1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _FAT_H 3 #define _FAT_H 4 5 #include <linux/buffer_head.h> 6 #include <linux/nls.h> 7 #include <linux/hash.h> 8 #include <linux/ratelimit.h> 9 #include <linux/msdos_fs.h> 10 #include <linux/fs_context.h> 11 #include <linux/fs_parser.h> 12 13 /* 14 * vfat shortname flags 15 */ 16 #define VFAT_SFN_DISPLAY_LOWER 0x0001 /* convert to lowercase for display */ 17 #define VFAT_SFN_DISPLAY_WIN95 0x0002 /* emulate win95 rule for display */ 18 #define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */ 19 #define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */ 20 #define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */ 21 22 #define FAT_ERRORS_CONT 1 /* ignore error and continue */ 23 #define FAT_ERRORS_PANIC 2 /* panic on error */ 24 #define FAT_ERRORS_RO 3 /* remount r/o on error */ 25 26 #define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */ 27 #define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */ 28 29 struct fat_mount_options { 30 kuid_t fs_uid; 31 kgid_t fs_gid; 32 unsigned short fs_fmask; 33 unsigned short fs_dmask; 34 unsigned short codepage; /* Codepage for shortname conversions */ 35 int time_offset; /* Offset of timestamps from UTC (in minutes) */ 36 char *iocharset; /* Charset used for filename input/display */ 37 unsigned short shortname; /* flags for shortname display/create rule */ 38 unsigned char name_check; /* r = relaxed, n = normal, s = strict */ 39 unsigned char errors; /* On error: continue, panic, remount-ro */ 40 unsigned char nfs; /* NFS support: nostale_ro, stale_rw */ 41 unsigned short allow_utime;/* permission for setting the [am]time */ 42 unsigned quiet:1, /* set = fake successful chmods and chowns */ 43 showexec:1, /* set = only set x bit for com/exe/bat */ 44 sys_immutable:1, /* set = system files are immutable */ 45 dotsOK:1, /* set = hidden and system files are named '.filename' */ 46 isvfat:1, /* 0=no vfat long filename support, 1=vfat support */ 47 utf8:1, /* Use of UTF-8 character set (Default) */ 48 unicode_xlate:1, /* create escape sequences for unhandled Unicode */ 49 numtail:1, /* Does first alias have a numeric '~1' type tail? */ 50 flush:1, /* write things quickly */ 51 nocase:1, /* Does this need case conversion? 0=need case conversion*/ 52 usefree:1, /* Use free_clusters for FAT32 */ 53 tz_set:1, /* Filesystem timestamps' offset set */ 54 rodir:1, /* allow ATTR_RO for directory */ 55 discard:1, /* Issue discard requests on deletions */ 56 dos1xfloppy:1, /* Assume default BPB for DOS 1.x floppies */ 57 debug:1; /* Not currently used */ 58 }; 59 60 #define FAT_HASH_BITS 8 61 #define FAT_HASH_SIZE (1UL << FAT_HASH_BITS) 62 63 /* 64 * MS-DOS file system in-core superblock data 65 */ 66 struct msdos_sb_info { 67 unsigned short sec_per_clus; /* sectors/cluster */ 68 unsigned short cluster_bits; /* log2(cluster_size) */ 69 unsigned int cluster_size; /* cluster size */ 70 unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */ 71 unsigned short fat_start; 72 unsigned long fat_length; /* FAT start & length (sec.) */ 73 unsigned long dir_start; 74 unsigned short dir_entries; /* root dir start & entries */ 75 unsigned long data_start; /* first data sector */ 76 unsigned long max_cluster; /* maximum cluster number */ 77 unsigned long root_cluster; /* first cluster of the root directory */ 78 unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */ 79 struct mutex fat_lock; 80 struct mutex nfs_build_inode_lock; 81 struct mutex s_lock; 82 unsigned int prev_free; /* previously allocated cluster number */ 83 unsigned int free_clusters; /* -1 if undefined */ 84 unsigned int free_clus_valid; /* is free_clusters valid? */ 85 struct fat_mount_options options; 86 struct nls_table *nls_disk; /* Codepage used on disk */ 87 struct nls_table *nls_io; /* Charset used for input and display */ 88 const void *dir_ops; /* Opaque; default directory operations */ 89 int dir_per_block; /* dir entries per block */ 90 int dir_per_block_bits; /* log2(dir_per_block) */ 91 unsigned int vol_id; /*volume ID*/ 92 93 int fatent_shift; 94 const struct fatent_operations *fatent_ops; 95 struct inode *fat_inode; 96 struct inode *fsinfo_inode; 97 98 struct ratelimit_state ratelimit; 