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
MSDOS_SB(struct super_block * sb)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 */
is_fat12(const struct msdos_sb_info * sbi)150 static inline bool is_fat12(const struct msdos_sb_info *sbi)
151 {
152 return sbi->fat_bits == 12;
153 }
154
is_fat16(const struct msdos_sb_info * sbi)155 static inline bool is_fat16(const struct msdos_sb_info *sbi)
156 {
157 return sbi->fat_bits == 16;
158 }
159
is_fat32(const struct msdos_sb_info * sbi)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 */
max_fat(struct super_block * sb)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
MSDOS_I(struct inode * inode)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 */
fat_mode_can_hold_ro(struct inode * inode)186 static inline int fat_mode_can_hold_ro(struct inode *inode)
187 {
188 struct msdos_sb_info *sbi = MSDOS_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. */
fat_make_mode(struct msdos_sb_info * sbi,u8 attrs,umode_t 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 */
fat_make_attrs(struct inode * 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
fat_save_attrs(struct inode * inode,u8 attrs)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
fat_checksum(const __u8 * name)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
fat_clus_to_blknr(struct msdos_sb_info * sbi,int clus)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
fat_get_blknr_offset(struct msdos_sb_info * sbi,loff_t i_pos,sector_t * blknr,int * offset)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
fat_i_pos_read(struct msdos_sb_info * sbi,struct inode * inode)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
fat16_towchar(wchar_t * dst,const __u8 * src,size_t len)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
fat_get_start(const struct msdos_sb_info * sbi,const struct msdos_dir_entry * de)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
fat_set_start(struct msdos_dir_entry * de,int cluster)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
fatwchar_to16(__u8 * dst,const wchar_t * src,size_t len)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
fatent_init(struct fat_entry * fatent)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
fatent_set_entry(struct fat_entry * fatent,int entry)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
fatent_brelse(struct fat_entry * fatent)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(fatent->bhs[i]);
375 fatent->nr_bhs = 0;
376 fatent->bhs[0] = fatent->bhs[1] = NULL;
377 fatent->fat_inode = NULL;
378 }
379
fat_valid_entry(struct msdos_sb_info * sbi,int entry)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);
fat_dir_hash(int logstart)424 static inline unsigned long fat_dir_hash(int logstart)
425 {
426 return hash_32(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