From: Eric Sandeen Subject: Re: Files full of zeros with coreutils-8.11 and xfs (FIEMAP related?) Date: Thu, 14 Apr 2011 11:14:59 -0500 Message-ID: <4DA71D83.5040601@sandeen.net> References: <20110414102608.GA1678@x4.trippels.de> <20110414120635.GB1678@x4.trippels.de> <20110414140222.GB1679@x4.trippels.de> <4DA70BD3.1070409@draigBrady.com> <4DA717B2.3020305@sandeen.net> <4DA7182B.8050409@draigBrady.com> <4DA71920.9@sandeen.net> <20110414160343.GA12787@x4.trippels.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: =?ISO-8859-1?Q?P=E1draig_Brady?= , xfs-oss , linux-ext4@vger.kernel.org, coreutils@gnu.org To: Markus Trippelsdorf Return-path: Received: from sandeen.net ([63.231.237.45]:37411 "EHLO mail.sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759028Ab1DNQPA (ORCPT ); Thu, 14 Apr 2011 12:15:00 -0400 In-Reply-To: <20110414160343.GA12787@x4.trippels.de> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 4/14/11 11:03 AM, Markus Trippelsdorf wrote: > On 2011.04.14 at 10:56 -0500, Eric Sandeen wrote: ... >> well, if I simply take the preallocation step out of the testcase, it works fine on xfs without a sync. >> >> So I still don't know what Markus hit... > > Maybe it's delalloc: > > x4 /tmp # dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=k > 10+0 records in > 10+0 records out > 5120 bytes (5.1 kB) copied, 0.0021822 s, 2.3 MB/s > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 0 16 unknown,delalloc,eof > k: 1 extent found > x4 /tmp # sync > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 26960045 16 eof > k: 1 extent found > well filefrag still returns that it knows of a valid range from logical blocks 0 to 16, so cp should have something to copy... -Eric