Re: [Qemu-block] [Nbd] write_zeroes/trim on the whole disk

[Carl-Daniel Hailfinger]

On 24.09.2016 19:33, Vladimir Sementsov-Ogievskiy wrote:
> On 24.09.2016 20:13, Vladimir Sementsov-Ogievskiy wrote:
>> I agree that requests larger than disk size are ugly.. But splitting
>> request brings me again to idea of having separate command or flag
>> for clearing the whole disk without that dance. Server may report
>> availability of this/flag command only if target driver supports fast
>> write_zeroes (qcow2 in our case). 
> Also, such flag may be used to satisfy all needs:
>
> flag BIG_REQUEST is set and length = 0    ->    request on the whole 
> disk, offset must be 0
> flag BIG_REQUEST is set and length > 0    ->    request on 
> (offset*block_size, length*block_size), length*block_size must be <= 
> disk_size

What happens if length*block_size<=disk_size, but
offset*block_size+length*block_size>disk_size? Wraparound?

Regards,
Carl-Daniel