
, &bs
->children
, next
) {
236 if (bdrv_requests_pending(child
->bs
)) {
244 static void bdrv_drain_recurse(BlockDriverState
*bs
)
248 if (bs
->drv
&& bs
->drv
->bdrv_drain
) {
249 bs
->drv
->bdrv_drain(bs
);
251 QLIST_FOREACH(child
, &bs
->children
, next
) {
252 bdrv_drain_recurse(child
->bs
);
257 * Wait for pending requests to complete on a single BlockDriverState subtree,
258 * and suspend block driver's internal I/O until next request arrives.
260 * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState
263 * Only this BlockDriverState's AioContext is run, so in-flight requests must
264 * not depend on events in other AioContexts. In that case, use
265 * bdrv_drain_all() instead.
267 void bdrv_drain(BlockDriverState
*bs
)
271 bdrv_drain_recurse(bs
);
274 bdrv_flush_io_queue(bs
);
275 busy
= bdrv_requests_pending(bs
);
276 busy
|= aio_poll(bdrv_get_aio_context(bs
), busy
);
281 * Wait for pending requests to complete across all BlockDriverStates
283 * This function does not flush data to disk, use bdrv_flush_all() for that
284 * after calling this function.
286 void bdrv_drain_all(void)
288 /* Always run first iteration so any pending completion BHs run */
290 BlockDriverState
*bs
= NULL
;
291 GSList
*aio_ctxs
= NULL
, *ctx
;
293 while ((bs
= bdrv_next(bs
))) {
294 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
296 aio_context_acquire(aio_context
);
298 block_job_pause(bs
->job
);
300 bdrv_drain_recurse(bs
);
301 aio_context_release(aio_context
);
303 if (!g_slist_find(aio_ctxs
, aio_context
)) {
304 aio_ctxs
= g_slist_prepend(aio_ctxs
, aio_context
);
308 /* Note that completion of an asynchronous I/O operation can trigger any
309 * number of other I/O operations on other devices---for example a
310 * coroutine can submit an I/O request to another device in response to
311 * request completion. Therefore we must keep looping until there was no
312 * more activity rather than simply draining each device independently.
317 for (ctx
= aio_ctxs
; ctx
!= NULL
; ctx
= ctx
->next
) {
318 AioContext
*aio_context
= ctx
->data
;
321 aio_context_acquire(aio_context
);
322 while ((bs
= bdrv_next(bs
))) {
323 if (aio_context
== bdrv_get_aio_context(bs
)) {
324 bdrv_flush_io_queue(bs
);
325 if (bdrv_requests_pending(bs
)) {
327 aio_poll(aio_context
, busy
);
331 busy
|= aio_poll(aio_context
, false);
332 aio_context_release(aio_context
);
337 while ((bs
= bdrv_next(bs
))) {
338 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
340 aio_context_acquire(aio_context
);
342 block_job_resume(bs
->job
);
344 aio_context_release(aio_context
);
346 g_slist_free(aio_ctxs
);
350 * Remove an active request from the tracked requests list
352 * This function should be called when a tracked request is completing.
354 static void tracked_request_end(BdrvTrackedRequest
*req
)
356 if (req
->serialising
) {
357 req
->bs
->serialising_in_flight
--;
360 QLIST_REMOVE(req
, list
);
361 qemu_co_queue_restart_all(&req
->wait_queue
);
365 * Add an active request to the tracked requests list
367 static void tracked_request_begin(BdrvTrackedRequest
*req
,
368 BlockDriverState
*bs
,
371 enum BdrvTrackedRequestType type
)
373 *req
= (BdrvTrackedRequest
){
378 .co
= qemu_coroutine_self(),
379 .serialising
= false,
380 .overlap_offset
= offset
,
381 .overlap_bytes
= bytes
,
384 qemu_co_queue_init(&req
->wait_queue
);
386 QLIST_INSERT_HEAD(&bs
->tracked_requests
, req
, list
);
389 static void mark_request_serialising(BdrvTrackedRequest
*req
, uint64_t align
)
391 int64_t overlap_offset
= req
->offset
& ~(align
- 1);
392 unsigned int overlap_bytes
= ROUND_UP(req
->offset
+ req
->bytes
, align
)
395 if (!req
->serialising
) {
396 req
->bs
->serialising_in_flight
++;
397 req
->serialising
= true;
400 req
->overlap_offset
= MIN(req
->overlap_offset
, overlap_offset
);
401 req
->overlap_bytes
= MAX(req
->overlap_bytes
, overlap_bytes
);
405 * Round a region to cluster boundaries
407 void bdrv_round_to_clusters(BlockDriverState
*bs
,
408 int64_t sector_num
, int nb_sectors
,
409 int64_t *cluster_sector_num
,
410 int *cluster_nb_sectors
)
414 if (bdrv_get_info(bs
, &bdi
) < 0 || bdi
.cluster_size
== 0) {
415 *cluster_sector_num
= sector_num
;
416 *cluster_nb_sectors
= nb_sectors
;
418 int64_t c
= bdi
.cluster_size
/ BDRV_SECTOR_SIZE
;
419 *cluster_sector_num
= QEMU_ALIGN_DOWN(sector_num
, c
);
420 *cluster_nb_sectors
= QEMU_ALIGN_UP(sector_num
- *cluster_sector_num
+
425 static int bdrv_get_cluster_size(BlockDriverState
*bs
)
430 ret
= bdrv_get_info(bs
, &bdi
);
431 if (ret
< 0 || bdi
.cluster_size
== 0) {
432 return bs
->request_alignment
;
434 return bdi
.cluster_size
;
438 static bool tracked_request_overlaps(BdrvTrackedRequest
*req
,
439 int64_t offset
, unsigned int bytes
)
442 if (offset
>= req
->overlap_offset
+ req
->overlap_bytes
) {
446 if (req
->overlap_offset
>= offset
+ bytes
) {
452 static bool coroutine_fn
wait_serialising_requests(BdrvTrackedRequest
*self
)
454 BlockDriverState
*bs
= self
->bs
;
455 BdrvTrackedRequest
*req
;
459 if (!bs
->serialising_in_flight
) {
465 QLIST_FOREACH(req
, &bs
->tracked_requests
, list
) {
466 if (req
== self
|| (!req
->serialising
&& !self
->serialising
)) {
469 if (tracked_request_overlaps(req
, self
->overlap_offset
,
470 self
->overlap_bytes
))
472 /* Hitting this means there was a reentrant request, for
473 * example, a block driver issuing nested requests. This must
474 * never happen since it means deadlock.
476 assert(qemu_coroutine_self() != req
->co
);
478 /* If the request is already (indirectly) waiting for us, or
479 * will wait for us as soon as it wakes up, then just go on
480 * (instead of producing a deadlock in the former case). */
481 if (!req
->waiting_for
) {
482 self
->waiting_for
= req
;
483 qemu_co_queue_wait(&req
->wait_queue
);
484 self
->waiting_for
= NULL
;
496 static int bdrv_check_byte_request(BlockDriverState
*bs
, int64_t offset
,
499 if (size
> BDRV_REQUEST_MAX_SECTORS
<< BDRV_SECTOR_BITS
) {
503 if (!bdrv_is_inserted(bs
)) {
514 static int bdrv_check_request(BlockDriverState
*bs
, int64_t sector_num
,
517 if (nb_sectors
< 0 || nb_sectors
> BDRV_REQUEST_MAX_SECTORS
) {
521 return bdrv_check_byte_request(bs
, sector_num
* BDRV_SECTOR_SIZE
,
522 nb_sectors
* BDRV_SECTOR_SIZE
);
525 typedef struct RwCo
{
526 BlockDriverState
*bs
;
531 BdrvRequestFlags flags
;
534 static void coroutine_fn
bdrv_rw_co_entry(void *opaque
)
538 if (!rwco
->is_write
) {
539 rwco
->ret
= bdrv_co_do_preadv(rwco
->bs
, rwco
->offset
,
540 rwco
->qiov
->size
, rwco
->qiov
,
543 rwco
->ret
= bdrv_co_do_pwritev(rwco
->bs
, rwco
->offset
,
544 rwco
->qiov
->size
, rwco
->qiov
,
550 * Process a vectored synchronous request using coroutines
552 static int bdrv_prwv_co(BlockDriverState
*bs
, int64_t offset
,
553 QEMUIOVector
*qiov
, bool is_write
,
554 BdrvRequestFlags flags
)
561 .is_write
= is_write
,
567 * In sync call context, when the vcpu is blocked, this throttling timer
568 * will not fire; so the I/O throttling function has to be disabled here
569 * if it has been enabled.
571 if (bs
->io_limits_enabled
) {
572 fprintf(stderr
, "Disabling I/O throttling on '%s' due "
573 "to synchronous I/O.\n", bdrv_get_device_name(bs
));
574 bdrv_io_limits_disable(bs
);
577 if (qemu_in_coroutine()) {
578 /* Fast-path if already in coroutine context */
579 bdrv_rw_co_entry(&rwco
);
581 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
583 co
= qemu_coroutine_create(bdrv_rw_co_entry
);
584 qemu_coroutine_enter(co
, &rwco
);
585 while (rwco
.ret
== NOT_DONE
) {
586 aio_poll(aio_context
, true);
593 * Process a synchronous request using coroutines
595 static int bdrv_rw_co(BlockDriverState
*bs
, int64_t sector_num
, uint8_t *buf
,
596 int nb_sectors
, bool is_write
, BdrvRequestFlags flags
)
600 .iov_base
= (void *)buf
,
601 .iov_len
= nb_sectors
* BDRV_SECTOR_SIZE
,
604 if (nb_sectors
< 0 || nb_sectors
> BDRV_REQUEST_MAX_SECTORS
) {
608 qemu_iovec_init_external(&qiov
, &iov
, 1);
609 return bdrv_prwv_co(bs
, sector_num
<< BDRV_SECTOR_BITS
,
610 &qiov
, is_write
, flags
);
613 /* return < 0 if error. See bdrv_write() for the return codes */
614 int bdrv_read(BlockDriverState
*bs
, int64_t sector_num
,
615 uint8_t *buf
, int nb_sectors
)
617 return bdrv_rw_co(bs
, sector_num
, buf
, nb_sectors
, false, 0);
620 /* Return < 0 if error. Important errors are:
621 -EIO generic I/O error (may happen for all errors)
622 -ENOMEDIUM No media inserted.
