ceph: request new max size only when there is auth cap

When there is no auth cap, check_max_size() can't do anything and may
cause an infinite loop inside ceph_get_caps().
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -2582,7 +2582,7 @@ static int try_get_cap_refs(struct inode *inode, int need, int want,
 			dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
 			     inode, endoff, ci->i_max_size);
 			if (endoff > ci->i_requested_max_size)
-				ret = -EFBIG;
+				ret = ci->i_auth_cap ? -EFBIG : -ESTALE;
 			goto out_unlock;
 		}
 		/*