From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [LSF/MM TOPIC][ATTEND] protection information and userspace Date: Thu, 07 Feb 2013 14:20:07 -0500 Message-ID: References: <20130206195122.GA30652@sgi.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:22170 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758711Ab3BGTUA (ORCPT ); Thu, 7 Feb 2013 14:20:00 -0500 In-Reply-To: <20130206195122.GA30652@sgi.com> (Ben Myers's message of "Wed, 6 Feb 2013 13:51:22 -0600") Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Ben Myers Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-scsi@vger.kernel.org, martin.petersen@oracle.com >>>>> "Ben" == Ben Myers writes: Ben> I'm interested in discussing how to pass protection information to Ben> and from userspace. Maybe Martin could be enlisted for the Ben> discussion. I'll be there, obviously. Ben> I read that some work has already been done in this area but have Ben> not been able to locate it. It looks like the bio-integrity code Ben> already makes it possible to generate the t10-dif crc in the Ben> filesystem. Yep. Although the block layer will generate the PI when the filesystem submits the bio. So until we have a userland conduit there hasn't been much point in the filesystems mucking with the PI explicitly. Ben> It would be good to be able to get the guard and application tags Ben> back out to backup applications such as xfsdump. Enabling other Ben> applications to generate their own tags in userspace is also Ben> interesting. However, the app tag is really only good for disk drives. Most array vendors use it internally. And going forward we're going to use it for access control instead of opaque storage. So exposing the application tag space to userland applications is of very limited use at this point. -- Martin K. Petersen Oracle Linux Engineering