#ifndef _FAT_H
  #define _FAT_H
  
  #include <linux/buffer_head.h>
  #include <linux/string.h>
  #include <linux/nls.h>
  #include <linux/fs.h>
  #include <linux/hash.h>
  #include <linux/mutex.h>
  #include <linux/ratelimit.h>
  #include <linux/msdos_fs.h>
  
  /*
   * vfat shortname flags
   */
  #define VFAT_SFN_DISPLAY_LOWER	0x0001 /* convert to lowercase for display */
  #define VFAT_SFN_DISPLAY_WIN95	0x0002 /* emulate win95 rule for display */
  #define VFAT_SFN_DISPLAY_WINNT	0x0004 /* emulate winnt rule for display */
  #define VFAT_SFN_CREATE_WIN95	0x0100 /* emulate win95 rule for create */
  #define VFAT_SFN_CREATE_WINNT	0x0200 /* emulate winnt rule for create */
  
  #define FAT_ERRORS_CONT		1      /* ignore error and continue */
  #define FAT_ERRORS_PANIC	2      /* panic on error */
  #define FAT_ERRORS_RO		3      /* remount r/o on error */
  
  #define FAT_NFS_STALE_RW	1      /* NFS RW support, can cause ESTALE */
  #define FAT_NFS_NOSTALE_RO	2      /* NFS RO support, no ESTALE issue */
  
  struct fat_mount_options {
  	kuid_t fs_uid;
  	kgid_t fs_gid;
  	unsigned short fs_fmask;
  	unsigned short fs_dmask;
  	unsigned short codepage;   /* Codepage for shortname conversions */
  	int time_offset;	   /* Offset of timestamps from UTC (in minutes) */
  	char *iocharset;           /* Charset used for filename input/display */
  	unsigned short shortname;  /* flags for shortname display/create rule */
  	unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
  	unsigned char errors;	   /* On error: continue, panic, remount-ro */
  	unsigned char nfs;	  /* NFS support: nostale_ro, stale_rw */
  	unsigned short allow_utime;/* permission for setting the [am]time */
  	unsigned quiet:1,          /* set = fake successful chmods and chowns */
  		 showexec:1,       /* set = only set x bit for com/exe/bat */
  		 sys_immutable:1,  /* set = system files are immutable */
  		 dotsOK:1,         /* set = hidden and system files are named '.filename' */
  		 isvfat:1,         /* 0=no vfat long filename support, 1=vfat support */
  		 utf8:1,	   /* Use of UTF-8 character set (Default) */
  		 unicode_xlate:1,  /* create escape sequences for unhandled Unicode */
  		 numtail:1,        /* Does first alias have a numeric '~1' type tail? */
  		 flush:1,	   /* write things quickly */
  		 nocase:1,	   /* Does this need case conversion? 0=need case conversion*/
  		 usefree:1,	   /* Use free_clusters for FAT32 */
  		 tz_set:1,	   /* Filesystem timestamps' offset set */
  		 rodir:1,	   /* allow ATTR_RO for directory */
  		 discard:1;	   /* Issue discard requests on deletions */
  };
  
  #define FAT_HASH_BITS	8
  #define FAT_HASH_SIZE	(1UL << FAT_HASH_BITS)
  
  /*
   * MS-DOS file system in-core superblock data
   */
  struct msdos_sb_info {
  	unsigned short sec_per_clus;  /* sectors/cluster */
  	unsigned short cluster_bits;  /* log2(cluster_size) */
  	unsigned int cluster_size;    /* cluster size */
  	unsigned char fats, fat_bits; /* number of FATs, FAT bits (12 or 16) */
  	unsigned short fat_start;
  	unsigned long fat_length;     /* FAT start & length (sec.) */
  	unsigned long dir_start;
  	unsigned short dir_entries;   /* root dir start & entries */
  	unsigned long data_start;     /* first data sector */
  	unsigned long max_cluster;    /* maximum cluster number */
  	unsigned long root_cluster;   /* first cluster of the root directory */
  	unsigned long fsinfo_sector;  /* sector number of FAT32 fsinfo */
  	struct mutex fat_lock;
  	struct mutex nfs_build_inode_lock;
  	struct mutex s_lock;
  	unsigned int prev_free;      /* previously allocated cluster number */
  	unsigned int free_clusters;  /* -1 if undefined */
  	unsigned int free_clus_valid; /* is free_clusters valid? */
  	struct fat_mount_options options;
  	struct nls_table *nls_disk;   /* Codepage used on disk */
  	struct nls_table *nls_io;     /* Charset used for input and display */
  	const void *dir_ops;	      /* Opaque; default directory operations */
  	int dir_per_block;	      /* dir entries per block */
  	int dir_per_block_bits;	      /* log2(dir_per_block) */
  	unsigned int vol_id;		/*volume ID*/
  
  	int fatent_shift;
  	struct fatent_operations *fatent_ops;
  	struct inode *fat_inode;
  	struct inode *fsinfo_inode;
  
  	struct ratelimit_state ratelimit;
  
  	spinlock_t inode_hash_lock;
  	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  
  	spinlock_t dir_hash_lock;
  	struct hlist_head dir_hashtable[FAT_HASH_SIZE];
  
  	unsigned int dirty;           /* fs state before mount */
  	struct rcu_head rcu;
  };
  