99 100 spinlock_t inode_hash_lock; 101 struct hlist_head inode_hashtable[FAT_HASH_SIZE]; 102 103 spinlock_t dir_hash_lock; 104 struct hlist_head dir_hashtable[FAT_HASH_SIZE]; 105 106 unsigned int dirty; /* fs state before mount */ 107 struct rcu_head rcu; 108 }; 109 110 #define FAT_CACHE_VALID 0 /* special case for valid cache */ 111 112 /* 113 * MS-DOS file system inode data in memory 114 */ 115 struct msdos_inode_info { 116 spinlock_t cache_lru_lock; 117 struct list_head cache_lru; 118 int nr_caches; 119 /* for avoiding the race between fat_free() and fat_get_cluster() */ 120 unsigned int cache_valid_id; 121 122 /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */ 123 loff_t mmu_private; /* physically allocated size */ 124 125 int i_start; /* first cluster or 0 */ 126 int i_logstart; /* logical first cluster */ 127 int i_attrs; /* unused attribute bits */ 128 loff_t i_pos; /* on-disk position of directory entry or 0 */ 129 struct hlist_node i_fat_hash; /* hash by i_location */ 130 struct hlist_node i_dir_hash; /* hash by i_logstart */ 131 struct rw_semaphore truncate_lock; /* protect bmap against truncate */ 132 struct timespec64 i_crtime; /* File creation (birth) time */ 133 struct inode vfs_inode; 134 }; 135 136 struct fat_slot_info { 137 loff_t i_pos; /* on-disk position of directory entry */ 138 loff_t slot_off; /* offset for slot or de start */ 139 int nr_slots; /* number of slots + 1(de) in filename */ 140 struct msdos_dir_entry *de; 141 struct buffer_head *bh; 142 }; 143 144 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb) 145 { 146 return sb->s_fs_info; 147 } 148 149 /* 150 * Functions that determine the variant of the FAT file system (i.e., 151 * whether this is FAT12, FAT16 or FAT32. 152 */ 153 static inline bool is_fat12(const struct msdos_sb_info *sbi) 154 { 155 return sbi->fat_bits == 12; 156 } 157 158 static inline bool is_fat16(const struct msdos_sb_info *sbi) 159 { 160 return sbi->fat_bits == 16; 161 } 162 163 static inline bool is_fat32(const struct msdos_sb_info *sbi) 164 { 165 return sbi->fat_bits == 32; 166 } 167 168 /* Maximum number of clusters */ 169 static inline u32 max_fat(struct super_block *sb) 170 { 171 struct msdos_sb_info *sbi = MSDOS_SB(sb); 172 173 return is_fat32(sbi) ? MAX_FAT32 : 174 is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12; 175 } 176 177 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode) 178 { 179 return container_of(inode, struct msdos_inode_info, vfs_inode); 180 } 181 182 /* 183 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to 184 * save ATTR_RO instead of ->i_mode. 185 * 186 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only 187 * bit, it's just used as flag for app. 188 */ 189 static inline int fat_mode_can_hold_ro(struct inode *inode) 190 { 191 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 192 umode_t mask; 193 194 if (S_ISDIR(inode->i_mode)) { 195 if (!sbi->options.rodir) 196 return 0; 197 mask = ~sbi->options.fs_dmask; 198 } else 199 mask = ~sbi->options.fs_fmask; 200 201 if (!(mask & S_IWUGO)) 202 return 0; 203 return 1; 204 } 205 206 /* Convert attribute bits and a mask to the UNIX mode. */ 207 static inline umode_t fat_make_mode(struct msdos_sb_info *sbi, 208 u8 attrs, umode_t mode) 209 { 210 if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir)) 211 mode &= ~S_IWUGO; 212 213 if (attrs & ATTR_DIR) 214 return (mode & ~sbi->options.fs_dmask) | S_IFDIR; 215 else 216 return (mode & ~sbi->options.fs_fmask) | S_IFREG; 217 } 218 219 /* Return the FAT attribute byte for this inode */ 220 static inline u8 fat_make_attrs(struct inode *inode) 221 { 222 u8 attrs = MSDOS_I(inode)->i_attrs; 223 if (S_ISDIR(inode->i_mode)) 224 attrs |= ATTR_DIR; 225 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO)) 226 attrs |= ATTR_RO; 227 return attrs; 228 } 229 230 static inline void fat_save_attrs(struct inode *inode, u8 attrs) 231 { 232 if (fat_mode_can_hold_ro(inode)) 233 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; 234 else 235 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO); 236 } 237 238 static inline unsigned char fat_checksum(const __u8 *name) 239 { 240 unsigned char s = name[0]; 241 s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2]; 242 