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block: Introduce bdrv_aligned_pwritev()

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This separates the part of bdrv_co_do_writev() 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: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
This commit is contained in:
Kevin Wolf 2013-12-03 14:02:23 +01:00
parent 1b0288ae7f
commit b404f72036
1 changed files with 41 additions and 21 deletions
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62
block.c
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@ -3144,34 +3144,20 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
}
/*
* Handle a write request in coroutine context
* Forwards an already correctly aligned write request to the BlockDriver.
*/
static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags)
static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)
{
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
int ret;
if (!bs->drv) {
return -ENOMEDIUM;
}
if (bs->read_only) {
return -EACCES;
}
if (bdrv_check_request(bs, sector_num, nb_sectors)) {
return -EIO;
}
int64_t sector_num = offset >> BDRV_SECTOR_BITS;
unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
if (bs->copy_on_read_in_flight) {
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, true);
}
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
@ -3203,6 +3189,40 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
return ret;
}
/*
* Handle a write request in coroutine context
*/
static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
int ret;
if (!bs->drv) {
return -ENOMEDIUM;
}
if (bs->read_only) {
return -EACCES;
}
if (bdrv_check_request(bs, sector_num, nb_sectors)) {
return -EIO;
}
if (bs->copy_on_read_in_flight) {
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, true);
}
ret = bdrv_aligned_pwritev(bs, sector_num << BDRV_SECTOR_BITS,
nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
return ret;
}
int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{