Re: [Qemu-devel] [PATCH v9 4/9] block: introduce BDRV_REQ_ALLOCATE flag

[Alberto Garcia]

On Tue 08 May 2018 04:58:11 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 must return -ENOTSUP if allocation cannot
> be done efficiently.
> This has to be made sure of by both
>   - the drivers that support the flag
>   - and the common block layer (so it will not fall back to any slowpath
>     (like writing zero buffers) in case the driver does not support
>     the flag).
>
> Signed-off-by: Anton Nefedov <address@hidden>

Reviewed-by: Alberto Garcia <address@hidden>

Berto