Re: [Bug-tar] tar doc question: what is "hard-dereference"; how is it done?

[Linda A. Walsh]

On 12/7/2013 9:00 AM, Sergey Poznyakoff wrote:
> Perhaps it might, but this would mean inventing a new archive format
> or extending one of the supported ones. Both ways would produce
> compatibility problems with prior releases of the GNU tar as well
> as with other tar implementations. I can't see any gain which
> would justify our going into such troubles.
>   
The gain was stated under option 3 in the 2nd note.

" either copy could be extracted separately, and only in the presence
of both would they be hardlinked. "

Meaning any linked copy of a file would retrieve the file -- the same as
on hard disk and only hardlinks between extracted files that are restored
would be restored.

That way you don't have the problem that the current design implies.

That is if you use the follow-hardlinks option, you won't get hard linked
files on the destination.

There's no way, if I understand, to both restore hard links and support
partial extractions with the current method.  I listed ways around that.

To support both partial extractions and restore hard links without problems
and have a tar that transparently, "just works", no matter which way it is
used, would be the motivation.

Or you can document the shortcomings due to the inaccurate model of the
file system gnu-tar uses -- which is the route currently being taken.

Other than something that works without exceptions, I can see no reason to
justify such a change...