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 timespec64 i_crtime; /* File creation (birth) time */ |
130 | struct inode vfs_inode; |
131 | }; |
132 | |
133 | struct fat_slot_info { |
134 | loff_t i_pos; /* on-disk position of directory entry */ |
135 | loff_t slot_off; /* offset for slot or de start */ |
136 | int nr_slots; /* number of slots + 1(de) in filename */ |
137 | struct msdos_dir_entry *de; |
138 | struct buffer_head *bh; |
139 | }; |
140 | |
141 | static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb) |
142 | { |
143 | return sb->s_fs_info; |
144 | } |
145 | |
146 | /* |
147 | * Functions that determine the variant of the FAT file system (i.e., |
148 | * whether this is FAT12, FAT16 or FAT32. |
149 | */ |
150 | static inline bool is_fat12(const struct msdos_sb_info *sbi) |
151 | { |
152 | return sbi->fat_bits == 12; |
153 | } |
154 | |
155 | static inline bool is_fat16(const struct msdos_sb_info *sbi) |
156 | { |
157 | return sbi->fat_bits == 16; |
158 | } |
159 | |
160 | static inline bool is_fat32(const struct msdos_sb_info *sbi) |
161 | { |
162 | return sbi->fat_bits == 32; |
163 | } |
164 | |
165 | /* Maximum number of clusters */ |
166 | static inline u32 max_fat(struct super_block *sb) |
167 | { |
168 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
169 | |
170 | return is_fat32(sbi) ? MAX_FAT32 : |
171 | is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12; |
172 | } |
173 | |
174 | static inline struct msdos_inode_info *MSDOS_I(struct inode *inode) |
175 | { |
176 | return container_of(inode, struct msdos_inode_info, vfs_inode); |
177 | } |
178 | |
179 | /* |
180 | * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to |
181 | * save ATTR_RO instead of ->i_mode. |
182 | * |
183 | * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only |
184 | * bit, it's just used as flag for app. |
185 | */ |
186 | static inline int fat_mode_can_hold_ro(struct inode *inode) |
187 | { |
188 | struct msdos_sb_info *sbi = MSDOS_SB(sb: inode->i_sb); |
189 | umode_t mask; |
190 | |
191 | if (S_ISDIR(inode->i_mode)) { |
192 | if (!sbi->options.rodir) |
193 | return 0; |
194 | mask = ~sbi->options.fs_dmask; |
195 | } else |
196 | mask = ~sbi->options.fs_fmask; |
197 | |
198 | if (!(mask & S_IWUGO)) |
199 | return 0; |
200 | return 1; |
201 | } |
202 | |
203 | /* Convert attribute bits and a mask to the UNIX mode. */ |
204 | static inline umode_t fat_make_mode(struct msdos_sb_info *sbi, |
205 | u8 attrs, umode_t mode) |
206 | { |
207 | if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir)) |
208 | mode &= ~S_IWUGO; |
209 | |
210 | if (attrs & ATTR_DIR) |
211 | return (mode & ~sbi->options.fs_dmask) | S_IFDIR; |
212 | else |
213 | return (mode & ~sbi->options.fs_fmask) | S_IFREG; |
214 | } |
215 | |
216 | /* Return the FAT attribute byte for this inode */ |
217 | static inline u8 fat_make_attrs(struct inode *inode) |
218 | { |
219 | u8 attrs = MSDOS_I(inode)->i_attrs; |
220 | if (S_ISDIR(inode->i_mode)) |
221 | attrs |= ATTR_DIR; |
222 | if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO)) |
223 | attrs |= ATTR_RO; |
224 | return attrs; |
225 | } |
226 | |
227 | static inline void fat_save_attrs(struct inode *inode, u8 attrs) |
228 | { |
229 | if (fat_mode_can_hold_ro(inode)) |
230 | MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; |
231 | else |
232 | MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO); |
233 | } |
234 | |
235 | static inline unsigned char fat_checksum(const __u8 *name) |
236 | { |
237 | unsigned char s = name[0]; |
238 | s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2]; |
239 | s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4]; |
240 | s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6]; |
241 | s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8]; |
242 | s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10]; |
243 | return s; |
244 | } |
245 | |
246 | static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus) |
247 | { |
248 | return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus |
249 | + sbi->data_start; |
250 | } |
251 | |
252 | static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi, |
253 | loff_t i_pos, sector_t *blknr, int *offset) |
254 | { |
255 | *blknr = i_pos >> sbi->dir_per_block_bits; |
