archive bit in xattr possible/exist?

David Lee t.d.lee at
Wed Jul 3 05:06:01 GMT 2002

On Tue, 2 Jul 2002, David Orman wrote:

> I know it is possible to use "map archive" to keep track of archive
> bits, but this is not very useful if you have real UNIX users.  I.e. I
> can't have samba arbitrarily playing with the execute bits.

It might be worth pausing at this point...

I agree that mapping those DOS bits onto UNIX-x bits is not ideal.

But, pragmatically, who does it harm and how?  The assessment of this
question will vary from site to site, so one site's pragmatic answer may
not be sufficient for another's more purist technical requirements.  But
the question is still worth considering. 

In our environment (15,000-20,000 registered users;  1,000+ simultaneous
connections; university staff and students) this odd-looking mapping has
not, in practice, been an issue.  Most folk sit at Windows PCs, and simply
see what appears to be a Windows fileserver: they never get anywhere close
to diddling with UNIX permission bits on the storage of their Windows

A few folk do also use UNIX directly, but they, as part of natural working
practice, rarely, if ever, use any particular file both from UNIX and from
a Windows box.

So, at our site, pragmatically, that mapping is not an issue.

(Now if _your_ users at _your_ site really are often using the same file
from both environments, and if they find this mapping to be troublesome,
then, I agree, you do have an issue that needs addressing.)

> Does anyone know of any attempted implementation of archive bits through
> extended attributes?  This would probably need a VFS layer, to get and
> set them appropriately.

Speaking as someone totally unqualified who has never yet used Samba's
VFS, that to me sounds a reasonable plan.  It just needs to get consensus
and then needs someone with an interest (who could I mean?!) to volunteer
to develop the module.  (Possible portability issue: some UNIX machines
(samba servers) don't have ACLs; those that do may have different ideas
and implementation details.)

But first of all, ask the pragmatic question of how significant this issue
really is for your users at your site.

Hope that helps.


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