xref: /linux/fs/exfat/exfat_fs.h (revision d786bdf2a70545a868cd0b06b5603cd5a5fec011)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4  */
5 
6 #ifndef _EXFAT_FS_H
7 #define _EXFAT_FS_H
8 
9 #include <linux/fs.h>
10 #include <linux/ratelimit.h>
11 #include <linux/nls.h>
12 
13 #define EXFAT_ROOT_INO		1
14 
15 #define EXFAT_CLUSTERS_UNTRACKED (~0u)
16 
17 /*
18  * exfat error flags
19  */
20 enum exfat_error_mode {
21 	EXFAT_ERRORS_CONT,	/* ignore error and continue */
22 	EXFAT_ERRORS_PANIC,	/* panic on error */
23 	EXFAT_ERRORS_RO,	/* remount r/o on error */
24 };
25 
26 /*
27  * exfat nls lossy flag
28  */
29 enum {
30 	NLS_NAME_NO_LOSSY,	/* no lossy */
31 	NLS_NAME_LOSSY,		/* just detected incorrect filename(s) */
32 	NLS_NAME_OVERLEN,	/* the length is over than its limit */
33 };
34 
35 #define EXFAT_HASH_BITS		8
36 #define EXFAT_HASH_SIZE		(1UL << EXFAT_HASH_BITS)
37 
38 /*
39  * Type Definitions
40  */
41 #define ES_2_ENTRIES		2
42 #define ES_ALL_ENTRIES		0
43 
44 #define DIR_DELETED		0xFFFF0321
45 
46 /* type values */
47 #define TYPE_UNUSED		0x0000
48 #define TYPE_DELETED		0x0001
49 #define TYPE_INVALID		0x0002
50 #define TYPE_CRITICAL_PRI	0x0100
51 #define TYPE_BITMAP		0x0101
52 #define TYPE_UPCASE		0x0102
53 #define TYPE_VOLUME		0x0103
54 #define TYPE_DIR		0x0104
55 #define TYPE_FILE		0x011F
56 #define TYPE_CRITICAL_SEC	0x0200
57 #define TYPE_STREAM		0x0201
58 #define TYPE_EXTEND		0x0202
59 #define TYPE_ACL		0x0203
60 #define TYPE_BENIGN_PRI		0x0400
61 #define TYPE_GUID		0x0401
62 #define TYPE_PADDING		0x0402
63 #define TYPE_ACLTAB		0x0403
64 #define TYPE_BENIGN_SEC		0x0800
65 #define TYPE_ALL		0x0FFF
66 
67 #define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
68 #define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
69 #define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
70 
71 /* Enough size to hold 256 dentry (even 512 Byte sector) */
72 #define DIR_CACHE_SIZE		(256*sizeof(struct exfat_dentry)/512+1)
73 
74 #define EXFAT_HINT_NONE		-1
75 #define EXFAT_MIN_SUBDIR	2
76 
77 /*
78  * helpers for cluster size to byte conversion.
79  */
80 #define EXFAT_CLU_TO_B(b, sbi)		((b) << (sbi)->cluster_size_bits)
81 #define EXFAT_B_TO_CLU(b, sbi)		((b) >> (sbi)->cluster_size_bits)
82 #define EXFAT_B_TO_CLU_ROUND_UP(b, sbi)	\
83 	(((b - 1) >> (sbi)->cluster_size_bits) + 1)
84 #define EXFAT_CLU_OFFSET(off, sbi)	((off) & ((sbi)->cluster_size - 1))
85 
86 /*
87  * helpers for block size to byte conversion.
88  */
89 #define EXFAT_BLK_TO_B(b, sb)		((b) << (sb)->s_blocksize_bits)
90 #define EXFAT_B_TO_BLK(b, sb)		((b) >> (sb)->s_blocksize_bits)
91 #define EXFAT_B_TO_BLK_ROUND_UP(b, sb)	\
92 	(((b - 1) >> (sb)->s_blocksize_bits) + 1)
93 #define EXFAT_BLK_OFFSET(off, sb)	((off) & ((sb)->s_blocksize - 1))
94 
95 /*
96  * helpers for block size to dentry size conversion.
