fs/fat/fat.h

   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 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
 366 /* fat/file.c */
 367 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 368                               unsigned long arg);
 369 extern const struct file_operations fat_file_operations;
 370 extern const struct inode_operations fat_file_inode_operations;
 371 extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
 372 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 373 extern int fat_getattr(const struct path *path, struct kstat *stat,
 374                        u32 request_mask, unsigned int flags);
 375 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
 376                           int datasync);
 377
 378 /* fat/inode.c */
 379 extern int fat_block_truncate_page(struct inode *inode, loff_t from);
 380 extern void fat_attach(struct inode *inode, loff_t i_pos);
 381 extern void fat_detach(struct inode *inode);
 382 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 383 extern struct inode *fat_build_inode(struct super_block *sb,
 384                         struct msdos_dir_entry *de, loff_t i_pos);
 385 extern int fat_sync_inode(struct inode *inode);
 386 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 387                           int isvfat, void (*setup)(struct super_block *));
 388 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
 389
 390 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 391                             struct inode *i2);
 392 static inline unsigned long fat_dir_hash(int logstart)
 393 {
 394         return hash_32(logstart, FAT_HASH_BITS);
 395 }
 396 extern int fat_add_cluster(struct inode *inode);
 397
 398 /* fat/misc.c */
 399 extern __printf(3, 4) __cold
 400 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
 401 #define fat_fs_error(sb, fmt, args...)          \
 402         __fat_fs_error(sb, 1, fmt , ## args)
 403 #define fat_fs_error_ratelimit(sb, fmt, args...) \
 404         __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 405 __printf(3, 4) __cold
 406 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
 407 #define fat_msg_ratelimit(sb, level, fmt, args...)      \
 408         do {    \
 409                         if (__ratelimit(&MSDOS_SB(sb)->ratelimit))      \
 410                                 fat_msg(sb, level, fmt, ## args);       \
 411          } while (0)
 412 extern int fat_clusters_flush(struct super_block *sb);
 413 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 414 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 415                               __le16 __time, __le16 __date, u8 time_cs);
 416 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 417                               __le16 *time, __le16 *date, u8 *time_cs);
 418 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 419
 420 int fat_cache_init(void);
 421 void fat_cache_destroy(void);
 422
 423 /* fat/nfs.c */
 424 extern const struct export_operations fat_export_ops;
 425 extern const struct export_operations fat_export_ops_nostale;
 426
 427 /* helper for printk */
 428 typedef unsigned long long      llu;
 429
 430 #endif /* !_FAT_H */