+int __bch2_btree_node_lock_write(struct btree_trans *, struct btree_path *,
+ struct btree_bkey_cached_common *b, bool);
+
+static inline int __btree_node_lock_write(struct btree_trans *trans,
+ struct btree_path *path,
+ struct btree_bkey_cached_common *b,
+ bool lock_may_not_fail)
+{
+ EBUG_ON(&path->l[b->level].b->c != b);
+ EBUG_ON(path->l[b->level].lock_seq != b->lock.state.seq);
+ EBUG_ON(!btree_node_intent_locked(path, b->level));
+
+ /*
+ * six locks are unfair, and read locks block while a thread wants a
+ * write lock: thus, we need to tell the cycle detector we have a write
+ * lock _before_ taking the lock:
+ */
+ mark_btree_node_locked_noreset(path, b->level, SIX_LOCK_write);
+
+ return likely(six_trylock_write(&b->lock))
+ ? 0
+ : __bch2_btree_node_lock_write(trans, path, b, lock_may_not_fail);
+}
+
+static inline void bch2_btree_node_lock_write_nofail(struct btree_trans *trans,
+ struct btree_path *path,
+ struct btree_bkey_cached_common *b)
+{
+ int ret = __btree_node_lock_write(trans, path, b, true);
+
+ BUG_ON(ret);
+}
+
+static inline int __must_check
+bch2_btree_node_lock_write(struct btree_trans *trans,
+ struct btree_path *path,
+ struct btree_bkey_cached_common *b)
+{
+ return __btree_node_lock_write(trans, path, b, false);
+}
+
+/* relock: */
+
+bool bch2_btree_path_relock_norestart(struct btree_trans *,
+ struct btree_path *, unsigned long);
+int __bch2_btree_path_relock(struct btree_trans *,
+ struct btree_path *, unsigned long);
+
+static inline int bch2_btree_path_relock(struct btree_trans *trans,
+ struct btree_path *path, unsigned long trace_ip)
+{
+ return btree_node_locked(path, path->level)
+ ? 0
+ : __bch2_btree_path_relock(trans, path, trace_ip);
+}
+
+bool __bch2_btree_node_relock(struct btree_trans *, struct btree_path *, unsigned, bool trace);