Le Friday 17 Jan 2014 à 15:15:01 (+0100), Kevin Wolf a écrit :
> 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 <kw...@redhat.com>
> Reviewed-by: Max Reitz <mre...@redhat.com>
> ---
> block.c | 62 +++++++++++++++++++++++++++++++++++++++++---------------------
> 1 file changed, 41 insertions(+), 21 deletions(-)
>
> diff --git a/block.c b/block.c
> index f378a10..70b72f0 100644
> --- a/block.c
> +++ b/block.c
> @@ -2964,34 +2964,20 @@ 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;
> - }
> -
> - if (bs->copy_on_read_in_flight) {
> - wait_for_overlapping_requests(bs, sector_num, nb_sectors);
> - }
> + int64_t sector_num = offset >> BDRV_SECTOR_BITS;
> + unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
>
> - /* 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);
>
> @@ -3023,6 +3009,40 @@ 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)
> {
> --
> 1.8.1.4
>
>
Reviewed-by: Benoit Canet <ben...@irqsave.net>
