rem: if (mount != NULL)
add: if (mount != NULL && mount->cookie != NULL)
context: fs_next_device(int32 *_cookie){	struct fs_mount *mount = NULL;	dev_t device = *_cookie;	mutex_lock(&sMountMutex);		// Since device IDs are assigned sequentially, this algorithm	// does work good enough. It makes sure that the device list	// returned is sorted, and that no device is skipped when an	// already visited device got unmounted.	while (device < sNextMountID) {		mount = find_mount(device++);		if (mount != NULL)			break;	}	*_cookie = device;	if (mount != NULL)		device = mount->id;	else		device = B_BAD_VALUE;	mutex_unlock(&sMountMutex);		return device;}