fs/exfat/exfat_fs.h

   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_SUPER_MAGIC       0x2011BAB0UL
  14 #define EXFAT_ROOT_INO          1
  15
  16 #define EXFAT_CLUSTERS_UNTRACKED (~0u)
  17
  18 /*
  19  * exfat error flags
  20  */
  21 enum exfat_error_mode {
  22         EXFAT_ERRORS_CONT,      /* ignore error and continue */
  23         EXFAT_ERRORS_PANIC,     /* panic on error */
  24         EXFAT_ERRORS_RO,        /* remount r/o on error */
  25 };
  26
  27 /*
  28  * exfat nls lossy flag
  29  */
  30 enum {
  31         NLS_NAME_NO_LOSSY,      /* no lossy */
  32         NLS_NAME_LOSSY,         /* just detected incorrect filename(s) */
  33         NLS_NAME_OVERLEN,       /* the length is over than its limit */
  34 };
  35
  36 #define EXFAT_HASH_BITS         8
  37 #define EXFAT_HASH_SIZE         (1UL << EXFAT_HASH_BITS)
  38
  39 /*
  40  * Type Definitions
  41  */
  42 #define ES_2_ENTRIES            2
  43 #define ES_ALL_ENTRIES          0
  44
  45 #define DIR_DELETED             0xFFFF0321
  46
  47 /* type values */
  48 #define TYPE_UNUSED             0x0000
  49 #define TYPE_DELETED            0x0001
  50 #define TYPE_INVALID            0x0002
  51 #define TYPE_CRITICAL_PRI       0x0100
  52 #define TYPE_BITMAP             0x0101
  53 #define TYPE_UPCASE             0x0102
  54 #define TYPE_VOLUME             0x0103
  55 #define TYPE_DIR                0x0104
  56 #define TYPE_FILE               0x011F
  57 #define TYPE_CRITICAL_SEC       0x0200
  58 #define TYPE_STREAM             0x0201
  59 #define TYPE_EXTEND             0x0202
  60 #define TYPE_ACL                0x0203
  61 #define TYPE_BENIGN_PRI         0x0400
  62 #define TYPE_GUID               0x0401
  63 #define TYPE_PADDING            0x0402
  64 #define TYPE_ACLTAB             0x0403
  65 #define TYPE_BENIGN_SEC         0x0800
  66 #define TYPE_ALL                0x0FFF
  67
  68 #define MAX_CHARSET_SIZE        6 /* max size of multi-byte character */
  69 #define MAX_NAME_LENGTH         255 /* max len of file name excluding NULL */
  70 #define MAX_VFSNAME_BUF_SIZE    ((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
  71
  72 /* Enough size to hold 256 dentry (even 512 Byte sector) */
  73 #define DIR_CACHE_SIZE          (256*sizeof(struct exfat_dentry)/512+1)
  74
  75 #define EXFAT_HINT_NONE         -1
  76 #define EXFAT_MIN_SUBDIR        2
  77
  78 /*
  79  * helpers for cluster size to byte conversion.
  80  */
  81 #define EXFAT_CLU_TO_B(b, sbi)          ((b) << (sbi)->cluster_size_bits)
  82 #define EXFAT_B_TO_CLU(b, sbi)          ((b) >> (sbi)->cluster_size_bits)
  83 #define EXFAT_B_TO_CLU_ROUND_UP(b, sbi) \
  84         (((b - 1) >> (sbi)->cluster_size_bits) + 1)
  85 #define EXFAT_CLU_OFFSET(off, sbi)      ((off) & ((sbi)->cluster_size - 1))
  86
  87 /*
  88  * helpers for block size to byte conversion.
  89  */
  90 #define EXFAT_BLK_TO_B(b, sb)           ((b) << (sb)->s_blocksize_bits)
  91 #define EXFAT_B_TO_BLK(b, sb)           ((b) >> (sb)->s_blocksize_bits)
  92 #define EXFAT_B_TO_BLK_ROUND_UP(b, sb)  \
  93         (((b - 1) >> (sb)->s_blocksize_bits) + 1)
  94 #define EXFAT_BLK_OFFSET(off, sb)       ((off) & ((sb)->s_blocksize - 1))
  95
  96 /*
  97  * helpers for block size to dentry size conversion.