256 | *offset = i_pos & (sbi->dir_per_block - 1); |
257 | } |
258 | |
259 | static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, |
260 | struct inode *inode) |
261 | { |
262 | loff_t i_pos; |
263 | #if BITS_PER_LONG == 32 |
264 | spin_lock(&sbi->inode_hash_lock); |
265 | #endif |
266 | i_pos = MSDOS_I(inode)->i_pos; |
267 | #if BITS_PER_LONG == 32 |
268 | spin_unlock(&sbi->inode_hash_lock); |
269 | #endif |
270 | return i_pos; |
271 | } |
272 | |
273 | static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len) |
274 | { |
275 | #ifdef __BIG_ENDIAN |
276 | while (len--) { |
277 | *dst++ = src[0] | (src[1] << 8); |
278 | src += 2; |
279 | } |
280 | #else |
281 | memcpy(dst, src, len * 2); |
282 | #endif |
283 | } |
284 | |
285 | static inline int fat_get_start(const struct msdos_sb_info *sbi, |
286 | const struct msdos_dir_entry *de) |
287 | { |
288 | int cluster = le16_to_cpu(de->start); |
289 | if (is_fat32(sbi)) |
290 | cluster |= (le16_to_cpu(de->starthi) << 16); |
291 | return cluster; |
292 | } |
293 | |
294 | static inline void fat_set_start(struct msdos_dir_entry *de, int cluster) |
295 | { |
296 | de->start = cpu_to_le16(cluster); |
297 | de->starthi = cpu_to_le16(cluster >> 16); |
298 | } |
299 | |
300 | static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len) |
301 | { |
302 | #ifdef __BIG_ENDIAN |
303 | while (len--) { |
304 | dst[0] = *src & 0x00FF; |
305 | dst[1] = (*src & 0xFF00) >> 8; |
306 | dst += 2; |
307 | src++; |
308 | } |
309 | #else |
310 | memcpy(dst, src, len * 2); |
311 | #endif |
312 | } |
313 | |
314 | /* fat/cache.c */ |
315 | extern void fat_cache_inval_inode(struct inode *inode); |
316 | extern int fat_get_cluster(struct inode *inode, int cluster, |
317 | int *fclus, int *dclus); |
318 | extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector, |
319 | sector_t last_block, |
320 | unsigned long *mapped_blocks, sector_t *bmap); |
321 | extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys, |
322 | unsigned long *mapped_blocks, int create, bool from_bmap); |
323 | |
324 | /* fat/dir.c */ |
325 | extern const struct file_operations fat_dir_operations; |
326 | extern int fat_search_long(struct inode *inode, const unsigned char *name, |
327 | int name_len, struct fat_slot_info *sinfo); |
328 | extern int fat_dir_empty(struct inode *dir); |
329 | extern int fat_subdirs(struct inode *dir); |
330 | extern int fat_scan(struct inode *dir, const unsigned char *name, |
331 | struct fat_slot_info *sinfo); |
332 | extern int fat_scan_logstart(struct inode *dir, int i_logstart, |
333 | struct fat_slot_info *sinfo); |
334 | extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, |
335 | struct msdos_dir_entry **de); |
336 | extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts); |
337 | extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots, |
338 | struct fat_slot_info *sinfo); |
339 | extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo); |
340 | |
341 | /* fat/fatent.c */ |
342 | struct fat_entry { |
343 | int entry; |
344 | union { |
345 | u8 *ent12_p[2]; |
346 | __le16 *ent16_p; |
347 | __le32 *ent32_p; |
348 | } u; |
349 | int nr_bhs; |
350 | struct buffer_head *bhs[2]; |
351 | struct inode *fat_inode; |
352 | }; |
353 | |
354 | static inline void fatent_init(struct fat_entry *fatent) |
355 | { |
356 | fatent->nr_bhs = 0; |
357 | fatent->entry = 0; |
358 | fatent->u.ent32_p = NULL; |
359 | fatent->bhs[0] = fatent->bhs[1] = NULL; |
360 | fatent->fat_inode = NULL; |
361 | } |
362 | |
363 | static inline void fatent_set_entry(struct fat_entry *fatent, int entry) |
364 | { |
365 | fatent->entry = entry; |
366 | fatent->u.ent32_p = NULL; |
367 | } |
368 | |
369 | static inline void fatent_brelse(struct fat_entry *fatent) |
370 | { |
371 | int i; |
372 | fatent->u.ent32_p = NULL; |
373 | for (i = 0; i < fatent->nr_bhs; i++) |
374 | brelse(bh: fatent->bhs[i]); |
375 | fatent->nr_bhs = 0; |
376 | fatent->bhs[0] = fatent->bhs[1] = NULL; |
377 | fatent->fat_inode = NULL; |
378 | } |
379 | |
380 | static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry) |
381 | { |
382 | return FAT_START_ENT <= entry && entry < sbi->max_cluster; |
383 | } |
384 | |
385 | extern void fat_ent_access_init(struct super_block *sb); |
