From: Eric Sandeen Subject: Re: [PATCH v3 0/3] Add XIP support to ext4 Date: Wed, 18 Dec 2013 12:13:01 -0600 Message-ID: <52B1E5AD.9070009@redhat.com> References: <20131217223050.GB20579@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Dave Chinner , Matthew Wilcox Return-path: Received: from mx1.redhat.com ([209.132.183.28]:65507 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754546Ab3LRSNH (ORCPT ); Wed, 18 Dec 2013 13:13:07 -0500 In-Reply-To: <20131217223050.GB20579@dastard> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 12/17/13, 4:30 PM, Dave Chinner wrote: > On Tue, Dec 17, 2013 at 02:18:25PM -0500, Matthew Wilcox wrote: >> For v3, we've addressed the problem with unwritten extents that Dave >> Chinner pointed out. > > No, you haven't addressed the problem. There is nothing in this > patch set that converts an unwritten extent after it is written to. > Hence on every subsequent read will return zeros because the block > is still marked as unwritten. I'd really strongly encourage you guys to try running through xfstests. IF you haven't seen this stuff fail yet, you're apparently not testing these paths - I'm guessing xfstests may expose these holes quite well. I'd be happy to help you get up & running on xfstests if you need a hand. -Eric