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TOMOYO Linux Cross Reference
Linux/fs/fat/fat.h

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  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 
140 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
141 {
142         return sb->s_fs_info;
143 }
144 
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  */
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. */
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 */
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 timespec *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 
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 
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 
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 
351 extern void fat_ent_access_init(struct super_block *sb);
352 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
353                         int entry);
354 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
355                          int new, int wait);
356 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
357                               int nr_cluster);
358 extern int fat_free_clusters(struct inode *inode, int cluster);
359 extern int fat_count_free_clusters(struct super_block *sb);
360 
361 /* fat/file.c */
362 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
363                               unsigned long arg);
364 extern const struct file_operations fat_file_operations;
365 extern const struct inode_operations fat_file_inode_operations;
366 extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
367 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
368 extern int fat_getattr(const struct path *path, struct kstat *stat,
369                        u32 request_mask, unsigned int flags);
370 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
371                           int datasync);
372 
373 /* fat/inode.c */
374 extern int fat_block_truncate_page(struct inode *inode, loff_t from);
375 extern void fat_attach(struct inode *inode, loff_t i_pos);
376 extern void fat_detach(struct inode *inode);
377 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
378 extern struct inode *fat_build_inode(struct super_block *sb,
379                         struct msdos_dir_entry *de, loff_t i_pos);
380 extern int fat_sync_inode(struct inode *inode);
381 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
382                           int isvfat, void (*setup)(struct super_block *));
383 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
384 
385 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
386                             struct inode *i2);
387 static inline unsigned long fat_dir_hash(int logstart)
388 {
389         return hash_32(logstart, FAT_HASH_BITS);
390 }
391 extern int fat_add_cluster(struct inode *inode);
392 
393 /* fat/misc.c */
394 extern __printf(3, 4) __cold
395 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
396 #define fat_fs_error(sb, fmt, args...)          \
397         __fat_fs_error(sb, 1, fmt , ## args)
398 #define fat_fs_error_ratelimit(sb, fmt, args...) \
399         __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
400 __printf(3, 4) __cold
401 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
402 #define fat_msg_ratelimit(sb, level, fmt, args...)      \
403         do {    \
404                         if (__ratelimit(&MSDOS_SB(sb)->ratelimit))      \
405                                 fat_msg(sb, level, fmt, ## args);       \
406          } while (0)
407 extern int fat_clusters_flush(struct super_block *sb);
408 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
409 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
410                               __le16 __time, __le16 __date, u8 time_cs);
411 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
412                               __le16 *time, __le16 *date, u8 *time_cs);
413 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
414 
415 int fat_cache_init(void);
416 void fat_cache_destroy(void);
417 
418 /* fat/nfs.c */
419 extern const struct export_operations fat_export_ops;
420 extern const struct export_operations fat_export_ops_nostale;
421 
422 /* helper for printk */
423 typedef unsigned long long      llu;
424 
425 #endif /* !_FAT_H */
426 

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