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