On Tue, Jun 11, 2002 at 12:22:07PM +0200, Matteo Centonza wrote:
>
> are you sure you have mastered all details?
unless something changed very recently yes.
> Using a reserved namespace, means ``Hey, this is administrator things'',
> so it's up to the administrator to set this kind of stuff, not to the
> user. With this approach, you're on the safe side IMHO. BTW, if the
> administrator smokes Crack then you're toast anyway ;)
there is no such namespace at this time. system.* is special, there
are only specific system namespaces defined and the user (even root)
cannot just make up new ones. right now there is
system.posix_acl_access (only file owner may write this attribute) and
system.posix_acl_default (same as _access). there is also an xfs
specific system.xfsroot (i think thats right) which only root may
read/write/see. the only other xattr namespace at the moment is
user.* which is entirely controled by the file/dirs permission
bits. (with exceptions for symlinks and special files).
there has been discussion about making a owner.* namespace or such,
which would only be writable by the file owner, but this does not
exist as of yet.
so you see there is no place for this per directory attribute except
perhaps the system.xfsroot namespace, but im not entirely sure this
namespace is really meant to be fscked with by end users.
> As you stated above ext* already have a similar feature.
ext2 allows the object *owner* to decide this, Ivan is of the opinion
that the file owner shouldn't have that authority in the case of a
directory, thats debatable. if we are discussing implementing the
ext2 feature as it works now there is NOT sufficient infrastructure in
the extended attributes to do it. (there is no xattr namespace that
allows arbitrary attributes which are only writable by the file owner).
i am of the opinion that if only root is to be allowed to exclude
directories then it should be done with an xfsdump command line
argument and not a filesystem attribute. i tend to agree with ivan
that allowing lusers to arbitrarly exclude directories from backups is
probably not a good idea. (fwiw all i use the ext2 chattr +d for is
crap like browser cache and large source trees i only plan to keep
temporarly and don't want my limited backup space exhausted by).
> As last, are you sure the needed infrastructure it's still not present
> here? (i've not yet found a paper describing the current implementation).
see above.
--
Ethan Benson
http://www.alaska.net/~erbenson/
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