Re: [Qemu-devel] [PATCH 4/4] block: Cater to iscsi with non-power-of-2 discard

[Peter Lieven]

Am 01.08.2016 um 11:22 schrieb Paolo Bonzini:
> On 28/07/2016 04:39, Eric Blake wrote:
> > On 07/27/2016 01:25 AM, Fam Zheng wrote:
> > > On Thu, 07/21 13:34, Eric Blake wrote:
> > > > +    max_write_zeroes = max_write_zeroes / alignment * alignment;
> > > Not using QEMU_ALIGN_DOWN despite patch 3?
> > Looks like I missed that on the rebase. Can fix if there is a reason for
> > a respin.
> Since Stefan acked this, I'm applying the patch and fixing it to use
> QEMU_ALIGN_DOWN.
>
> Paolo

Hi,

I came across a sort of regression we introduced with the dropping of head and 
tail
of an unaligned discard.

The discard alignment that we use to trim the discard request is just a hint.

I learned on the equallogics that a page (which is this unusal 15MB large) is
unallocated even if the discard happens in pieces. E.g. in slices of 1MB 
requests.

From my point of view I would like to restore the old behaviour. What do you 
think?

Thanks,
Peter