s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4]; 243 s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6]; 244 s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8]; 245 s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10]; 246 return s; 247 } 248 249 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus) 250 { 251 return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus 252 + sbi->data_start; 253 } 254 255 static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi, 256 loff_t i_pos, sector_t *blknr, int *offset) 257 { 258 *blknr = i_pos >> sbi->dir_per_block_bits; 259 *offset = i_pos & (sbi->dir_per_block - 1); 260 } 261 262 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 263 struct inode *inode) 264 { 265 loff_t i_pos; 266 #if BITS_PER_LONG == 32 267 spin_lock(&sbi->inode_hash_lock); 268 #endif 269 i_pos = MSDOS_I(inode)->i_pos; 270 #if BITS_PER_LONG == 32 271 spin_unlock(&sbi->inode_hash_lock); 272 #endif 273 return i_pos; 274 } 275 276 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len) 277 { 278 #ifdef __BIG_ENDIAN 279 while (len--) { 280 *dst++ = src[0] | (src[1] << 8); 281 src += 2; 282 } 283 #else 284 memcpy(dst, src, len * 2); 285 #endif 286 } 287 288 static inline int fat_get_start(const struct msdos_sb_info *sbi, 289 const struct msdos_dir_entry *de) 290 { 291 int cluster = le16_to_cpu(de->start); 292 if (is_fat32(sbi)) 293 cluster |= (le16_to_cpu(de->starthi) << 16); 294 return cluster; 295 } 296 297 static inline void fat_set_start(struct msdos_dir_entry *de, int cluster) 298 { 299 de->start = cpu_to_le16(cluster); 300 de->starthi = cpu_to_le16(cluster >> 16); 301 } 302 303 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len) 304 { 305 #ifdef __BIG_ENDIAN 306 while (len--) { 307 dst[0] = *src & 0x00FF; 308 dst[1] = (*src & 0xFF00) >> 8; 309 dst += 2; 310 src++; 311 } 312 #else 313 memcpy(dst, src, len * 2); 314 #endif 315 } 316 317 /* fat/cache.c */ 318 extern void fat_cache_inval_inode(struct inode *inode); 319 extern int fat_get_cluster(struct inode *inode, int cluster, 320 int *fclus, int *dclus); 321 extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector, 322 sector_t last_block, 323 unsigned long *mapped_blocks, sector_t *bmap); 324 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys, 325 unsigned long *mapped_blocks, int create, bool from_bmap); 326 327 /* fat/dir.c */ 328 extern const struct file_operations fat_dir_operations; 329 extern int fat_search_long(struct inode *inode, const unsigned char *name, 330 int name_len, struct fat_slot_info *sinfo); 331 extern int fat_dir_empty(struct inode *dir); 332 extern int fat_subdirs(struct inode *dir); 333 extern int fat_scan(struct inode *dir, const unsigned char *name, 334 struct fat_slot_info *sinfo); 335 extern int fat_scan_logstart(struct inode *dir, int i_logstart, 336 struct fat_slot_info *sinfo); 337 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, 338 struct msdos_dir_entry **de); 339 extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts); 340 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots, 341 struct fat_slot_info *sinfo); 342 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo); 343 344 /* fat/fatent.c */ 345 struct fat_entry { 346 int entry; 347 union { 348 u8 *ent12_p[2]; 349 __le16 *ent16_p; 350 __le32 *ent32_p; 351 } u; 352 int nr_bhs; 353 struct buffer_head *bhs[2]; 354 struct inode *fat_inode; 355 }; 356 357 static inline void fatent_init(struct fat_entry *fatent) 358 { 359 fatent->nr_bhs = 0; 360 fatent->entry = 0; 361 fatent->u.ent32_p = NULL; 362 fatent->bhs[0] = fatent->bhs[1] = NULL; 363 fatent->fat_inode = NULL; 364 } 365 366 static inline void fatent_set_entry(struct fat_entry *fatent, int entry) 367 { 368 fatent->entry = entry; 369 fatent->u.ent32_p = NULL; 370 } 371 372 static inline void fatent_brelse(struct fat_entry *fatent) 373 { 374 int i; 375 fatent->u.ent32_p = NULL; 376 for (i = 0; i < fatent->nr_bhs; i++) 377 brelse(fatent->bhs[i]); 378 fatent->nr_bhs = 0; 379 fatent->bhs[0] = fatent->bhs[1] = NULL; 380 fatent->fat_inode = NULL; 381 } 382 383 static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry) 384 { 385 return FAT_START_ENT <= entry && entry < sbi->max_cluster; 386 } 387 388 