From: Eric Sandeen Subject: Re: Oops with ext4 from 2.6.27-rc3 Date: Wed, 13 Aug 2008 17:19:55 -0500 Message-ID: <48A35E0B.5050907@redhat.com> References: <47983.10.5.1.205.1218652098.squirrel@webmail.lugor.de> <200808132255.10194.mail@eworm.de> <20080813210408.GC6142@mit.edu> <200808132307.07437.mail@eworm.de> <20080813220100.GE6142@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Christian Hesse , linux-ext4@vger.kernel.org To: Theodore Tso Return-path: Received: from mx1.redhat.com ([66.187.233.31]:60854 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752719AbYHMWUD (ORCPT ); Wed, 13 Aug 2008 18:20:03 -0400 In-Reply-To: <20080813220100.GE6142@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Tso wrote: > On Wed, Aug 13, 2008 at 11:07:06PM +0200, Christian Hesse wrote: >> Please look at the bottom of my last two mails... That was with your patch >> applied. > > Sorry, I missed it. The new BUG seems to be a bug in the delayed > allocation code, specifically here, in fs/ext4/inode.c:ext4_da_release_space(): > > /* figure out how many metablocks to release */ > BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks); > mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb; > > I've quickly looked at the code, and how i_reserved_meta_blocks gets > updated, and nothing *obviously* wrong is jumping out at me. Anyone > else have time to investigate this a bit more deeply? I don't :), but I tried a quick reproducer anyway and couldn't hit it ... mkfs.ext3, mount, create non-extents file umount, tune2fs to ext4 mount as ext4, write to file, open file O_TRUNC ... didn't oops for me :( -Eric