text: #ifndef FILESYS_FILESYS_H
  #define FILESYS_FILESYS_H
  
  #include <stdbool.h>
  #include "filesys/off_t.h"
  
  #include "threads/synch.h"
  
  /* Sectors of system file inodes. */
  #define FREE_MAP_SECTOR 0       /* Free map file inode sector. */
  #define ROOT_DIR_SECTOR 1       /* Root directory file inode sector. */
  
  /* Block device that contains the file system. */
  struct block *fs_device;
  
  /* added by taeguk for project 2-2 */
  struct lock filesys_lock;
  
  void filesys_init (bool format);
  void filesys_done (void);
  bool filesys_create (const char *name, off_t initial_size);
  struct file *filesys_open (const char *name);
  bool filesys_remove (const char *name);
  
  #endif /* filesys/filesys.h */
  