include/linux/msdos_fs.h

   1 #ifndef _LINUX_MSDOS_FS_H
   2 #define _LINUX_MSDOS_FS_H
   3
   4 /*
   5  * The MS-DOS filesystem constants/structures
   6  */
   7 #include <asm/byteorder.h>
   8
   9 #define SECTOR_SIZE     512             /* sector size (bytes) */
  10 #define SECTOR_BITS     9               /* log2(SECTOR_SIZE) */
  11 #define MSDOS_DPB       (MSDOS_DPS)     /* dir entries per block */
  12 #define MSDOS_DPB_BITS  4               /* log2(MSDOS_DPB) */
  13 #define MSDOS_DPS       (SECTOR_SIZE / sizeof(struct msdos_dir_entry))
  14 #define MSDOS_DPS_BITS  4               /* log2(MSDOS_DPS) */
  15 #define CF_LE_W(v)      le16_to_cpu(v)
  16 #define CF_LE_L(v)      le32_to_cpu(v)
  17 #define CT_LE_W(v)      cpu_to_le16(v)
  18 #define CT_LE_L(v)      cpu_to_le32(v)
  19
  20
  21 #define MSDOS_SUPER_MAGIC 0x4d44 /* MD */
  22
  23 #define MSDOS_ROOT_INO  1       /* == MINIX_ROOT_INO */
  24 #define MSDOS_DIR_BITS  5       /* log2(sizeof(struct msdos_dir_entry)) */
  25
  26 /* directory limit */
  27 #define FAT_MAX_DIR_ENTRIES     (65536)
  28 #define FAT_MAX_DIR_SIZE        (FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
  29
  30 #define ATTR_NONE       0       /* no attribute bits */
  31 #define ATTR_RO         1       /* read-only */
  32 #define ATTR_HIDDEN     2       /* hidden */
  33 #define ATTR_SYS        4       /* system */
  34 #define ATTR_VOLUME     8       /* volume label */
  35 #define ATTR_DIR        16      /* directory */
  36 #define ATTR_ARCH       32      /* archived */
  37
  38 /* attribute bits that are copied "as is" */
  39 #define ATTR_UNUSED     (ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
  40 /* bits that are used by the Windows 95/Windows NT extended FAT */
  41 #define ATTR_EXT        (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
  42
  43 #define CASE_LOWER_BASE 8       /* base is lower case */
  44 #define CASE_LOWER_EXT  16      /* extension is lower case */
  45
  46 #define DELETED_FLAG    0xe5    /* marks file as deleted when in name[0] */
  47 #define IS_FREE(n)      (!*(n) || *(n) == DELETED_FLAG)
  48
  49 /* valid file mode bits */
  50 #define MSDOS_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO)
  51 /* Convert attribute bits and a mask to the UNIX mode. */
  52 #define MSDOS_MKMODE(a, m) (m & (a & ATTR_RO ? S_IRUGO|S_IXUGO : S_IRWXUGO))
  53
  54 #define MSDOS_NAME      11      /* maximum name length */
  55 #define MSDOS_LONGNAME  256     /* maximum name length */
  56 #define MSDOS_SLOTS     21      /* max # of slots for short and long names */
  57 #define MSDOS_DOT       ".          "   /* ".", padded to MSDOS_NAME chars */
  58 #define MSDOS_DOTDOT    "..         "   /* "..", padded to MSDOS_NAME chars */
  59
  60 /* media of boot sector */
  61 #define FAT_VALID_MEDIA(x)      ((0xF8 <= (x) && (x) <= 0xFF) || (x) == 0xF0)
  62 #define FAT_FIRST_ENT(s, x)     ((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
  63         MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
  64
  65 /* start of data cluster's entry (number of reserved clusters) */
  66 #define FAT_START_ENT   2
  67
  68 /* maximum number of clusters */
  69 #define MAX_FAT12       0xFF4
  70 #define MAX_FAT16       0xFFF4
  71 #define MAX_FAT32       0x0FFFFFF6
  72 #define MAX_FAT(s)      (MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
  73         MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
  74
  75 /* bad cluster mark */
  76 #define BAD_FAT12       0xFF7
  77 #define BAD_FAT16       0xFFF7
  78 #define BAD_FAT32       0x0FFFFFF7
  79
  80 /* standard EOF */
  81 #define EOF_FAT12       0xFFF
  82 #define EOF_FAT16       0xFFFF
  83 #define EOF_FAT32       0x0FFFFFFF
  84
  85 #define FAT_ENT_FREE    (0)
  86 #define FAT_ENT_BAD     (BAD_FAT32)
  87 #define FAT_ENT_EOF     (EOF_FAT32)
  88
  89 #define FAT_FSINFO_SIG1 0x41615252
  90 #define FAT_FSINFO_SIG2 0x61417272
  91 #define IS_FSINFO(x)    (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
  92                          && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
  93
  94 /*
  95  * ioctl commands
  96  */
  97 #define VFAT_IOCTL_READDIR_BOTH         _IOR('r', 1, struct dirent [2])
  98 #define VFAT_IOCTL_READDIR_SHORT        _IOR('r', 2, struct dirent [2])
  99 /* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
 100 #define FAT_IOCTL_GET_ATTRIBUTES        _IOR('r', 0x10, __u32)
 101 #define FAT_IOCTL_SET_ATTRIBUTES        _IOW('r', 0x11, __u32)
 102
 103 /*
 104  * vfat shortname flags
 105  */
 106 #define VFAT_SFN_DISPLAY_LOWER  0x0001 /* convert to lowercase for display */
 107 #define VFAT_SFN_DISPLAY_WIN95  0x0002 /* emulate win95 rule for display */
