On Wed, Sep 05, 2012 at 02:49:18PM +0000, Myklebust, Trond wrote: > On Wed, 2012-09-05 at 14:40 +0200, Diego Moreno wrote: > > 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. > > ]If you can reproduce the same issues on the upstream kernel, then it is > on topic for this list, otherwise it is a question for Red Hat. I believe sed -i is actually doing a rename not a file modification. So the problem is likely another symptom of the bug that delegations aren't revoked on rename/link/unlink. Hoping to post the latest draft of patches to fix that later today. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
