From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754233AbaAGVoZ (ORCPT ); Tue, 7 Jan 2014 16:44:25 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:28442 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753480AbaAGVoO (ORCPT ); Tue, 7 Jan 2014 16:44:14 -0500 To: Hannes Reinecke Cc: "Darrick J. Wong" , "Martin K. Petersen" , chuck.lever@oracle.com, Christoph Hellwig , Jens Axboe , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: status of block-integrity From: "Martin K. Petersen" Organization: Oracle Corporation References: <20131222192128.GA28532@infradead.org> <52C6D0DB.1050906@suse.de> <20140107013646.GB10297@birch.djwong.org> <52CBAA1B.7000509@suse.de> Date: Tue, 07 Jan 2014 16:43:40 -0500 In-Reply-To: <52CBAA1B.7000509@suse.de> (Hannes Reinecke's message of "Tue, 07 Jan 2014 08:17:47 +0100") Message-ID: User-Agent: Gnus/5.130005 (Ma Gnus v0.5) Emacs/24.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Hannes" == Hannes Reinecke writes: Hannes> Plus (as hch rightly pointed out) as there is no defined Hannes> userland interface the question is why we bother with all the Hannes> DIX stuff in the block layer. Because it catches problems in the path between block layer and HBA ASIC? FWIW, we find more issues there than we do between initiator and target. API issues aside, another reason adoption has been slow is that very few applications truly care about this stuff. The current approach in which data is protected when the I/O is submitted by the filesystem is good enough for most things. Saves the filesystem people the trouble of dealing with it too. In reality there are only a handful of applications that would actually benefit from an explicit userland API. Mostly in the database department. All the potential consumers of an interface I talked to wanted to use aio so that's why we've focused our efforts there. Both Darrick and I have been busy with other projects the last little while. I'll start looking at this again when I'm done with copy offload... -- Martin K. Petersen Oracle Linux Engineering