void free_extent_map(struct extent_map *em);
int __init extent_map_init(void);
void extent_map_exit(void);
+int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len);
+struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
+ u64 start, u64 len);
#endif