From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH] sd: always scan VPD pages if thin provisioning is enabled Date: Wed, 25 Jan 2017 21:45:17 -0500 Message-ID: References: <1485329165-64825-1-git-send-email-hare@suse.de> <20170125102329.GA17657@lst.de> <022cd098-4156-6e17-a308-adff544bf99f@suse.de> <1485354425.5280.76.camel@localhost.localdomain> <02181dcf-0177-d2f3-545e-264d87bc489b@suse.de> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:45310 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752453AbdAZCpl (ORCPT ); Wed, 25 Jan 2017 21:45:41 -0500 In-Reply-To: <02181dcf-0177-d2f3-545e-264d87bc489b@suse.de> (Hannes Reinecke's message of "Wed, 25 Jan 2017 15:38:35 +0100") Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: emilne@redhat.com, Christoph Hellwig , "Martin K. Petersen" , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke >>>>> "Hannes" == Hannes Reinecke writes: Hannes, Hannes> Thing is, setting 'WS16' here is arguably wrong, as LPBME just Hannes> means 'logical block provisioning management enabled', not Hannes> 'WRITE SAME 16 with UNMAP' supported. Things are the way they are because many devices predate the final SBC spec. They report LBPME=1 but do not have the VPD page indicating their preferred deprovisioning command. The VPD was added very late in the spec and there are a ton of devices that don't have it. As a result, we default to WS16 unless the device reports the UNMAP parameters in the Block Limits VPD. That has been a very solid heuristic for a long time so please don't mess with that. -- Martin K. Petersen Oracle Linux Engineering