On Tue 01 Aug 2017 04:19:00 PM CEST, Anton Nefedov wrote:
> The flag is supposed to indicate that the region of the disk image has
> to be sufficiently allocated so it reads as zeroes. The call with the flag
> set has to return -ENOTSUP if allocation cannot be done efficiently
> (i.e. without falling back to writing actual buffers)
>
> Signed-off-by: Anton Nefedov <anton.nefe...@virtuozzo.com>
Reviewed-by: Alberto Garcia <be...@igalia.com>
> + /* allocation request with qiov provided doesn't make much sense */
> + assert(!(qiov && flags & BDRV_REQ_ALLOCATE));
> + assert(!(flags & BDRV_REQ_MAY_UNMAP && flags & BDRV_REQ_ALLOCATE));
> +
> + if (flags & BDRV_REQ_ALLOCATE &&
> + !(child->bs->supported_zero_flags & BDRV_REQ_ALLOCATE))
I find it more readable with parentheses like this:
assert(!(qiov && (flags & BDRV_REQ_ALLOCATE)));
assert(!((flags & BDRV_REQ_MAY_UNMAP) && (flags & BDRV_REQ_ALLOCATE)));
if ((flags & BDRV_REQ_ALLOCATE) &&
!(child->bs->supported_zero_flags & BDRV_REQ_ALLOCATE))
but your code is correct as it is.
Berto
