Re: [Qemu-devel] [PATCH v3 16/29] block: Make zero-after-EOF work with larger alignment

[Benoît Canet]

Le Friday 17 Jan 2014 à 15:15:06 (+0100), Kevin Wolf a écrit :
> Odd file sizes could make bdrv_aligned_preadv() shorten the request in
> non-aligned ways. Fix it by rounding to the required alignment instead
> of 512 bytes.
> 
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  block.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 18dcd43..d7156ce 100644
> --- a/block.c
> +++ b/block.c
> @@ -2730,7 +2730,7 @@ err:
>   */
>  static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
>      BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
> -    QEMUIOVector *qiov, int flags)
> +    int64_t align, QEMUIOVector *qiov, int flags)
>  {
>      BlockDriver *drv = bs->drv;
>      int ret;
> @@ -2778,7 +2778,8 @@ static int coroutine_fn 
> bdrv_aligned_preadv(BlockDriverState *bs,
>          }
>  
>          total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE);
> -        max_nb_sectors = MAX(0, total_sectors - sector_num);
> +        max_nb_sectors = MAX(0, ROUND_UP(total_sectors - sector_num,
> +                                         align >> BDRV_SECTOR_BITS));
>          if (max_nb_sectors > 0) {
>              ret = drv->bdrv_co_readv(bs, sector_num,
>                                       MIN(nb_sectors, max_nb_sectors), qiov);
> @@ -2864,7 +2865,7 @@ static int coroutine_fn 
> bdrv_co_do_preadv(BlockDriverState *bs,
>      }
>  
>      tracked_request_begin(&req, bs, offset, bytes, false);
> -    ret = bdrv_aligned_preadv(bs, &req, offset, bytes,
> +    ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align,
>                                use_local_qiov ? &local_qiov : qiov,
>                                flags);
>      tracked_request_end(&req);
> -- 
> 1.8.1.4
> 
> 
Reviewed-by: Benoit Canet <address@hidden>