Re: [Qemu-devel] [PATCH v10 6/9] file-posix: support BDRV_REQ_ALLOCATE

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

03.12.2018 13:14, Anton Nefedov wrote:
> Current write_zeroes implementation is good enough to satisfy this flag too
> 
> Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
> ---
>   block/file-posix.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 07bbdab953..b0b7ab0159 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -603,6 +603,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
>           } else {
>               s->discard_zeroes = true;
>               s->has_fallocate = true;
> +            bs->supported_zero_flags = BDRV_REQ_ALLOCATE;
>           }
>       } else {
>           if (!(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
> @@ -646,10 +647,11 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
>   #ifdef CONFIG_XFS
>       if (platform_test_xfs_fd(s->fd)) {
>           s->is_xfs = true;
> +        bs->supported_zero_flags = BDRV_REQ_ALLOCATE;

why we should handle xfs separately? is there a case with xfs, not handled by previous generic if ()?

>       }
>   #endif
>   
> -    bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
> +    bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
>       ret = 0;
>   fail:
>       if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
> @@ -1520,6 +1522,10 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
>           }
>           s->has_fallocate = false;
>       }
> +
> +    if (!s->has_fallocate) {
> +        aiocb->bs->supported_zero_flags &= ~BDRV_REQ_ALLOCATE;
> +    }
>   #endif
>   
>       return -ENOTSUP;
> 


-- 
Best regards,
Vladimir