hammer_node_lock
struct hammer_node_lock;
TAILQ_HEAD(hammer_node_lock_list, hammer_node_lock);
TAILQ_ENTRY(hammer_node_lock) entry;
struct hammer_node_lock *parent;
struct hammer_node_lock lockroot;
struct hammer_node_lock lockroot;
struct hammer_node_lock lcache;
struct hammer_node_lock lockroot;