623 -EINVAL Invalid sector number or nb_sectors
624 -EACCES Trying to write a read-only device
626 int bdrv_write(BlockDriverState
*bs
, int64_t sector_num
,
627 const uint8_t *buf
, int nb_sectors
)
629 return bdrv_rw_co(bs
, sector_num
, (uint8_t *)buf
, nb_sectors
, true, 0);
632 int bdrv_write_zeroes(BlockDriverState
*bs
, int64_t sector_num
,
633 int nb_sectors
, BdrvRequestFlags flags
)
635 return bdrv_rw_co(bs
, sector_num
, NULL
, nb_sectors
, true,
636 BDRV_REQ_ZERO_WRITE
| flags
);
640 * Completely zero out a block device with the help of bdrv_write_zeroes.
641 * The operation is sped up by checking the block status and only writing
642 * zeroes to the device if they currently do not return zeroes. Optional
643 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP).
645 * Returns < 0 on error, 0 on success. For error codes see bdrv_write().
647 int bdrv_make_zero(BlockDriverState
*bs
, BdrvRequestFlags flags
)
649 int64_t target_sectors
, ret
, nb_sectors
, sector_num
= 0;
650 BlockDriverState
*file
;
653 target_sectors
= bdrv_nb_sectors(bs
);
654 if (target_sectors
< 0) {
655 return target_sectors
;
659 nb_sectors
= MIN(target_sectors
- sector_num
, BDRV_REQUEST_MAX_SECTORS
);
660 if (nb_sectors
<= 0) {
663 ret
= bdrv_get_block_status(bs
, sector_num
, nb_sectors
, &n
, &file
);
665 error_report("error getting block status at sector %" PRId64
": %s",
666 sector_num
, strerror(-ret
));
669 if (ret
& BDRV_BLOCK_ZERO
) {
673 ret
= bdrv_write_zeroes(bs
, sector_num
, n
, flags
);
675 error_report("error writing zeroes at sector %" PRId64
": %s",
676 sector_num
, strerror(-ret
));
683 int bdrv_pread(BlockDriverState
*bs
, int64_t offset
, void *buf
, int bytes
)
687 .iov_base
= (void *)buf
,
696 qemu_iovec_init_external(&qiov
, &iov
, 1);
697 ret
= bdrv_prwv_co(bs
, offset
, &qiov
, false, 0);
705 int bdrv_pwritev(BlockDriverState
*bs
, int64_t offset
, QEMUIOVector
*qiov
)
709 ret
= bdrv_prwv_co(bs
, offset
, qiov
, true, 0);
717 int bdrv_pwrite(BlockDriverState
*bs
, int64_t offset
,
718 const void *buf
, int bytes
)
722 .iov_base
= (void *) buf
,
730 qemu_iovec_init_external(&qiov
, &iov
, 1);
731 return bdrv_pwritev(bs
, offset
, &qiov
);
735 * Writes to the file and ensures that no writes are reordered across this
736 * request (acts as a barrier)
738 * Returns 0 on success, -errno in error cases.
740 int bdrv_pwrite_sync(BlockDriverState
*bs
, int64_t offset
,
741 const void *buf
, int count
)
745 ret
= bdrv_pwrite(bs
, offset
, buf
, count
);
750 /* No flush needed for cache modes that already do it */
751 if (bs
->enable_write_cache
) {
758 static int coroutine_fn
bdrv_co_do_copy_on_readv(BlockDriverState
*bs
,
759 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
)
761 /* Perform I/O through a temporary buffer so that users who scribble over
762 * their read buffer while the operation is in progress do not end up
763 * modifying the image file. This is critical for zero-copy guest I/O
764 * where anything might happen inside guest memory.
768 BlockDriver
*drv
= bs
->drv
;
770 QEMUIOVector bounce_qiov
;
771 int64_t cluster_sector_num
;
772 int cluster_nb_sectors
;
776 /* Cover entire cluster so no additional backing file I/O is required when
777 * allocating cluster in the image file.
779 bdrv_round_to_clusters(bs
, sector_num
, nb_sectors
,
780 &cluster_sector_num
, &cluster_nb_sectors
);
782 trace_bdrv_co_do_copy_on_readv(bs
, sector_num
, nb_sectors
,
783 cluster_sector_num
, cluster_nb_sectors
);
785 iov
.iov_len
= cluster_nb_sectors
* BDRV_SECTOR_SIZE
;
786 iov
.iov_base
= bounce_buffer
= qemu_try_blockalign(bs
, iov
.iov_len
);
787 if (bounce_buffer
== NULL
) {
792 qemu_iovec_init_external(&bounce_qiov
, &iov
, 1);
794 ret
= drv
->bdrv_co_readv(bs
, cluster_sector_num
, cluster_nb_sectors
,
800 if (drv
->bdrv_co_write_zeroes
&&
801 buffer_is_zero(bounce_buffer
, iov
.iov_len
)) {
802 ret
= bdrv_co_do_write_zeroes(bs
, cluster_sector_num
,
803 cluster_nb_sectors
, 0);
805 /* This does not change the data on the disk, it is not necessary
806 * to flush even in cache=writethrough mode.
808 ret
= drv
->bdrv_co_writev(bs
, cluster_sector_num
, cluster_nb_sectors
,
813 /* It might be okay to ignore write errors for guest requests. If this
814 * is a deliberate copy-on-read then we don't want to ignore the error.
815 * Simply report it in all cases.
820 skip_bytes
= (sector_num
- cluster_sector_num
) * BDRV_SECTOR_SIZE
;
821 qemu_iovec_from_buf(qiov
, 0, bounce_buffer
+ skip_bytes
,
822 nb_sectors
* BDRV_SECTOR_SIZE
);
825 qemu_vfree(bounce_buffer
);
830 * Forwards an already correctly aligned request to the BlockDriver. This
831 * handles copy on read and zeroing after EOF; any other features must be
832 * implemented by the caller.
834 static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState
*bs
,
835 BdrvTrackedRequest
*req
, int64_t offset
, unsigned int bytes
,
836 int64_t align
, QEMUIOVector
*qiov
, int flags
)
838 BlockDriver
*drv
= bs
->drv
;
841 int64_t sector_num
= offset
>> BDRV_SECTOR_BITS
;
842 unsigned int nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
844 assert((offset
& (BDRV_SECTOR_SIZE
- 1)) == 0);
845 assert((bytes
& (BDRV_SECTOR_SIZE
- 1)) == 0);
846 assert(!qiov
|| bytes
== qiov
->size
);
848 /* Handle Copy on Read and associated serialisation */
849 if (flags
& BDRV_REQ_COPY_ON_READ
) {
850 /* If we touch the same cluster it counts as an overlap. This
851 * guarantees that allocating writes will be serialized and not race
852 * with each other for the same cluster. For example, in copy-on-read
853 * it ensures that the CoR read and write operations are atomic and
854 * guest writes cannot interleave between them. */
855 mark_request_serialising(req
, bdrv_get_cluster_size(bs
));
858 if (!(flags
& BDRV_REQ_NO_SERIALISING
)) {
859 wait_serialising_requests(req
);
862 if (flags
& BDRV_REQ_COPY_ON_READ
) {
865 ret
= bdrv_is_allocated(bs
, sector_num
, nb_sectors
, &pnum
);
870 if (!ret
|| pnum
!= nb_sectors
) {
871 ret
= bdrv_co_do_copy_on_readv(bs
, sector_num
, nb_sectors
, qiov
);
876 /* Forward the request to the BlockDriver */
877 if (!bs
->zero_beyond_eof
) {
878 ret
= drv
->bdrv_co_readv(bs
, sector_num
, nb_sectors
, qiov
);
880 /* Read zeros after EOF */
881 int64_t total_sectors
, max_nb_sectors
;
883 total_sectors
= bdrv_nb_sectors(bs
);
884 if (total_sectors
< 0) {
889 max_nb_sectors
= ROUND_UP(MAX(0, total_sectors
- sector_num
),
890 align
>> BDRV_SECTOR_BITS
);
891 if (nb_sectors
< max_nb_sectors
) {
892 ret
= drv
->bdrv_co_readv(bs
, sector_num
, nb_sectors
, qiov
);
893 } else if (max_nb_sectors
> 0) {
894 QEMUIOVector local_qiov
;
896 qemu_iovec_init(&local_qiov
, qiov
->niov
);
897 qemu_iovec_concat(&local_qiov
, qiov
, 0,
898 max_nb_sectors
* BDRV_SECTOR_SIZE
);
900 ret
= drv
->bdrv_co_readv(bs
, sector_num
, max_nb_sectors
,
903 qemu_iovec_destroy(&local_qiov
);
908 /* Reading beyond end of file is supposed to produce zeroes */
909 if (ret
== 0 && total_sectors
< sector_num
+ nb_sectors
) {
910 uint64_t offset
= MAX(0, total_sectors
- sector_num
);
911 uint64_t bytes
= (sector_num
+ nb_sectors
- offset
) *
913 qemu_iovec_memset(qiov
, offset
* BDRV_SECTOR_SIZE
, 0, bytes
);
922 * Handle a read request in coroutine context
924 int coroutine_fn
bdrv_co_do_preadv(BlockDriverState
*bs
,
925 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
