[Samba] Operation Not Supported error for GETXATTR when VFS plugin "nfs4acl_xattr" is used

[Ralph Böhme]

On Fri, Apr 06, 2018 at 10:27:32AM -0700, Jeremy Allison via samba wrote:
> On Fri, Apr 06, 2018 at 01:44:50PM +0530, Akash Jain wrote:
> > Hi All
> > 
> > I found there is one bug in the plugin. The name of the attribute for ACL as
> > per strace output of nfs4_setfacl is system.nfs4_acl.
> > The source code has defined it as
> > #define NFS4ACL_XATTR_NAME      ( "system.nfs4acl" )
> > 
> > Note there is missing underscore.
> > 
> > After this, the EOPNOTSUPP error is not observed.
> > 
> > Hope this helps
> 
> Hmmm. This has been changed for Samba 4.8.0 and above,
> with commit df99ac27106dededcf0a98a251e58c24b90bf6d1.
> 
> This would seem to be a correct fix, as it seems
> 
> "The "system" xattr namespace is reserved for the kernel. Any attempt to
>     use xattrs in that namesspace will fail with EOPNOTSUPP, regardless of
>     priveleges."
> 
> Can you check with 4.8.x ?

I guess that statement may not be correct, depending on which kernel subsystem
exposes the xattr? My testing was with local filesytems, not with nfsv4
mounts. Apparantly it works with nfs4_getfacl|nfs4_setfacl...

-slow

-- 
Ralph Boehme, Samba Team       https://samba.org/
Samba Developer, SerNet GmbH   https://sernet.de/en/samba/
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