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SubjectRe: Your backup is unsafe!
Hi Robert.

> DONT PANIC! It's only Win9X, nothing serious.

8-)

> The problem is that you don't see the whole name on a VFAT
> partition. As you'll know there are two parts to the name the
> 8+3 part and the fakename but you can only see one bit at a
> time.

> Suppose you do something like this:

> mount -t vfat /dev/hda1 /dos
> tar cvf /dev/rmt0 /dos

> This will save the fakename but not the 8+3 name, if you do a
> restore linux will _normally_ regenerate the same 8+3 name, but
> not always.

> "So what" you say, well it's like this; there are LFN programs
> that store the 8+3 name not the long one, for example MS Office.
> If everything has gone just right and the 8+3 name of one of the
> few bad files changes the restore will fail for no visable
> reason.

What I'd like to see is this dealt with in a SENSIBLE way, so both
operating systems see both versions of the name. That way, all such
problems vanish.

One obvious way round this would be to have the file always appear
under the MSDOS version of the name, with the LFN version appearing as
a hard link to it. Throw that in, and the problem mentioned above goes
away since tar then sees and records both versions of the name.

This would place two limitations on the hard link facility:

1. Only one hard link to any given file. Therefore, the link
count field in long directory listings is limited to show
either 1 link (for a file without an LFN) or 2 links (for
a file with an LFN).

2. The hard link must be in the same directory as the file it
points to.

I don't see either of those limitations as being any more restrictive
than what's already in use.

As far as I can se, the following problems would need dealing with if
this approach was adopted:

1. Attempts to delete the MSDOS named link without deleting the
LFN named link first.

2. Attempts to rename the MSDOS named link to a name that is not
compatible with the MSDOS 8.3 requirements.

3. Attempts to rename the LFN named link to an MSDOS named link.

Attempts to delete the LFN name would succeed, resulting in the file
only having its MSDOS format name, and attempts to delete an MSDOS
named file with no LFN attached to it would succeed and remove the
file.

Comments?

Best wishes from Riley.

+----------------------------------------------------------------------+
| There is something frustrating about the quality and speed of Linux |
| development, ie., the quality is too high and the speed is too high, |
| in other words, I can implement this XXXX feature, but I bet someone |
| else has already done so and is just about to release their patch. |
+----------------------------------------------------------------------+
* ftp://ftp.MemAlpha.cx/pub/rhw/Linux
* http://www.MemAlpha.cx/kernel.versions.html


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