  #define FAT_CACHE_VALID	0	/* special case for valid cache */
  
  /*
   * MS-DOS file system inode data in memory
   */
  struct msdos_inode_info {
  	spinlock_t cache_lru_lock;
  	struct list_head cache_lru;
  	int nr_caches;
  	/* for avoiding the race between fat_free() and fat_get_cluster() */
  	unsigned int cache_valid_id;
  
  	/* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
  	loff_t mmu_private;	/* physically allocated size */
  
  	int i_start;		/* first cluster or 0 */
  	int i_logstart;		/* logical first cluster */
  	int i_attrs;		/* unused attribute bits */
  	loff_t i_pos;		/* on-disk position of directory entry or 0 */
  	struct hlist_node i_fat_hash;	/* hash by i_location */
  	struct hlist_node i_dir_hash;	/* hash by i_logstart */
  	struct rw_semaphore truncate_lock; /* protect bmap against truncate */
  	struct inode vfs_inode;
  };
  
  struct fat_slot_info {
  	loff_t i_pos;		/* on-disk position of directory entry */
  	loff_t slot_off;	/* offset for slot or de start */
  	int nr_slots;		/* number of slots + 1(de) in filename */
  	struct msdos_dir_entry *de;
  	struct buffer_head *bh;
  };
  
  static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
  {
  	return sb->s_fs_info;
  }
  
  static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
  {
  	return container_of(inode, struct msdos_inode_info, vfs_inode);
  }
  
  /*
   * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
   * save ATTR_RO instead of ->i_mode.
   *
   * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
   * bit, it's just used as flag for app.
   */
  static inline int fat_mode_can_hold_ro(struct inode *inode)
  {
  	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
  	umode_t mask;
  
  	if (S_ISDIR(inode->i_mode)) {
  		if (!sbi->options.rodir)
  			return 0;
  		mask = ~sbi->options.fs_dmask;
  	} else
  		mask = ~sbi->options.fs_fmask;
  
  	if (!(mask & S_IWUGO))
  		return 0;
  	return 1;
  }
  
  /* Convert attribute bits and a mask to the UNIX mode. */
  static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
  				   u8 attrs, umode_t mode)
  {
  	if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
  		mode &= ~S_IWUGO;
  
  	if (attrs & ATTR_DIR)
  		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
  	else
  		return (mode & ~sbi->options.fs_fmask) | S_IFREG;
  }
  
  /* Return the FAT attribute byte for this inode */
  static inline u8 fat_make_attrs(struct inode *inode)
  {
  	u8 attrs = MSDOS_I(inode)->i_attrs;
  	if (S_ISDIR(inode->i_mode))
  		attrs |= ATTR_DIR;
  	if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
  		attrs |= ATTR_RO;
  	return attrs;
  }
  
  static inline void fat_save_attrs(struct inode *inode, u8 attrs)
  {
  	if (fat_mode_can_hold_ro(inode))
  		MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
  	else
  		MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
  }
  
  static inline unsigned char fat_checksum(const __u8 *name)
  {
  	unsigned char s = name[0];
  	s = (s<<7) + (s>>1) + name[1];	s = (s<<7) + (s>>1) + name[2];
  	s = (s<<7) + (s>>1) + name[3];	s = (s<<7) + (s>>1) + name[4];
  	s = (s<<7) + (s>>1) + name[5];	s = (s<<7) + (s>>1) + name[6];
  	s = (s<<7) + (s>>1) + name[7];	s = (s<<7) + (s>>1) + name[8];
  	s = (s<<7) + (s>>1) + name[9];	s = (s<<7) + (s>>1) + name[10];
  	return s;
  }
  
  static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
  {
  	return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
  		+ sbi->data_start;
  }
  
  static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
  				loff_t i_pos, sector_t *blknr, int *offset)
  {
  	*blknr = i_pos >> sbi->dir_per_block_bits;
  	*offset = i_pos & (sbi->dir_per_block - 1);
  }
  
  static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
  					struct inode *inode)
  {
  	loff_t i_pos;
  #if BITS_PER_LONG == 32
  	spin_lock(&sbi->inode_hash_lock);
  #endif
  	i_pos = MSDOS_I(inode)->i_pos;
  #if BITS_PER_LONG == 32
  	spin_unlock(&sbi->inode_hash_lock);
  #endif
  	return i_pos;
  }
  
  static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
  {
  #ifdef __BIG_ENDIAN
  	while (len--) {
  		*dst++ = src[0] | (src[1] << 8);
  		src += 2;
  	}
  #else
  	memcpy(dst, src, len * 2);
  #endif
  }
  
  static inline int fat_get_start(const struct msdos_sb_info *sbi,
  				const struct msdos_dir_entry *de)
  {
  	int cluster = le16_to_cpu(de->start);
  	if (sbi->fat_bits == 32)
  		cluster |= (le16_to_cpu(de->starthi) << 16);
  	return cluster;
  }
  
  static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
  {
  	de->start   = cpu_to_le16(cluster);
  	de->starthi = cpu_to_le16(cluster >> 16);
  }
  
  static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
  {
  #ifdef __BIG_ENDIAN
  	while (len--) {
  		dst[0] = *src & 0x00FF;
  		dst[1] = (*src & 0xFF00) >> 8;
  		dst += 2;
  		src++;
  	}
  #else
  	memcpy(dst, src, len * 2);
  #endif
  }
  
