From: Eric Sandeen Subject: Re: [PATCH V2] xfstests: make 275 pass Date: Wed, 04 Jan 2012 17:21:00 -0600 Message-ID: <4F04DEDC.6020807@redhat.com> References: <4F04A6E6.1090304@redhat.com> <4F04BC81.1000207@redhat.com> <20120104231725.GB24466@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: xfs-oss , ext4 development , Eryu Guan To: Dave Chinner Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2517 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752281Ab2ADXVR (ORCPT ); Wed, 4 Jan 2012 18:21:17 -0500 In-Reply-To: <20120104231725.GB24466@dastard> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 1/4/12 5:17 PM, Dave Chinner wrote: > On Wed, Jan 04, 2012 at 02:54:25PM -0600, Eric Sandeen wrote: >> Ok, this is a significant rework of 275, which made too many >> assumptions about details of space usage and failed on several >> filesystems (it passed on xfs, but only by accident). >> >> This new version tries to leave about 256k free, then tries >> a single 1M IO, and fails only if 0 bytes are written. >> >> It also sends a lot more to $seq.full for debugging on failure >> and fixes a few other stylistic things. >> >> Signed-off-by: Eric Sandeen > > I just had another thought about this, Eric.... > >> +# And at least some of it should succeed. >> +_filesize=`du $SCRATCH_MNT/tmp1 | awk '{print $1}'` >> +[ $_filesize -eq 0 ] && _fail "write file err: Partial write until enospc failed; wrote 0 bytes." > > The question that just came to mind was this assumes that allocation > succeeded so therefore the partial write succeeded. But that's not > necessary the case. The partial write might not succeed leaving the > file size as zero, but the underlying FS might not remove all the > blocks it allocated (nothing says that it has to). Hence to > determine if a partial write succeeded, we also need to check that > the file size itself is greater than zero.... Probably need to read up on what posix says it should do. I think what you're saying is that it might leave blocks allocated past EOF? That'd be surprising to me, but maybe I misunderstand? Anyway, testing file size as well as space is simple enough. -Eric > Cheers, > > Dave.