kern/79336: [nfs] NFS client doesn't detect file updates on Novell NFS server

[Bob Johnson]

The following reply was made to PR kern/79336; it has been noted by GNATS.

From: Bob Johnson <bob89 at eng.ufl.edu>
To: freebsd-gnats-submit at FreeBSD.org, bob89 at eng.ufl.edu
Cc:  
Subject: Re: kern/79336: [nfs] NFS client doesn't detect file updates on Novell NFS server
Date: Fri, 8 Apr 2005 00:16:14 -0400

 Novell has informed us that they believe their server complies with the NFS 
 RFCs and they will not fix this problem.
 
 I have done a packet trace and confirmed their description: when a file is 
 replaced by a new copy of the file on a Novell NFS server, the file 
 timestamps sent to the NFS client do not change.  According to Novell, the 
 NFS client is expected to detect that the mtime of the parent directory has 
 changed, and do new LOOKUPs to get the timestamps for the file itself.  The 
 FreeBSD client instead does an ACCESS query on the file, which shows the 
 timestamps unchanged.  The FreeBSD server thus uses its cached copy rather 
 than fetching the new file contents from the server.  I do not agree with 
 Novell's contention that their server complies with the NFS RFCs, but that 
 doesn't solve the problem.
 
 touch-ing the file on the BSD server seems to force the timestamps to be 
 updated, thus forcing the file contents on the client to update and may be 
 the basis of a usable workaround in some situations.
 
 Deleting the file from the Novell NFS server before copying the new version to 
 the server does not cause this problem, and should be a workaround for some 
 situations.  Similarly, editing the file in place on the NFS server does not 
 seem to cause the problem.
 
 It does not appear to be possible to disable the cache on the FreeBSD client.