  /* fat/cache.c */
  extern void fat_cache_inval_inode(struct inode *inode);
  extern int fat_get_cluster(struct inode *inode, int cluster,
  			   int *fclus, int *dclus);
  extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
  		    unsigned long *mapped_blocks, int create);
  
  /* fat/dir.c */
  extern const struct file_operations fat_dir_operations;
  extern int fat_search_long(struct inode *inode, const unsigned char *name,
  			   int name_len, struct fat_slot_info *sinfo);
  extern int fat_dir_empty(struct inode *dir);
  extern int fat_subdirs(struct inode *dir);
  extern int fat_scan(struct inode *dir, const unsigned char *name,
  		    struct fat_slot_info *sinfo);
  extern int fat_scan_logstart(struct inode *dir, int i_logstart,
  			     struct fat_slot_info *sinfo);
  extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
  				struct msdos_dir_entry **de);
  extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
  extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
  			   struct fat_slot_info *sinfo);
  extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
  
  /* fat/fatent.c */
  struct fat_entry {
  	int entry;
  	union {
  		u8 *ent12_p[2];
  		__le16 *ent16_p;
  		__le32 *ent32_p;
  	} u;
  	int nr_bhs;
  	struct buffer_head *bhs[2];
  	struct inode *fat_inode;
  };
  
  static inline void fatent_init(struct fat_entry *fatent)
  {
  	fatent->nr_bhs = 0;
  	fatent->entry = 0;
  	fatent->u.ent32_p = NULL;
  	fatent->bhs[0] = fatent->bhs[1] = NULL;
  	fatent->fat_inode = NULL;
  }
  
  static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
  {
  	fatent->entry = entry;
  	fatent->u.ent32_p = NULL;
  }
  
  static inline void fatent_brelse(struct fat_entry *fatent)
  {
  	int i;
  	fatent->u.ent32_p = NULL;
  	for (i = 0; i < fatent->nr_bhs; i++)
  		brelse(fatent->bhs[i]);
  	fatent->nr_bhs = 0;
  	fatent->bhs[0] = fatent->bhs[1] = NULL;
  	fatent->fat_inode = NULL;
  }
  
  extern void fat_ent_access_init(struct super_block *sb);
  extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
  			int entry);
  extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
  			 int new, int wait);
  extern int fat_alloc_clusters(struct inode *inode, int *cluster,
  			      int nr_cluster);
  extern int fat_free_clusters(struct inode *inode, int cluster);
  extern int fat_count_free_clusters(struct super_block *sb);
  
  /* fat/file.c */
  extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
  			      unsigned long arg);
  extern const struct file_operations fat_file_operations;
  extern const struct inode_operations fat_file_inode_operations;
  extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
  extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
  extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
  		       struct kstat *stat);
  extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
  			  int datasync);
  
  /* fat/inode.c */
  extern void fat_attach(struct inode *inode, loff_t i_pos);
  extern void fat_detach(struct inode *inode);
  extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
  extern struct inode *fat_build_inode(struct super_block *sb,
  			struct msdos_dir_entry *de, loff_t i_pos);
  extern int fat_sync_inode(struct inode *inode);
  extern int fat_fill_super(struct super_block *sb, void *data, int silent,
  			  int isvfat, void (*setup)(struct super_block *));
  extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
  
  extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
  			    struct inode *i2);
  static inline unsigned long fat_dir_hash(int logstart)
  {
  	return hash_32(logstart, FAT_HASH_BITS);
  }
  
  /* fat/misc.c */
  extern __printf(3, 4) __cold
  void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
  #define fat_fs_error(sb, fmt, args...)		\
  	__fat_fs_error(sb, 1, fmt , ## args)
  #define fat_fs_error_ratelimit(sb, fmt, args...) \
  	__fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
  __printf(3, 4) __cold
  void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
  #define fat_msg_ratelimit(sb, level, fmt, args...)	\
  	do {	\
  			if (__ratelimit(&MSDOS_SB(sb)->ratelimit))	\
  				fat_msg(sb, level, fmt, ## args);	\
  	 } while (0)
  extern int fat_clusters_flush(struct super_block *sb);
  extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
  extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
  			      __le16 __time, __le16 __date, u8 time_cs);
  extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
  			      __le16 *time, __le16 *date, u8 *time_cs);
  extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
  
  int fat_cache_init(void);
  void fat_cache_destroy(void);
  
  /* fat/nfs.c */
  extern const struct export_operations fat_export_ops;
  extern const struct export_operations fat_export_ops_nostale;
  
  /* helper for printk */
  typedef unsigned long long	llu;
  
  #endif /* !_FAT_H */