#include <linux/fs.h>
  #include <linux/ext2_fs.h>
  
  /*

   * ext2 mount options
   */
  struct ext2_mount_options {
  	unsigned long s_mount_opt;
  	uid_t s_resuid;
  	gid_t s_resgid;
  };
  
  /*

   * second extended file system inode data in memory
   */
  struct ext2_inode_info {
  	__le32	i_data[15];
  	__u32	i_flags;
  	__u32	i_faddr;
  	__u8	i_frag_no;
  	__u8	i_frag_size;
  	__u16	i_state;
  	__u32	i_file_acl;
  	__u32	i_dir_acl;
  	__u32	i_dtime;
  
  	/*
  	 * i_block_group is the number of the block group which contains
  	 * this file's inode.  Constant across the lifetime of the inode,

  	 * it is used for making block allocation decisions - we try to

  	 * place a file's data blocks near its inode block, and new inodes
  	 * near to their parent directory's inode.
  	 */
  	__u32	i_block_group;

  	/* block reservation info */
  	struct ext2_block_alloc_info *i_block_alloc_info;

  	__u32	i_dir_start_lookup;
  #ifdef CONFIG_EXT2_FS_XATTR
  	/*
  	 * Extended attributes can be read independently of the main file

  	 * data. Taking i_mutex even when reading would cause contention

  	 * between readers of EAs and writers of regular file data, so
  	 * instead we synchronize on xattr_sem when reading or changing
  	 * EAs.
  	 */
  	struct rw_semaphore xattr_sem;
  #endif

  	rwlock_t i_meta_lock;

  
  	/*
  	 * truncate_mutex is for serialising ext2_truncate() against
  	 * ext2_getblock().  It also protects the internals of the inode's
  	 * reservation data structures: ext2_reserve_window and
  	 * ext2_reserve_window_node.
  	 */
  	struct mutex truncate_mutex;

  	struct inode	vfs_inode;

  	struct list_head i_orphan;	/* unlinked but open inodes */

  };
  
  /*
   * Inode dynamic state flags
   */
  #define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
  
  
  /*
   * Function prototypes
   */
  
  /*
   * Ok, these declarations are also in <linux/kernel.h> but none of the
   * ext2 source programs needs to include it so they are duplicated here.
   */
  
  static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
  {
  	return container_of(inode, struct ext2_inode_info, vfs_inode);
  }
  
  /* balloc.c */
  extern int ext2_bg_has_super(struct super_block *sb, int group);
  extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);

  extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
  extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
  				unsigned long *, int *);

  extern void ext2_free_blocks (struct inode *, unsigned long,
  			      unsigned long);
  extern unsigned long ext2_count_free_blocks (struct super_block *);
  extern unsigned long ext2_count_dirs (struct super_block *);
  extern void ext2_check_blocks_bitmap (struct super_block *);
  extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
  						    unsigned int block_group,
  						    struct buffer_head ** bh);

  extern void ext2_discard_reservation (struct inode *);
  extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
  extern void ext2_init_block_alloc_info(struct inode *);
  extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);

  
  /* dir.c */
  extern int ext2_add_link (struct dentry *, struct inode *);

  extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);

  extern int ext2_make_empty(struct inode *, struct inode *);

  extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, struct page **);

  extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
  extern int ext2_empty_dir (struct inode *);
  extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);

  extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);

  /* ialloc.c */

  extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);

  extern void ext2_free_inode (struct inode *);
  extern unsigned long ext2_count_free_inodes (struct super_block *);
  extern void ext2_check_inodes_bitmap (struct super_block *);
  extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
  
  /* inode.c */

  extern struct inode *ext2_iget (struct super_block *, unsigned long);

  extern int ext2_write_inode (struct inode *, struct writeback_control *);

  extern void ext2_evict_inode(struct inode *);

  extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);

  extern int ext2_setattr (struct dentry *, struct iattr *);
  extern void ext2_set_inode_flags(struct inode *inode);

  extern void ext2_get_inode_flags(struct ext2_inode_info *);

  extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  		       u64 start, u64 len);

  
  /* ioctl.c */

  extern long ext2_ioctl(struct file *, unsigned int, unsigned long);

  extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);

  /* namei.c */
  struct dentry *ext2_get_parent(struct dentry *child);

  /* super.c */

  extern __printf(3, 4)
  void ext2_error(struct super_block *, const char *, const char *, ...);
  extern __printf(3, 4)
  void ext2_msg(struct super_block *, const char *, const char *, ...);

  extern void ext2_update_dynamic_rev (struct super_block *sb);
  extern void ext2_write_super (struct super_block *);
  
  /*
   * Inodes and files operations
   */
  
  /* dir.c */

  extern const struct file_operations ext2_dir_operations;

  
  /* file.c */

  extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
  		      int datasync);

  extern const struct inode_operations ext2_file_inode_operations;

  extern const struct file_operations ext2_file_operations;
  extern const struct file_operations ext2_xip_file_operations;

  
  /* inode.c */

  extern const struct address_space_operations ext2_aops;
  extern const struct address_space_operations ext2_aops_xip;
  extern const struct address_space_operations ext2_nobh_aops;

  
  /* namei.c */

  extern const struct inode_operations ext2_dir_inode_operations;
  extern const struct inode_operations ext2_special_inode_operations;

  
  /* symlink.c */

  extern const struct inode_operations ext2_fast_symlink_inode_operations;
  extern const struct inode_operations ext2_symlink_inode_operations;

  
  static inline ext2_fsblk_t
  ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
  {
  	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
  		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
  }

  
  #define ext2_set_bit	__test_and_set_bit_le
  #define ext2_clear_bit	__test_and_clear_bit_le
  #define ext2_test_bit	test_bit_le
  #define ext2_find_first_zero_bit	find_first_zero_bit_le
  #define ext2_find_next_zero_bit		find_next_zero_bit_le