  98  */
  99 #define EXFAT_B_TO_DEN_IDX(b, sbi)      \
 100         ((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
 101 #define EXFAT_B_TO_DEN(b)               ((b) >> DENTRY_SIZE_BITS)
 102 #define EXFAT_DEN_TO_B(b)               ((b) << DENTRY_SIZE_BITS)
 103
 104 /*
 105  * helpers for fat entry.
 106  */
 107 #define FAT_ENT_SIZE (4)
 108 #define FAT_ENT_SIZE_BITS (2)
 109 #define FAT_ENT_OFFSET_SECTOR(sb, loc) (EXFAT_SB(sb)->FAT1_start_sector + \
 110         (((u64)loc << FAT_ENT_SIZE_BITS) >> sb->s_blocksize_bits))
 111 #define FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc)  \
 112         ((loc << FAT_ENT_SIZE_BITS) & (sb->s_blocksize - 1))
 113
 114 /*
 115  * helpers for bitmap.
 116  */
 117 #define CLUSTER_TO_BITMAP_ENT(clu) ((clu) - EXFAT_RESERVED_CLUSTERS)
 118 #define BITMAP_ENT_TO_CLUSTER(ent) ((ent) + EXFAT_RESERVED_CLUSTERS)
 119 #define BITS_PER_SECTOR(sb) ((sb)->s_blocksize * BITS_PER_BYTE)
 120 #define BITS_PER_SECTOR_MASK(sb) (BITS_PER_SECTOR(sb) - 1)
 121 #define BITMAP_OFFSET_SECTOR_INDEX(sb, ent) \
 122         ((ent / BITS_PER_BYTE) >> (sb)->s_blocksize_bits)
 123 #define BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent) (ent & BITS_PER_SECTOR_MASK(sb))
 124 #define BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent) \
 125         ((ent / BITS_PER_BYTE) & ((sb)->s_blocksize - 1))
 126 #define BITS_PER_BYTE_MASK      0x7
 127 #define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1)
 128
 129 struct exfat_dentry_namebuf {
 130         char *lfn;
 131         int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */
 132 };
 133
 134 /* unicode name structure */
 135 struct exfat_uni_name {
 136         /* +3 for null and for converting */
 137         unsigned short name[MAX_NAME_LENGTH + 3];
 138         u16 name_hash;
 139         unsigned char name_len;
 140 };
 141
 142 /* directory structure */
 143 struct exfat_chain {
 144         unsigned int dir;
 145         unsigned int size;
 146         unsigned char flags;
 147 };
 148
 149 /* first empty entry hint information */
 150 struct exfat_hint_femp {
 151         /* entry index of a directory */
 152         int eidx;
 153         /* count of continuous empty entry */
 154         int count;
 155         /* the cluster that first empty slot exists in */
 156         struct exfat_chain cur;
 157 };
 158
 159 /* hint structure */
 160 struct exfat_hint {
 161         unsigned int clu;
 162         union {
 163                 unsigned int off; /* cluster offset */
 164                 int eidx; /* entry index */
 165         };
 166 };
 167
 168 struct exfat_entry_set_cache {
 169         struct super_block *sb;
 170         bool modified;
 171         unsigned int start_off;
 172         int num_bh;
 173         struct buffer_head *bh[DIR_CACHE_SIZE];
 174         unsigned int num_entries;
 175 };
 176
 177 struct exfat_dir_entry {
 178         struct exfat_chain dir;
 179         int entry;
 180         unsigned int type;
 181         unsigned int start_clu;
 182         unsigned char flags;
 183         unsigned short attr;
 184         loff_t size;
 185         unsigned int num_subdirs;
 186         struct timespec64 atime;
 187         struct timespec64 mtime;
 188         struct timespec64 crtime;
 189         struct exfat_dentry_namebuf namebuf;
 190 };
 191
 192 /*
 193  * exfat mount in-memory data
 194  */
 195 struct exfat_mount_options {
 196         kuid_t fs_uid;
 197         kgid_t fs_gid;
 198         unsigned short fs_fmask;
 199         unsigned short fs_dmask;
 200         /* permission for setting the [am]time */
