From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from odin2.bull.net ([129.184.85.11]:43165 "EHLO odin2.bull.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981Ab2IENDn (ORCPT ); Wed, 5 Sep 2012 09:03:43 -0400 Received: from MSGC-003.bull.fr (MSGC-003.frcl.bull.fr [129.184.87.131]) by odin2.bull.net (Bull S.A.) with ESMTP id 1907118144 for ; Wed, 5 Sep 2012 14:39:46 +0200 (CEST) Message-ID: <50474858.1020801@bull.net> Date: Wed, 05 Sep 2012 14:40:56 +0200 From: Diego Moreno MIME-Version: 1.0 To: linux-nfs@vger.kernel.org Subject: NFSv3 caching vs NFSv4 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: Hello everyone, Performing some attribute caching tests I think I found some inconsistencies between nfsv3 and nfsv4. Running a kernel based on rhel6.3 (2.6.32-279.el6.x86_64) I found nfsv4 doesn't manage a file modified on the server side (even with the noac mount option) while nfsv3 does. My test will be modifying a file every second on the server mount point: [root@nfs ~]# FILE=/tmp/nfs_server/myfile ; while true ; do sleep 1 ; sed -i 's/text1/text2/g' $FILE ; cat $FILE ; sleep 1; sed -i 's/text2/text1/g' $FILE ; cat $FILE ; done text2 text1 text2 text1 text2 (and so on...) Meanwhile, the client (which BTW is the same machine) will read the file every second : With NFSv4: [root@nfs ~]# mount -o noac,vers=4 nfs:/tmp/nfs_server/ /tmp/nfs_client/ [root@nfs ~]# for i in 1 2 3 4 5 ; do cat /tmp/nfs_client/myfile; sleep 1 ; done text2 text1 text1 text1 text1 With NFSv3: [root@nfs ~]# mount -o noac,vers=3 nfs:/tmp/nfs_server/ /tmp/nfs_client/ [root@nfs ~]# for i in 1 2 3 4 5 ; do cat /tmp/nfs_client/myfile; sleep 1 ; done text1 text2 text1 text2 text1 I can see in the tcpdump traces how the new change attribute and the FATTR4_TIME_MODIFY attributes are well received but it's as if the nfs client were ignoring these changes. I've been searching in the NFS list but I didn't find anything similar. Is this a bug or just a normal behavior? Sorry if it has been already pointed out. Regards, Diego Moreno