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 struct file_kattr; 14 15 /* 16 * vfat shortname flags 17 */ 18 #define VFAT_SFN_DISPLAY_LOWER 0x0001 /* convert to lowercase for display */ 19 #define VFAT_SFN_DISPLAY_WIN95 0x0002 /* emulate win95 rule for display */ 20 #define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */ 21 #define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */ 22 #define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */ 23 24 #define FAT_ERRORS_CONT 1 /* ignore error and continue */ 25 #define FAT_ERRORS_PANIC 2 /* panic on error */ 26 #define FAT_ERRORS_RO 3 /* remount r/o on error */ 27 28 #define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */ 29 #define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */ 30 31 struct fat_mount_options { 32 kuid_t fs_uid; 33 kgid_t fs_gid; 34 unsigned short fs_fmask; 35 unsigned short fs_dmask; 36 unsigned short codepage; /* Codepage for shortname conversions */ 37 int time_offset; /* Offset of timestamps from UTC (in minutes) */ 38 char *iocharset; /* Charset used for filename input/display */ 39 unsigned short shortname; /* flags for shortname display/create rule */ 40 unsigned char name_check; /* r = relaxed, n = normal, s = strict */ 41 unsigned char errors; /* On error: continue, panic, remount-ro */ 42 unsigned char nfs; /* NFS support: nostale_ro, stale_rw */ 43 unsigned short allow_utime;/* permission for setting the [am]time */ 44 unsigned quiet:1, /* set = fake successful chmods and chowns */ 45 showexec:1, /* set = only set x bit for com/exe/bat */ 46 sys_immutable:1, /* set = system files are immutable */ 47 dotsOK:1, /* set = hidden and system files are named '.filename' */ 48 isvfat:1, /* 0=no vfat long filename support, 1=vfat support */ 49 utf8:1, /* Use of UTF-8 character set (Default) */ 50 unicode_xlate:1, /* create escape sequences for unhandled Unicode */ 51 numtail:1, /* Does first alias have a numeric '~1' type tail? */ 52 flush:1, /* write things quickly */ 53 nocase:1, /* Does this need case conversion? 0=need case conversion*/ 54 usefree:1, /* Use free_clusters for FAT32 */ 55 tz_set:1, /* Filesystem timestamps' offset set */ 56 rodir:1, /* allow ATTR_RO for directory */ 57 discard:1, /* Issue discard requests on deletions */ 58 dos1xfloppy:1, /* Assume default BPB for DOS 1.x floppies */ 59 debug:1; /* Not currently used */ 60 }; 61 62 #define FAT_HASH_BITS 8 63 #define FAT_HASH_SIZE (1UL << FAT_HASH_BITS) 64 65 /* 66 * MS-DOS file system in-core superblock data 67 */ 68 struct msdos_sb_info { 69 unsigned short sec_per_clus; /* sectors/cluster */ 70 unsigned short cluster_bits; /* log2(cluster_size) */ 71 unsigned int cluster_size; /* cluster size */ 72 unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */ 73 unsigned short fat_start; 74 unsigned long fat_length; /* FAT start & length (sec.) */ 75 unsigned long dir_start; 76 unsigned short dir_entries; /* root dir start & entries */ 77 unsigned long data_start; /* first data sector */ 78 unsigned long max_cluster; /* maximum cluster number */ 79 unsigned long root_cluster; /* first cluster of the root directory */ 80 unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */ 81 struct mutex fat_lock; 82 struct mutex nfs_build_inode_lock; 83 struct mutex s_lock; 84 unsigned int prev_free; /* previously allocated cluster number */ 85 unsigned int free_clusters; /* -1 if undefined */ 86 unsigned int free_clus_valid; /* is free_clusters valid? */ 87 struct fat_mount_options options; 88 struct nls_table *nls_disk; /* Codepage used on disk */ 89 struct nls_table *nls_io; /* Charset used for input and display */ 90 const void *dir_ops; /* Opaque; default directory operations */ 91 int dir_per_block; /* dir entries per block */ 92 int dir_per_block_bits; /* log2(dir_per_block) */ 93 unsigned int vol_id; /*volume ID*/ 94 95 int fatent_shift; 96 const struct fatent_operations *fatent_ops; 97 struct inode *fat_inode; 98 struct inode *fsinfo_inode; 99 100 struct ratelimit_state ratelimit; 101 102 spinlock_t inode_hash_lock; 103 struct hlist_head inode_hashtable[FAT_HASH_SIZE]; 104 105 spinlock_t dir_hash_lock; 106 struct hlist_head dir_hashtable[FAT_HASH_SIZE]; 107 108 unsigned int