Re: [Qemu-devel] [PATCH v3 4/5] block: add flush callback

[Kevin Wolf <kwolf@redhat.com>]

Am 01.03.2016 um 12:07 hat Pavel Dovgalyuk geschrieben:
> This patch adds callback for flush request. This callback is responsible
> for flushing whole block devices stack. bdrv_flush function does not
> proceed to underlying devices. It should be performed by this callback
> function, if needed.
> 
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
> ---
>  block/io.c                |    6 ++++++
>  include/block/block_int.h |    7 +++++++
>  2 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index a69bfc4..9e05dfe 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -2369,6 +2369,12 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
>      }
>  
>      tracked_request_begin(&req, bs, 0, 0, BDRV_TRACKED_FLUSH);
> +    /* Write back all layers by calling one driver function */
> +    if (bs->drv->bdrv_co_flush) {
> +        ret = bs->drv->bdrv_co_flush(bs);
> +        goto out;
> +    }
> +    

Trailing whitespace.

Also, while you update the formatting, how about an empty line before
the comment?

>      /* Write back cached data to the OS even with cache=unsafe */
>      BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS);
>      if (bs->drv->bdrv_co_flush_to_os) {
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 9ef823a..9cc2c58 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -176,6 +176,13 @@ struct BlockDriver {
>      int (*bdrv_inactivate)(BlockDriverState *bs);
>  
>      /*
> +     * Flushes all data for all layers by calling bdrv_co_flush for underlying
> +     * layers, if needed. This function is needed for deterministic
> +     * synchronization of the flush finishing callback.
> +     */
> +    int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs);
> +    

Trailing whitespace again.

Otherwise, the patch looks good.

Kevin