RE: [PATCH 4/8] Drivers: scsi: storvsc: Filter WRITE_SAME_16

KY Srinivasan
2014-07-09T19:52:54Z

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@infradead.org]
> Sent: Wednesday, July 9, 2014 1:43 AM
> To: KY Srinivasan
> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> ohering@suse.com; jbottomley@parallels.com; jasowang@redhat.com;
> apw@canonical.com; linux-scsi@vger.kernel.org; stable@vger.kernel.org
> Subject: Re: [PATCH 4/8] Drivers: scsi: storvsc: Filter WRITE_SAME_16
>
> On Tue, Jul 08, 2014 at 05:46:48PM -0700, K. Y. Srinivasan wrote:
> > Host does not handle WRITE_SAME_16; filter this command out. This
> > patch is required to handle large devices (greater than 2 TB disks).
>
> Storvsc already sets the no_write_same flag, where is the command coming
> from?

In spite of this flag, I see WRITE_SAME_16 being issued when I format a device bigger than 2 TB;
I tried both xfs and ext4. Windows hosts currently do not handle unsupported commands correctly -
The information returned is not sufficient to effect recovery in the Linux guest. While this may be addressed in
future hosts, this patch fixes the problem.

K. Y