97  */
98 #define EXFAT_B_TO_DEN_IDX(b, sbi)	\
99 	((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
100 #define EXFAT_B_TO_DEN(b)		((b) >> DENTRY_SIZE_BITS)
101 #define EXFAT_DEN_TO_B(b)		((b) << DENTRY_SIZE_BITS)
102 
103 /*
104  * helpers for fat entry.
105  */
106 #define FAT_ENT_SIZE (4)
107 #define FAT_ENT_SIZE_BITS (2)
108 #define FAT_ENT_OFFSET_SECTOR(sb, loc) (EXFAT_SB(sb)->FAT1_start_sector + \
109 	(((u64)loc << FAT_ENT_SIZE_BITS) >> sb->s_blocksize_bits))
110 #define FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc)	\
111 	((loc << FAT_ENT_SIZE_BITS) & (sb->s_blocksize - 1))
112 
113 /*
114  * helpers for bitmap.
115  */
116 #define CLUSTER_TO_BITMAP_ENT(clu) ((clu) - EXFAT_RESERVED_CLUSTERS)
117 #define BITMAP_ENT_TO_CLUSTER(ent) ((ent) + EXFAT_RESERVED_CLUSTERS)
118 #define BITS_PER_SECTOR(sb) ((sb)->s_blocksize * BITS_PER_BYTE)
119 #define BITS_PER_SECTOR_MASK(sb) (BITS_PER_SECTOR(sb) - 1)
120 #define BITMAP_OFFSET_SECTOR_INDEX(sb, ent) \
121 	((ent / BITS_PER_BYTE) >> (sb)->s_blocksize_bits)
122 #define BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent) (ent & BITS_PER_SECTOR_MASK(sb))
123 #define BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent) \
124 	((ent / BITS_PER_BYTE) & ((sb)->s_blocksize - 1))
125 #define BITS_PER_BYTE_MASK	0x7
126 #define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1)
127 
128 struct exfat_dentry_namebuf {
129 	char *lfn;
130 	int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */
131 };
132 
133 /* unicode name structure */
134 struct exfat_uni_name {
135 	/* +3 for null and for converting */
136 	unsigned short name[MAX_NAME_LENGTH + 3];
137 	u16 name_hash;
138 	unsigned char name_len;
139 };
140 
141 /* directory structure */
142 struct exfat_chain {
143 	unsigned int dir;
144 	unsigned int size;
145 	unsigned char flags;
146 };
147 
148 /* first empty entry hint information */
149 struct exfat_hint_femp {
150 	/* entry index of a directory */
151 	int eidx;
152 	/* count of continuous empty entry */
153 	int count;
154 	/* the cluster that first empty slot exists in */
155 	struct exfat_chain cur;
156 };
157 
158 /* hint structure */
159 struct exfat_hint {
160 	unsigned int clu;
161 	union {
162 		unsigned int off; /* cluster offset */
163 		int eidx; /* entry index */
164 	};
165 };
166 
167 struct exfat_entry_set_cache {
168 	struct super_block *sb;
169 	bool modified;
170 	unsigned int start_off;
171 	int num_bh;
172 	struct buffer_head *bh[DIR_CACHE_SIZE];
173 	unsigned int num_entries;
174 };
175 
176 struct exfat_dir_entry {
177 	struct exfat_chain dir;
178 	int entry;
179 	unsigned int type;
180 	unsigned int start_clu;
181 	unsigned char flags;
182 	unsigned short attr;
183 	loff_t size;
184 	unsigned int num_subdirs;
185 	struct timespec64 atime;
186 	struct timespec64 mtime;
187 	struct timespec64 crtime;
188 	struct exfat_dentry_namebuf namebuf;
189 };
190 
191 /*
192  * exfat mount in-memory data
193  */
194 struct exfat_mount_options {
195 	kuid_t fs_uid;
196 	kgid_t fs_gid;
197 	unsigned short fs_fmask;
198 	unsigned short fs_dmask;
199 	/* permission for setting the [am]time */
200 	unsigned short allow_utime;
