bt_lock
bt_lock(&bhp->bh_lock);
bt_lock(&bhp->bh_strlock);
bt_lock(&bhp->bh_lock);
bt_lock(&bhp->bh_lock);
bt_lock(&bhp->bh_lock);
bt_lock(&bhp->bh_bkts[bktno].bb_lock);
bt_lock(&bhp->bh_lock);
UPDATE_TOTALS_WR(be, writing, bt_lock, ts, vts);
backend_spent_t bt_lock; /* waiting for lock */