On 09/24/2013 07:35 AM, Peter Lieven wrote:
> this patch adds a call to completely zero out a block device.
> the operation is sped up by checking the block status and
> only writing zeroes to the device if they currently do not
> return zeroes. optionally the zero writing can be sped up
> by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero
> write by unmapping if the driver supports it.
> 
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  block.c               |   37 +++++++++++++++++++++++++++++++++++++
>  include/block/block.h |    1 +
>  2 files changed, 38 insertions(+)
> 

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

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org