201 	/* charset for filename input/display */
202 	char *iocharset;
203 	/* on error: continue, panic, remount-ro */
204 	enum exfat_error_mode errors;
205 	unsigned utf8:1, /* Use of UTF-8 character set */
206 		 sys_tz:1, /* Use local timezone */
207 		 discard:1, /* Issue discard requests on deletions */
208 		 keep_last_dots:1; /* Keep trailing periods in paths */
209 	int time_offset; /* Offset of timestamps from UTC (in minutes) */
210 };
211 
212 /*
213  * EXFAT file system superblock in-memory data
214  */
215 struct exfat_sb_info {
216 	unsigned long long num_sectors; /* num of sectors in volume */
217 	unsigned int num_clusters; /* num of clusters in volume */
218 	unsigned int cluster_size; /* cluster size in bytes */
219 	unsigned int cluster_size_bits;
220 	unsigned int sect_per_clus; /* cluster size in sectors */
221 	unsigned int sect_per_clus_bits;
222 	unsigned long long FAT1_start_sector; /* FAT1 start sector */
223 	unsigned long long FAT2_start_sector; /* FAT2 start sector */
224 	unsigned long long data_start_sector; /* data area start sector */
225 	unsigned int num_FAT_sectors; /* num of FAT sectors */
226 	unsigned int root_dir; /* root dir cluster */
227 	unsigned int dentries_per_clu; /* num of dentries per cluster */
228 	unsigned int vol_flags; /* volume flags */
229 	unsigned int vol_flags_persistent; /* volume flags to retain */
230 	struct buffer_head *boot_bh; /* buffer_head of BOOT sector */
231 
232 	unsigned int map_clu; /* allocation bitmap start cluster */
233 	unsigned int map_sectors; /* num of allocation bitmap sectors */
234 	struct buffer_head **vol_amap; /* allocation bitmap */
235 
236 	unsigned short *vol_utbl; /* upcase table */
237 
238 	unsigned int clu_srch_ptr; /* cluster search pointer */
239 	unsigned int used_clusters; /* number of used clusters */
240 
241 	struct mutex s_lock; /* superblock lock */
242 	struct mutex bitmap_lock; /* bitmap lock */
243 	struct exfat_mount_options options;
244 	struct nls_table *nls_io; /* Charset used for input and display */
245 	struct ratelimit_state ratelimit;
246 
247 	spinlock_t inode_hash_lock;
248 	struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
249 
250 	struct rcu_head rcu;
251 };
252 
253 #define EXFAT_CACHE_VALID	0
254 
255 /*
256  * EXFAT file system inode in-memory data
257  */
258 struct exfat_inode_info {
259 	struct exfat_chain dir;
260 	int entry;
261 	unsigned int type;
262 	unsigned short attr;
263 	unsigned int start_clu;
264 	unsigned char flags;
265 	/*
266 	 * the copy of low 32bit of i_version to check
267 	 * the validation of hint_stat.
268 	 */
269 	unsigned int version;
270 
271 	/* hint for cluster last accessed */
272 	struct exfat_hint hint_bmap;
273 	/* hint for entry index we try to lookup next time */
274 	struct exfat_hint hint_stat;
275 	/* hint for first empty entry */
276 	struct exfat_hint_femp hint_femp;
277 
278 	spinlock_t cache_lru_lock;
279 	struct list_head cache_lru;
280 	int nr_caches;
281 	/* for avoiding the race between alloc and free */
282 	unsigned int cache_valid_id;
283 
284 	/*
285 	 * NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
286 	 * physically allocated size.
