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 #include <linux/fs_context.h>
11 #include <linux/fs_parser.h>
12
13 /*
14 * vfat shortname flags
15 */
16 #define VFAT_SFN_DISPLAY_LOWER 0x0001 /* convert to lowercase for display */
17 #define VFAT_SFN_DISPLAY_WIN95 0x0002 /* emulate win95 rule for display */
18 #define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */
19 #define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */
20 #define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */
21
22 #define FAT_ERRORS_CONT 1 /* ignore error and continue */
23 #define FAT_ERRORS_PANIC 2 /* panic on error */
24 #define FAT_ERRORS_RO 3 /* remount r/o on error */
25
26 #define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */
27 #define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */
28
29 struct fat_mount_options {
30 kuid_t fs_uid;
31 kgid_t fs_gid;
32 unsigned short fs_fmask;
33 unsigned short fs_dmask;
34 unsigned short codepage; /* Codepage for shortname conversions */
35 int time_offset; /* Offset of timestamps from UTC (in minutes) */
36 char *iocharset; /* Charset used for filename input/display */
37 unsigned short shortname; /* flags for shortname display/create rule */
38 unsigned char name_check; /* r = relaxed, n = normal, s = strict */
39 unsigned char errors; /* On error: continue, panic, remount-ro */
40 unsigned char nfs; /* NFS support: nostale_ro, stale_rw */
41 unsigned short allow_utime;/* permission for setting the [am]time */
42 unsigned quiet:1, /* set = fake successful chmods and chowns */
43 showexec:1, /* set = only set x bit for com/exe/bat */
44 sys_immutable:1, /* set = system files are immutable */
45 dotsOK:1, /* set = hidden and system files are named '.filename' */
46 isvfat:1, /* 0=no vfat long filename support, 1=vfat support */
47 utf8:1, /* Use of UTF-8 character set (Default) */
48 unicode_xlate:1, /* create escape sequences for unhandled Unicode */
49 numtail:1, /* Does first alias have a numeric '~1' type tail? */
50 flush:1, /* write things quickly */
51 nocase:1, /* Does this need case conversion? 0=need case conversion*/
52 usefree:1, /* Use free_clusters for FAT32 */
53 tz_set:1, /* Filesystem timestamps' offset set */
54 rodir:1, /* allow ATTR_RO for directory */
55 discard:1, /* Issue discard requests on deletions */
56 dos1xfloppy:1, /* Assume default BPB for DOS 1.x floppies */
57 debug:1; /* Not currently used */
58 };
59
60 #define FAT_HASH_BITS 8
61 #define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)
62
63 /*
64 * MS-DOS file system in-core superblock data
65 */
66 struct msdos_sb_info {
67 unsigned short sec_per_clus; /* sectors/cluster */
68 unsigned short cluster_bits; /* log2(cluster_size) */
69 unsigned int cluster_size; /* cluster size */
70 unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */
71 unsigned short fat_start;
72 unsigned long fat_length; /* FAT start & length (sec.) */
73 unsigned long dir_start;
74 unsigned short dir_entries; /* root dir start & entries */
75 unsigned long data_start; /* first data sector */
76 unsigned long max_cluster; /* maximum cluster number */
77 unsigned long root_cluster; /* first cluster of the root directory */
78 unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
79 struct mutex fat_lock;
80 struct mutex nfs_build_inode_lock;
81 struct mutex s_lock;
82 unsigned int prev_free; /* previously allocated cluster number */
83 unsigned int free_clusters; /* -1 if undefined */
84 unsigned int free_clus_valid; /* is free_clusters valid? */
85 struct fat_mount_options options;
86 struct nls_table *nls_disk; /* Codepage used on disk */
87 struct nls_table *nls_io; /* Charset used for input and display */
88 const void *dir_ops; /* Opaque; default directory operations */
89 int dir_per_block; /* dir entries per block */
90 int dir_per_block_bits; /* log2(dir_per_block) */
91 unsigned int vol_id; /*volume ID*/
92
93 int fatent_shift;
94 const struct fatent_operations *fatent_ops;
95 struct inode *fat_inode;
96 struct inode *fsinfo_inode;
97
98 struct ratelimit_state ratelimit;
99
100 spinlock_t inode_hash_lock;
101 struct hlist_head inode_hashtable[FAT_HASH_SIZE];
102
103 spinlock_t dir_hash_lock;
104 struct hlist_head dir_hashtable[FAT_HASH_SIZE];
105
106 unsigned int dirty; /* fs state before mount */
107 struct rcu_head rcu;
108 };
109
110 #define FAT_CACHE_VALID 0 /* special case for valid cache */
111
112 /*
