From: James Bottomley Subject: Re: [PATCH 0/3] scsi: Add Hyper-V logical block provisioning quirks Date: Sat, 11 Oct 2014 10:41:53 -0700 Message-ID: <1413049313.2068.48.camel@jarvis.lan> References: <20141010074901.GA32028@sucs.org> <20141011173902.GA1946@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141011173902.GA1946@infradead.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Christoph Hellwig Cc: linux-scsi@vger.kernel.org, Haiyang Zhang , linux-kernel@vger.kernel.org, Hannes Reinecke , devel@linuxdriverproject.org, Christoph Hellwig , Sitsofe Wheeler List-Id: linux-scsi@vger.kernel.org On Sat, 2014-10-11 at 10:39 -0700, Christoph Hellwig wrote: > On Fri, Oct 10, 2014 at 08:49:01AM +0100, Sitsofe Wheeler wrote: > > Microsoft Hyper-V virtual disks currently only claim SPC-2 compliance > > even though they implement post SPC-2 features (such as thin > > provisioning) which means the Linux kernel does not go on to test for > > those features even though they are advertised. > > > > A previous patch attempted to add a quirk to workaround this but the > > quirk was only enabled after the features had been scanned for, wouldn't > > work for "small" disks and would quirk on all Hyper-V SCSI devices > > (e.g. passthrough disks). > > > > The new patches partially revert the previous effort, add the quirk in a > > more traditional manner to only Hyper-V virtual disks and work on small > > virtual disks. > > This seems like might want a quirk to simply "force" a SPC3 compliance > level? This was initially suggested, but rejected by Microsoft because of other problems advertising SPC-3 compliance brings. Perhaps the hyper-v emulator has matured sufficiently that it will now work OK? James