fs/9p: Add xattr callbacks for POSIX ACL

This patch implement fetching POSIX ACL from the server

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

fs/9p/xattr.h

@@ -20,6 +20,8 @@
 
 extern const struct xattr_handler *v9fs_xattr_handlers[];
 extern struct xattr_handler v9fs_xattr_user_handler;
+extern const struct xattr_handler v9fs_xattr_acl_access_handler;
+extern const struct xattr_handler v9fs_xattr_acl_default_handler;
 
 extern ssize_t v9fs_fid_xattr_get(struct p9_fid *, const char *,
 				  void *, size_t);