LinuxSA Mailing list archives

  From: Alan Kennington <akenning@topology.org>
  To  : LinuxSA <linuxsa@linuxsa.org.au>
  Date: Mon, 2 Jul 2001 23:07:09 +0930

Re: Basic NFS Question

On Mon, Jul 02, 2001 at 11:03:40PM +0930, Richard Russell wrote:
> 
> > More specifically, the link call refuses to link to a directory.
> > Symlinks were born as a way to link across file systems (since hard
> > links use the inode number, they are, perforce, constrained to linking
> > objects on the same file system) and to link to directories.
> 
> 
> hmmm -- I never knew that links wouldn't link dirs... interesting... why is
> this? (I understand why you can't link across fs's)...
> 


The way the unix manuals used to explain this was that
if you accidentally linked directories in a cyclic fashion - i.e.
not as a directed acyclic graph - then you would get very nasty
outcomes from recursive actions such as a "find" command.

Therefore, in the olden days at least,  only root was allowed
to make a hard link to a directory, and this was not at all
encouraged.

Where symbolic links and NFS become interesting is where you
make a symbolic link outside a file system on the _exporting_
side of the NFS relation. Then can the importing side follow
that link into the file system which is _not_ mounted
by the importing host and _not_ exported by the exporting side?

I think that this is in fact allowed under some circumstance,
but I don't remember the details.

But making a symbolic link from system to system on the
importing side is without "issues".

Cheers,
Alan Kennington.

-- 
LinuxSA WWW: http://www.linuxsa.org.au/  IRC: #linuxsa on irc.linux.org.au
To unsubscribe from the LinuxSA list:
  mail linuxsa-request@linuxsa.org.au with "unsubscribe" as the subject