dirty; /* fs state before mount */ 109 struct rcu_head rcu; 110 }; 111 112 #define FAT_CACHE_VALID 0 /* special case for valid cache */ 113 114 /* 115 * MS-DOS file system inode data in memory 116 */ 117 struct msdos_inode_info { 118 spinlock_t cache_lru_lock; 119 struct list_head cache_lru; 120 int nr_caches; 121 /* for avoiding the race between fat_free() and fat_get_cluster() */ 122 unsigned int cache_valid_id; 123 124 /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */ 125 loff_t mmu_private; /* physically allocated size */ 126 127 int i_start; /* first cluster or 0 */ 128 int i_logstart; /* logical first cluster */ 129 int i_attrs; /* unused attribute bits */ 130 loff_t i_pos; /* on-disk position of directory entry or 0 */ 131 struct hlist_node i_fat_hash; /* hash by i_location */ 132 struct hlist_node i_dir_hash; /* hash by i_logstart */ 133 struct rw_semaphore truncate_lock; /* protect bmap against truncate */ 134 struct timespec64 i_crtime; /* File creation (birth) time */ 135 struct mapping_metadata_bhs i_metadata_bhs; 136 struct inode vfs_inode; 137 }; 138 139 struct fat_slot_info { 140 loff_t i_pos; /* on-disk position of directory entry */ 141 loff_t slot_off; /* offset for slot or de start */ 142 int nr_slots; /* number of slots + 1(de) in filename */ 143 struct msdos_dir_entry *de; 144 struct buffer_head *bh; 145 }; 146 147 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb) 148 { 149 return sb->s_fs_info; 150 } 151 152 /* 153 * Functions that determine the variant of the FAT file system (i.e., 154 * whether this is FAT12, FAT16 or FAT32. 155 */ 156 static inline bool is_fat12(const struct msdos_sb_info *sbi) 157 { 158 return sbi->fat_bits == 12; 159 } 160 161 static inline bool is_fat16(const struct msdos_sb_info *sbi) 162 { 163 return sbi->fat_bits == 16; 164 } 165 166 static inline bool is_fat32(const struct msdos_sb_info *sbi) 167 { 168 return sbi->fat_bits == 32; 169 } 170 171 /* Maximum number of clusters */ 172 static inline u32 max_fat(struct super_block *sb) 173 { 174 struct msdos_sb_info *sbi = MSDOS_SB(sb); 175 176 return is_fat32(sbi) ? MAX_FAT32 : 177 is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12; 178 } 179 180 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode) 181 { 182 return container_of(inode, struct msdos_inode_info, vfs_inode); 183 } 184 185 /* 186 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to 187 * save ATTR_RO instead of ->i_mode. 188 * 189 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only 190 * bit, it's just used as flag for app. 191 */ 192 static inline int fat_mode_can_hold_ro(struct inode *inode) 193 { 194 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 195 umode_t mask; 196 197 if (S_ISDIR(inode->i_mode)) { 198 if (!sbi->options.rodir) 199 return 0; 200 mask = ~sbi->options.fs_dmask; 201 } else 202 mask = ~sbi->options.fs_fmask; 203 204 if (!(mask & S_IWUGO)) 205 return 0; 206 return 1; 207 } 208 209 /* Convert attribute bits and a mask to the UNIX mode. */ 210 static inline umode_t fat_make_mode(struct msdos_sb_info *sbi, 211 u8 attrs, umode_t mode) 212 { 213 if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir)) 214 mode &= ~S_IWUGO; 215 216 if (attrs & ATTR_DIR) 217 return (mode & ~sbi->options.fs_dmask) | S_IFDIR; 218 else 219 return (mode & ~sbi->options.fs_fmask) | S_IFREG; 220 } 221 222 /* Return the FAT attribute byte for this inode */ 223 static inline u8 fat_make_attrs(struct inode *inode) 224 { 225 u8 attrs = MSDOS_I(inode)->i_attrs; 226 if (S_ISDIR(inode->i_mode)) 227 attrs |= ATTR_DIR; 228 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO)) 229 attrs |= ATTR_RO; 230 return attrs; 231 } 232 233 static inline void fat_save_attrs(struct inode *inode, u8 attrs) 234 { 235 if (fat_mode_can_hold_ro(inode)) 236 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; 237 else 238 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO); 239 } 240 241 static inline unsigned char fat_checksum(const __u8 *name) 242 { 243 unsigned char s = name[0]; 244 s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2]; 245 s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4]; 246 s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6]; 247 