NFS 'noac' attr

[T. Horsnell]

I have a hundred or so FC6 NFS clients which manipulate a particular
directory served by a RHEL4 server. For historical reasons I have my
own locking scheme whereby each client takes out the lock before
processing the directory, and releases it on completion, but since
moving to FC6 I am getting inconsistency problems - entries in the
directory change or disappear while a client is processing it.
The directory in question is specifically exported, (it's not part
of an exported filesystem), and it's mounted 'noac' on the clients.

Should the 'noac' attribute guarantee that directory contents are
collected from the master and written back to the master rather
than being cached locally? And is this done at diropen/dirclose?

Cheers,
Terry