*/
unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
bool f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
+void f2fs_drop_extent_tree(struct inode *);
unsigned int f2fs_destroy_extent_node(struct inode *);
void f2fs_destroy_extent_tree(struct inode *);
bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);