fs/fat/fat.h

   1 #ifndef _FAT_H
   2 #define _FAT_H
   3
   4 #include <linux/buffer_head.h>
   5 #include <linux/string.h>
   6 #include <linux/nls.h>
   7 #include <linux/fs.h>
   8 #include <linux/mutex.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 struct fat_mount_options {
  21         uid_t fs_uid;
  22         gid_t fs_gid;
  23         unsigned short fs_fmask;
  24         unsigned short fs_dmask;
  25         unsigned short codepage;  /* Codepage for shortname conversions */
  26         char *iocharset;          /* Charset used for filename input/display */
  27         unsigned short shortname; /* flags for shortname display/create rule */
  28         unsigned char name_check; /* r = relaxed, n = normal, s = strict */
  29         unsigned short allow_utime;/* permission for setting the [am]time */
  30         unsigned quiet:1,         /* set = fake successful chmods and chowns */
  31                  showexec:1,      /* set = only set x bit for com/exe/bat */
  32                  sys_immutable:1, /* set = system files are immutable */
  33                  dotsOK:1,        /* set = hidden and system files are named '.filename' */
  34                  isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
  35                  utf8:1,          /* Use of UTF-8 character set (Default) */
  36                  unicode_xlate:1, /* create escape sequences for unhandled Unicode */
  37                  numtail:1,       /* Does first alias have a numeric '~1' type tail? */
  38                  flush:1,         /* write things quickly */
  39                  nocase:1,        /* Does this need case conversion? 0=need case conversion*/
  40                  usefree:1,       /* Use free_clusters for FAT32 */
  41                  tz_utc:1,        /* Filesystem timestamps are in UTC */
  42                  rodir:1;         /* allow ATTR_RO for directory */
  43 };
  44
  45 #define FAT_HASH_BITS   8
  46 #define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)
  47
  48 /*
  49  * MS-DOS file system in-core superblock data
  50  */
  51 struct msdos_sb_info {
  52         unsigned short sec_per_clus; /* sectors/cluster */
  53         unsigned short cluster_bits; /* log2(cluster_size) */
  54         unsigned int cluster_size;   /* cluster size */
  55         unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
  56         unsigned short fat_start;
  57         unsigned long fat_length;    /* FAT start & length (sec.) */
  58         unsigned long dir_start;
  59         unsigned short dir_entries;  /* root dir start & entries */
  60         unsigned long data_start;    /* first data sector */
  61         unsigned long max_cluster;   /* maximum cluster number */
  62         unsigned long root_cluster;  /* first cluster of the root directory */
  63         unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
  64         struct mutex fat_lock;
  65         unsigned int prev_free;      /* previously allocated cluster number */
  66         unsigned int free_clusters;  /* -1 if undefined */
  67         unsigned int free_clus_valid; /* is free_clusters valid? */
  68         struct fat_mount_options options;
  69         struct nls_table *nls_disk;  /* Codepage used on disk */
  70         struct nls_table *nls_io;    /* Charset used for input and display */
  71         const void *dir_ops;                 /* Opaque; default directory operations */
  72         int dir_per_block;           /* dir entries per block */
  73         int dir_per_block_bits;      /* log2(dir_per_block) */
  74
  75         int fatent_shift;
  76         struct fatent_operations *fatent_ops;
  77
  78         spinlock_t inode_hash_lock;
  79         struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  80 };
  81
  82 #define FAT_CACHE_VALID 0       /* special case for valid cache */
  83
  84 /*
  85  * MS-DOS file system inode data in memory
  86  */
  87 struct msdos_inode_info {
  88         spinlock_t cache_lru_lock;
  89         struct list_head cache_lru;
  90         int nr_caches;
  91         /* for avoiding the race between fat_free() and fat_get_cluster() */
  92         unsigned int cache_valid_id;
  93
  94         loff_t mmu_private;
  95         int i_start;            /* first cluster or 0 */
  96         int i_logstart;         /* logical first cluster */
  97         int i_attrs;            /* unused attribute bits */
  98         loff_t i_pos;           /* on-disk position of directory entry or 0 */
  99         struct hlist_node i_fat_hash;   /* hash by i_location */
 100         struct inode vfs_inode;
 101 };
 102
 103 struct fat_slot_info {
 104         loff_t i_pos;           /* on-disk position of directory entry */
 105         loff_t slot_off;        /* offset for slot or de start */
 106         int nr_slots;           /* number of slots + 1(de) in filename */
 107         struct msdos_dir_entry *de;
 108         struct buffer_head *bh;
 109 };
 110
 111 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 112 {
 113         return sb->s_fs_info;
 114 }
 115
 116 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 117 {
 118         return container_of(inode, struct msdos_inode_info, vfs_inode);
 119 }
 120
 121 /*
 122  * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 123  * save ATTR_RO instead of ->i_mode.
 124  *
 125  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 126  * bit, it's just used as flag for app.
