Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations

[Kevin Wolf]

Am 08.03.2012 18:15, schrieb Paolo Bonzini:
> Remove the bdrv_co_write_zeroes callback.  Instead use the discard
> information from bdrv_get_info to choose between bdrv_co_discard
> and a normal write.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>

I'm not sure if this a good idea.

The goal of discard is to remove data from the image (or not add it if
it isn't there yet) and ideally deallocate the used clusters. The goal
of write_zeroes is to mark space as zero and explicitly allocate it for
this purpose.

>From a guest point of view these are pretty similar, but from a host
perspective I'd say there's a difference.

Kevin