-struct dir;
-bool dir_create (disk_sector_t sector, size_t entry_cnt);
-bool dir_open (struct inode *, struct dir **);
-bool dir_open_root (struct dir **);
+
+/* Opening and closing directories. */
+bool dir_create (block_sector_t sector, size_t entry_cnt);
+struct dir *dir_open (struct inode *);
+struct dir *dir_open_root (void);
+struct dir *dir_reopen (struct dir *);