926 BdrvRequestFlags flags
)
928 BlockDriver
*drv
= bs
->drv
;
929 BdrvTrackedRequest req
;
931 /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
932 uint64_t align
= MAX(BDRV_SECTOR_SIZE
, bs
->request_alignment
);
933 uint8_t *head_buf
= NULL
;
934 uint8_t *tail_buf
= NULL
;
935 QEMUIOVector local_qiov
;
936 bool use_local_qiov
= false;
943 ret
= bdrv_check_byte_request(bs
, offset
, bytes
);
948 /* Don't do copy-on-read if we read data before write operation */
949 if (bs
->copy_on_read
&& !(flags
& BDRV_REQ_NO_SERIALISING
)) {
950 flags
|= BDRV_REQ_COPY_ON_READ
;
953 /* throttling disk I/O */
954 if (bs
->io_limits_enabled
) {
955 throttle_group_co_io_limits_intercept(bs
, bytes
, false);
958 /* Align read if necessary by padding qiov */
959 if (offset
& (align
- 1)) {
960 head_buf
= qemu_blockalign(bs
, align
);
961 qemu_iovec_init(&local_qiov
, qiov
->niov
+ 2);
962 qemu_iovec_add(&local_qiov
, head_buf
, offset
& (align
- 1));
963 qemu_iovec_concat(&local_qiov
, qiov
, 0, qiov
->size
);
964 use_local_qiov
= true;
966 bytes
+= offset
& (align
- 1);
967 offset
= offset
& ~(align
- 1);
970 if ((offset
+ bytes
) & (align
- 1)) {
971 if (!use_local_qiov
) {
972 qemu_iovec_init(&local_qiov
, qiov
->niov
+ 1);
973 qemu_iovec_concat(&local_qiov
, qiov
, 0, qiov
->size
);
974 use_local_qiov
= true;
976 tail_buf
= qemu_blockalign(bs
, align
);
977 qemu_iovec_add(&local_qiov
, tail_buf
,
978 align
- ((offset
+ bytes
) & (align
- 1)));
980 bytes
= ROUND_UP(bytes
, align
);
983 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_READ
);
984 ret
= bdrv_aligned_preadv(bs
, &req
, offset
, bytes
, align
,
985 use_local_qiov
? &local_qiov
: qiov
,
987 tracked_request_end(&req
);
989 if (use_local_qiov
) {
990 qemu_iovec_destroy(&local_qiov
);
991 qemu_vfree(head_buf
);
992 qemu_vfree(tail_buf
);
998 static int coroutine_fn
bdrv_co_do_readv(BlockDriverState
*bs
,
999 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
,
1000 BdrvRequestFlags flags
)
1002 if (nb_sectors
< 0 || nb_sectors
> BDRV_REQUEST_MAX_SECTORS
) {
1006 return bdrv_co_do_preadv(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1007 nb_sectors
<< BDRV_SECTOR_BITS
, qiov
, flags
);
1010 int coroutine_fn
bdrv_co_readv(BlockDriverState
*bs
, int64_t sector_num
,
1011 int nb_sectors
, QEMUIOVector
*qiov
)
1013 trace_bdrv_co_readv(bs
, sector_num
, nb_sectors
);
1015 return bdrv_co_do_readv(bs
, sector_num
, nb_sectors
, qiov
, 0);
1018 int coroutine_fn
bdrv_co_readv_no_serialising(BlockDriverState
*bs
,
1019 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
)
1021 trace_bdrv_co_readv_no_serialising(bs
, sector_num
, nb_sectors
);
1023 return bdrv_co_do_readv(bs
, sector_num
, nb_sectors
, qiov
,
1024 BDRV_REQ_NO_SERIALISING
);
1027 int coroutine_fn
bdrv_co_copy_on_readv(BlockDriverState
*bs
,
1028 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
)
1030 trace_bdrv_co_copy_on_readv(bs
, sector_num
, nb_sectors
);
1032 return bdrv_co_do_readv(bs
, sector_num
, nb_sectors
, qiov
,
1033 BDRV_REQ_COPY_ON_READ
);
1036 #define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768
1038 static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState
*bs
,
1039 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
)
1041 BlockDriver
*drv
= bs
->drv
;
1043 struct iovec iov
= {0};
1046 int max_write_zeroes
= MIN_NON_ZERO(bs
->bl
.max_write_zeroes
,
1047 BDRV_REQUEST_MAX_SECTORS
);
1049 while (nb_sectors
> 0 && !ret
) {
1050 int num
= nb_sectors
;
1052 /* Align request. Block drivers can expect the "bulk" of the request
1055 if (bs
->bl
.write_zeroes_alignment
1056 && num
> bs
->bl
.write_zeroes_alignment
) {
1057 if (sector_num
% bs
->bl
.write_zeroes_alignment
!= 0) {
1058 /* Make a small request up to the first aligned sector. */
1059 num
= bs
->bl
.write_zeroes_alignment
;
1060 num
-= sector_num
% bs
->bl
.write_zeroes_alignment
;
1061 } else if ((sector_num
+ num
) % bs
->bl
.write_zeroes_alignment
!= 0) {
1062 /* Shorten the request to the last aligned sector. num cannot
1063 * underflow because num > bs->bl.write_zeroes_alignment.
1065 num
-= (sector_num
+ num
) % bs
->bl
.write_zeroes_alignment
;
1069 /* limit request size */
1070 if (num
> max_write_zeroes
) {
1071 num
= max_write_zeroes
;
1075 /* First try the efficient write zeroes operation */
1076 if (drv
->bdrv_co_write_zeroes
) {
1077 ret
= drv
->bdrv_co_write_zeroes(bs
, sector_num
, num
, flags
);
1080 if (ret
== -ENOTSUP
) {
1081 /* Fall back to bounce buffer if write zeroes is unsupported */
1082 int max_xfer_len
= MIN_NON_ZERO(bs
->bl
.max_transfer_length
,
1083 MAX_WRITE_ZEROES_BOUNCE_BUFFER
);
1084 num
= MIN(num
, max_xfer_len
);
1085 iov
.iov_len
= num
* BDRV_SECTOR_SIZE
;
1086 if (iov
.iov_base
== NULL
) {
1087 iov
.iov_base
= qemu_try_blockalign(bs
, num
* BDRV_SECTOR_SIZE
);
1088 if (iov
.iov_base
== NULL
) {
1092 memset(iov
.iov_base
, 0, num
* BDRV_SECTOR_SIZE
);
1094 qemu_iovec_init_external(&qiov
, &iov
, 1);
1096 ret
= drv
->bdrv_co_writev(bs
, sector_num
, num
, &qiov
);
1098 /* Keep bounce buffer around if it is big enough for all
1099 * all future requests.
1101 if (num
< max_xfer_len
) {
1102 qemu_vfree(iov
.iov_base
);
1103 iov
.iov_base
= NULL
;
1112 qemu_vfree(iov
.iov_base
);
1117 * Forwards an already correctly aligned write request to the BlockDriver.
1119 static int coroutine_fn
bdrv_aligned_pwritev(BlockDriverState
*bs
,
1120 BdrvTrackedRequest
*req
, int64_t offset
, unsigned int bytes
,
1121 QEMUIOVector
*qiov
, int flags
)
1123 BlockDriver
*drv
= bs
->drv
;
1127 int64_t sector_num
= offset
>> BDRV_SECTOR_BITS
;
1128 unsigned int nb_sectors
= bytes
>> BDRV_SECTOR_BITS
;
1130 assert((offset
& (BDRV_SECTOR_SIZE
- 1)) == 0);
1131 assert((bytes
& (BDRV_SECTOR_SIZE
- 1)) == 0);
1132 assert(!qiov
|| bytes
== qiov
->size
);
1134 waited
= wait_serialising_requests(req
);
1135 assert(!waited
|| !req
->serialising
);
1136 assert(req
->overlap_offset
<= offset
);
1137 assert(offset
+ bytes
<= req
->overlap_offset
+ req
->overlap_bytes
);
1139 ret
= notifier_with_return_list_notify(&bs
->before_write_notifiers
, req
);
1141 if (!ret
&& bs
->detect_zeroes
!= BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF
&&
1142 !(flags
& BDRV_REQ_ZERO_WRITE
) && drv
->bdrv_co_write_zeroes
&&
1143 qemu_iovec_is_zero(qiov
)) {
1144 flags
|= BDRV_REQ_ZERO_WRITE
;
1145 if (bs
->detect_zeroes
== BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP
) {
1146 flags
|= BDRV_REQ_MAY_UNMAP
;
1151 /* Do nothing, write notifier decided to fail this request */
1152 } else if (flags
& BDRV_REQ_ZERO_WRITE
) {
1153 bdrv_debug_event(bs
, BLKDBG_PWRITEV_ZERO
);
1154 ret
= bdrv_co_do_write_zeroes(bs
, sector_num
, nb_sectors
, flags
);
1156 bdrv_debug_event(bs
, BLKDBG_PWRITEV
);
1157 ret
= drv
->bdrv_co_writev(bs
, sector_num
, nb_sectors
, qiov
);
1159 bdrv_debug_event(bs
, BLKDBG_PWRITEV_DONE
);
1161 if (ret
== 0 && !bs
->enable_write_cache
) {
1162 ret
= bdrv_co_flush(bs
);
1165 bdrv_set_dirty(bs
, sector_num
, nb_sectors
);
1167 if (bs
->wr_highest_offset
< offset
+ bytes
) {
1168 bs
->wr_highest_offset
= offset
+ bytes
;
1172 bs
->total_sectors
= MAX(bs
->total_sectors
, sector_num
+ nb_sectors
);
1178 static int coroutine_fn
bdrv_co_do_zero_pwritev(BlockDriverState
*bs
,
1181 BdrvRequestFlags flags
,
1182 BdrvTrackedRequest
*req
)