287 	 */
288 	loff_t i_size_ondisk;
289 	/* block-aligned i_size (used in cont_write_begin) */
290 	loff_t i_size_aligned;
291 	/* on-disk position of directory entry or 0 */
292 	loff_t i_pos;
293 	/* hash by i_location */
294 	struct hlist_node i_hash_fat;
295 	/* protect bmap against truncate */
296 	struct rw_semaphore truncate_lock;
297 	struct inode vfs_inode;
298 	/* File creation time */
299 	struct timespec64 i_crtime;
300 };
301 
302 static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
303 {
304 	return sb->s_fs_info;
305 }
306 
307 static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
308 {
309 	return container_of(inode, struct exfat_inode_info, vfs_inode);
310 }
311 
312 /*
313  * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
314  * save ATTR_RO instead of ->i_mode.
315  *
316  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
317  * bit, it's just used as flag for app.
318  */
319 static inline int exfat_mode_can_hold_ro(struct inode *inode)
320 {
321 	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
322 
323 	if (S_ISDIR(inode->i_mode))
324 		return 0;
325 
326 	if ((~sbi->options.fs_fmask) & 0222)
327 		return 1;
328 	return 0;
329 }
330 
331 /* Convert attribute bits and a mask to the UNIX mode. */
332 static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
333 		unsigned short attr, mode_t mode)
334 {
335 	if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
336 		mode &= ~0222;
337 
338 	if (attr & ATTR_SUBDIR)
339 		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
340 
341 	return (mode & ~sbi->options.fs_fmask) | S_IFREG;
342 }
343 
344 /* Return the FAT attribute byte for this inode */
345 static inline unsigned short exfat_make_attr(struct inode *inode)
346 {
347 	unsigned short attr = EXFAT_I(inode)->attr;
348 
349 	if (S_ISDIR(inode->i_mode))
350 		attr |= ATTR_SUBDIR;
351 	if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
352 		attr |= ATTR_READONLY;
353 	return attr;
354 }
355 
356 static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
357 {
358 	if (exfat_mode_can_hold_ro(inode))
359 		EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
360 	else
361 		EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
362 }
363 
364 static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
365 		sector_t sec)
366 {
367 	return ((sec - sbi->data_start_sector + 1) &
368 		((1 << sbi->sect_per_clus_bits) - 1)) == 0;
369 }
370 
371 static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
372 		unsigned int clus)
373 {
374 	return ((sector_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +
375 		sbi->data_start_sector;
376 }
377 
378 static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
379 		sector_t sec)
380 {
381 	return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
382 		EXFAT_RESERVED_CLUSTERS;
383 }
384 
385 static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
386 		unsigned int clus)
387 {
388 	return clus >= EXFAT_FIRST_CLUSTER && clus < sbi->num_clusters;
389 }
390 
391 /* super.c */
392 int exfat_set_volume_dirty(struct super_block *sb);
393 int exfat_clear_volume_dirty(struct super_block *sb);
394 
395 /* fatent.c */
396 #define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
397 
398 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
399 		struct exfat_chain *p_chain, bool sync_bmap);
400 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
401 int exfat_ent_get(struct super_block *sb, unsigned int loc,
402 		unsigned int *content);
403 int exfat_ent_set(struct super_block *sb, unsigned int loc,
404 		unsigned int content);
405 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
406 		int entry, struct exfat_dentry *p_entry);
407 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
408 		unsigned int len);
409 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
410 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
411 		unsigned int *ret_clu);
412 int exfat_count_num_clusters(struct super_block *sb,
413 		struct exfat_chain *p_chain, unsigned int *ret_count);
414 
415 /* balloc.c */
416 int exfat_load_bitmap(struct super_block *sb);
417 void exfat_free_bitmap(struct exfat_sb_info *sbi);
418 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync);
419 void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync);
420 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);
421 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
422 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range);
423 
424 /* file.c */
425 extern const struct file_operations exfat_file_operations;
426 int __exfat_truncate(struct inode *inode, loff_t new_size);
427 void exfat_truncate(struct inode *inode, loff_t size);
428 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
429 		  struct iattr *attr);
430 int exfat_getattr(struct user_namespace *mnt_userns, const struct path *path,
431 		  struct kstat *stat, unsigned int request_mask,
