Re: [Qemu-devel] [PATCH v2 13/24] block: Introduce bdrv_co_do_pwritev()

[Kevin Wolf <kwolf@redhat.com>]

Am 13.12.2013 um 14:22 hat Kevin Wolf geschrieben:
> This is going to become the bdrv_co_do_preadv() equivalent for writes.
> In this patch, however, just a function taking byte offsets is created,
> it doesn't align anything yet.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 385fb8a..a80db2e 100644
> --- a/block.c
> +++ b/block.c
> @@ -3010,8 +3010,8 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
>  /*
>   * 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,
> +static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
> +    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
>      BdrvRequestFlags flags)
>  {
>      int ret;
> @@ -3022,21 +3022,32 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
>      if (bs->read_only) {
>          return -EACCES;
>      }
> -    if (bdrv_check_request(bs, sector_num, nb_sectors)) {
> +    if (bdrv_check_byte_request(bs, offset, bytes)) {
>          return -EIO;
>      }
>  
>      /* throttling disk I/O */
>      if (bs->io_limits_enabled) {
> -        bdrv_io_limits_intercept(bs, nb_sectors, true);
> +        bdrv_io_limits_intercept(bs, bytes << BDRV_SECTOR_BITS, true);
>      }

Oh nice, this shifts in the wrong direction.

If somebody feels like writing a test case, something testing that I/O
throttling actually throttles would be useful...

Kevin