1184 uint8_t *buf
= NULL
;
1185 QEMUIOVector local_qiov
;
1187 uint64_t align
= MAX(BDRV_SECTOR_SIZE
, bs
->request_alignment
);
1188 unsigned int head_padding_bytes
, tail_padding_bytes
;
1191 head_padding_bytes
= offset
& (align
- 1);
1192 tail_padding_bytes
= align
- ((offset
+ bytes
) & (align
- 1));
1195 assert(flags
& BDRV_REQ_ZERO_WRITE
);
1196 if (head_padding_bytes
|| tail_padding_bytes
) {
1197 buf
= qemu_blockalign(bs
, align
);
1198 iov
= (struct iovec
) {
1202 qemu_iovec_init_external(&local_qiov
, &iov
, 1);
1204 if (head_padding_bytes
) {
1205 uint64_t zero_bytes
= MIN(bytes
, align
- head_padding_bytes
);
1207 /* RMW the unaligned part before head. */
1208 mark_request_serialising(req
, align
);
1209 wait_serialising_requests(req
);
1210 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_HEAD
);
1211 ret
= bdrv_aligned_preadv(bs
, req
, offset
& ~(align
- 1), align
,
1212 align
, &local_qiov
, 0);
1216 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_HEAD
);
1218 memset(buf
+ head_padding_bytes
, 0, zero_bytes
);
1219 ret
= bdrv_aligned_pwritev(bs
, req
, offset
& ~(align
- 1), align
,
1221 flags
& ~BDRV_REQ_ZERO_WRITE
);
1225 offset
+= zero_bytes
;
1226 bytes
-= zero_bytes
;
1229 assert(!bytes
|| (offset
& (align
- 1)) == 0);
1230 if (bytes
>= align
) {
1231 /* Write the aligned part in the middle. */
1232 uint64_t aligned_bytes
= bytes
& ~(align
- 1);
1233 ret
= bdrv_aligned_pwritev(bs
, req
, offset
, aligned_bytes
,
1238 bytes
-= aligned_bytes
;
1239 offset
+= aligned_bytes
;
1242 assert(!bytes
|| (offset
& (align
- 1)) == 0);
1244 assert(align
== tail_padding_bytes
+ bytes
);
1245 /* RMW the unaligned part after tail. */
1246 mark_request_serialising(req
, align
);
1247 wait_serialising_requests(req
);
1248 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1249 ret
= bdrv_aligned_preadv(bs
, req
, offset
, align
,
1250 align
, &local_qiov
, 0);
1254 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1256 memset(buf
, 0, bytes
);
1257 ret
= bdrv_aligned_pwritev(bs
, req
, offset
, align
,
1258 &local_qiov
, flags
& ~BDRV_REQ_ZERO_WRITE
);
1267 * Handle a write request in coroutine context
1269 int coroutine_fn
bdrv_co_do_pwritev(BlockDriverState
*bs
,
1270 int64_t offset
, unsigned int bytes
, QEMUIOVector
*qiov
,
1271 BdrvRequestFlags flags
)
1273 BdrvTrackedRequest req
;
1274 /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
1275 uint64_t align
= MAX(BDRV_SECTOR_SIZE
, bs
->request_alignment
);
1276 uint8_t *head_buf
= NULL
;
1277 uint8_t *tail_buf
= NULL
;
1278 QEMUIOVector local_qiov
;
1279 bool use_local_qiov
= false;
1285 if (bs
->read_only
) {
1288 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
1290 ret
= bdrv_check_byte_request(bs
, offset
, bytes
);
1295 /* throttling disk I/O */
1296 if (bs
->io_limits_enabled
) {
1297 throttle_group_co_io_limits_intercept(bs
, bytes
, true);
1301 * Align write if necessary by performing a read-modify-write cycle.
1302 * Pad qiov with the read parts and be sure to have a tracked request not
1303 * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle.
1305 tracked_request_begin(&req
, bs
, offset
, bytes
, BDRV_TRACKED_WRITE
);
1308 ret
= bdrv_co_do_zero_pwritev(bs
, offset
, bytes
, flags
, &req
);
1312 if (offset
& (align
- 1)) {
1313 QEMUIOVector head_qiov
;
1314 struct iovec head_iov
;
1316 mark_request_serialising(&req
, align
);
1317 wait_serialising_requests(&req
);
1319 head_buf
= qemu_blockalign(bs
, align
);
1320 head_iov
= (struct iovec
) {
1321 .iov_base
= head_buf
,
1324 qemu_iovec_init_external(&head_qiov
, &head_iov
, 1);
1326 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_HEAD
);
1327 ret
= bdrv_aligned_preadv(bs
, &req
, offset
& ~(align
- 1), align
,
1328 align
, &head_qiov
, 0);
1332 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_HEAD
);
1334 qemu_iovec_init(&local_qiov
, qiov
->niov
+ 2);
1335 qemu_iovec_add(&local_qiov
, head_buf
, offset
& (align
- 1));
1336 qemu_iovec_concat(&local_qiov
, qiov
, 0, qiov
->size
);
1337 use_local_qiov
= true;
1339 bytes
+= offset
& (align
- 1);
1340 offset
= offset
& ~(align
- 1);
1343 if ((offset
+ bytes
) & (align
- 1)) {
1344 QEMUIOVector tail_qiov
;
1345 struct iovec tail_iov
;
1349 mark_request_serialising(&req
, align
);
1350 waited
= wait_serialising_requests(&req
);
1351 assert(!waited
|| !use_local_qiov
);
1353 tail_buf
= qemu_blockalign(bs
, align
);
1354 tail_iov
= (struct iovec
) {
1355 .iov_base
= tail_buf
,
1358 qemu_iovec_init_external(&tail_qiov
, &tail_iov
, 1);
1360 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_TAIL
);
1361 ret
= bdrv_aligned_preadv(bs
, &req
, (offset
+ bytes
) & ~(align
- 1), align
,
1362 align
, &tail_qiov
, 0);
1366 bdrv_debug_event(bs
, BLKDBG_PWRITEV_RMW_AFTER_TAIL
);
1368 if (!use_local_qiov
) {
1369 qemu_iovec_init(&local_qiov
, qiov
->niov
+ 1);
1370 qemu_iovec_concat(&local_qiov
, qiov
, 0, qiov
->size
);
1371 use_local_qiov
= true;
1374 tail_bytes
= (offset
+ bytes
) & (align
- 1);
1375 qemu_iovec_add(&local_qiov
, tail_buf
+ tail_bytes
, align
- tail_bytes
);
1377 bytes
= ROUND_UP(bytes
, align
);
1380 ret
= bdrv_aligned_pwritev(bs
, &req
, offset
, bytes
,
1381 use_local_qiov
? &local_qiov
: qiov
,
1386 if (use_local_qiov
) {
1387 qemu_iovec_destroy(&local_qiov
);
1389 qemu_vfree(head_buf
);
1390 qemu_vfree(tail_buf
);
1392 tracked_request_end(&req
);
1396 static int coroutine_fn
bdrv_co_do_writev(BlockDriverState
*bs
,
1397 int64_t sector_num
, int nb_sectors
, QEMUIOVector
*qiov
,
1398 BdrvRequestFlags flags
)
1400 if (nb_sectors
< 0 || nb_sectors
> BDRV_REQUEST_MAX_SECTORS
) {
1404 return bdrv_co_do_pwritev(bs
, sector_num
<< BDRV_SECTOR_BITS
,
1405 nb_sectors
<< BDRV_SECTOR_BITS
, qiov
, flags
);
1408 int coroutine_fn
bdrv_co_writev(BlockDriverState
*bs
, int64_t sector_num
,
1409 int nb_sectors
, QEMUIOVector
*qiov
)
1411 trace_bdrv_co_writev(bs
, sector_num
, nb_sectors
);
1413 return bdrv_co_do_writev(bs
, sector_num
, nb_sectors
, qiov
, 0);
1416 int coroutine_fn
bdrv_co_write_zeroes(BlockDriverState
*bs
,
1417 int64_t sector_num
, int nb_sectors
,
1418 BdrvRequestFlags flags
)
1420 trace_bdrv_co_write_zeroes(bs
, sector_num
, nb_sectors
, flags
);
1422 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
1423 flags
&= ~BDRV_REQ_MAY_UNMAP
;
1426 return bdrv_co_do_writev(bs
, sector_num
, nb_sectors
, NULL
,
1427 BDRV_REQ_ZERO_WRITE
| flags
);
1430 typedef struct BdrvCoGetBlockStatusData
{
1431 BlockDriverState
*bs
;
1432 BlockDriverState
*base
;
1433 BlockDriverState
**file
;
1439 } BdrvCoGetBlockStatusData
;
1442 * Returns the allocation status of the specified sectors.
1443 * Drivers not implementing the functionality are assumed to not support
1444 * backing files, hence all their sectors are reported as allocated.
1446 * If 'sector_num' is beyond the end of the disk image the return value is 0
1447 * and 'pnum' is set to 0.
1449 * 'pnum' is set to the number of sectors (including and immediately following
1450 * the specified sector) that are known to be in the same
1451 * allocated/unallocated state.
1453 * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes
1454 * beyond the end of the disk image it will be clamped.
1456 * If returned value is positive and BDRV_BLOCK_OFFSET_VALID bit is set, 'file'
1457 * points to the BDS which the sector range is allocated in.