386 | extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent, |
387 | int entry); |
388 | extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent, |
389 | int new, int wait); |
390 | extern int fat_alloc_clusters(struct inode *inode, int *cluster, |
391 | int nr_cluster); |
392 | extern int fat_free_clusters(struct inode *inode, int cluster); |
393 | extern int fat_count_free_clusters(struct super_block *sb); |
394 | extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range); |
395 | |
396 | /* fat/file.c */ |
397 | extern long fat_generic_ioctl(struct file *filp, unsigned int cmd, |
398 | unsigned long arg); |
399 | extern const struct file_operations fat_file_operations; |
400 | extern const struct inode_operations fat_file_inode_operations; |
401 | extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
402 | struct iattr *attr); |
403 | extern void fat_truncate_blocks(struct inode *inode, loff_t offset); |
404 | extern int fat_getattr(struct mnt_idmap *idmap, |
405 | const struct path *path, struct kstat *stat, |
406 | u32 request_mask, unsigned int flags); |
407 | extern int fat_file_fsync(struct file *file, loff_t start, loff_t end, |
408 | int datasync); |
409 | |
410 | /* fat/inode.c */ |
411 | extern int fat_block_truncate_page(struct inode *inode, loff_t from); |
412 | extern void fat_attach(struct inode *inode, loff_t i_pos); |
413 | extern void fat_detach(struct inode *inode); |
414 | extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos); |
415 | extern struct inode *fat_build_inode(struct super_block *sb, |
416 | struct msdos_dir_entry *de, loff_t i_pos); |
417 | extern int fat_sync_inode(struct inode *inode); |
418 | extern int fat_fill_super(struct super_block *sb, void *data, int silent, |
419 | int isvfat, void (*setup)(struct super_block *)); |
420 | extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de); |
421 | |
422 | extern int fat_flush_inodes(struct super_block *sb, struct inode *i1, |
423 | struct inode *i2); |
424 | static inline unsigned long fat_dir_hash(int logstart) |
425 | { |
426 | return hash_32(val: logstart, FAT_HASH_BITS); |
427 | } |
428 | extern int fat_add_cluster(struct inode *inode); |
429 | |
430 | /* fat/misc.c */ |
431 | extern __printf(3, 4) __cold |
432 | void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...); |
433 | #define fat_fs_error(sb, fmt, args...) \ |
434 | __fat_fs_error(sb, 1, fmt , ## args) |
435 | #define fat_fs_error_ratelimit(sb, fmt, args...) \ |
436 | __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args) |
437 | |
438 | #define FAT_PRINTK_PREFIX "%sFAT-fs (%s): " |
439 | #define fat_msg(sb, level, fmt, args...) \ |
440 | do { \ |
441 | printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\ |
442 | _fat_msg(sb, level, fmt, ##args); \ |
443 | } while (0) |
444 | __printf(3, 4) __cold |
445 | void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...); |
446 | #define fat_msg_ratelimit(sb, level, fmt, args...) \ |
447 | do { \ |
448 | if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \ |
449 | fat_msg(sb, level, fmt, ## args); \ |
450 | } while (0) |
451 | extern int fat_clusters_flush(struct super_block *sb); |
452 | extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster); |
453 | extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, |
454 | __le16 __time, __le16 __date, u8 time_cs); |
455 | extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, |
456 | __le16 *time, __le16 *date, u8 *time_cs); |
457 | extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, |
458 | const struct timespec64 *ts); |
459 | extern struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi, |
460 | const struct timespec64 *ts); |
461 | extern int fat_truncate_time(struct inode *inode, struct timespec64 *now, |
462 | int flags); |
463 | extern int fat_update_time(struct inode *inode, int flags); |
464 | extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs); |
465 | |
466 | int fat_cache_init(void); |
467 | void fat_cache_destroy(void); |
468 | |
469 | /* fat/nfs.c */ |
470 | extern const struct export_operations fat_export_ops; |
471 | extern const struct export_operations fat_export_ops_nostale; |
472 | |
473 | /* helper for printk */ |
474 | typedef unsigned long long llu; |
475 | |
476 | #endif /* !_FAT_H */ |
477 | |