fat.h 15 KB

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