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
MSDOS_SB(struct super_block * sb)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 */
is_fat12(const struct msdos_sb_info * sbi)149 static inline bool is_fat12(const struct msdos_sb_info *sbi)
150 {
151 return sbi->fat_bits == 12;
152 }
153
is_fat16(const struct msdos_sb_info * sbi)154 static inline bool is_fat16(const struct msdos_sb_info *sbi)
155 {
156 return sbi->fat_bits == 16;
157 }
158
is_fat32(const struct msdos_sb_info * sbi)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 */
max_fat(struct super_block * sb)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
MSDOS_I(struct inode * inode)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 */
fat_mode_can_hold_ro(struct inode * inode)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. */
fat_make_mode(struct msdos_sb_info * sbi,u8 attrs,umode_t 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 */
fat_make_attrs(struct inode * 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
fat_save_attrs(struct inode * inode,u8 attrs)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
fat_checksum(const __u8 * name)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
fat_clus_to_blknr(struct msdos_sb_info * sbi,int clus)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
fat_get_blknr_offset(struct msdos_sb_info * sbi,loff_t i_pos,sector_t * blknr,int * offset)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
fat_i_pos_read(struct msdos_sb_info * sbi,struct inode * inode)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
fat16_towchar(wchar_t * dst,const __u8 * src,size_t len)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
fat_get_start(const struct msdos_sb_info * sbi,const struct msdos_dir_entry * de)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
fat_set_start(struct msdos_dir_entry * de,int cluster)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
fatwchar_to16(__u8 * dst,const wchar_t * src,size_t len)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
fatent_init(struct fat_entry * fatent)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
fatent_set_entry(struct fat_entry * fatent,int entry)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
fatent_brelse(struct fat_entry * fatent)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
fat_valid_entry(struct msdos_sb_info * sbi,int entry)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);
fat_dir_hash(int logstart)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