ClabureDB: Classified Bug-Reports Database

{
        assert_spin_locked(&res->spinlock);
        if (res->state & DLM_LOCK_RES_MIGRATING) {
                __dlm_print_one_lock_resource(res);
        }
        BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);

        atomic_inc(&res->asts_reserved);
}

/*
 * used to drop the reserved ast, either because it went unused,
 * or because the ast/bast was actually called.
 *
 * also, if there is a pending migration on this lockres,
 * and this was the last pending ast on the lockres,
 * atomically set the MIGRATING flag before we drop the lock.
 * this is how we ensure that migration can proceed with no
 * asts in progress.  note that it is ok if the state of the
 * queues is such that a lock should be granted in the future
 * or that a bast should be fired, because the new master will
 * shuffle the lists on this lockres as soon as it is migrated.
 */
void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
                             struct dlm_lock_resource *res)
{
        if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
                return;

        if (!res->migration_pending) {
                spin_unlock(&res->spinlock);
                return;
        }

        BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
        res->migration_pending = 0;
        res->state |= DLM_LOCK_RES_MIGRATING;
        spin_unlock(&res->spinlock);
        wake_up(&res->wq);
        wake_up(&dlm->migration_wq);
}