s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8]; 248 s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10]; 249 return s; 250 } 251 252 static inline sector_t fat_clus_to_blknr(const struct msdos_sb_info *sbi, int clus) 253 { 254 return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus 255 + sbi->data_start; 256 } 257 258 static inline void fat_get_blknr_offset(const struct msdos_sb_info *sbi, 259 loff_t i_pos, sector_t *blknr, int *offset) 260 { 261 *blknr = i_pos >> sbi->dir_per_block_bits; 262 *offset = i_pos & (sbi->dir_per_block - 1); 263 } 264 265 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 266 struct inode *inode) 267 { 268 loff_t i_pos; 269 #if BITS_PER_LONG == 32 270 spin_lock(&sbi->inode_hash_lock); 271 #endif 272 i_pos = MSDOS_I(inode)->i_pos; 273 #if BITS_PER_LONG == 32 274 spin_unlock(&sbi->inode_hash_lock); 275 #endif 276 return i_pos; 277 } 278 279 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len) 280 { 281 #ifdef __BIG_ENDIAN 282 while (len--) { 283 *dst++ = src[0] | (src[1] << 8); 284 src += 2; 285 } 286 #else 287 memcpy(dst, src, len * 2); 288 #endif 289 } 290 291 static inline int fat_get_start(const struct msdos_sb_info *sbi, 292 const struct msdos_dir_entry *de) 293 { 294 int cluster = le16_to_cpu(de->start); 295 if (is_fat32(sbi)) 296 cluster |= (le16_to_cpu(de->starthi) << 16); 297 return cluster; 298 } 299 300 static inline void fat_set_start(struct msdos_dir_entry *de, int cluster) 301 { 302 de->start = cpu_to_le16(cluster); 303 de->starthi = cpu_to_le16(cluster >> 16); 304 } 305 306 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len) 307 { 308 #ifdef __BIG_ENDIAN 309 while (len--) { 310 dst[0] = *src & 0x00FF; 311 dst[1] = (*src & 0xFF00) >> 8; 312 dst += 2; 313 src++; 314 } 315 #else 316 memcpy(dst, src, len * 2); 317 #endif 318 } 319 320 /* fat/cache.c */ 321 extern void fat_cache_inval_inode(struct inode *inode); 322 extern int fat_get_cluster(struct inode *inode, int cluster, 323 int *fclus, int *dclus); 324 extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector, 325 sector_t last_block, 326 unsigned long *mapped_blocks, sector_t *bmap); 327 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys, 328 unsigned long *mapped_blocks, int create, bool from_bmap); 329 330 /* fat/dir.c */ 331 extern const struct file_operations fat_dir_operations; 332 extern int fat_search_long(struct inode *inode, const unsigned char *name, 333 int name_len, struct fat_slot_info *sinfo); 334 extern int fat_dir_empty(struct inode *dir); 335 extern int fat_subdirs(struct inode *dir); 336 extern int fat_scan(struct inode *dir, const unsigned char *name, 337 struct fat_slot_info *sinfo); 338 extern int fat_scan_logstart(struct inode *dir, int i_logstart, 339 struct fat_slot_info *sinfo); 340 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, 341 struct msdos_dir_entry **de); 342 extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts); 343 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots, 344 struct fat_slot_info *sinfo); 345 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo); 346 347 /* fat/fatent.c */ 348 struct fat_entry { 349 int entry; 350 union { 351 u8 *ent12_p[2]; 352 __le16 *ent16_p; 353 __le32 *ent32_p; 354 } u; 355 int nr_bhs; 356 struct buffer_head *bhs[2]; 357 struct inode *fat_inode; 358 }; 359 360 static inline void fatent_init(struct fat_entry *fatent) 361 { 362 fatent->nr_bhs = 0; 363 fatent->entry = 0; 364 fatent->u.ent32_p = NULL; 365 fatent->bhs[0] = fatent->bhs[1] = NULL; 366 fatent->fat_inode = NULL; 367 } 368 369 static inline void fatent_set_entry(struct fat_entry *fatent, int entry) 370 { 371 fatent->entry = entry; 372 fatent->u.ent32_p = NULL; 373 } 374 375 static inline void fatent_brelse(struct fat_entry *fatent) 376 { 377 int i; 378 fatent->u.ent32_p = NULL; 379 for (i = 0; i < fatent->nr_bhs; i++) 380 brelse(fatent->bhs[i]); 381 fatent->nr_bhs = 0; 382 fatent->bhs[0] = fatent->bhs[1] = NULL; 383 fatent->fat_inode = NULL; 384 } 385 386 static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry) 387 { 388 return FAT_START_ENT <= entry && entry < sbi->max_cluster; 389 } 390 391 extern void fat_ent_access_init(struct super_block *sb); 392 