Reason for delay in inclusion of ACLs to mainstream kernel?

[<kend@xxxxxxxxxxxx>]

Howdy, all -- I'm doing some research, and was wondering if anyone can
give me a quick-n-dirty summary of why ACLs took so long to be included by
Linus.  I believe it had to do with elevation of user privs., but I'd
prefer to have it from the horse's mouth, as it were.

Thanks for any info...

-Ken