 127  */
 128 static inline int fat_mode_can_hold_ro(struct inode *inode)
 129 {
 130         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 131         mode_t mask;
 132
 133         if (S_ISDIR(inode->i_mode)) {
 134                 if (!sbi->options.rodir)
 135                         return 0;
 136                 mask = ~sbi->options.fs_dmask;
 137         } else
 138                 mask = ~sbi->options.fs_fmask;
 139
 140         if (!(mask & S_IWUGO))
 141                 return 0;
 142         return 1;
 143 }
 144
 145 /* Convert attribute bits and a mask to the UNIX mode. */
 146 static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
 147                                    u8 attrs, mode_t mode)
 148 {
 149         if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
 150                 mode &= ~S_IWUGO;
 151
 152         if (attrs & ATTR_DIR)
 153                 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 154         else
 155                 return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 156 }
 157
 158 /* Return the FAT attribute byte for this inode */
 159 static inline u8 fat_make_attrs(struct inode *inode)
 160 {
 161         u8 attrs = MSDOS_I(inode)->i_attrs;
 162         if (S_ISDIR(inode->i_mode))
 163                 attrs |= ATTR_DIR;
 164         if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
 165                 attrs |= ATTR_RO;
 166         return attrs;
 167 }
 168
 169 static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 170 {
 171         if (fat_mode_can_hold_ro(inode))
 172                 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
 173         else
 174                 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 175 }
 176
 177 static inline unsigned char fat_checksum(const __u8 *name)
 178 {
 179         unsigned char s = name[0];
 180         s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 181         s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 182         s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 183         s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 184         s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 185         return s;
 186 }
 187
 188 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 189 {
 190         return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 191                 + sbi->data_start;
 192 }
 193
 194 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 195 {
 196 #ifdef __BIG_ENDIAN
 197         while (len--) {
 198                 *dst++ = src[0] | (src[1] << 8);
 199                 src += 2;
 200         }
 201 #else
 202         memcpy(dst, src, len * 2);
 203 #endif
 204 }
 205
 206 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 207 {
 208 #ifdef __BIG_ENDIAN
 209         while (len--) {
 210                 dst[0] = *src & 0x00FF;
 211                 dst[1] = (*src & 0xFF00) >> 8;
 212                 dst += 2;
 213                 src++;
 214         }
 215 #else
 216         memcpy(dst, src, len * 2);
 217 #endif
 218 }
 219
 220 /* fat/cache.c */
 221 extern void fat_cache_inval_inode(struct inode *inode);
 222 extern int fat_get_cluster(struct inode *inode, int cluster,
 223                            int *fclus, int *dclus);
 224 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 225                     unsigned long *mapped_blocks);
 226
 227 /* fat/dir.c */
 228 extern const struct file_operations fat_dir_operations;
 229 extern int fat_search_long(struct inode *inode, const unsigned char *name,
 230                            int name_len, struct fat_slot_info *sinfo);
 231 extern int fat_dir_empty(struct inode *dir);
 232 extern int fat_subdirs(struct inode *dir);
 233 extern int fat_scan(struct inode *dir, const unsigned char *name,
 234                     struct fat_slot_info *sinfo);
 235 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 236                                 struct msdos_dir_entry **de, loff_t *i_pos);
 237 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 238 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 239                            struct fat_slot_info *sinfo);
 240 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 241
 242 /* fat/fatent.c */
 243 struct fat_entry {
 244         int entry;
 245         union {
 246                 u8 *ent12_p[2];
 247                 __le16 *ent16_p;
 248                 __le32 *ent32_p;
 249         } u;
 250         int nr_bhs;
 251         struct buffer_head *bhs[2];
 252 };
 253
 254 static inline void fatent_init(struct fat_entry *fatent)
 255 {
 256         fatent->nr_bhs = 0;
 257         fatent->entry = 0;
 258         fatent->u.ent32_p = NULL;
 259         fatent->bhs[0] = fatent->bhs[1] = NULL;
 260 }
 261
 262 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 263 {
 264         fatent->entry = entry;
 265         fatent->u.ent32_p = NULL;
 266 }
 267
 268 static inline void fatent_brelse(struct fat_entry *fatent)
 269 {
 270         int i;
 271         fatent->u.ent32_p = NULL;
 272         for (i = 0; i < fatent->nr_bhs; i++)
 273                 brelse(fatent->bhs[i]);
 274         fatent->nr_bhs = 0;
 275         fatent->bhs[0] = fatent->bhs[1] = NULL;
 276 }
 277
 278 extern void fat_ent_access_init(struct super_block *sb);
 279 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 280                         int entry);
 281 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 282                          int new, int wait);
 283 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 284                               int nr_cluster);
 285 extern int fat_free_clusters(struct inode *inode, int cluster);
 286 extern int fat_count_free_clusters(struct super_block *sb);
 287
 288 /* fat/file.c */
 289 extern int fat_generic_ioctl(struct inode *inode, struct file *filp,
 290                              unsigned int cmd, unsigned long arg);
 291 extern const struct file_operations fat_file_operations;
 292 extern const struct inode_operations fat_file_inode_operations;
 293 extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
 294 extern void fat_truncate(struct inode *inode);
 295 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 296                        struct kstat *stat);
 297
 298 /* fat/inode.c */
 299 extern void fat_attach(struct inode *inode, loff_t i_pos);
 300 extern void fat_detach(struct inode *inode);
 301 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 302 extern struct inode *fat_build_inode(struct super_block *sb,
 303                         struct msdos_dir_entry *de, loff_t i_pos);
 304 extern int fat_sync_inode(struct inode *inode);
 305 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 306                         const struct inode_operations *fs_dir_inode_ops, int isvfat);
 307
 308 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 309                             struct inode *i2);
 310 /* fat/misc.c */
 311 extern void fat_fs_panic(struct super_block *s, const char *fmt, ...)
 312         __attribute__ ((format (printf, 2, 3))) __cold;
 313 extern void fat_clusters_flush(struct super_block *sb);
 314 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 315 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 316                               __le16 __time, __le16 __date, u8 time_cs);
 317 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 318                               __le16 *time, __le16 *date, u8 *time_cs);
 319 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 320
 321 int fat_cache_init(void);
 322 void fat_cache_destroy(void);
 323
 324 #endif /* !_FAT_H */