From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 18 Jun 2002 00:11:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 18 Jun 2002 00:11:37 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:26631 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Tue, 18 Jun 2002 00:11:36 -0400 Message-ID: <3D0EB3F2.C128F97C@zip.com.au> Date: Mon, 17 Jun 2002 21:15:46 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-pre9 i686) X-Accept-Language: en MIME-Version: 1.0 To: Andreas Dilger CC: "David S. Miller" , linux-kernel@vger.kernel.org Subject: Re: ext2 errors w/2.5.x References: <20020617.195611.61846581.davem@redhat.com> <20020618032544.GM22427@clusterfs.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andreas Dilger wrote: > > On Jun 17, 2002 19:56 -0700, David S. Miller wrote: > > I started seeing these occaisionally on my SMP boxes about a month or > > two ago, is anyone else seeing something similar? > > > > EXT2-fs error (device sd(8,17)): ext2_find_entry: zero-length directory entry > > > > Upon reboot e2fsck is forced to run (since the partition is marked as > > having errors by the kernel) and no problems are discovered. > > > > Any clues? > > This would appear to be from accessing a buffer (page) which has not yet > been read from disk. Otherwise you would have an error from e2fsck also. > Andrew has been mucking the most in this area... > Not that, I hope. Possibly it's the interaction between block_write_full_pages's memset outside i_size, truncate and lookup. It took me a ridiculous amount of time to get that "correct", so it's a suspicion point. Or possibly locking between lookup and truncate (rmdir) and/or creat. Dave, I assume this is with 8k pages and 4k blocks? Is it repeatable enough to conduct a little experiment? Like, lock the page in ext2_find_entry? --- linux-2.5.22/fs/ext2/dir.c Wed May 29 11:42:43 2002 +++ 25/fs/ext2/dir.c Mon Jun 17 20:50:48 2002 @@ -348,6 +348,7 @@ struct ext2_dir_entry_2 * ext2_find_entr char *kaddr; page = ext2_get_page(dir, n); if (!IS_ERR(page)) { + lock_page(page); kaddr = page_address(page); de = (ext2_dirent *) kaddr; kaddr += ext2_last_byte(dir, n) - reclen; @@ -355,6 +356,7 @@ struct ext2_dir_entry_2 * ext2_find_entr if (de->rec_len == 0) { ext2_error(dir->i_sb, __FUNCTION__, "zero-length directory entry"); + unlock_page(page); ext2_put_page(page); goto out; } @@ -367,10 +369,12 @@ struct ext2_dir_entry_2 * ext2_find_entr if (++n >= npages) n = 0; } while (n != start); + unlock_page(page); out: return NULL; found: + unlock_page(page); *res_page = page; ei->i_dir_start_lookup = n; return de; -