is support planned for user.* xattrs?

[J. Bruce Fields]

On Tue, May 08, 2007 at 12:12:08PM -1000, Joshua Hoblitt wrote:
> I'd like to start by apologizing for sending this message to a
> development list.  The documentation (wiki, etc.) don't make it
> clear if user xattrs are currently supported or not but seem suggest that
> such functionally is at least planned.  I decided it give it a try 
> with the nfsv4 implementation as shipped with 2.6.19.  Indeed, only
> ACL xattrs are supported.  Looking through nfs4proc.c in 2.6.21 confirms
> that there is no support of xattrs beyond what is necessary for ACLs.

That's correct, sorry for the confusion.

> So I guess my questions are: Is there any design issue that prevents
> user xattrs from being implemented in mainline?

We experimented with the idea a bit and decided that xattrs weren't
really that much like NFSv4 named attributes, which are more like real
files (e.g., NFSv4 named attributes can be read from and written to like
ordinary files, and can have attributes of their own).  The reiserfs
people were pushing for something like this at one point, and there was
some discussion of how it might be implemented on the kernel mailing
list, but it never got very far.

> Is there a patch floating around some where that supports this
> already?

Not that I know of.

> Alternatively, is there any one else interested in this functionality?

I'm told selinux wants named/extended attributes.  Other than that I'm
not sure what exactly people need them for.

--b.