1459 static int64_t coroutine_fn
bdrv_co_get_block_status(BlockDriverState
*bs
,
1461 int nb_sectors
, int *pnum
,
1462 BlockDriverState
**file
)
1464 int64_t total_sectors
;
1468 total_sectors
= bdrv_nb_sectors(bs
);
1469 if (total_sectors
< 0) {
1470 return total_sectors
;
1473 if (sector_num
>= total_sectors
) {
1478 n
= total_sectors
- sector_num
;
1479 if (n
< nb_sectors
) {
1483 if (!bs
->drv
->bdrv_co_get_block_status
) {
1485 ret
= BDRV_BLOCK_DATA
| BDRV_BLOCK_ALLOCATED
;
1486 if (bs
->drv
->protocol_name
) {
1487 ret
|= BDRV_BLOCK_OFFSET_VALID
| (sector_num
* BDRV_SECTOR_SIZE
);
1493 ret
= bs
->drv
->bdrv_co_get_block_status(bs
, sector_num
, nb_sectors
, pnum
,
1500 if (ret
& BDRV_BLOCK_RAW
) {
1501 assert(ret
& BDRV_BLOCK_OFFSET_VALID
);
1502 return bdrv_get_block_status(bs
->file
->bs
, ret
>> BDRV_SECTOR_BITS
,
1506 if (ret
& (BDRV_BLOCK_DATA
| BDRV_BLOCK_ZERO
)) {
1507 ret
|= BDRV_BLOCK_ALLOCATED
;
1509 if (bdrv_unallocated_blocks_are_zero(bs
)) {
1510 ret
|= BDRV_BLOCK_ZERO
;
1511 } else if (bs
->backing
) {
1512 BlockDriverState
*bs2
= bs
->backing
->bs
;
1513 int64_t nb_sectors2
= bdrv_nb_sectors(bs2
);
1514 if (nb_sectors2
>= 0 && sector_num
>= nb_sectors2
) {
1515 ret
|= BDRV_BLOCK_ZERO
;
1520 if (*file
&& *file
!= bs
&&
1521 (ret
& BDRV_BLOCK_DATA
) && !(ret
& BDRV_BLOCK_ZERO
) &&
1522 (ret
& BDRV_BLOCK_OFFSET_VALID
)) {
1523 BlockDriverState
*file2
;
1526 ret2
= bdrv_co_get_block_status(*file
, ret
>> BDRV_SECTOR_BITS
,
1527 *pnum
, &file_pnum
, &file2
);
1529 /* Ignore errors. This is just providing extra information, it
1530 * is useful but not necessary.
1533 /* !file_pnum indicates an offset at or beyond the EOF; it is
1534 * perfectly valid for the format block driver to point to such
1535 * offsets, so catch it and mark everything as zero */
1536 ret
|= BDRV_BLOCK_ZERO
;
1538 /* Limit request to the range reported by the protocol driver */
1540 ret
|= (ret2
& BDRV_BLOCK_ZERO
);
1548 static int64_t coroutine_fn
bdrv_co_get_block_status_above(BlockDriverState
*bs
,
1549 BlockDriverState
*base
,
1553 BlockDriverState
**file
)
1555 BlockDriverState
*p
;
1559 for (p
= bs
; p
!= base
; p
= backing_bs(p
)) {
1560 ret
= bdrv_co_get_block_status(p
, sector_num
, nb_sectors
, pnum
, file
);
1561 if (ret
< 0 || ret
& BDRV_BLOCK_ALLOCATED
) {
1564 /* [sector_num, pnum] unallocated on this layer, which could be only
1565 * the first part of [sector_num, nb_sectors]. */
1566 nb_sectors
= MIN(nb_sectors
, *pnum
);
1571 /* Coroutine wrapper for bdrv_get_block_status_above() */
1572 static void coroutine_fn
bdrv_get_block_status_above_co_entry(void *opaque
)
1574 BdrvCoGetBlockStatusData
*data
= opaque
;
1576 data
->ret
= bdrv_co_get_block_status_above(data
->bs
, data
->base
,
1585 * Synchronous wrapper around bdrv_co_get_block_status_above().
1587 * See bdrv_co_get_block_status_above() for details.
1589 int64_t bdrv_get_block_status_above(BlockDriverState
*bs
,
1590 BlockDriverState
*base
,
1592 int nb_sectors
, int *pnum
,
1593 BlockDriverState
**file
)
1596 BdrvCoGetBlockStatusData data
= {
1600 .sector_num
= sector_num
,
1601 .nb_sectors
= nb_sectors
,
1606 if (qemu_in_coroutine()) {
1607 /* Fast-path if already in coroutine context */
1608 bdrv_get_block_status_above_co_entry(&data
);
1610 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
1612 co
= qemu_coroutine_create(bdrv_get_block_status_above_co_entry
);
1613 qemu_coroutine_enter(co
, &data
);
1614 while (!data
.done
) {
1615 aio_poll(aio_context
, true);
1621 int64_t bdrv_get_block_status(BlockDriverState
*bs
,
1623 int nb_sectors
, int *pnum
,
1624 BlockDriverState
**file
)
1626 return bdrv_get_block_status_above(bs
, backing_bs(bs
),
1627 sector_num
, nb_sectors
, pnum
, file
);
1630 int coroutine_fn
bdrv_is_allocated(BlockDriverState
*bs
, int64_t sector_num
,
1631 int nb_sectors
, int *pnum
)
1633 BlockDriverState
*file
;
1634 int64_t ret
= bdrv_get_block_status(bs
, sector_num
, nb_sectors
, pnum
,
1639 return !!(ret
& BDRV_BLOCK_ALLOCATED
);
1643 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
1645 * Return true if the given sector is allocated in any image between
1646 * BASE and TOP (inclusive). BASE can be NULL to check if the given
1647 * sector is allocated in any image of the chain. Return false otherwise.
1649 * 'pnum' is set to the number of sectors (including and immediately following
1650 * the specified sector) that are known to be in the same
1651 * allocated/unallocated state.
1654 int bdrv_is_allocated_above(BlockDriverState
*top
,
1655 BlockDriverState
*base
,
1657 int nb_sectors
, int *pnum
)
1659 BlockDriverState
*intermediate
;
1660 int ret
, n
= nb_sectors
;
1663 while (intermediate
&& intermediate
!= base
) {
1665 ret
= bdrv_is_allocated(intermediate
, sector_num
, nb_sectors
,
1675 * [sector_num, nb_sectors] is unallocated on top but intermediate
1678 * [sector_num+x, nr_sectors] allocated.
1680 if (n
> pnum_inter
&&
1681 (intermediate
== top
||
1682 sector_num
+ pnum_inter
< intermediate
->total_sectors
)) {
1686 intermediate
= backing_bs(intermediate
);
1693 int bdrv_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1694 const uint8_t *buf
, int nb_sectors
)
1696 BlockDriver
*drv
= bs
->drv
;
1702 if (!drv
->bdrv_write_compressed
) {
1705 ret
= bdrv_check_request(bs
, sector_num
, nb_sectors
);
1710 assert(QLIST_EMPTY(&bs
->dirty_bitmaps
));
1712 return drv
->bdrv_write_compressed(bs
, sector_num
, buf
, nb_sectors
);
1715 int bdrv_save_vmstate(BlockDriverState
*bs
, const uint8_t *buf
,
1716 int64_t pos
, int size
)
1719 struct iovec iov
= {
1720 .iov_base
= (void *) buf
,
1724 qemu_iovec_init_external(&qiov
, &iov
, 1);
1725 return bdrv_writev_vmstate(bs
, &qiov
, pos
);
1728 int bdrv_writev_vmstate(BlockDriverState
*bs
, QEMUIOVector
*qiov
, int64_t pos
)
1730 BlockDriver
*drv
= bs
->drv
;
1734 } else if (drv
->bdrv_save_vmstate
) {
1735 return drv
->bdrv_save_vmstate(bs
, qiov
, pos
);
1736 } else if (bs
->file
) {
1737 return bdrv_writev_vmstate(bs
->file
->bs
, qiov
, pos
);
1743 int bdrv_load_vmstate(BlockDriverState
*bs
, uint8_t *buf
,
1744 int64_t pos
, int size
)
1746 BlockDriver
*drv
= bs
->drv
;
1749 if (drv
->bdrv_load_vmstate
)
1750 return drv
->bdrv_load_vmstate(bs
, buf
, pos
, size
);
1752 return bdrv_load_vmstate(bs
->file
->bs
, buf
, pos
, size
);
1756 /**************************************************************/
1759 BlockAIOCB
*bdrv_aio_readv(BlockDriverState
*bs
, int64_t sector_num
,
1760 QEMUIOVector
*qiov
, int nb_sectors
,
1761 BlockCompletionFunc
*cb
, void *opaque
)
1763 trace_bdrv_aio_readv(bs
, sector_num
, nb_sectors
, opaque
);
1765 return bdrv_co_aio_rw_vector(bs
, sector_num
, qiov
, nb_sectors
, 0,
1769 BlockAIOCB
*bdrv_aio_writev(BlockDriverState
*bs
, int64_t sector_num
,
1770 QEMUIOVector
*qiov
, int nb_sectors
,
1771 BlockCompletionFunc
*cb
, void *opaque
)
1773 trace_bdrv_aio_writev(bs
, sector_num
, nb_sectors
, opaque
);
1775 return bdrv_co_aio_rw_vector(bs
, sector_num
, qiov
, nb_sectors
, 0,
1779 BlockAIOCB
*bdrv_aio_write_zeroes(BlockDriverState
*bs
,
1780 int64_t sector_num
, int nb_sectors
, BdrvRequestFlags flags
,
1781 BlockCompletionFunc
*cb
, void *opaque
)
1783 trace_bdrv_aio_write_zeroes(bs
, sector_num
, nb_sectors
, flags
, opaque
);
1785 return bdrv_co_aio_rw_vector(bs
, sector_num
, NULL
, nb_sectors
,
1786 BDRV_REQ_ZERO_WRITE
| flags
,
1791 typedef struct MultiwriteCB
{
1796 BlockCompletionFunc
*cb
;
1798 QEMUIOVector
*free_qiov
;
1802 static void multiwrite_user_cb(MultiwriteCB
*mcb
)
1806 for (i
= 0; i
< mcb
->num_callbacks
; i
++) {
1807 mcb
->callbacks
[i
].cb(mcb
->callbacks
[i
].opaque
, mcb
->error
);
1808 if (mcb
->callbacks
[i
].free_qiov
) {
1809 qemu_iovec_destroy(mcb
->callbacks
[i
].free_qiov
);
1811 g_free(mcb
->callbacks
[i
].free_qiov
);
1815 static void multiwrite_cb(void *opaque
, int ret
)
1817 MultiwriteCB
*mcb
= opaque
;
1819 trace_multiwrite_cb(mcb
, ret
);
1821 if (ret
< 0 && !mcb
->error
) {
1825 mcb
->num_requests
--;
1826 if (mcb
->num_requests
== 0) {
1827 multiwrite_user_cb(mcb
);
1832 static int multiwrite_req_compare(const void *a
, const void *b
)
1834 const BlockRequest
*req1
= a
, *req2
= b
;
1837 * Note that we can't simply subtract req2->sector from req1->sector
1838 * here as that could overflow the return value.