432 		  unsigned int query_flags);
433 int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
434 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
435 long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
436 				unsigned long arg);
437 
438 /* namei.c */
439 extern const struct dentry_operations exfat_dentry_ops;
440 extern const struct dentry_operations exfat_utf8_dentry_ops;
441 
442 /* cache.c */
443 int exfat_cache_init(void);
444 void exfat_cache_shutdown(void);
445 void exfat_cache_inval_inode(struct inode *inode);
446 int exfat_get_cluster(struct inode *inode, unsigned int cluster,
447 		unsigned int *fclus, unsigned int *dclus,
448 		unsigned int *last_dclus, int allow_eof);
449 
450 /* dir.c */
451 extern const struct inode_operations exfat_dir_inode_operations;
452 extern const struct file_operations exfat_dir_operations;
453 unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
454 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
455 		int entry, unsigned int type, unsigned int start_clu,
456 		unsigned long long size);
457 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
458 		int entry, int num_entries, struct exfat_uni_name *p_uniname);
459 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
460 		int entry, int order, int num_entries);
461 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
462 		int entry);
463 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
464 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
465 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
466 		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
467 		int num_entries, unsigned int type, struct exfat_hint *hint_opt);
468 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
469 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
470 		struct exfat_chain *p_dir, int entry, struct buffer_head **bh);
471 struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
472 		int num);
473 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
474 		struct exfat_chain *p_dir, int entry, unsigned int type);
475 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
476 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
477 
478 /* inode.c */
479 extern const struct inode_operations exfat_file_inode_operations;
480 void exfat_sync_inode(struct inode *inode);
481 struct inode *exfat_build_inode(struct super_block *sb,
482 		struct exfat_dir_entry *info, loff_t i_pos);
483 void exfat_hash_inode(struct inode *inode, loff_t i_pos);
484 void exfat_unhash_inode(struct inode *inode);
485 struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
486 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
487 void exfat_evict_inode(struct inode *inode);
488 int exfat_block_truncate_page(struct inode *inode, loff_t from);
489 
490 /* exfat/nls.c */
491 unsigned short exfat_toupper(struct super_block *sb, unsigned short a);
492 int exfat_uniname_ncmp(struct super_block *sb, unsigned short *a,
493 		unsigned short *b, unsigned int len);
494 int exfat_utf16_to_nls(struct super_block *sb,
495 		struct exfat_uni_name *uniname, unsigned char *p_cstring,
496 		int len);
497 int exfat_nls_to_utf16(struct super_block *sb,
498 		const unsigned char *p_cstring, const int len,
499 		struct exfat_uni_name *uniname, int *p_lossy);
500 int exfat_create_upcase_table(struct super_block *sb);
501 void exfat_free_upcase_table(struct exfat_sb_info *sbi);
502 
503 /* exfat/misc.c */
504 void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
505 		__printf(3, 4) __cold;
506 #define exfat_fs_error(sb, fmt, args...)          \
507 		__exfat_fs_error(sb, 1, fmt, ## args)
508 #define exfat_fs_error_ratelimit(sb, fmt, args...) \
509 		__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
510 		fmt, ## args)
511 void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
512 		__printf(3, 4) __cold;
513 #define exfat_err(sb, fmt, ...)						\
514 	exfat_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
515 #define exfat_warn(sb, fmt, ...)					\
516 	exfat_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
517 #define exfat_info(sb, fmt, ...)					\
518 	exfat_msg(sb, KERN_INFO, fmt, ##__VA_ARGS__)
519 
520 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
521 		u8 tz, __le16 time, __le16 date, u8 time_cs);
522 void exfat_truncate_atime(struct timespec64 *ts);
523 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
524 		u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
525 u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
526 u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type);
527 void exfat_update_bh(struct buffer_head *bh, int sync);
528 int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync);
529 void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
530 		unsigned int size, unsigned char flags);
531 void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec);
532 
533 #endif /* !_EXFAT_FS_H */
534