From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ewan D. Milne" Subject: Re: [PATCH] sd: always scan VPD pages if thin provisioning is enabled Date: Wed, 25 Jan 2017 09:27:05 -0500 Message-ID: <1485354425.5280.76.camel@localhost.localdomain> References: <1485329165-64825-1-git-send-email-hare@suse.de> <20170125102329.GA17657@lst.de> <022cd098-4156-6e17-a308-adff544bf99f@suse.de> Reply-To: emilne@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47616 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750870AbdAYO1G (ORCPT ); Wed, 25 Jan 2017 09:27:06 -0500 In-Reply-To: <022cd098-4156-6e17-a308-adff544bf99f@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: Christoph Hellwig , "Martin K. Petersen" , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke On Wed, 2017-01-25 at 11:38 +0100, Hannes Reinecke wrote: > On 01/25/2017 11:23 AM, Christoph Hellwig wrote: > > On Wed, Jan 25, 2017 at 08:26:05AM +0100, Hannes Reinecke wrote: > >> For any device with an older SCSI revision we might not > >> be scanning VPD pages, which results in a wrongly configured > >> discard mode if thin provisioned is enabled. > >> According to sbc3 any thin provisioned device (ie devices which > >> have the LBPME bit set in the output of READ CAPACITY(16)) need > >> to support VPD pages. So this patch always enables VPD pages > >> even for older SCSI revisions if thin provisioning is enabled. > > > > Can you explain what you need this for? A device with a per-SBC3 > > revision that wants us to use UNMAP? > > > Some storage arrays essentially lie about the SCSI revision (most > notably Hitachi :-), and some claim to support SPC-2 (or even SPC) but > support newer features, too. Most notably VPD pages support. > In this case it was an HP EVA claiming to support SPC-2 only, but > providing thin provisioning. Um, isn't this why we added: commit c1d40a527e885a40bb9ea6c46a1b1145d42b66a0 Author: Martin K. Petersen Date: Tue Jul 15 12:49:17 2014 -0400 scsi: add a blacklist flag which enables VPD page inquiries (well, it was for storvsc, but we could add an entry for the HP EVA) > >> + /* > >> + * sbc3r36 states: > >> + * The device server in a logical unit the supports > >> + * logical block provisioning management shall support > >> + * the Logical Block Provisioning VPD page. > >> + * So VPD pages should be supported if lbpme is set. > >> + */ > > > > It's a bit odd to quote SBC3 when the device clearly is pre-SBC3 > > to need this workaround.. > > > _Actually_ it's pre-SPC-3. > > But that was the earliest draft I had :-( > I'd be happy to modify this if I had access to sbc-2 drafts. > > >> + if (!scsi_device_supports_vpd(sdp)) > >> + sdp->try_vpd_pages = 1; > > > > Do the assignment unconditionally? > > > Yeah, can do. > > Cheers, > > Hannes