It allows accessing i_shared_gen without holding i_ceph_lock. It is
preparation for later patch.
Signed-off-by: N"Yan, Zheng" <zyan@redhat.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>