 108 #define VFAT_SFN_DISPLAY_WINNT  0x0004 /* emulate winnt rule for display */
 109 #define VFAT_SFN_CREATE_WIN95   0x0100 /* emulate win95 rule for create */
 110 #define VFAT_SFN_CREATE_WINNT   0x0200 /* emulate winnt rule for create */
 111
 112 struct fat_boot_sector {
 113         __u8    ignored[3];     /* Boot strap short or near jump */
 114         __u8    system_id[8];   /* Name - can be used to special case
 115                                    partition manager volumes */
 116         __u8    sector_size[2]; /* bytes per logical sector */
 117         __u8    sec_per_clus;   /* sectors/cluster */
 118         __le16  reserved;       /* reserved sectors */
 119         __u8    fats;           /* number of FATs */
 120         __u8    dir_entries[2]; /* root directory entries */
 121         __u8    sectors[2];     /* number of sectors */
 122         __u8    media;          /* media code */
 123         __le16  fat_length;     /* sectors/FAT */
 124         __le16  secs_track;     /* sectors per track */
 125         __le16  heads;          /* number of heads */
 126         __le32  hidden;         /* hidden sectors (unused) */
 127         __le32  total_sect;     /* number of sectors (if sectors == 0) */
 128
 129         /* The following fields are only used by FAT32 */
 130         __le32  fat32_length;   /* sectors/FAT */
 131         __le16  flags;          /* bit 8: fat mirroring, low 4: active fat */
 132         __u8    version[2];     /* major, minor filesystem version */
 133         __le32  root_cluster;   /* first cluster in root directory */
 134         __le16  info_sector;    /* filesystem info sector */
 135         __le16  backup_boot;    /* backup boot sector */
 136         __le16  reserved2[6];   /* Unused */
 137 };
 138
 139 struct fat_boot_fsinfo {
 140         __le32   signature1;    /* 0x41615252L */
 141         __le32   reserved1[120];        /* Nothing as far as I can tell */
 142         __le32   signature2;    /* 0x61417272L */
 143         __le32   free_clusters; /* Free cluster count.  -1 if unknown */
 144         __le32   next_cluster;  /* Most recently allocated cluster */
 145         __le32   reserved2[4];
 146 };
 147
 148 struct msdos_dir_entry {
 149         __u8    name[8],ext[3]; /* name and extension */
 150         __u8    attr;           /* attribute bits */
 151         __u8    lcase;          /* Case for base and extension */
 152         __u8    ctime_cs;       /* Creation time, centiseconds (0-199) */
 153         __le16  ctime;          /* Creation time */
 154         __le16  cdate;          /* Creation date */
 155         __le16  adate;          /* Last access date */
 156         __le16  starthi;        /* High 16 bits of cluster in FAT32 */
 157         __le16  time,date,start;/* time, date and first cluster */
 158         __le32  size;           /* file size (in bytes) */
 159 };
 160
 161 /* Up to 13 characters of the name */
 162 struct msdos_dir_slot {
 163         __u8    id;             /* sequence number for slot */
 164         __u8    name0_4[10];    /* first 5 characters in name */
 165         __u8    attr;           /* attribute byte */
 166         __u8    reserved;       /* always 0 */
 167         __u8    alias_checksum; /* checksum for 8.3 alias */
 168         __u8    name5_10[12];   /* 6 more characters in name */
 169         __le16   start;         /* starting cluster number, 0 in long slots */
 170         __u8    name11_12[4];   /* last 2 characters in name */
 171 };
 172
 173 struct fat_slot_info {
 174         loff_t i_pos;           /* on-disk position of directory entry */
 175         loff_t slot_off;        /* offset for slot or de start */
 176         int nr_slots;           /* number of slots + 1(de) in filename */
 177         struct msdos_dir_entry *de;
 178         struct buffer_head *bh;
 179 };
 180
 181 #ifdef __KERNEL__
 182
 183 #include <linux/buffer_head.h>
 184 #include <linux/string.h>
 185 #include <linux/nls.h>
 186 #include <linux/fs.h>
 187 #include <linux/mutex.h>
 188
 189 struct fat_mount_options {
 190         uid_t fs_uid;
 191         gid_t fs_gid;
 192         unsigned short fs_fmask;
 193         unsigned short fs_dmask;
 194         unsigned short codepage;  /* Codepage for shortname conversions */
 195         char *iocharset;          /* Charset used for filename input/display */
 196         unsigned short shortname; /* flags for shortname display/create rule */
 197         unsigned char name_check; /* r = relaxed, n = normal, s = strict */
 198         unsigned quiet:1,         /* set = fake successful chmods and chowns */
 199                  showexec:1,      /* set = only set x bit for com/exe/bat */
