+void free_extent_cache_tree(struct cache_tree *tree);
+
+/*
+ * Search a cache_extent with same objectid, and covers start.
+ *
+ * If not found, return next if possible.
+ */
+struct cache_extent *search_cache_extent2(struct cache_tree *tree,
+ u64 objectid, u64 start);
+/*
+ * Search a cache_extent with same objectid, and covers the range
+ * [start, start + size)
+ *
+ * If not found, return next cache_extent if possible.
+ */
+struct cache_extent *lookup_cache_extent2(struct cache_tree *tree,
+ u64 objectid, u64 start, u64 size);
+int add_cache_extent2(struct cache_tree *tree,
+ u64 objectid, u64 start, u64 size);
+int insert_cache_extent2(struct cache_tree *tree, struct cache_extent *pe);