From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: REGRESSION: [PATCH 04/12] ext4: Disable merging of uninitialized extents Date: Thu, 14 Feb 2013 14:05:55 -0500 Message-ID: <20130214190555.GA6641@thunk.org> References: <1358510446-19174-1-git-send-email-jack@suse.cz> <1358510446-19174-5-git-send-email-jack@suse.cz> <20130209171015.GC8091@thunk.org> <20130214161116.GB31269@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dmitry Monakhov , linux-ext4@vger.kernel.org To: Jan Kara Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:48305 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758544Ab3BNTGZ (ORCPT ); Thu, 14 Feb 2013 14:06:25 -0500 Content-Disposition: inline In-Reply-To: <20130214161116.GB31269@quack.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Feb 14, 2013 at 05:11:16PM +0100, Jan Kara wrote: > OK, so I've debugged this. It wasn't actually that hard. The problem is > that mpage_da_map_and_submit() prepares extent with e.g. 256 blocks but > later we submit a shorter bio e.g. because it cannot carry that many pages. > So ->end_io is called only for first 128 blocks or so. I spotted this > problem already before, just it didn't come up when Ted sent me this bug > report. So can we get a corruption without these patches, but it was a lot harder to hit that case before? - Ted