Re: JFS extended attributes and ACLs - New Patches

[Nathan Scott <nathans@sgi.com>]

hi Dave,

On Thu, Sep 12, 2002 at 12:34:29PM -0500, Dave Kleikamp wrote:
> On Thursday 12 September 2002 12:04, Andreas Gruenbacher wrote:
> 
> > Can you implement the `os2.' namespace in the JFS patches? I'd be
> > much happier with the patch.
> 
> I believe I can.  I will use the 'os2.' prefix externally, but store it 
> without the prefix.  On the other side, any attribute that doesn't 
> begin with a known prefix will get 'os2.' prepended when listing the 
> xattrs.

This is basically what we do in XFS - we have a separate namespace
for accessing the actual ondisk names &/ values of what on IRIX is
called the ROOT namespace - on Linux the "xfsroot" namespace.  This
is how xfsdump and xfsrestore are able to work with the same on-tape
format that is used in IRIX - they manipulate attributes in this
XFS-specific namespace while the generic ACL tools (setfacl, getfacl,
and co) access the system.posix_acl names, which are then independent
of the underlying filesystem type.

I would shy away from a "hierarchical" namespace approach; if I grok
what you're saying, I think it would mean that the value for the name
"user.os2.a" would be different between filesystems (for JFS it would
mean "a" in the user.os2 namespace, for everyone else it would mean
"os2.a" in the user namespace) - that'd be pretty confusing.

cheers.

-- 
Nathan