From: "Aneesh Kumar K.V" Subject: Fallocate and DirectIO Date: Fri, 12 Jun 2009 18:01:12 +0530 Message-ID: <20090612123112.GB25239@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: "linux-ext4@vger.kernel.org" , Theodore Tso , Eric Sandeen , Andreas Dilger Return-path: Received: from e23smtp03.au.ibm.com ([202.81.31.145]:49403 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783AbZFLMb1 (ORCPT ); Fri, 12 Jun 2009 08:31:27 -0400 Received: from d23relay01.au.ibm.com (d23relay01.au.ibm.com [202.81.31.243]) by e23smtp03.au.ibm.com (8.13.1/8.13.1) with ESMTP id n5CCTQiJ012758 for ; Fri, 12 Jun 2009 22:29:26 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay01.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n5CCVN4v565354 for ; Fri, 12 Jun 2009 22:31:28 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n5CCVNV8013119 for ; Fri, 12 Jun 2009 22:31:23 +1000 Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi, I noticed yesterday that a write to fallocate space via directIO results in fallback to buffer_IO. ie the userspace pages get copied to the page cache and then call a sync. I guess this defeat the purpose of using directIO. May be we should consider this a high priority bug. -aneesh