1840 if (req1
->sector
> req2
->sector
) {
1842 } else if (req1
->sector
< req2
->sector
) {
1850 * Takes a bunch of requests and tries to merge them. Returns the number of
1851 * requests that remain after merging.
1853 static int multiwrite_merge(BlockDriverState
*bs
, BlockRequest
*reqs
,
1854 int num_reqs
, MultiwriteCB
*mcb
)
1858 // Sort requests by start sector
1859 qsort(reqs
, num_reqs
, sizeof(*reqs
), &multiwrite_req_compare
);
1861 // Check if adjacent requests touch the same clusters. If so, combine them,
1862 // filling up gaps with zero sectors.
1864 for (i
= 1; i
< num_reqs
; i
++) {
1866 int64_t oldreq_last
= reqs
[outidx
].sector
+ reqs
[outidx
].nb_sectors
;
1868 // Handle exactly sequential writes and overlapping writes.
1869 if (reqs
[i
].sector
<= oldreq_last
) {
1873 if (reqs
[outidx
].qiov
->niov
+ reqs
[i
].qiov
->niov
+ 1 >
1878 if (bs
->bl
.max_transfer_length
&& reqs
[outidx
].nb_sectors
+
1879 reqs
[i
].nb_sectors
> bs
->bl
.max_transfer_length
) {
1885 QEMUIOVector
*qiov
= g_malloc0(sizeof(*qiov
));
1886 qemu_iovec_init(qiov
,
1887 reqs
[outidx
].qiov
->niov
+ reqs
[i
].qiov
->niov
+ 1);
1889 // Add the first request to the merged one. If the requests are
1890 // overlapping, drop the last sectors of the first request.
1891 size
= (reqs
[i
].sector
- reqs
[outidx
].sector
) << 9;
1892 qemu_iovec_concat(qiov
, reqs
[outidx
].qiov
, 0, size
);
1894 // We should need to add any zeros between the two requests
1895 assert (reqs
[i
].sector
<= oldreq_last
);
1897 // Add the second request
1898 qemu_iovec_concat(qiov
, reqs
[i
].qiov
, 0, reqs
[i
].qiov
->size
);
1900 // Add tail of first request, if necessary
1901 if (qiov
->size
< reqs
[outidx
].qiov
->size
) {
1902 qemu_iovec_concat(qiov
, reqs
[outidx
].qiov
, qiov
->size
,
1903 reqs
[outidx
].qiov
->size
- qiov
->size
);
1906 reqs
[outidx
].nb_sectors
= qiov
->size
>> 9;
1907 reqs
[outidx
].qiov
= qiov
;
1909 mcb
->callbacks
[i
].free_qiov
= reqs
[outidx
].qiov
;
1912 reqs
[outidx
].sector
= reqs
[i
].sector
;
1913 reqs
[outidx
].nb_sectors
= reqs
[i
].nb_sectors
;
1914 reqs
[outidx
].qiov
= reqs
[i
].qiov
;
1919 block_acct_merge_done(blk_get_stats(bs
->blk
), BLOCK_ACCT_WRITE
,
1920 num_reqs
- outidx
- 1);
1927 * Submit multiple AIO write requests at once.
1929 * On success, the function returns 0 and all requests in the reqs array have
1930 * been submitted. In error case this function returns -1, and any of the
1931 * requests may or may not be submitted yet. In particular, this means that the
1932 * callback will be called for some of the requests, for others it won't. The
1933 * caller must check the error field of the BlockRequest to wait for the right
1934 * callbacks (if error != 0, no callback will be called).
1936 * The implementation may modify the contents of the reqs array, e.g. to merge
1937 * requests. However, the fields opaque and error are left unmodified as they
1938 * are used to signal failure for a single request to the caller.
1940 int bdrv_aio_multiwrite(BlockDriverState
*bs
, BlockRequest
*reqs
, int num_reqs
)
1945 /* don't submit writes if we don't have a medium */
1946 if (bs
->drv
== NULL
) {
1947 for (i
= 0; i
< num_reqs
; i
++) {
1948 reqs
[i
].error
= -ENOMEDIUM
;
1953 if (num_reqs
== 0) {
1957 // Create MultiwriteCB structure
1958 mcb
= g_malloc0(sizeof(*mcb
) + num_reqs
* sizeof(*mcb
->callbacks
));
1959 mcb
->num_requests
= 0;
1960 mcb
->num_callbacks
= num_reqs
;
1962 for (i
= 0; i
< num_reqs
; i
++) {
1963 mcb
->callbacks
[i
].cb
= reqs
[i
].cb
;
1964 mcb
->callbacks
[i
].opaque
= reqs
[i
].opaque
;
1967 // Check for mergable requests
1968 num_reqs
= multiwrite_merge(bs
, reqs
, num_reqs
, mcb
);
1970 trace_bdrv_aio_multiwrite(mcb
, mcb
->num_callbacks
, num_reqs
);
1972 /* Run the aio requests. */
1973 mcb
->num_requests
= num_reqs
;
1974 for (i
= 0; i
< num_reqs
; i
++) {
1975 bdrv_co_aio_rw_vector(bs
, reqs
[i
].sector
, reqs
[i
].qiov
,
1976 reqs
[i
].nb_sectors
, reqs
[i
].flags
,
1984 void bdrv_aio_cancel(BlockAIOCB
*acb
)
1987 bdrv_aio_cancel_async(acb
);
1988 while (acb
->refcnt
> 1) {
1989 if (acb
->aiocb_info
->get_aio_context
) {
1990 aio_poll(acb
->aiocb_info
->get_aio_context(acb
), true);
1991 } else if (acb
->bs
) {
1992 aio_poll(bdrv_get_aio_context(acb
->bs
), true);
1997 qemu_aio_unref(acb
);
2000 /* Async version of aio cancel. The caller is not blocked if the acb implements
2001 * cancel_async, otherwise we do nothing and let the request normally complete.
2002 * In either case the completion callback must be called. */
2003 void bdrv_aio_cancel_async(BlockAIOCB
*acb
)
2005 if (acb
->aiocb_info
->cancel_async
) {
2006 acb
->aiocb_info
->cancel_async(acb
);
2010 /**************************************************************/
2011 /* async block device emulation */
2013 typedef struct BlockAIOCBSync
{
2017 /* vector translation state */
2023 static const AIOCBInfo bdrv_em_aiocb_info
= {
2024 .aiocb_size
= sizeof(BlockAIOCBSync
),
2027 static void bdrv_aio_bh_cb(void *opaque
)
2029 BlockAIOCBSync
*acb
= opaque
;
2031 if (!acb
->is_write
&& acb
->ret
>= 0) {
2032 qemu_iovec_from_buf(acb
->qiov
, 0, acb
->bounce
, acb
->qiov
->size
);
2034 qemu_vfree(acb
->bounce
);
2035 acb
->common
.cb(acb
->common
.opaque
, acb
->ret
);
2036 qemu_bh_delete(acb
->bh
);
2038 qemu_aio_unref(acb
);
2041 static BlockAIOCB
*bdrv_aio_rw_vector(BlockDriverState
*bs
,
2045 BlockCompletionFunc
*cb
,
2050 BlockAIOCBSync
*acb
;
2052 acb
= qemu_aio_get(&bdrv_em_aiocb_info
, bs
, cb
, opaque
);
2053 acb
->is_write
= is_write
;
2055 acb
->bounce
= qemu_try_blockalign(bs
, qiov
->size
);
2056 acb
->bh
= aio_bh_new(bdrv_get_aio_context(bs
), bdrv_aio_bh_cb
, acb
);
2058 if (acb
->bounce
== NULL
) {
2060 } else if (is_write
) {
2061 qemu_iovec_to_buf(acb
->qiov
, 0, acb
->bounce
, qiov
->size
);
2062 acb
->ret
= bs
->drv
->bdrv_write(bs
, sector_num
, acb
->bounce
, nb_sectors
);
2064 acb
->ret
= bs
->drv
->bdrv_read(bs
, sector_num
, acb
->bounce
, nb_sectors
);
2067 qemu_bh_schedule(acb
->bh
);
2069 return &acb
->common
;
2072 static BlockAIOCB
*bdrv_aio_readv_em(BlockDriverState
*bs
,
2073 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
2074 BlockCompletionFunc
*cb
, void *opaque
)
2076 return bdrv_aio_rw_vector(bs
, sector_num
, qiov
, nb_sectors
, cb
, opaque
, 0);
2079 static BlockAIOCB
*bdrv_aio_writev_em(BlockDriverState
*bs
,
2080 int64_t sector_num
, QEMUIOVector
*qiov
, int nb_sectors
,
2081 BlockCompletionFunc
*cb
, void *opaque
)
2083 return bdrv_aio_rw_vector(bs
, sector_num
, qiov
, nb_sectors
, cb
, opaque
, 1);
2087 typedef struct BlockAIOCBCoroutine
{
2094 } BlockAIOCBCoroutine
;
2096 static const AIOCBInfo bdrv_em_co_aiocb_info
= {
2097 .aiocb_size
= sizeof(BlockAIOCBCoroutine
),
2100 static void bdrv_co_complete(BlockAIOCBCoroutine
