fat.h 16 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 timespec64 i_crtime; /* File creation (birth) time */
  114. struct inode vfs_inode;
  115. };
  116. struct fat_slot_info {
  117. loff_t i_pos; /* on-disk position of directory entry */
  118. loff_t slot_off; /* offset for slot or de start */
  119. int nr_slots; /* number of slots + 1(de) in filename */
  120. struct msdos_dir_entry *de;
  121. struct buffer_head *bh;
  122. };
  123. static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
  124. {
  125. return sb->s_fs_info;
  126. }
  127. /*
  128. * Functions that determine the variant of the FAT file system (i.e.,
  129. * whether this is FAT12, FAT16 or FAT32.
  130. */
  131. static inline bool is_fat12(const struct msdos_sb_info *sbi)
  132. {
  133. return sbi->fat_bits == 12;
  134. }
  135. static inline bool is_fat16(const struct msdos_sb_info *sbi)
  136. {
  137. return sbi->fat_bits == 16;
  138. }
  139. static inline bool is_fat32(const struct msdos_sb_info *sbi)
  140. {
  141. return sbi->fat_bits == 32;
  142. }
  143. /* Maximum number of clusters */
  144. static inline u32 max_fat(struct super_block *sb)
  145. {
  146. struct msdos_sb_info *sbi = MSDOS_SB(sb);
  147. return is_fat32(sbi) ? MAX_FAT32 :
  148. is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
  149. }
  150. static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
  151. {
  152. return container_of(inode, struct msdos_inode_info, vfs_inode);
  153. }
  154. /*
  155. * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
  156. * save ATTR_RO instead of ->i_mode.
  157. *
  158. * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
  159. * bit, it's just used as flag for app.
  160. */
  161. static inline int fat_mode_can_hold_ro(struct inode *inode)
  162. {
  163. struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
  164. umode_t mask;
  165. if (S_ISDIR(inode->i_mode)) {
  166. if (!sbi->options.rodir)
  167. return 0;
  168. mask = ~sbi->options.fs_dmask;
  169. } else
  170. mask = ~sbi->options.fs_fmask;
  171. if (!(mask & S_IWUGO))
  172. return 0;
  173. return 1;
  174. }
  175. /* Convert attribute bits and a mask to the UNIX mode. */
  176. static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
  177. u8 attrs, umode_t mode)
  178. {
  179. if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
  180. mode &= ~S_IWUGO;
  181. if (attrs & ATTR_DIR)
  182. return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
  183. else
  184. return (mode & ~sbi->options.fs_fmask) | S_IFREG;
  185. }
  186. /* Return the FAT attribute byte for this inode */
  187. static inline u8 fat_make_attrs(struct inode *inode)
  188. {
  189. u8 attrs = MSDOS_I(inode)->i_attrs;
  190. if (S_ISDIR(inode->i_mode))
  191. attrs |= ATTR_DIR;
  192. if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
  193. attrs |= ATTR_RO;
  194. return attrs;
  195. }
  196. static inline void fat_save_attrs(struct inode *inode, u8 attrs)
  197. {
  198. if (fat_mode_can_hold_ro(inode))
  199. MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
  200. else
  201. MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
  202. }
  203. static inline unsigned char fat_checksum(const __u8 *name)
  204. {
  205. unsigned char s = name[0];
  206. s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2];
  207. s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4];
  208. s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6];
  209. s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8];
  210. s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10];
  211. return s;
  212. }
  213. static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
  214. {
  215. return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
  216. + sbi->data_start;
  217. }
  218. static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
  219. loff_t i_pos, sector_t *blknr, int *offset)
  220. {
  221. *blknr = i_pos >> sbi->dir_per_block_bits;
  222. *offset = i_pos & (sbi->dir_per_block - 1);
  223. }
  224. static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
  225. struct inode *inode)
  226. {
  227. loff_t i_pos;
  228. #if BITS_PER_LONG == 32
  229. spin_lock(&sbi->inode_hash_lock);
  230. #endif
  231. i_pos = MSDOS_I(inode)->i_pos;
  232. #if BITS_PER_LONG == 32
  233. spin_unlock(&sbi->inode_hash_lock);
  234. #endif
  235. return i_pos;
  236. }
  237. static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
  238. {
  239. #ifdef __BIG_ENDIAN
  240. while (len--) {
  241. *dst++ = src[0] | (src[1] << 8);
  242. src += 2;
  243. }
  244. #else
  245. memcpy(dst, src, len * 2);
  246. #endif
  247. }
  248. static inline int fat_get_start(const struct msdos_sb_info *sbi,
  249. const struct msdos_dir_entry *de)
  250. {
  251. int cluster = le16_to_cpu(de->start);
  252. if (is_fat32(sbi))
  253. cluster |= (le16_to_cpu(de->starthi) << 16);
  254. return cluster;
  255. }
  256. static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
  257. {
  258. de->start = cpu_to_le16(cluster);
  259. de->starthi = cpu_to_le16(cluster >> 16);
  260. }
  261. static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
  262. {
  263. #ifdef __BIG_ENDIAN
  264. while (len--) {
  265. dst[0] = *src & 0x00FF;
  266. dst[1] = (*src & 0xFF00) >> 8;
  267. dst += 2;
  268. src++;
  269. }
  270. #else
  271. memcpy(dst, src, len * 2);
  272. #endif
  273. }
  274. /* fat/cache.c */
  275. extern void fat_cache_inval_inode(struct inode *inode);
  276. extern int fat_get_cluster(struct inode *inode, int cluster,
  277. int *fclus, int *dclus);
  278. extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
  279. sector_t last_block,
  280. unsigned long *mapped_blocks, sector_t *bmap);
  281. extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
  282. unsigned long *mapped_blocks, int create, bool from_bmap);
  283. /* fat/dir.c */
  284. extern const struct file_operations fat_dir_operations;
