Re: FS: hardlinks on directories

[Helge Hafting <helgehaf@aitel.hist.no>]

On Sun, Aug 24, 2003 at 09:35:57PM +0400, Hans Reiser wrote:
> Helge Hafting wrote:
> >
> So, he needs links that count as references, 
Plain hard links.

> links that don't count as 
> references but disappear if the object disappears (without dangling like 
> symlinks),

Current filesystems would need a fs-wide search for soft links,
but this is avoidable by storing a list of links in the inode.
That must be done carefully though, or you'll get another
problem:  if I move a high-level directory, will I have
to update links and inodes linked to 
that exists deep within some subsubsubdirectory?
This had better be unnecessary, meaning the in-inode list
of "reverse links" can't contain paths.
Perhaps the can contain the inode numbers of the referencing directories.

Deleting a file with this new kind of links will then cause
searches in various directories containing those links.

>  and unlinkall(), which removes an object and all of its 
> links.  He needs for the first reference to a directory to be removable 
> only by removing all links to the object, or designating another link to 
> be the "first" reference.
> 
> Sounds clean to me.  This is not to say that I am funded to write 
> it.;-)  I'd look at a patch though.....;-)
> 
> I need to write up a taxonomy of links..... after reiser4 ships.....
> 

This stuff is possible if we get a new type of link then.
I wonder how exisitng link-aware tools will cope.

Helge Hafting