Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265083AbTFRH6d (ORCPT ); Wed, 18 Jun 2003 03:58:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265085AbTFRH6d (ORCPT ); Wed, 18 Jun 2003 03:58:33 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:29350 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S265083AbTFRH6c (ORCPT ); Wed, 18 Jun 2003 03:58:32 -0400 Date: Wed, 18 Jun 2003 09:12:28 +0100 From: viro@parcelfarce.linux.theplanet.co.uk To: "Perez-Gonzalez, Inaky" Cc: "'Kevin P. Fleming'" , "'Alan Stern'" , "'Patrick Mochel'" , "'Russell King'" , "'Greg KH'" , "'linux-kernel@vger.kernel.org'" Subject: Re: Flaw in the driver-model implementation of attributes Message-ID: <20030618081227.GA6754@parcelfarce.linux.theplanet.co.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1825 Lines: 38 On Wed, Jun 18, 2003 at 12:48:59AM -0700, Perez-Gonzalez, Inaky wrote: > [I happen not to know the block layer as well as you and many others > do, so please correct me where I am wrong ...] > > So what? _every_ block device will have some form of physical > back-up that can be linked back into sysfs. ... except ones that will not. Wonderful. I bow to that logics - there is nothing it wouldn't cover. > In cases like this, doesn't it make sense to have some > /sys/devices/SOMETHING/ hierarchy for those "logical" or "virtual" > devices that back-up those block devices? > > You could even say that RAID and ramdisks -as used in the example > above- would belong to /sys/devices/"virtual"/raid/ and > ...../ramdisks/; after all, you have to create those devices before > being able to attach them (last time I checked): > In the tree structure it makes sense, because each block > device, at the end is or a partition (and thus is embedded > in a "true" block device) or a true block device on a 1:1 > relationship with a physical device. BS. There is nothing to stop you from having a block device that talks to userland process instead of any form of hardware. As the matter of fact, we already have such a beast - nbd. There is also RAID - where there fsck is 1:1 here? There's also such thing as RAID5 over partitions that sit on several disks - where do you see 1:1 or 1:n or n:1? There is such thing as e.g. encrypted loop over NFS. There are all sorts of interesting things, with all sorts of interesting relationship to some pieces of hardware. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/