From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754161AbYEZRDA (ORCPT ); Mon, 26 May 2008 13:03:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754241AbYEZRCk (ORCPT ); Mon, 26 May 2008 13:02:40 -0400 Received: from www.church-of-our-saviour.org ([69.25.196.31]:54092 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754010AbYEZRCi (ORCPT ); Mon, 26 May 2008 13:02:38 -0400 Date: Mon, 26 May 2008 13:01:48 -0400 From: Theodore Tso To: Ingo Molnar Cc: Jan Kara , Arjan van de Ven , Linux Kernel Mailing List , Linus Torvalds , Greg KH , Andrew Morton Subject: Re: Top 10 bugs/warnings for the week of March 23rd, 2008 Message-ID: <20080526170147.GB9893@mit.edu> Mail-Followup-To: Theodore Tso , Ingo Molnar , Jan Kara , Arjan van de Ven , Linux Kernel Mailing List , Linus Torvalds , Greg KH , Andrew Morton References: <4836EE8C.1010200@linux.intel.com> <20080524222304.GD20563@atrey.karlin.mff.cuni.cz> <20080524153020.1df96cf2@linux.intel.com> <20080524224554.GA5970@mit.edu> <20080526093913.GG13529@elte.hu> <20080526101646.GD24507@mit.edu> <20080526104832.GG23261@elte.hu> <20080526162048.GH32407@duck.suse.cz> <20080526164858.GA24098@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080526164858.GA24098@elte.hu> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@mit.edu X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 26, 2008 at 06:48:58PM +0200, Ingo Molnar wrote: > > What if the USB stick was pulled mistakenly, the user notices her > mistake later on and plugs the USB stick back in and expects all the > data to not be corrupted? If the USB stack folks would like to work on how to recognize that it's the same USB stick that had been previously pulled, so that it gets the same block device, and we can decide for how long we should keep dirty buffers around associated with a pulled USB stick, we can certainly have that conversation. :-) > And any such problems do come up in the enterprise space as well, in > terms of multipath IO issues - and Linux still does quite poorly in that > area. We definitely have problems here, I agree. But at least with a multipath I/O device we have something that sticks around even when the last I/O path is pulled. We could talk about setting up dm-multipath with USB, I suppose --- that would have the benefit of getting the dm-multipath code much more widely exercised without needing exotic (and expensive) hardware kit being required. - Ted