113 * MS-DOS file system inode data in memory
114 */
115 struct msdos_inode_info {
116 spinlock_t cache_lru_lock;
117 struct list_head cache_lru;
118 int nr_caches;
119 /* for avoiding the race between fat_free() and fat_get_cluster() */
120 unsigned int cache_valid_id;
121
122 /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
123 loff_t mmu_private; /* physically allocated size */
124
125 int i_start; /* first cluster or 0 */
126 int i_logstart; /* logical first cluster */
127 int i_attrs; /* unused attribute bits */
128 loff_t i_pos; /* on-disk position of directory entry or 0 */
129 struct hlist_node i_fat_hash; /* hash by i_location */
130 struct hlist_node i_dir_hash; /* hash by i_logstart */
131 struct rw_semaphore truncate_lock; /* protect bmap against truncate */
132 struct timespec64 i_crtime; /* File creation (birth) time */
133 struct mapping_metadata_bhs i_metadata_bhs;
134 struct inode vfs_inode;
135 };
136
137 struct fat_slot_info {
138 loff_t i_pos; /* on-disk position of directory entry */
139 loff_t slot_off; /* offset for slot or de start */
140 int nr_slots; /* number of slots + 1(de) in filename */
141 struct msdos_dir_entry *de;
142 struct buffer_head *bh;
143 };
144
MSDOS_SB(struct super_block * sb)145 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
146 {
147 return sb->s_fs_info;
148 }
149
150 /*
151 * Functions that determine the variant of the FAT file system (i.e.,
152 * whether this is FAT12, FAT16 or FAT32.
153 */
is_fat12(const struct msdos_sb_info * sbi)154 static inline bool is_fat12(const struct msdos_sb_info *sbi)
155 {
156 return sbi->fat_bits == 12;
157 }
158
is_fat16(const struct msdos_sb_info * sbi)159 static inline bool is_fat16(const struct msdos_sb_info *sbi)
160 {
161 return sbi->fat_bits == 16;
162 }
163
is_fat32(const struct msdos_sb_info * sbi)164 static inline bool is_fat32(const struct msdos_sb_info *sbi)
165 {
166 return sbi->fat_bits == 32;
167 }
168
169 /* Maximum number of clusters */
max_fat(struct super_block * sb)170 static inline u32 max_fat(struct super_block *sb)
171 {
172 struct msdos_sb_info *sbi = MSDOS_SB(sb);
173
174 return is_fat32(sbi) ? MAX_FAT32 :
175 is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
176 }
177
MSDOS_I(struct inode * inode)178 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
179 {
180 return container_of(inode, struct msdos_inode_info, vfs_inode);
181 }
182
183 /*
184 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
185 * save ATTR_RO instead of ->i_mode.
186 *
187 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
188 * bit, it's just used as flag for app.
189 */
fat_mode_can_hold_ro(struct inode * inode)190 static inline int fat_mode_can_hold_ro(struct inode *inode)
191 {
192 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
193 umode_t mask;
194
195 if (S_ISDIR(inode->i_mode)) {
196 if (!sbi->options.rodir)
197 return 0;
198 mask = ~sbi->options.fs_dmask;
199 } else
200 mask = ~sbi->options.fs_fmask;
201
202 if (!(mask & S_IWUGO))
203 return 0;
204 return 1;
205 }
206
207 /* Convert attribute bits and a mask to the UNIX mode. */
fat_make_mode(struct msdos_sb_info * sbi,u8 attrs,umode_t mode)208 static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
209 u8 attrs, umode_t mode)
210 {
211 if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
212 mode &= ~S_IWUGO;
213
214 if (attrs & ATTR_DIR)
215 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
216 else
217 return (mode & ~sbi->options.fs_fmask) | S_IFREG;
218 }
219
220 /* Return the FAT attribute byte for this inode */
fat_make_attrs(struct inode * inode)221 static inline u8 fat_make_attrs(struct inode *inode)
222 {
223 u8 attrs = MSDOS_I(inode)->i_attrs;
224 if (S_ISDIR(inode->i_mode))
225 attrs |= ATTR_DIR;
226 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
227 attrs |= ATTR_RO;
228 return attrs;
229 }
230
fat_save_attrs(struct inode * inode,u8 attrs)231 static inline void fat_save_attrs(struct inode *inode, u8 attrs)
232 {
233 if (fat_mode_can_hold_ro(inode))
234 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
235 else
236 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
237 }
238
fat_checksum(const __u8 * name)239 static inline unsigned char fat_checksum(const __u8 *name)
240 {
241 unsigned char s = name[0];
242 s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2];
243 s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4];
244 s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6];
