byte range locking

[Andrew Tridgell]

> 	Well... maybe 2^31 support should be a compile-time flag.  If the
> particular nfs lock daemon WILL permit it, it'd be nice to have.

I might even make that the default - hopefully those old lock daemons
are getting less common.

> 	Hmm... if something else wins the race, is there a way to signal the
> broken lock to the client?

no, the client hasn't done a lock operation. 

the only alternative I can think of is to not close the file at all if
any mapped locks are present and instead defer the close until all
locks are gone or all copies of the file are closed in this smbd.

it should be a pretty rare situation anyway.