 201         unsigned short allow_utime;
 202         /* charset for filename input/display */
 203         char *iocharset;
 204         /* on error: continue, panic, remount-ro */
 205         enum exfat_error_mode errors;
 206         unsigned utf8:1, /* Use of UTF-8 character set */
 207                  discard:1; /* Issue discard requests on deletions */
 208         int time_offset; /* Offset of timestamps from UTC (in minutes) */
 209 };
 210
 211 /*
 212  * EXFAT file system superblock in-memory data
 213  */
 214 struct exfat_sb_info {
 215         unsigned long long num_sectors; /* num of sectors in volume */
 216         unsigned int num_clusters; /* num of clusters in volume */
 217         unsigned int cluster_size; /* cluster size in bytes */
 218         unsigned int cluster_size_bits;
 219         unsigned int sect_per_clus; /* cluster size in sectors */
 220         unsigned int sect_per_clus_bits;
 221         unsigned long long FAT1_start_sector; /* FAT1 start sector */
 222         unsigned long long FAT2_start_sector; /* FAT2 start sector */
 223         unsigned long long data_start_sector; /* data area start sector */
 224         unsigned int num_FAT_sectors; /* num of FAT sectors */
 225         unsigned int root_dir; /* root dir cluster */
 226         unsigned int dentries_per_clu; /* num of dentries per cluster */
 227         unsigned int vol_flags; /* volume flags */
 228         unsigned int vol_flags_persistent; /* volume flags to retain */
 229         struct buffer_head *boot_bh; /* buffer_head of BOOT sector */
 230
 231         unsigned int map_clu; /* allocation bitmap start cluster */
 232         unsigned int map_sectors; /* num of allocation bitmap sectors */
 233         struct buffer_head **vol_amap; /* allocation bitmap */
 234
 235         unsigned short *vol_utbl; /* upcase table */
 236
 237         unsigned int clu_srch_ptr; /* cluster search pointer */
 238         unsigned int used_clusters; /* number of used clusters */
 239
 240         struct mutex s_lock; /* superblock lock */
 241         struct exfat_mount_options options;
 242         struct nls_table *nls_io; /* Charset used for input and display */
 243         struct ratelimit_state ratelimit;
 244
 245         spinlock_t inode_hash_lock;
 246         struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
 247
 248         struct rcu_head rcu;
 249 };
 250
 251 #define EXFAT_CACHE_VALID       0
 252
 253 /*
 254  * EXFAT file system inode in-memory data
 255  */
 256 struct exfat_inode_info {
 257         struct exfat_chain dir;
 258         int entry;
 259         unsigned int type;
 260         unsigned short attr;
 261         unsigned int start_clu;
 262         unsigned char flags;
 263         /*
 264          * the copy of low 32bit of i_version to check
 265          * the validation of hint_stat.
 266          */
 267         unsigned int version;
 268
 269         /* hint for cluster last accessed */
 270         struct exfat_hint hint_bmap;
 271         /* hint for entry index we try to lookup next time */
 272         struct exfat_hint hint_stat;
 273         /* hint for first empty entry */
 274         struct exfat_hint_femp hint_femp;
 275
 276         spinlock_t cache_lru_lock;
 277         struct list_head cache_lru;
 278         int nr_caches;
 279         /* for avoiding the race between alloc and free */
 280         unsigned int cache_valid_id;
 281
 282         /*
 283          * NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
 284          * physically allocated size.
