From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752909AbYI2Ow0 (ORCPT ); Mon, 29 Sep 2008 10:52:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751562AbYI2OwS (ORCPT ); Mon, 29 Sep 2008 10:52:18 -0400 Received: from rgminet01.oracle.com ([148.87.113.118]:59229 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbYI2OwR (ORCPT ); Mon, 29 Sep 2008 10:52:17 -0400 To: Neil Brown Cc: "Martin K. Petersen" , jens.axboe@oracle.com, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: [PATCH] md: Add support for data integrity to MD From: "Martin K. Petersen" Organization: Oracle References: <18649.43504.157272.351801@notabene.brown> Date: Mon, 29 Sep 2008 10:51:54 -0400 In-Reply-To: <18649.43504.157272.351801@notabene.brown> (Neil Brown's message of "Wed\, 24 Sep 2008 12\:46\:08 +1000") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Brightmail-Tracker: AAAAAQAAAAI= X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Neil" == Neil Brown writes: Neil> But what if we subsequently add a different device to that array Neil> which uses a different protection format. Would we be able to Neil> tell the filesystem that integrity protection isn't available Neil> any more? Or can we detect if the filesystem is using integrity Neil> protection, and reject the new device if it doesn't match? Generally the filesystem will look at the block device's integrity profile every time it prepares an I/O. So if we add a subdevice and detect a mismatch the mddev integrity profile should be removed. Neil> In either case, some extra handling is needed in Neil> bind_rdev_to_array. This code has been sitting in my patch queue for several months waiting for the core of the integrity stuff to go in. So I'm a bit fuzzy on the details. I'll take a look... -- Martin K. Petersen Oracle Linux Engineering