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