 285          */
 286         loff_t i_size_ondisk;
 287         /* block-aligned i_size (used in cont_write_begin) */
 288         loff_t i_size_aligned;
 289         /* on-disk position of directory entry or 0 */
 290         loff_t i_pos;
 291         /* hash by i_location */
 292         struct hlist_node i_hash_fat;
 293         /* protect bmap against truncate */
 294         struct rw_semaphore truncate_lock;
 295         struct inode vfs_inode;
 296         /* File creation time */
 297         struct timespec64 i_crtime;
 298 };
 299
 300 static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
 301 {
 302         return sb->s_fs_info;
 303 }
 304
 305 static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
 306 {
 307         return container_of(inode, struct exfat_inode_info, vfs_inode);
 308 }
 309
 310 /*
 311  * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
 312  * save ATTR_RO instead of ->i_mode.
 313  *
 314  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 315  * bit, it's just used as flag for app.
 316  */
 317 static inline int exfat_mode_can_hold_ro(struct inode *inode)
 318 {
 319         struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
 320
 321         if (S_ISDIR(inode->i_mode))
 322                 return 0;
 323
 324         if ((~sbi->options.fs_fmask) & 0222)
 325                 return 1;
 326         return 0;
 327 }
 328
 329 /* Convert attribute bits and a mask to the UNIX mode. */
 330 static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
 331                 unsigned short attr, mode_t mode)
 332 {
 333         if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
 334                 mode &= ~0222;
 335
 336         if (attr & ATTR_SUBDIR)
 337                 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 338
 339         return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 340 }
 341
 342 /* Return the FAT attribute byte for this inode */
 343 static inline unsigned short exfat_make_attr(struct inode *inode)
 344 {
 345         unsigned short attr = EXFAT_I(inode)->attr;
 346
 347         if (S_ISDIR(inode->i_mode))
 348                 attr |= ATTR_SUBDIR;
 349         if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
 350                 attr |= ATTR_READONLY;
 351         return attr;
 352 }
 353
 354 static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
 355 {
 356         if (exfat_mode_can_hold_ro(inode))
 357                 EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
 358         else
 359                 EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
 360 }
 361
 362 static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
 363                 sector_t sec)
 364 {
 365         return ((sec - sbi->data_start_sector + 1) &
 366                 ((1 << sbi->sect_per_clus_bits) - 1)) == 0;
 367 }
 368
 369 static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
 370                 unsigned int clus)
 371 {
 372         return ((sector_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +
 373                 sbi->data_start_sector;
 374 }
 375
 376 static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
 377                 sector_t sec)
 378 {
 379         return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
 380                 EXFAT_RESERVED_CLUSTERS;
 381 }
 382
 383 /* super.c */
 384 int exfat_set_volume_dirty(struct super_block *sb);
 385 int exfat_clear_volume_dirty(struct super_block *sb);
 386
 387 /* fatent.c */
 388 #define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
 389
 390 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 391                 struct exfat_chain *p_chain);
 392 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
 393 int exfat_ent_get(struct super_block *sb, unsigned int loc,
 394                 unsigned int *content);
 395 int exfat_ent_set(struct super_block *sb, unsigned int loc,
 396                 unsigned int content);
 397 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
 398                 int entry, struct exfat_dentry *p_entry);
 399 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
 400                 unsigned int len);
 401 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
 402 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
 403                 unsigned int *ret_clu);
 404 int exfat_count_num_clusters(struct super_block *sb,
 405                 struct exfat_chain *p_chain, unsigned int *ret_count);
 406
 407 /* balloc.c */
 408 int exfat_load_bitmap(struct super_block *sb);
 409 void exfat_free_bitmap(struct exfat_sb_info *sbi);
 410 int exfat_set_bitmap(struct inode *inode, unsigned int clu);
 411 void exfat_clear_bitmap(struct inode *inode, unsigned int clu);
 412 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);
 413 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
 414
 415 /* file.c */
 416 extern const struct file_operations exfat_file_operations;
 417 int __exfat_truncate(struct inode *inode, loff_t new_size);
 418 void exfat_truncate(struct inode *inode, loff_t size);
 419 int exfat_setattr(struct dentry *dentry, struct iattr *attr);
 420 int exfat_getattr(const struct path *path, struct kstat *stat,
 421                 unsigned int request_mask, unsigned int query_flags);
 422 int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
