[Linux-cluster] GFS

[Gradimir Starovic]

> > I thought GFS had its gfs_lock file operation, but must say 
> my knowledge
> > of GFS is not great. The problem is, how can fcntl locking 
> be cluster-wide, 
> > for nfs on a cluster, if it's done only locally and the 
> cluster fs is
> > not even told about that. 
> 
> That may have been misleading -- I know very little about nfs's fcntl
> locking and I may not understand your question either.  GFS 
> does have a
> gfs_lock file operation which makes flock/fcntl locks 
> cluster-wide when
> requested through flock() or fcntl() on gfs directly.
> 
> However, if the lock is requested on an nfs file (where nfs 
> is above gfs),
> that request isn't passed on to gfs AFAIK.  This means two nfs servers
> sharing one gfs file system have independent 
> (not-cluster-wide) views of
> the locks.  So, I think the answer to your question is, fcntl 
> locking is
> not cluster wide when it's through nfs.
> 

That's what I thought, sorry if my prev mail wasn't clear. I've seen 
some versions of nfs code, eg Suse based on 2.6.5, do call f_op->lock().
Don't know the reason this isn't done in 2.6.9, it would be good to have 
it working cluster-wide when accessed over nfs as well.


cheers
gradimir 

 
> -- 
> Dave Teigland  <teigland at redhat.com>
>