[Gluster-devel] xattr support

[Jeff Darcy]

On 05/06/2011 08:47 AM, Hans K. Rosbach wrote:
> Hi, I am receiving mixed signals on whether GlusterFS actually
> support xattrs on the client side. I am told that it does support
> xattrs but my tests seems to indicate that it does not. I also
> seem to recollect reading a post to this list saying that it does
> not support xattrs, but I am not able to find it now.
> 
> Also a google search pretty much only tells me what I already
> know; that GlusterFS uses xattrs extensively on the server side.
> 
> Here is a test on the clients root filesystem (ext4):
> [root /]# touch testfile
> [root /]# attr -s testattr -V 2 testfile

When I attempt this same operation on an ext4 filesystem, I get
EOPNOTSUPP. When I do "man attr" it tells me why:

	attr - extended attributes on XFS filesystem objects

The filesystem-independent programs for manipulating xattrs are getfattr
and setxattr. When I do this it works fine:

	setfattr -n user.testattr -v "foo" testfile

Note that, in addition to using setfattr instead of attr, the above
conforms to the namespace requirements of generic xattrs by using the
"user" namespace - which depends on the filesystem being mounted with
the "user_xattr" flag.  Use "man 5 attr" for more information about
how to use non-XFS xattrs.