extern void fat_ent_access_init(struct super_block *sb); 389 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent, 390 int entry); 391 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent, 392 int new, int wait); 393 extern int fat_alloc_clusters(struct inode *inode, int *cluster, 394 int nr_cluster); 395 extern int fat_free_clusters(struct inode *inode, int cluster); 396 extern int fat_count_free_clusters(struct super_block *sb); 397 extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range); 398 399 /* fat/file.c */ 400 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd, 401 unsigned long arg); 402 extern const struct file_operations fat_file_operations; 403 extern const struct inode_operations fat_file_inode_operations; 404 extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 405 struct iattr *attr); 406 extern void fat_truncate_blocks(struct inode *inode, loff_t offset); 407 extern int fat_getattr(struct mnt_idmap *idmap, 408 const struct path *path, struct kstat *stat, 409 u32 request_mask, unsigned int flags); 410 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end, 411 int datasync); 412 413 /* fat/inode.c */ 414 extern int fat_block_truncate_page(struct inode *inode, loff_t from); 415 extern void fat_attach(struct inode *inode, loff_t i_pos); 416 extern void fat_detach(struct inode *inode); 417 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos); 418 extern struct inode *fat_build_inode(struct super_block *sb, 419 struct msdos_dir_entry *de, loff_t i_pos); 420 extern int fat_sync_inode(struct inode *inode); 421 extern int fat_fill_super(struct super_block *sb, struct fs_context *fc, 422 void (*setup)(struct super_block *)); 423 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de); 424 425 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1, 426 struct inode *i2); 427 428 extern const struct fs_parameter_spec fat_param_spec[]; 429 int fat_init_fs_context(struct fs_context *fc, bool is_vfat); 430 void fat_free_fc(struct fs_context *fc); 431 432 int fat_parse_param(struct fs_context *fc, struct fs_parameter *param, 433 bool is_vfat); 434 int fat_reconfigure(struct fs_context *fc); 435 436 static inline unsigned long fat_dir_hash(int logstart) 437 { 438 return hash_32(logstart, FAT_HASH_BITS); 439 } 440 extern int fat_add_cluster(struct inode *inode); 441 442 /* fat/misc.c */ 443 extern __printf(3, 4) __cold 444 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...); 445 #define fat_fs_error(sb, fmt, args...) \ 446 __fat_fs_error(sb, 1, fmt , ## args) 447 #define fat_fs_error_ratelimit(sb, fmt, args...) \ 448 __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args) 449 450 #define FAT_PRINTK_PREFIX "%sFAT-fs (%s): " 451 #define fat_msg(sb, level, fmt, args...) \ 452 do { \ 453 printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\ 454 _fat_msg(sb, level, fmt, ##args); \ 455 } while (0) 456 __printf(3, 4) __cold 457 void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...); 458 #define fat_msg_ratelimit(sb, level, fmt, args...) \ 459 do { \ 460 if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \ 461 fat_msg(sb, level, fmt, ## args); \ 462 } while (0) 463 extern int fat_clusters_flush(struct super_block *sb); 464 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster); 465 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, 466 __le16 __time, __le16 __date, u8 time_cs); 467 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, 468 __le16 *time, __le16 *date, u8 *time_cs); 469 extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, 470 const struct timespec64 *ts); 471 extern struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi, 472 const struct timespec64 *ts); 473 extern int fat_truncate_time(struct inode *inode, struct timespec64 *now, 474 int flags); 475 extern int fat_update_time(struct inode *inode, int flags); 476 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs); 477 478 int fat_cache_init(void); 479 void fat_cache_destroy(void); 480 481 /* fat/nfs.c */ 482 extern const struct export_operations fat_export_ops; 483 extern const struct export_operations fat_export_ops_nostale; 484 485 /* helper for printk */ 486 typedef unsigned long long llu; 487 488 #endif /* !_FAT_H */ 489