  285. extern int fat_search_long(struct inode *inode, const unsigned char *name,
  286. int name_len, struct fat_slot_info *sinfo);
  287. extern int fat_dir_empty(struct inode *dir);
  288. extern int fat_subdirs(struct inode *dir);
  289. extern int fat_scan(struct inode *dir, const unsigned char *name,
  290. struct fat_slot_info *sinfo);
  291. extern int fat_scan_logstart(struct inode *dir, int i_logstart,
  292. struct fat_slot_info *sinfo);
  293. extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
  294. struct msdos_dir_entry **de);
  295. extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
  296. extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
  297. struct fat_slot_info *sinfo);
  298. extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
  299. /* fat/fatent.c */
  300. struct fat_entry {
  301. int entry;
  302. union {
  303. u8 *ent12_p[2];
  304. __le16 *ent16_p;
  305. __le32 *ent32_p;
  306. } u;
  307. int nr_bhs;
  308. struct buffer_head *bhs[2];
  309. struct inode *fat_inode;
  310. };
  311. static inline void fatent_init(struct fat_entry *fatent)
  312. {
  313. fatent->nr_bhs = 0;
  314. fatent->entry = 0;
  315. fatent->u.ent32_p = NULL;
  316. fatent->bhs[0] = fatent->bhs[1] = NULL;
  317. fatent->fat_inode = NULL;
  318. }
  319. static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
  320. {
  321. fatent->entry = entry;
  322. fatent->u.ent32_p = NULL;
  323. }
  324. static inline void fatent_brelse(struct fat_entry *fatent)
  325. {
  326. int i;
  327. fatent->u.ent32_p = NULL;
  328. for (i = 0; i < fatent->nr_bhs; i++)
  329. brelse(fatent->bhs[i]);
  330. fatent->nr_bhs = 0;
  331. fatent->bhs[0] = fatent->bhs[1] = NULL;
  332. fatent->fat_inode = NULL;
  333. }
  334. static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)
  335. {
  336. return FAT_START_ENT <= entry && entry < sbi->max_cluster;
  337. }
  338. extern void fat_ent_access_init(struct super_block *sb);
  339. extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
  340. int entry);
  341. extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
  342. int new, int wait);
  343. extern int fat_alloc_clusters(struct inode *inode, int *cluster,
  344. int nr_cluster);
  345. extern int fat_free_clusters(struct inode *inode, int cluster);
  346. extern int fat_count_free_clusters(struct super_block *sb);
  347. extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);
  348. /* fat/file.c */
  349. extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
  350. unsigned long arg);
  351. extern const struct file_operations fat_file_operations;
  352. extern const struct inode_operations fat_file_inode_operations;
  353. extern int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
  354. struct iattr *attr);
  355. extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
  356. extern int fat_getattr(struct user_namespace *mnt_userns,
  357. const struct path *path, struct kstat *stat,
  358. u32 request_mask, unsigned int flags);
  359. extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
  360. int datasync);
  361. /* fat/inode.c */
  362. extern int fat_block_truncate_page(struct inode *inode, loff_t from);
  363. extern void fat_attach(struct inode *inode, loff_t i_pos);
  364. extern void fat_detach(struct inode *inode);
  365. extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
  366. extern struct inode *fat_build_inode(struct super_block *sb,
  367. struct msdos_dir_entry *de, loff_t i_pos);
  368. extern int fat_sync_inode(struct inode *inode);
  369. extern int fat_fill_super(struct super_block *sb, void *data, int silent,
  370. int isvfat, void (*setup)(struct super_block *));
  371. extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
  372. extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
  373. struct inode *i2);
  374. static inline unsigned long fat_dir_hash(int logstart)
  375. {
  376. return hash_32(logstart, FAT_HASH_BITS);
  377. }
  378. extern int fat_add_cluster(struct inode *inode);
  379. /* fat/misc.c */
  380. extern __printf(3, 4) __cold
  381. void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
  382. #define fat_fs_error(sb, fmt, args...) \
  383. __fat_fs_error(sb, 1, fmt , ## args)
  384. #define fat_fs_error_ratelimit(sb, fmt, args...) \
  385. __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
  386. #define FAT_PRINTK_PREFIX "%sFAT-fs (%s): "
  387. #define fat_msg(sb, level, fmt, args...) \
  388. do { \
  389. printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\
  390. _fat_msg(sb, level, fmt, ##args); \
  391. } while (0)
  392. __printf(3, 4) __cold
  393. void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
  394. #define fat_msg_ratelimit(sb, level, fmt, args...) \
  395. do { \
  396. if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \
  397. fat_msg(sb, level, fmt, ## args); \
  398. } while (0)
  399. extern int fat_clusters_flush(struct super_block *sb);
  400. extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
  401. extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
  402. __le16 __time, __le16 __date, u8 time_cs);
  403. extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
  404. __le16 *time, __le16 *date, u8 *time_cs);
  405. extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,
  406. const struct timespec64 *ts);
  407. extern struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi,
  408. const struct timespec64 *ts);
  409. extern int fat_truncate_time(struct inode *inode, struct timespec64 *now,
  410. int flags);
  411. extern int fat_update_time(struct inode *inode, struct timespec64 *now,
  412. int flags);
  413. extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
  414. int fat_cache_init(void);
  415. void fat_cache_destroy(void);
  416. /* fat/nfs.c */
  417. extern const struct export_operations fat_export_ops;
  418. extern const struct export_operations fat_export_ops_nostale;
  419. /* helper for printk */
  420. typedef unsigned long long llu;
  421. #endif /* !_FAT_H */