Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751008AbWELGpb (ORCPT ); Fri, 12 May 2006 02:45:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751010AbWELGpb (ORCPT ); Fri, 12 May 2006 02:45:31 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:10692 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751004AbWELGpa (ORCPT ); Fri, 12 May 2006 02:45:30 -0400 Message-ID: <44642F0E.4050500@in.ibm.com> Date: Fri, 12 May 2006 12:15:34 +0530 From: Suzuki Organization: IBM Software Labs User-Agent: Mozilla Thunderbird 1.0 (X11/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Randy.Dunlap" CC: reiserfs-dev@namesys.com, linux-kernel@vger.kernel.org, reiserfs-list@namesys.com, akpm@osdl.org, suparna@in.ibm.com, amitarora@in.ibm.com Subject: Re: [BUG] Reiserfs: reiserfs_panic while running fs stress tests References: <445ADA05.5000801@in.ibm.com> <20060511105006.e4811957.rdunlap@xenotime.net> In-Reply-To: <20060511105006.e4811957.rdunlap@xenotime.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2029 Lines: 63 Randy.Dunlap wrote: > On Fri, 05 May 2006 10:22:21 +0530 Suzuki wrote: > > >>Hi, >> >> >>I was working on a reiserfs panic with 2.6.17-rc3, while running fs >>stress tests. > > > Hi, > What test(s) do you use? The problem was initially hit while running the following tests simultaneously.. IOZone, bonnie++, dbench, fs_inod, fs_maim, fsstress, fsx_linux, postmark, tiobench. As I had mentioned in my post, I have a simple testcase to trigger the panic which can hit the code path explained below. The root cause of the problem is (as mentioned in the earlier post): Whenever there is an extending DIO write operation, the fs would create a safe link so as to ensure the file size consistent, if there is crash in between the DIO. This will be deleted once the write operation finishes. If the DIO write happens to go through a "HOLE" region in the file, it will fall into normal "buffered write", which is done through the address space operations prepare_write() & commit_write(). Now, the prepare_write() might allocate blocks for the file (if needed). So if there is some error at a later point (say ENOSPC) in prepare_write(), we need to discard the allocated blocks. This is done by calling "vmtruncate()" on the file. This call leads to reiserfs specific truncate, which would try to add a save link for the file. This addition causes a reiserfs_panic, since there is already a "save link" stored for the file. Thanks Suzuki > > >>The panic message looked like : >> >>" REISERFS: panic (device Null superblock): reiserfs[4248]: assertion >>!(truncate && (REISERFS_I(inode)->i_flags & i_link_saved_truncate_mask) >>) failed at fs/reiserfs/super.c:328:add_save_link: saved link already re >>exists for truncated inode 13b5a " > > > Thanks, > --- > ~Randy - 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/