fs/fat/fat.h - maze/linux - Git at Google

 #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/mutex.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 */

 struct fat_mount_options {
 	uid_t fs_uid;
 	gid_t fs_gid;
 	unsigned short fs_fmask;
 	unsigned short fs_dmask;
 	unsigned short codepage;  /* Codepage for shortname conversions */
 	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 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_utc:1,	  /* Filesystem timestamps are in UTC */
 		 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;
 	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) */

 	int fatent_shift;
 	struct fatent_operations *fatent_ops;
 	struct inode *fat_inode;

 	spinlock_t inode_hash_lock;
 	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
 };

 #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 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);
 	mode_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 mode_t fat_make_mode(struct msdos_sb_info *sbi,
 				   u8 attrs, mode_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 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 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_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 				struct msdos_dir_entry **de, loff_t *i_pos);
 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 int fat_generic_ioctl(struct inode *inode, 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(struct inode *inode);
 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		       struct kstat *stat);
 extern int fat_file_fsync(struct file *file, struct dentry *dentry,
 			  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,
 			const struct inode_operations *fs_dir_inode_ops, int isvfat);

 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 		            struct inode *i2);
 /* fat/misc.c */
 extern void fat_fs_error(struct super_block *s, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3))) __cold;
 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);

 /* helper for printk */
 typedef unsigned long long	llu;

 #endif /* !_FAT_H */
	#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/mutex.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 */

	struct fat_mount_options {
	uid_t fs_uid;
	gid_t fs_gid;
	unsigned short fs_fmask;
	unsigned short fs_dmask;
	unsigned short codepage; /* Codepage for shortname conversions */
	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 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_utc:1, /* Filesystem timestamps are in UTC */
	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;
	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) */

	int fatent_shift;
	struct fatent_operations *fatent_ops;
	struct inode *fat_inode;

	spinlock_t inode_hash_lock;
	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
	};

	#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 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);
	mode_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 mode_t fat_make_mode(struct msdos_sb_info *sbi,
	u8 attrs, mode_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 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 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_get_dotdot_entry(struct inode dir, struct buffer_head *bh,
	struct msdos_dir_entry *de, loff_t i_pos);
	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 int fat_generic_ioctl(struct inode inode, 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(struct inode *inode);
	extern int fat_getattr(struct vfsmount mnt, struct dentry dentry,
	struct kstat *stat);
	extern int fat_file_fsync(struct file file, struct dentry dentry,
	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,
	const struct inode_operations *fs_dir_inode_ops, int isvfat);

	extern int fat_flush_inodes(struct super_block sb, struct inode i1,
	struct inode *i2);
	/* fat/misc.c */
	extern void fat_fs_error(struct super_block s, const char fmt, ...)
	__attribute__ ((format (printf, 2, 3))) __cold;
	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);

	/* helper for printk */
	typedef unsigned long long llu;

	#endif /* !_FAT_H */