 200                  sys_immutable:1, /* set = system files are immutable */
 201                  dotsOK:1,        /* set = hidden and system files are named '.filename' */
 202                  isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
 203                  utf8:1,          /* Use of UTF-8 character set (Default) */
 204                  unicode_xlate:1, /* create escape sequences for unhandled Unicode */
 205                  numtail:1,       /* Does first alias have a numeric '~1' type tail? */
 206                  atari:1,         /* Use Atari GEMDOS variation of MS-DOS fs */
 207                  nocase:1;        /* Does this need case conversion? 0=need case conversion*/
 208 };
 209
 210 #define FAT_HASH_BITS   8
 211 #define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)
 212 #define FAT_HASH_MASK   (FAT_HASH_SIZE-1)
 213
 214 /*
 215  * MS-DOS file system in-core superblock data
 216  */
 217 struct msdos_sb_info {
 218         unsigned short sec_per_clus; /* sectors/cluster */
 219         unsigned short cluster_bits; /* log2(cluster_size) */
 220         unsigned int cluster_size;   /* cluster size */
 221         unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
 222         unsigned short fat_start;
 223         unsigned long fat_length;    /* FAT start & length (sec.) */
 224         unsigned long dir_start;
 225         unsigned short dir_entries;  /* root dir start & entries */
 226         unsigned long data_start;    /* first data sector */
 227         unsigned long max_cluster;   /* maximum cluster number */
 228         unsigned long root_cluster;  /* first cluster of the root directory */
 229         unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
 230         struct mutex fat_lock;
 231         unsigned int prev_free;      /* previously allocated cluster number */
 232         unsigned int free_clusters;  /* -1 if undefined */
 233         struct fat_mount_options options;
 234         struct nls_table *nls_disk;  /* Codepage used on disk */
 235         struct nls_table *nls_io;    /* Charset used for input and display */
 236         void *dir_ops;               /* Opaque; default directory operations */
 237         int dir_per_block;           /* dir entries per block */
 238         int dir_per_block_bits;      /* log2(dir_per_block) */
 239
 240         int fatent_shift;
 241         struct fatent_operations *fatent_ops;
 242
 243         spinlock_t inode_hash_lock;
 244         struct hlist_head inode_hashtable[FAT_HASH_SIZE];
 245 };
 246
 247 #define FAT_CACHE_VALID 0       /* special case for valid cache */
 248
 249 /*
 250  * MS-DOS file system inode data in memory
 251  */
 252 struct msdos_inode_info {
 253         spinlock_t cache_lru_lock;
 254         struct list_head cache_lru;
 255         int nr_caches;
 256         /* for avoiding the race between fat_free() and fat_get_cluster() */
 257         unsigned int cache_valid_id;
 258
 259         loff_t mmu_private;
 260         int i_start;            /* first cluster or 0 */
 261         int i_logstart;         /* logical first cluster */
 262         int i_attrs;            /* unused attribute bits */
 263         loff_t i_pos;           /* on-disk position of directory entry or 0 */
 264         struct hlist_node i_fat_hash;   /* hash by i_location */
 265         struct inode vfs_inode;
 266 };
 267
 268 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 269 {
 270         return sb->s_fs_info;
 271 }
 272
 273 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 274 {
 275         return container_of(inode, struct msdos_inode_info, vfs_inode);
 276 }
 277
 278 /* Return the FAT attribute byte for this inode */
 279 static inline u8 fat_attr(struct inode *inode)
 280 {
 281         return ((inode->i_mode & S_IWUGO) ? ATTR_NONE : ATTR_RO) |
 282                 (S_ISDIR(inode->i_mode) ? ATTR_DIR : ATTR_NONE) |
 283                 MSDOS_I(inode)->i_attrs;
 284 }
 285
 286 static inline unsigned char fat_checksum(const __u8 *name)
 287 {
 288         unsigned char s = name[0];
 289         s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 290         s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 291         s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 292         s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 293         s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 294         return s;
 295 }
 296
 297 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 298 {
 299         return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 300                 + sbi->data_start;
 301 }
 302
 303 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 304 {
 305 #ifdef __BIG_ENDIAN
 306         while (len--) {
