Hard links to directories

[Max <max@mcs.st-and.ac.uk>]

Dear All,

Is there a way of switching on permission to have hard links to 
directories?

Is there a rationale for disallowing this?  What I'm trying to do is to 
set up my file system so that, rather as with apt-get, files and entire 
directories survive only as long as they are wanted.  Wanted 
can be cheaply and easily implemented as a hard link for files, but my 
attempts to make hard directory links throw up a message saying that this 
isn't allowed.

Is the no hard links to directories policy a function of the file system 
or of the OS?  At the moment I'm using Reiserfs - not sure which version 
as the installer didn't say but I'd guess v3.  I am under the impression 
that v1&2 were experimental only and that 4 hasn't been out long.  Please 
don't quote me on that and do correct me if I'm wrong!

Thanks all.

-- 
Max