*acb
)
2102 if (!acb
->need_bh
) {
2103 acb
->common
.cb(acb
->common
.opaque
, acb
->req
.error
);
2104 qemu_aio_unref(acb
);
2108 static void bdrv_co_em_bh(void *opaque
)
2110 BlockAIOCBCoroutine
*acb
= opaque
;
2112 assert(!acb
->need_bh
);
2113 qemu_bh_delete(acb
->bh
);
2114 bdrv_co_complete(acb
);
2117 static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine
*acb
)
2119 acb
->need_bh
= false;
2120 if (acb
->req
.error
!= -EINPROGRESS
) {
2121 BlockDriverState
*bs
= acb
->common
.bs
;
2123 acb
->bh
= aio_bh_new(bdrv_get_aio_context(bs
), bdrv_co_em_bh
, acb
);
2124 qemu_bh_schedule(acb
->bh
);
2128 /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
2129 static void coroutine_fn
bdrv_co_do_rw(void *opaque
)
2131 BlockAIOCBCoroutine
*acb
= opaque
;
2132 BlockDriverState
*bs
= acb
->common
.bs
;
2134 if (!acb
->is_write
) {
2135 acb
->req
.error
= bdrv_co_do_readv(bs
, acb
->req
.sector
,
2136 acb
->req
.nb_sectors
, acb
->req
.qiov
, acb
->req
.flags
);
2138 acb
->req
.error
= bdrv_co_do_writev(bs
, acb
->req
.sector
,
2139 acb
->req
.nb_sectors
, acb
->req
.qiov
, acb
->req
.flags
);
2142 bdrv_co_complete(acb
);
2145 static BlockAIOCB
*bdrv_co_aio_rw_vector(BlockDriverState
*bs
,
2149 BdrvRequestFlags flags
,
2150 BlockCompletionFunc
*cb
,
2155 BlockAIOCBCoroutine
*acb
;
2157 acb
= qemu_aio_get(&bdrv_em_co_aiocb_info
, bs
, cb
, opaque
);
2158 acb
->need_bh
= true;
2159 acb
->req
.error
= -EINPROGRESS
;
2160 acb
->req
.sector
= sector_num
;
2161 acb
->req
.nb_sectors
= nb_sectors
;
2162 acb
->req
.qiov
= qiov
;
2163 acb
->req
.flags
= flags
;
2164 acb
->is_write
= is_write
;
2166 co
= qemu_coroutine_create(bdrv_co_do_rw
);
2167 qemu_coroutine_enter(co
, acb
);
2169 bdrv_co_maybe_schedule_bh(acb
);
2170 return &acb
->common
;
2173 static void coroutine_fn
bdrv_aio_flush_co_entry(void *opaque
)
2175 BlockAIOCBCoroutine
*acb
= opaque
;
2176 BlockDriverState
*bs
= acb
->common
.bs
;
2178 acb
->req
.error
= bdrv_co_flush(bs
);
2179 bdrv_co_complete(acb
);
2182 BlockAIOCB
*bdrv_aio_flush(BlockDriverState
*bs
,
2183 BlockCompletionFunc
*cb
, void *opaque
)
2185 trace_bdrv_aio_flush(bs
, opaque
);
2188 BlockAIOCBCoroutine
*acb
;
2190 acb
= qemu_aio_get(&bdrv_em_co_aiocb_info
, bs
, cb
, opaque
);
2191 acb
->need_bh
= true;
2192 acb
->req
.error
= -EINPROGRESS
;
2194 co
= qemu_coroutine_create(bdrv_aio_flush_co_entry
);
2195 qemu_coroutine_enter(co
, acb
);
2197 bdrv_co_maybe_schedule_bh(acb
);
2198 return &acb
->common
;
2201 static void coroutine_fn
bdrv_aio_discard_co_entry(void *opaque
)
2203 BlockAIOCBCoroutine
*acb
= opaque
;
2204 BlockDriverState
*bs
= acb
->common
.bs
;
2206 acb
->req
.error
= bdrv_co_discard(bs
, acb
->req
.sector
, acb
->req
.nb_sectors
);
2207 bdrv_co_complete(acb
);
2210 BlockAIOCB
*bdrv_aio_discard(BlockDriverState
*bs
,
2211 int64_t sector_num
, int nb_sectors
,
2212 BlockCompletionFunc
*cb
, void *opaque
)
2215 BlockAIOCBCoroutine
*acb
;
2217 trace_bdrv_aio_discard(bs
, sector_num
, nb_sectors
, opaque
);
2219 acb
= qemu_aio_get(&bdrv_em_co_aiocb_info
, bs
, cb
, opaque
);
2220 acb
->need_bh
= true;
2221 acb
->req
.error
= -EINPROGRESS
;
2222 acb
->req
.sector
= sector_num
;
2223 acb
->req
.nb_sectors
= nb_sectors
;
2224 co
= qemu_coroutine_create(bdrv_aio_discard_co_entry
);
2225 qemu_coroutine_enter(co
, acb
);
2227 bdrv_co_maybe_schedule_bh(acb
);
2228 return &acb
->common
;
2231 void *qemu_aio_get(const AIOCBInfo
*aiocb_info
, BlockDriverState
*bs
,
2232 BlockCompletionFunc
*cb
, void *opaque
)
2236 acb
= g_malloc(aiocb_info
->aiocb_size
);
2237 acb
->aiocb_info
= aiocb_info
;
2240 acb
->opaque
= opaque
;
2245 void qemu_aio_ref(void *p
)
2247 BlockAIOCB
*acb
= p
;
2251 void qemu_aio_unref(void *p
)
2253 BlockAIOCB
*acb
= p
;
2254 assert(acb
->refcnt
> 0);
2255 if (--acb
->refcnt
== 0) {
2260 /**************************************************************/
2261 /* Coroutine block device emulation */
2263 typedef struct CoroutineIOCompletion
{
2264 Coroutine
*coroutine
;
2266 } CoroutineIOCompletion
;
2268 static void bdrv_co_io_em_complete(void *opaque
, int ret
)
2270 CoroutineIOCompletion
*co
= opaque
;
2273 qemu_coroutine_enter(co
->coroutine
, NULL
);
2276 static int coroutine_fn
bdrv_co_io_em(BlockDriverState
*bs
, int64_t sector_num
,
2277 int nb_sectors
, QEMUIOVector
*iov
,
2280 CoroutineIOCompletion co
= {
2281 .coroutine
= qemu_coroutine_self(),
2286 acb
= bs
->drv
->bdrv_aio_writev(bs
, sector_num
, iov
, nb_sectors
,
2287 bdrv_co_io_em_complete
, &co
);
2289 acb
= bs
->drv
->bdrv_aio_readv(bs
, sector_num
, iov
, nb_sectors
,
2290 bdrv_co_io_em_complete
, &co
);
2293 trace_bdrv_co_io_em(bs
, sector_num
, nb_sectors
, is_write
, acb
);
2297 qemu_coroutine_yield();
2302 static int coroutine_fn
bdrv_co_readv_em(BlockDriverState
*bs
,
2303 int64_t sector_num
, int nb_sectors
,
2306 return bdrv_co_io_em(bs
, sector_num
, nb_sectors
, iov
, false);
2309 static int coroutine_fn
bdrv_co_writev_em(BlockDriverState
*bs
,
2310 int64_t sector_num
, int nb_sectors
,
2313 return bdrv_co_io_em(bs
, sector_num
, nb_sectors
, iov
, true);
2316 static void coroutine_fn
bdrv_flush_co_entry(void *opaque
)
2318 RwCo
*rwco
= opaque
;
2320 rwco
->ret
= bdrv_co_flush(rwco
->bs
);
2323 int coroutine_fn
bdrv_co_flush(BlockDriverState
*bs
)
2326 BdrvTrackedRequest req
;
2328 if (!bs
|| !bdrv_is_inserted(bs
) || bdrv_is_read_only(bs
) ||
2333 tracked_request_begin(&req
, bs
, 0, 0, BDRV_TRACKED_FLUSH
);
2334 /* Write back cached data to the OS even with cache=unsafe */
2335 BLKDBG_EVENT(bs
->file
, BLKDBG_FLUSH_TO_OS
);
2336 if (bs
->drv
->bdrv_co_flush_to_os
) {
2337 ret
= bs
->drv
->bdrv_co_flush_to_os(bs
);
2343 /* But don't actually force it to the disk with cache=unsafe */
2344 if (bs
->open_flags
& BDRV_O_NO_FLUSH
) {
2348 BLKDBG_EVENT(bs
->file
, BLKDBG_FLUSH_TO_DISK
);
2349 if (bs
->drv
->bdrv_co_flush_to_disk
) {
2350 ret
= bs
->drv
->bdrv_co_flush_to_disk(bs
);
2351 } else if (bs
->drv
->bdrv_aio_flush
) {
2353 CoroutineIOCompletion co
= {
2354 .coroutine
= qemu_coroutine_self(),
2357 acb
= bs
->drv
->bdrv_aio_flush(bs
, bdrv_co_io_em_complete
, &co
);
2361 qemu_coroutine_yield();
2366 * Some block drivers always operate in either writethrough or unsafe
2367 * mode and don't support bdrv_flush therefore. Usually qemu doesn't
2368 * know how the server works (because the behaviour is hardcoded or
2369 * depends on server-side configuration), so we can't ensure that
2370 * everything is safe on disk. Returning an error doesn't work because
2371 * that would break guests even if the server operates in writethrough
2374 * Let's hope the user knows what he's doing.
2382 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH
2383 * in the case of cache=unsafe, so there are no useless flushes.
