block: Introduce bdrv_aligned_preadv()
This separates the part of bdrv_co_do_readv() that needs to happen before the request is modified to match the backend alignment, and a part that needs to be executed afterwards and passes the request to the BlockDriver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
parent
c25f53b06e
commit
d0c7f642f5
61
block.c
61
block.c
|
@ -2885,26 +2885,24 @@ err:
|
||||||
}
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* Handle a read request in coroutine context
|
* Forwards an already correctly aligned request to the BlockDriver. This
|
||||||
|
* handles copy on read and zeroing after EOF; any other features must be
|
||||||
|
* implemented by the caller.
|
||||||
*/
|
*/
|
||||||
static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
|
static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
|
||||||
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)
|
||||||
BdrvRequestFlags flags)
|
|
||||||
{
|
{
|
||||||
BlockDriver *drv = bs->drv;
|
BlockDriver *drv = bs->drv;
|
||||||
BdrvTrackedRequest req;
|
BdrvTrackedRequest req;
|
||||||
int ret;
|
int ret;
|
||||||
|
|
||||||
if (!drv) {
|
int64_t sector_num = offset >> BDRV_SECTOR_BITS;
|
||||||
return -ENOMEDIUM;
|
unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
||||||
}
|
|
||||||
if (bdrv_check_request(bs, sector_num, nb_sectors)) {
|
|
||||||
return -EIO;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (bs->copy_on_read) {
|
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
|
||||||
flags |= BDRV_REQ_COPY_ON_READ;
|
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
|
||||||
}
|
|
||||||
|
/* Handle Copy on Read and associated serialisation */
|
||||||
if (flags & BDRV_REQ_COPY_ON_READ) {
|
if (flags & BDRV_REQ_COPY_ON_READ) {
|
||||||
bs->copy_on_read_in_flight++;
|
bs->copy_on_read_in_flight++;
|
||||||
}
|
}
|
||||||
|
@ -2913,11 +2911,6 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
|
||||||
wait_for_overlapping_requests(bs, sector_num, nb_sectors);
|
wait_for_overlapping_requests(bs, sector_num, nb_sectors);
|
||||||
}
|
}
|
||||||
|
|
||||||
/* throttling disk I/O */
|
|
||||||
if (bs->io_limits_enabled) {
|
|
||||||
bdrv_io_limits_intercept(bs, nb_sectors, false);
|
|
||||||
}
|
|
||||||
|
|
||||||
tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
|
tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
|
||||||
|
|
||||||
if (flags & BDRV_REQ_COPY_ON_READ) {
|
if (flags & BDRV_REQ_COPY_ON_READ) {
|
||||||
|
@ -2934,6 +2927,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/* Forward the request to the BlockDriver */
|
||||||
if (!(bs->zero_beyond_eof && bs->growable)) {
|
if (!(bs->zero_beyond_eof && bs->growable)) {
|
||||||
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
|
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
|
||||||
} else {
|
} else {
|
||||||
|
@ -2974,6 +2968,37 @@ out:
|
||||||
return ret;
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Handle a read request in coroutine context
|
||||||
|
*/
|
||||||
|
static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
|
||||||
|
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
|
||||||
|
BdrvRequestFlags flags)
|
||||||
|
{
|
||||||
|
BlockDriver *drv = bs->drv;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
if (!drv) {
|
||||||
|
return -ENOMEDIUM;
|
||||||
|
}
|
||||||
|
if (bdrv_check_request(bs, sector_num, nb_sectors)) {
|
||||||
|
return -EIO;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (bs->copy_on_read) {
|
||||||
|
flags |= BDRV_REQ_COPY_ON_READ;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* throttling disk I/O */
|
||||||
|
if (bs->io_limits_enabled) {
|
||||||
|
bdrv_io_limits_intercept(bs, nb_sectors, false);
|
||||||
|
}
|
||||||
|
|
||||||
|
ret = bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS,
|
||||||
|
nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
|
int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
|
||||||
int nb_sectors, QEMUIOVector *qiov)
|
int nb_sectors, QEMUIOVector *qiov)
|
||||||
{
|
{
|
||||||
|
|
Loading…
Reference in New Issue