 307                 *dst++ = src[0] | (src[1] << 8);
 308                 src += 2;
 309         }
 310 #else
 311         memcpy(dst, src, len * 2);
 312 #endif
 313 }
 314
 315 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 316 {
 317 #ifdef __BIG_ENDIAN
 318         while (len--) {
 319                 dst[0] = *src & 0x00FF;
 320                 dst[1] = (*src & 0xFF00) >> 8;
 321                 dst += 2;
 322                 src++;
 323         }
 324 #else
 325         memcpy(dst, src, len * 2);
 326 #endif
 327 }
 328
 329 /* fat/cache.c */
 330 extern void fat_cache_inval_inode(struct inode *inode);
 331 extern int fat_get_cluster(struct inode *inode, int cluster,
 332                            int *fclus, int *dclus);
 333 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 334                     unsigned long *mapped_blocks);
 335
 336 /* fat/dir.c */
 337 extern const struct file_operations fat_dir_operations;
 338 extern int fat_search_long(struct inode *inode, const unsigned char *name,
 339                            int name_len, struct fat_slot_info *sinfo);
 340 extern int fat_dir_empty(struct inode *dir);
 341 extern int fat_subdirs(struct inode *dir);
 342 extern int fat_scan(struct inode *dir, const unsigned char *name,
 343                     struct fat_slot_info *sinfo);
 344 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 345                                 struct msdos_dir_entry **de, loff_t *i_pos);
 346 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 347 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 348                            struct fat_slot_info *sinfo);
 349 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 350
 351 /* fat/fatent.c */
 352 struct fat_entry {
 353         int entry;
 354         union {
 355                 u8 *ent12_p[2];
 356                 __le16 *ent16_p;
 357                 __le32 *ent32_p;
 358         } u;
 359         int nr_bhs;
 360         struct buffer_head *bhs[2];
 361 };
 362
 363 static inline void fatent_init(struct fat_entry *fatent)
 364 {
 365         fatent->nr_bhs = 0;
 366         fatent->entry = 0;
 367         fatent->u.ent32_p = NULL;
 368         fatent->bhs[0] = fatent->bhs[1] = NULL;
 369 }
 370
 371 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 372 {
 373         fatent->entry = entry;
 374         fatent->u.ent32_p = NULL;
 375 }
 376
 377 static inline void fatent_brelse(struct fat_entry *fatent)
 378 {
 379         int i;
 380         fatent->u.ent32_p = NULL;
 381         for (i = 0; i < fatent->nr_bhs; i++)
 382                 brelse(fatent->bhs[i]);
 383         fatent->nr_bhs = 0;
 384         fatent->bhs[0] = fatent->bhs[1] = NULL;
 385 }
 386
 387 extern void fat_ent_access_init(struct super_block *sb);
 388 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 389                         int entry);
 390 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 391                          int new, int wait);
 392 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 393                               int nr_cluster);
 394 extern int fat_free_clusters(struct inode *inode, int cluster);
 395 extern int fat_count_free_clusters(struct super_block *sb);
 396
 397 /* fat/file.c */
 398 extern int fat_generic_ioctl(struct inode *inode, struct file *filp,
 399                              unsigned int cmd, unsigned long arg);
 400 extern const struct file_operations fat_file_operations;
 401 extern struct inode_operations fat_file_inode_operations;
 402 extern int fat_notify_change(struct dentry * dentry, struct iattr * attr);
 403 extern void fat_truncate(struct inode *inode);
 404
 405 /* fat/inode.c */
 406 extern void fat_attach(struct inode *inode, loff_t i_pos);
 407 extern void fat_detach(struct inode *inode);
 408 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 409 extern struct inode *fat_build_inode(struct super_block *sb,
 410                         struct msdos_dir_entry *de, loff_t i_pos);
 411 extern int fat_sync_inode(struct inode *inode);
 412 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 413                         struct inode_operations *fs_dir_inode_ops, int isvfat);
 414
 415 /* fat/misc.c */
 416 extern void fat_fs_panic(struct super_block *s, const char *fmt, ...);
 417 extern void fat_clusters_flush(struct super_block *sb);
 418 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 419 extern int date_dos2unix(unsigned short time, unsigned short date);
 420 extern void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date);
 421 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 422
 423 int fat_cache_init(void);
 424 void fat_cache_destroy(void);
 425
 426 #endif /* __KERNEL__ */
 427
 428 #endif