From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sandeen.net ([63.231.237.45]:38038 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751169AbdDFQ2D (ORCPT ); Thu, 6 Apr 2017 12:28:03 -0400 Subject: Re: [PATCH] fstests: generic: Check if cycle mount and sleep can affect fiemap result To: "Theodore Ts'o" , Eryu Guan References: <20170403070923.18518-1-quwenruo@cn.fujitsu.com> <20170405023526.GS22845@eguan.usersys.redhat.com> <20170406162616.zsnbgx6vy2fgugmq@thunk.org> Cc: Qu Wenruo , linux-btrfs@vger.kernel.org, fstests@vger.kernel.org, linux-ext4@vger.kernel.org From: Eric Sandeen Message-ID: <36663e81-9520-0c52-5e72-1d54ddbfb0b7@sandeen.net> Date: Thu, 6 Apr 2017 11:28:01 -0500 MIME-Version: 1.0 In-Reply-To: <20170406162616.zsnbgx6vy2fgugmq@thunk.org> Content-Type: text/plain; charset=windows-1252 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 4/6/17 11:26 AM, Theodore Ts'o wrote: > On Wed, Apr 05, 2017 at 10:35:26AM +0800, Eryu Guan wrote: >> >> Test fails with ext3/2 when driving with ext4 driver, fiemap changed >> after umount/mount cycle, then changed back to original result after >> sleeping some time. An ext4 bug? (cc'ed linux-ext4 list.) > > I haven't had time to look at this, but I'm not sure this test is a > reasonable one on the face of it. > > A file system may choose to optimize a file's extent tree for whatever > reason it wants, whenever it wants, including on an unmount --- and > that would not be an invalid thing to do. So to have an xfstests that > causes a test failure if a file system were to, say, do some cleanup > at mount or unmount time, or when the file is next opened, to merge > adjacent extents together (and hence change what is returned by > FIEMAP) might be strange, or even weird --- but is this any of user > space's business? Or anything we want to enforce as wrong wrong wrong > by xfstests? I had the same question. If the exact behavior isn't defined anywhere, I don't know what we can be testing, TBH. -Eric > - Ted