NFS safety in 6.1-RELEASE

[Scott Long]

Dmitry Marakasov wrote:

> Hi!
> 
> In the TODO list for 6.1 RELEASE there was (and still is -
> http://www.freebsd.org/releases/6.1R/todo.html) one entry that
> bugs me:
> 
>       Issue: NFS data corruption between two 7.0 machines
>      Status: In progress
> Responsible: Mohan Srinivasan
> Description: Running fsx between a 7.0 NFS client and server detects
> data corruption. This problem can also be reproduced by using 6.1
> NFS server. The problem seems to be avoidable by turning off the
> attribute cache on the NFS client.
> 
> So I wanted to ask what's status of NFS for release - was that issue
> fixed and is it safe to use client and server NFS on 6.1 RELEASE?
> If there's still data corruption possible, how do I turn off the
> attribute cache?
> 

Dang, I meant to document that before the release, sorry.  There are two 
variants
that I've seen with 6.1.  One is between a Linux client and a FreeBSD 
server.  This
seems to be effectively fixed by using a 2.6.12 or later Linux kernel. 
The other is
due to any client or server disagreeing on the precision of the 
timestamps that are
passed in the attributes.  This disagreement can lead to the attribue 
cache getting
confused and returning incorrect data to the caller.  It can be turned 
off by either
changing the default timeouts to 0 that are defined in the nfsclient 
code, or by setting
the appropriate mount options in mount_nfs as per the man page.

Scott