Re: FS: hardlinks on directories

From: Stephan von Krawczynski (skraw_at_ithnet.com)
Date: 08/04/03

  • Next message: Joerg Schilling: "Re: CDrecord -> Kernel panic" 
    Date:	Mon, 4 Aug 2003 17:05:06 +0200
To: Jesse Pollard <jesse@cats-chateau.net>

    On Mon, 4 Aug 2003 09:33:44 -0500
    Jesse Pollard <jesse@cats-chateau.net> wrote:

    > Find for one. Any application that must scan the tree in a search. Any
    > application that must backup every file for another (I know, dump bypasses
    > the filesystem to make backups, tar doesn't).

    All that can handle symlinks already have the same problem nowadays. Where is
    the difference? And yet again: it is no _must_ for the feature to use it for
    creating complete loops inside your fs.
    You _can_ as well dd if=/dev/zero of=/dev/hda, but of course you shouldn't.
    Have you therefore deleted dd from your bin ?

    > It introduces too many unique problems to be easily handled. That is why
    > symbolic links actually work. Symbolic links are not hard links, therefore
    > they are not processed as part of the tree. and do not cause loops.

    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.

    > 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?

    > The KIS principle is the key. A graph is NOT simple to maintain.

    This is true. But I am very willing to believe reiserfs is not simple either,
    still it is there ;-)

    Regards,
    Stephan
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