drbd_uuid_set
extern void drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
drbd_uuid_set(device, UI_BITMAP, uuid);
drbd_uuid_set(device, UI_BITMAP, 0); /* Rotate UI_BITMAP to History 1, etc... */
drbd_uuid_set(device, UI_BITMAP, device->ldev->md.uuid[UI_CURRENT]);