How is this ACL stuff going to affect all the user-land code that
calculates access permissions by calling stat(), getuid(), getgroups()
because of the generations of programmers that have been told the evils
of calling access().

How is the ACL stuff going to interact with NFS?  If the ACL info is
stored on the server, how is the client supposed to check whether a
process is allowed to open() a file based on the (possibly cached)
attributes it fetched from the server.

			---  Truck