245 s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8];
246 s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10];
247 return s;
248 }
249
fat_clus_to_blknr(struct msdos_sb_info * sbi,int clus)250 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
251 {
252 return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
253 + sbi->data_start;
254 }
255
fat_get_blknr_offset(struct msdos_sb_info * sbi,loff_t i_pos,sector_t * blknr,int * offset)256 static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
257 loff_t i_pos, sector_t *blknr, int *offset)
258 {
259 *blknr = i_pos >> sbi->dir_per_block_bits;
260 *offset = i_pos & (sbi->dir_per_block - 1);
261 }
262
fat_i_pos_read(struct msdos_sb_info * sbi,struct inode * inode)263 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
264 struct inode *inode)
265 {
266 loff_t i_pos;
267 #if BITS_PER_LONG == 32
268 spin_lock(&sbi->inode_hash_lock);
269 #endif
270 i_pos = MSDOS_I(inode)->i_pos;
271 #if BITS_PER_LONG == 32
272 spin_unlock(&sbi->inode_hash_lock);
273 #endif
274 return i_pos;
275 }
276
fat16_towchar(wchar_t * dst,const __u8 * src,size_t len)277 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
278 {
279 #ifdef __BIG_ENDIAN
280 while (len--) {
281 *dst++ = src[0] | (src[1] << 8);
282 src += 2;
283 }
284 #else
285 memcpy(dst, src, len * 2);
286 #endif
287 }
288
fat_get_start(const struct msdos_sb_info * sbi,const struct msdos_dir_entry * de)289 static inline int fat_get_start(const struct msdos_sb_info *sbi,
290 const struct msdos_dir_entry *de)
291 {
292 int cluster = le16_to_cpu(de->start);
293 if (is_fat32(sbi))
294 cluster |= (le16_to_cpu(de->starthi) << 16);
295 return cluster;
296 }
297
fat_set_start(struct msdos_dir_entry * de,int cluster)298 static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
299 {
300 de->start = cpu_to_le16(cluster);
301 de->starthi = cpu_to_le16(cluster >> 16);
302 }
303
fatwchar_to16(__u8 * dst,const wchar_t * src,size_t len)304 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
305 {
306 #ifdef __BIG_ENDIAN
307 while (len--) {
308 dst[0] = *src & 0x00FF;
309 dst[1] = (*src & 0xFF00) >> 8;
310 dst += 2;
311 src++;
312 }
313 #else
314 memcpy(dst, src, len * 2);
315 #endif
316 }
317
318 /* fat/cache.c */
319 extern void fat_cache_inval_inode(struct inode *inode);
320 extern int fat_get_cluster(struct inode *inode, int cluster,
321 int *fclus, int *dclus);
322 extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
323 sector_t last_block,
324 unsigned long *mapped_blocks, sector_t *bmap);
325 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
326 unsigned long *mapped_blocks, int create, bool from_bmap);
327
328 /* fat/dir.c */
329 extern const struct file_operations fat_dir_operations;
330 extern int fat_search_long(struct inode *inode, const unsigned char *name,
331 int name_len, struct fat_slot_info *sinfo);
332 extern int fat_dir_empty(struct inode *dir);
333 extern int fat_subdirs(struct inode *dir);
334 extern int fat_scan(struct inode *dir, const unsigned char *name,
335 struct fat_slot_info *sinfo);
336 extern int fat_scan_logstart(struct inode *dir, int i_logstart,
337 struct fat_slot_info *sinfo);
338 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
339 struct msdos_dir_entry **de);
340 extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
341 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
342 struct fat_slot_info *sinfo);
343 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
344
345 /* fat/fatent.c */
346 struct fat_entry {
347 int entry;
348 union {
349 u8 *ent12_p[2];
350 __le16 *ent16_p;
351 __le32 *ent32_p;
352 } u;
353 int nr_bhs;
354 struct buffer_head *bhs[2];
355 struct inode *fat_inode;
356 };
357
fatent_init(struct fat_entry * fatent)358 static inline void fatent_init(struct fat_entry *fatent)
359 {
360 fatent->nr_bhs = 0;
361 fatent->entry = 0;
362 fatent->u.ent32_p = NULL;
363 fatent->bhs[0] = fatent->bhs[1] = NULL;
364 fatent->fat_inode = NULL;
365 }
366
fatent_set_entry(struct fat_entry * fatent,int entry)367 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
368 {
369 fatent->entry = entry;
370 fatent->u.ent32_p = NULL;
371 }
372
fatent_brelse(struct fat_entry * fatent)373 static inline void fatent_brelse(struct fat_entry *fatent)
374 {
375 int i;
376 fatent->u.ent32_p = NULL;
377 for (i = 0; i < fatent->nr_bhs; i++)
378 brelse(fatent->bhs[i]);
379 fatent->nr_bhs = 0;
380 fatent->bhs[0] = fatent->bhs[1] = NULL;
