Re: [PATCH v4 04/16] block/io: refactor bdrv_pad_request(): move bdrv_pad_request() up

[Eric Blake]

On 12/11/20 12:39 PM, Vladimir Sementsov-Ogievskiy wrote:
> Prepare to the following patch when bdrv_pad_request() will be able to

s/Prepare to/Prepare for/

> fail. Update the comments.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/io.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
> 

> -    if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) {
> +    if (padded) {
> +        /*
> +         * Request was unaligned to request_alignment and therefore padded.
> +         * We are going to do read-modify-write. User is not prepared to 
> widened
> +         * request intersections with other requests, so we serialize the
> +         * request.

We are going to do read-modify-write, and must serialize the request to
prevent interactions of the widened region with other transactions.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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