 423
 424 /* namei.c */
 425 extern const struct dentry_operations exfat_dentry_ops;
 426 extern const struct dentry_operations exfat_utf8_dentry_ops;
 427
 428 /* cache.c */
 429 int exfat_cache_init(void);
 430 void exfat_cache_shutdown(void);
 431 void exfat_cache_inval_inode(struct inode *inode);
 432 int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 433                 unsigned int *fclus, unsigned int *dclus,
 434                 unsigned int *last_dclus, int allow_eof);
 435
 436 /* dir.c */
 437 extern const struct inode_operations exfat_dir_inode_operations;
 438 extern const struct file_operations exfat_dir_operations;
 439 unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
 440 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 441                 int entry, unsigned int type, unsigned int start_clu,
 442                 unsigned long long size);
 443 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 444                 int entry, int num_entries, struct exfat_uni_name *p_uniname);
 445 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 446                 int entry, int order, int num_entries);
 447 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 448                 int entry);
 449 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
 450 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
 451 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 452                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 453                 int num_entries, unsigned int type);
 454 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
 455 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 456                 int entry, sector_t *sector, int *offset);
 457 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 458                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 459                 sector_t *sector);
 460 struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
 461                 int num);
 462 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 463                 struct exfat_chain *p_dir, int entry, unsigned int type);
 464 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
 465 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
 466
 467 /* inode.c */
 468 extern const struct inode_operations exfat_file_inode_operations;
 469 void exfat_sync_inode(struct inode *inode);
 470 struct inode *exfat_build_inode(struct super_block *sb,
 471                 struct exfat_dir_entry *info, loff_t i_pos);
 472 void exfat_hash_inode(struct inode *inode, loff_t i_pos);
 473 void exfat_unhash_inode(struct inode *inode);
 474 struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
 475 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
 476 void exfat_evict_inode(struct inode *inode);
 477 int exfat_block_truncate_page(struct inode *inode, loff_t from);
 478
 479 /* exfat/nls.c */
 480 unsigned short exfat_toupper(struct super_block *sb, unsigned short a);
 481 int exfat_uniname_ncmp(struct super_block *sb, unsigned short *a,
 482                 unsigned short *b, unsigned int len);
 483 int exfat_utf16_to_nls(struct super_block *sb,
 484                 struct exfat_uni_name *uniname, unsigned char *p_cstring,
 485                 int len);
 486 int exfat_nls_to_utf16(struct super_block *sb,
 487                 const unsigned char *p_cstring, const int len,
 488                 struct exfat_uni_name *uniname, int *p_lossy);
 489 int exfat_create_upcase_table(struct super_block *sb);
 490 void exfat_free_upcase_table(struct exfat_sb_info *sbi);
 491
 492 /* exfat/misc.c */
 493 void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 494                 __printf(3, 4) __cold;
 495 #define exfat_fs_error(sb, fmt, args...)          \
 496                 __exfat_fs_error(sb, 1, fmt, ## args)
 497 #define exfat_fs_error_ratelimit(sb, fmt, args...) \
 498                 __exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
 499                 fmt, ## args)
 500 void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
 501                 __printf(3, 4) __cold;
 502 #define exfat_err(sb, fmt, ...)                                         \
 503         exfat_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
 504 #define exfat_warn(sb, fmt, ...)                                        \
 505         exfat_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
 506 #define exfat_info(sb, fmt, ...)                                        \
 507         exfat_msg(sb, KERN_INFO, fmt, ##__VA_ARGS__)
 508
 509 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 510                 u8 tz, __le16 time, __le16 date, u8 time_cs);
 511 void exfat_truncate_atime(struct timespec64 *ts);
 512 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 513                 u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
 514 u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
 515 u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type);
 516 void exfat_update_bh(struct buffer_head *bh, int sync);
 517 int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync);
 518 void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
 519                 unsigned int size, unsigned char flags);
 520 void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec);
 521
 522 #endif /* !_EXFAT_FS_H */