read_seqbegin_or_lock
read_seqbegin_or_lock(&cell->volume_lock, &seq);
read_seqbegin_or_lock(&mount_lock, &m_seq);
read_seqbegin_or_lock(&rename_lock, &seq);
read_seqbegin_or_lock(&rename_lock, &seq);
read_seqbegin_or_lock(&rename_lock, &seq);
read_seqbegin_or_lock(&peer->service_conn_lock, &seq);