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent, 393 int entry); 394 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent, 395 int new, int wait); 396 extern int fat_alloc_clusters(struct inode *inode, int *cluster, 397 int nr_cluster); 398 extern int fat_free_clusters(struct inode *inode, int cluster); 399 extern int fat_count_free_clusters(struct super_block *sb); 400 extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range); 401 402 /* fat/file.c */ 403 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd, 404 unsigned long arg); 405 extern const struct file_operations fat_file_operations; 406 extern const struct inode_operations fat_file_inode_operations; 407 extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 408 struct iattr *attr); 409 extern void fat_truncate_blocks(struct inode *inode, loff_t offset); 410 extern int fat_getattr(struct mnt_idmap *idmap, 411 const struct path *path, struct kstat *stat, 412 u32 request_mask, unsigned int flags); 413 int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa); 414 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end, 415 int datasync); 416 417 /* fat/inode.c */ 418 extern int fat_block_truncate_page(struct inode *inode, loff_t from); 419 extern void fat_attach(struct inode *inode, loff_t i_pos); 420 extern void fat_detach(struct inode *inode); 421 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos); 422 extern struct inode *fat_build_inode(struct super_block *sb, 423 struct msdos_dir_entry *de, loff_t i_pos); 424 extern int fat_sync_inode(struct inode *inode); 425 extern int fat_fill_super(struct super_block *sb, struct fs_context *fc, 426 void (*setup)(struct super_block *)); 427 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de); 428 429 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1, 430 struct inode *i2); 431 432 extern const struct fs_parameter_spec fat_param_spec[]; 433 int fat_init_fs_context(struct fs_context *fc, bool is_vfat); 434 void fat_free_fc(struct fs_context *fc); 435 436 int fat_parse_param(struct fs_context *fc, struct fs_parameter *param, 437 bool is_vfat); 438 int fat_reconfigure(struct fs_context *fc); 439 440 static inline unsigned long fat_dir_hash(int logstart) 441 { 442 return hash_32(logstart, FAT_HASH_BITS); 443 } 444 extern int fat_add_cluster(struct inode *inode); 445 446 /* fat/misc.c */ 447 extern __printf(3, 4) __cold 448 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...); 449 #define fat_fs_error(sb, fmt, args...) \ 450 __fat_fs_error(sb, 1, fmt , ## args) 451 #define fat_fs_error_ratelimit(sb, fmt, args...) \ 452 __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args) 453 454 #define FAT_PRINTK_PREFIX "%sFAT-fs (%s): " 455 #define fat_msg(sb, level, fmt, args...) \ 456 do { \ 457 printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\ 458 _fat_msg(sb, level, fmt, ##args); \ 459 } while (0) 460 __printf(3, 4) __cold 461 void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...); 462 #define fat_msg_ratelimit(sb, level, fmt, args...) \ 463 do { \ 464 if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \ 465 fat_msg(sb, level, fmt, ## args); \ 466 } while (0) 467 extern int fat_clusters_flush(struct super_block *sb); 468 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster); 469 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, 470 __le16 __time, __le16 __date, u8 time_cs); 471 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, 472 __le16 *time, __le16 *date, u8 *time_cs); 473 extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, 474 const struct timespec64 *ts); 475 #define FAT_UPDATE_ATIME (1u << 0) 476 #define FAT_UPDATE_CMTIME (1u << 1) 477 void fat_truncate_time(struct inode *inode, struct timespec64 *now, 478 unsigned int flags); 479 int fat_update_time(struct inode *inode, enum fs_update_time type, 480 unsigned int flags); 481 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs); 482 483 int fat_cache_init(void); 484 void fat_cache_destroy(void); 485 486 /* fat/nfs.c */ 487 extern const struct export_operations fat_export_ops; 488 extern const struct export_operations fat_export_ops_nostale; 489 490 /* helper for printk */ 491 typedef unsigned long long llu; 492 493 #endif /* !_FAT_H */ 494