From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754009AbYJUOfT (ORCPT ); Tue, 21 Oct 2008 10:35:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751883AbYJUOfF (ORCPT ); Tue, 21 Oct 2008 10:35:05 -0400 Received: from hope.ime.usp.br ([143.107.45.8]:52512 "HELO hope.ime.usp.br" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751552AbYJUOfE (ORCPT ); Tue, 21 Oct 2008 10:35:04 -0400 Date: Tue, 21 Oct 2008 12:35:00 -0200 From: =?iso-8859-1?Q?Rog=E9rio?= Brito To: Theodore Tso , Alexandre Lymberopoulos , 502583@bugs.debian.org, 502583-submitter@bugs.debian.org, linux-kernel@vger.kernel.org, rafael@debian.org Subject: Re: Bug#502583: scary messages in dmesg Message-ID: <20081021143500.GA18469@ime.usp.br> References: <2bfaaf400810172145g4aba4827l87a19e67b9742815@mail.gmail.com> <20081018060400.GB916@ime.usp.br> <2bfaaf400810201654u21c9d950o72b2afa9496ba3da@mail.gmail.com> <20081021101510.GA16244@ime.usp.br> <20081021123348.GB15685@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20081021123348.GB15685@mit.edu> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org First of all, Thanks Theodore. On Oct 21 2008, Theodore Tso wrote: > On Tue, Oct 21, 2008 at 08:15:10AM -0200, Rogério Brito wrote: > > Did you sync the device? From the message, it seems that some data were > > to be written to the device, but the device was already gone by that > > time, but I'm not a specialist on the filesystem subsystem and perhaps > > others could say more about it. > > A patch to suppress the WARN information will be in 2.6.28 when the > user does something stupid (i.e., yank out a USB stick without > unmounting the filesystem first). Right. I will put a big, fat warning on the installation of usbmount and tell the users about it. Besides that, depending on the filesystem, the superblock may be marked as dirty. > This was done mainly to suppress the "scary message" in dmesg, which on > distributions that support uploading such messages to > http://www.kerneloops.org for analysis, was cluttering the reports. Right... > > > > [39071.160167] Buffer I/O error on device sda1, logical block 1545 > > > > [39071.160170] lost page write due to I/O error on sda1 > > > > [39071.160184] Buffer I/O error on device sda1, logical block 1545 > > > > [39071.160187] lost page write due to I/O error on sda1 > > These errors you'd still get, since these messages are the sound of > users' data being irretrivably being lost. Good that not all messages will be going... BTW, this reminded me of a patch that eliminated a whole lot of messages (BUG()'s) for embedded devices... I didn't find it anymore... Also, the same thing with the hash tables that could turn into linked lists eventually... But I'm drifting away from the main topic. > > Well, it is a bug. It just needs more investigation to see where the bug > > lies. > > I don't know if you would call it a bug or not. Fundamentally, > yanking out a USB stick without unmounting it first is dangerous, and > can lead to data loss. At least sync'ing... [snip] > If you see "lost page write due to I/O error", then you will have lost > data due to premature removal of the USB stick, and fundamentally > *that* bug exists between the keyboard and the chair. Ok, so I'm closing this bug in the next upload. Thanks, Rogério Brito. -- Rogério Brito : rbrito@{mackenzie,ime.usp}.br : GPG key 1024D/7C2CAEB8 http://www.ime.usp.br/~rbrito : http://meusite.mackenzie.com.br/rbrito Projects: algorithms.berlios.de : lame.sf.net : vrms.alioth.debian.org