Messages in this thread | | | Date | Tue, 5 Aug 2003 00:32:10 +0200 | From | Stephan von Krawczynski <> | Subject | Re: FS: hardlinks on directories |
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On Mon, 4 Aug 2003 16:09:28 -0500 Jesse Pollard <jesse@cats-chateau.net> wrote:
> > tar --dereference loops on symlinks _today_, to name an example. > > All you have to do is to provide a way to find out if a directory is a > > hardlink, nothing more. And that should be easy. > > Yup - because a symlink is NOT a hard link. it is a file. > > If you use hard links then there is no way to determine which is the "proper" > link.
Where does it say that an fs is not allowed to give you this information in some way?
> > > > > > It was also done in one of the "popular" code management systems under > > > unix. (it allowed a "mount" of the system root to be under the CVS > > > repository to detect unauthorized modifications...). Unfortunately, > > > the system could not be backed up anymore. 1. A dump of the CVS > > > filesystem turned into a dump of the entire system... 2. You could not > > > restore the backups... The dumps failed (bru at the time) because the > > > pathnames got too long, the restore failed since it ran out of disk space > > > due to the multiple copies of the tree being created. > > > > And they never heard of "--exclude" in tar, did they? > > Doesn't work. Remember - you have to --exclude EVERY possible loop. And > unless you know ahead of time, you can't exclude it. The only way we found > to reliably do the backup was to dismount the CVS.
And if you completely run out of ideas in your wild-mounts-throughout-the-tree problem you should simply use "tar -l".
And in just the same way fs could provide a mode bit saying "hi, I am a hardlink", and tar can then easily provide option number 1345 saying "stay away from hardlinks".
If you can do the fs patch, I can do the tar patch.
Regards, Stephan
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