381 fatent->fat_inode = NULL;
382 }
383
fat_valid_entry(struct msdos_sb_info * sbi,int entry)384 static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)
385 {
386 return FAT_START_ENT <= entry && entry < sbi->max_cluster;
387 }
388
389 extern void fat_ent_access_init(struct super_block *sb);
390 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
391 int entry);
392 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
393 int new, int wait);
394 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
395 int nr_cluster);
396 extern int fat_free_clusters(struct inode *inode, int cluster);
397 extern int fat_count_free_clusters(struct super_block *sb);
398 extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);
399
400 /* fat/file.c */
401 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
402 unsigned long arg);
403 extern const struct file_operations fat_file_operations;
404 extern const struct inode_operations fat_file_inode_operations;
405 extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
406 struct iattr *attr);
407 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
408 extern int fat_getattr(struct mnt_idmap *idmap,
409 const struct path *path, struct kstat *stat,
410 u32 request_mask, unsigned int flags);
411 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
412 int datasync);
413
414 /* fat/inode.c */
415 extern int fat_block_truncate_page(struct inode *inode, loff_t from);
416 extern void fat_attach(struct inode *inode, loff_t i_pos);
417 extern void fat_detach(struct inode *inode);
418 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
419 extern struct inode *fat_build_inode(struct super_block *sb,
420 struct msdos_dir_entry *de, loff_t i_pos);
421 extern int fat_sync_inode(struct inode *inode);
422 extern int fat_fill_super(struct super_block *sb, struct fs_context *fc,
423 void (*setup)(struct super_block *));
424 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
425
426 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
427 struct inode *i2);
428
429 extern const struct fs_parameter_spec fat_param_spec[];
430 int fat_init_fs_context(struct fs_context *fc, bool is_vfat);
431 void fat_free_fc(struct fs_context *fc);
432
433 int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,
434 bool is_vfat);
435 int fat_reconfigure(struct fs_context *fc);
436
fat_dir_hash(int logstart)437 static inline unsigned long fat_dir_hash(int logstart)
438 {
439 return hash_32(logstart, FAT_HASH_BITS);
440 }
441 extern int fat_add_cluster(struct inode *inode);
442
443 /* fat/misc.c */
444 extern __printf(3, 4) __cold
445 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
446 #define fat_fs_error(sb, fmt, args...) \
447 __fat_fs_error(sb, 1, fmt , ## args)
448 #define fat_fs_error_ratelimit(sb, fmt, args...) \
449 __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
450
451 #define FAT_PRINTK_PREFIX "%sFAT-fs (%s): "
452 #define fat_msg(sb, level, fmt, args...) \
453 do { \
454 printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\
455 _fat_msg(sb, level, fmt, ##args); \
456 } while (0)
457 __printf(3, 4) __cold
458 void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
459 #define fat_msg_ratelimit(sb, level, fmt, args...) \
460 do { \
461 if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \
462 fat_msg(sb, level, fmt, ## args); \
463 } while (0)
464 extern int fat_clusters_flush(struct super_block *sb);
465 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
466 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
467 __le16 __time, __le16 __date, u8 time_cs);
468 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
469 __le16 *time, __le16 *date, u8 *time_cs);
470 extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,
471 const struct timespec64 *ts);
472 #define FAT_UPDATE_ATIME (1u << 0)
473 #define FAT_UPDATE_CMTIME (1u << 1)
474 void fat_truncate_time(struct inode *inode, struct timespec64 *now,
475 unsigned int flags);
476 int fat_update_time(struct inode *inode, enum fs_update_time type,
477 unsigned int flags);
478 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
479
480 int fat_cache_init(void);
481 void fat_cache_destroy(void);
482
483 /* fat/nfs.c */
484 extern const struct export_operations fat_export_ops;
485 extern const struct export_operations fat_export_ops_nostale;
486
487 /* helper for printk */
488 typedef unsigned long long llu;
489
490 #endif /* !_FAT_H */
491