can't delete /foo

[Aaron Solochek <aarons@andrew.cmu.edu>]

I created a directory, /foo, which was its own partition.

I first wanted to change the group of /foo to bar, but it wouldn't let
me do that, even as root.  I got the error message "operation not
premitted: /foo"  Then I thought this is screwed up, so I tried to
delete /foo, but rm -r /foo just says operation not premitted, and it
doesn't go away.  rm -rf /foo doesn't echo any errors, but it also
doesn't delete /foo.  Any clue what could be causing this?

-Aaron Solochek
 leko@cmu.edu