Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751862AbWIGT4J (ORCPT ); Thu, 7 Sep 2006 15:56:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751863AbWIGT4I (ORCPT ); Thu, 7 Sep 2006 15:56:08 -0400 Received: from smtp.osdl.org ([65.172.181.4]:28082 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751861AbWIGT4F (ORCPT ); Thu, 7 Sep 2006 15:56:05 -0400 Date: Thu, 7 Sep 2006 12:55:55 -0700 From: Andrew Morton To: Badari Pulavarty Cc: lkml , ext4 , Will Simoneau , cmm@us.ibm.com Subject: Re: [PATCH] ext3_getblk should handle HOLE correctly Message-Id: <20060907125555.5bc44e33.akpm@osdl.org> In-Reply-To: <1157656947.7725.21.camel@dyn9047017100.beaverton.ibm.com> References: <1157564346.23501.49.camel@dyn9047017100.beaverton.ibm.com> <20060907114500.fe9fcf82.akpm@osdl.org> <1157656947.7725.21.camel@dyn9047017100.beaverton.ibm.com> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 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 Content-Length: 2769 Lines: 70 On Thu, 07 Sep 2006 12:22:27 -0700 Badari Pulavarty wrote: > On Thu, 2006-09-07 at 11:45 -0700, Andrew Morton wrote: > > On Wed, 06 Sep 2006 10:39:06 -0700 > > Badari Pulavarty wrote: > > > > > Hi Andrew, > > > > > > Its been reported that ext3_getblk() is not doing the right thing > > > and triggering following WARN(): > > > > > > BUG: warning at fs/ext3/inode.c:1016/ext3_getblk() > > > ext3_getblk+0x98/0x2a6 md_wakeup_thread > > > +0x26/0x2a > > > ext3_bread+0x1f/0x88 ext3_quota_read+0x136/0x1ae > > > v1_read_dqblk+0x61/0xac dquot_acquire+0xf6/0x107 > > > ext3_acquire_dquot+0x46/0x68 dqget+0x155/0x1e7 > > > dquot_transfer+0x3e0/0x3e9 dput+0x23/0x13e > > > ext3_setattr+0xc3/0x240 current_fs_time > > > +0x52/0x6a > > > notify_change+0x2bd/0x30d chown_common+0x9c/0xc5 > > > strncpy_from_user+0x3b/0x68 do_path_lookup > > > +0xdf/0x266 > > > __user_walk_fd+0x44/0x5a sys_chown+0x4a/0x55 > > > vfs_write+0xe7/0x13c sys_mkdir+0x1f/0x23 > > > syscall_call+0x7/0xb > > > > > > Looking at the code, it looks like its not handle HOLE correctly. > > > It ends up returning -EIO. > > > > Strange. The fs should be spewing these warnings all over the place. For > > some reason this code is hard to trigger. Why?? > > I guess - ext3_getblk() mostly used by ext3_bread() and most callers > to it would be reading already allocated block. OK. > > > > > - if (err == 1) { > > > + /* > > > + * ext3_get_blocks_handle() returns number of blocks > > > + * mapped. 0 in case of a HOLE. > > > + */ > > > + if (err > 0) { > > > err = 0; > > > - } else if (err >= 0) { > > > - WARN_ON(1); > > > - err = -EIO; > > > } > > > > That removes the warning if ext3_get_blocks_handle() returned a positive > > number greater than one. And it looks like we still need debugging support > > in this area. > > I am not sure why we need it ? All we care about is one block. If > ext3_get_blocks_handle() returns more than one (which it shouldn't) - The operative part is "which it shouldn't". This code is fairly fresh, and ext3 is paranoid. Once it's all settled down then after a year or so we might decide that the debugging code is no longer needed. Then again, we have plenty of five-year-old assertions in there.. - 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/