2386 ret
= bs
->file
? bdrv_co_flush(bs
->file
->bs
) : 0;
2388 tracked_request_end(&req
);
2392 int bdrv_flush(BlockDriverState
*bs
)
2400 if (qemu_in_coroutine()) {
2401 /* Fast-path if already in coroutine context */
2402 bdrv_flush_co_entry(&rwco
);
2404 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
2406 co
= qemu_coroutine_create(bdrv_flush_co_entry
);
2407 qemu_coroutine_enter(co
, &rwco
);
2408 while (rwco
.ret
== NOT_DONE
) {
2409 aio_poll(aio_context
, true);
2416 typedef struct DiscardCo
{
2417 BlockDriverState
*bs
;
2422 static void coroutine_fn
bdrv_discard_co_entry(void *opaque
)
2424 DiscardCo
*rwco
= opaque
;
2426 rwco
->ret
= bdrv_co_discard(rwco
->bs
, rwco
->sector_num
, rwco
->nb_sectors
);
2429 int coroutine_fn
bdrv_co_discard(BlockDriverState
*bs
, int64_t sector_num
,
2432 BdrvTrackedRequest req
;
2433 int max_discard
, ret
;
2439 ret
= bdrv_check_request(bs
, sector_num
, nb_sectors
);
2442 } else if (bs
->read_only
) {
2445 assert(!(bs
->open_flags
& BDRV_O_INACTIVE
));
2447 /* Do nothing if disabled. */
2448 if (!(bs
->open_flags
& BDRV_O_UNMAP
)) {
2452 if (!bs
->drv
->bdrv_co_discard
&& !bs
->drv
->bdrv_aio_discard
) {
2456 tracked_request_begin(&req
, bs
, sector_num
, nb_sectors
,
2457 BDRV_TRACKED_DISCARD
);
2458 bdrv_set_dirty(bs
, sector_num
, nb_sectors
);
2460 max_discard
= MIN_NON_ZERO(bs
->bl
.max_discard
, BDRV_REQUEST_MAX_SECTORS
);
2461 while (nb_sectors
> 0) {
2463 int num
= nb_sectors
;
2466 if (bs
->bl
.discard_alignment
&&
2467 num
>= bs
->bl
.discard_alignment
&&
2468 sector_num
% bs
->bl
.discard_alignment
) {
2469 if (num
> bs
->bl
.discard_alignment
) {
2470 num
= bs
->bl
.discard_alignment
;
2472 num
-= sector_num
% bs
->bl
.discard_alignment
;
2475 /* limit request size */
2476 if (num
> max_discard
) {
2480 if (bs
->drv
->bdrv_co_discard
) {
2481 ret
= bs
->drv
->bdrv_co_discard(bs
, sector_num
, num
);
2484 CoroutineIOCompletion co
= {
2485 .coroutine
= qemu_coroutine_self(),
2488 acb
= bs
->drv
->bdrv_aio_discard(bs
, sector_num
, nb_sectors
,
2489 bdrv_co_io_em_complete
, &co
);
2494 qemu_coroutine_yield();
2498 if (ret
&& ret
!= -ENOTSUP
) {
2507 tracked_request_end(&req
);
2511 int bdrv_discard(BlockDriverState
*bs
, int64_t sector_num
, int nb_sectors
)
2516 .sector_num
= sector_num
,
2517 .nb_sectors
= nb_sectors
,
2521 if (qemu_in_coroutine()) {
2522 /* Fast-path if already in coroutine context */
2523 bdrv_discard_co_entry(&rwco
);
2525 AioContext
*aio_context
= bdrv_get_aio_context(bs
);
2527 co
= qemu_coroutine_create(bdrv_discard_co_entry
);
2528 qemu_coroutine_enter(co
, &rwco
);
2529 while (rwco
.ret
== NOT_DONE
) {
2530 aio_poll(aio_context
, true);
2538 CoroutineIOCompletion
*co
;
2540 } BdrvIoctlCompletionData
;
2542 static void bdrv_ioctl_bh_cb(void *opaque
)
2544 BdrvIoctlCompletionData
*data
= opaque
;
2546 bdrv_co_io_em_complete(data
->co
, -ENOTSUP
);
2547 qemu_bh_delete(data
->bh
);
2550 static int bdrv_co_do_ioctl(BlockDriverState
*bs
, int req
, void *buf
)
2552 BlockDriver
*drv
= bs
->drv
;
2553 BdrvTrackedRequest tracked_req
;
2554 CoroutineIOCompletion co
= {
2555 .coroutine
= qemu_coroutine_self(),
2559 tracked_request_begin(&tracked_req
, bs
, 0, 0, BDRV_TRACKED_IOCTL
);
2560 if (!drv
|| !drv
->bdrv_aio_ioctl
) {
2565 acb
= drv
->bdrv_aio_ioctl(bs
, req
, buf
, bdrv_co_io_em_complete
, &co
);
2567 BdrvIoctlCompletionData
*data
= g_new(BdrvIoctlCompletionData
, 1);
2568 data
->bh
= aio_bh_new(bdrv_get_aio_context(bs
),
2569 bdrv_ioctl_bh_cb
, data
);
2571 qemu_bh_schedule(data
->bh
);
2573 qemu_coroutine_yield();
2575 tracked_request_end(&tracked_req
);
2580 BlockDriverState
*bs
;
2586 static void coroutine_fn
bdrv_co_ioctl_entry(void *opaque
)
2588 BdrvIoctlCoData
*data
= opaque
;
2589 data
->ret
= bdrv_co_do_ioctl(data
->bs
, data
->req
, data
->buf
);
2592 /* needed for generic scsi interface */
2593 int bdrv_ioctl(BlockDriverState
*bs
, unsigned long int req
, void *buf
)
2595 BdrvIoctlCoData data
= {
2599 .ret
= -EINPROGRESS
,
2602 if (qemu_in_coroutine()) {
2603 /* Fast-path if already in coroutine context */
2604 bdrv_co_ioctl_entry(&data
);
2606 Coroutine
*co
= qemu_coroutine_create(bdrv_co_ioctl_entry
);
2608 qemu_coroutine_enter(co
, &data
);
2609 while (data
.ret
== -EINPROGRESS
) {
2610 aio_poll(bdrv_get_aio_context(bs
), true);
2616 static void coroutine_fn
bdrv_co_aio_ioctl_entry(void *opaque
)
2618 BlockAIOCBCoroutine
*acb
= opaque
;
2619 acb
->req
.error
= bdrv_co_do_ioctl(acb
->common
.bs
,
2620 acb
->req
.req
, acb
->req
.buf
);
2621 bdrv_co_complete(acb
);
2624 BlockAIOCB
*bdrv_aio_ioctl(BlockDriverState
*bs
,
2625 unsigned long int req
, void *buf
,
2626 BlockCompletionFunc
*cb
, void *opaque
)
2628 BlockAIOCBCoroutine
*acb
= qemu_aio_get(&bdrv_em_co_aiocb_info
,
2632 acb
->need_bh
= true;
2633 acb
->req
.error
= -EINPROGRESS
;
2636 co
= qemu_coroutine_create(bdrv_co_aio_ioctl_entry
);
2637 qemu_coroutine_enter(co
, acb
);
2639 bdrv_co_maybe_schedule_bh(acb
);
2640 return &acb
->common
;
2643 void *qemu_blockalign(BlockDriverState
*bs
, size_t size
)
2645 return qemu_memalign(bdrv_opt_mem_align(bs
), size
);
2648 void *qemu_blockalign0(BlockDriverState
*bs
, size_t size
)
2650 return memset(qemu_blockalign(bs
, size
), 0, size
);
2653 void *qemu_try_blockalign(BlockDriverState
*bs
, size_t size
)
2655 size_t align
= bdrv_opt_mem_align(bs
);
2657 /* Ensure that NULL is never returned on success */
2663 return qemu_try_memalign(align
, size
);
2666 void *qemu_try_blockalign0(BlockDriverState
*bs
, size_t size
)
2668 void *mem
= qemu_try_blockalign(bs
, size
);
2671 memset(mem
, 0, size
);
2678 * Check if all memory in this vector is sector aligned.
2680 bool bdrv_qiov_is_aligned(BlockDriverState
*bs
, QEMUIOVector
*qiov
)
2683 size_t alignment
= bdrv_min_mem_align(bs
);
2685 for (i
= 0; i
< qiov
->niov
; i
++) {
2686 if ((uintptr_t) qiov
->iov
[i
].iov_base
% alignment
) {
2689 if (qiov
->iov
[i
].iov_len
% alignment
) {
2697 void bdrv_add_before_write_notifier(BlockDriverState
*bs
,
2698 NotifierWithReturn
*notifier
)
2700 notifier_with_return_list_add(&bs
->before_write_notifiers
, notifier
);
2703 void bdrv_io_plug(BlockDriverState
*bs
)
2705 BlockDriver
*drv
= bs
->drv
;
2706 if (drv
&& drv
->bdrv_io_plug
) {
2707 drv
->bdrv_io_plug(bs
);
2708 } else if (bs
->file
) {
2709 bdrv_io_plug(bs
->file
->bs
);
2713 void bdrv_io_unplug(BlockDriverState
*bs
)
2715 BlockDriver
*drv
= bs
->drv
;
2716 if (drv
&& drv
->bdrv_io_unplug
) {
2717 drv
->bdrv_io_unplug(bs
);
2718 } else if (bs
->file
) {
2719 bdrv_io_unplug(bs
->file
->bs
);
2723 void bdrv_flush_io_queue(BlockDriverState
*bs
)
2725 BlockDriver
*drv
= bs
->drv
;
2726 if (drv
&& drv
->bdrv_flush_io_queue
) {
2727 drv
->bdrv_flush_io_queue(bs
);
2728 } else if (bs
->file
) {
2729 bdrv_flush_io_queue(bs
->file
->bs
);
2731 bdrv_start_throttled_reqs(bs
);
2734 void bdrv_drained_begin(BlockDriverState
*bs
)
2736 if (!bs
->quiesce_counter
++) {
2737 aio_disable_external(bdrv_get_aio_context(bs
));
2742 void bdrv_drained_end(BlockDriverState
*bs
)
2744 assert(bs
->quiesce_counter
> 0);
2745 if (--bs
->quiesce_counter
> 0) {
2748 aio_enable_external(bdrv_get_aio_context(bs
));