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/ratelimit.h>
  10 #include <linux/msdos_fs.h>
  11
  12 /*
  13  * vfat shortname flags
  14  */
  15 #define VFAT_SFN_DISPLAY_LOWER  0x0001 /* convert to lowercase for display */
  16 #define VFAT_SFN_DISPLAY_WIN95  0x0002 /* emulate win95 rule for display */
  17 #define VFAT_SFN_DISPLAY_WINNT  0x0004 /* emulate winnt rule for display */
  18 #define VFAT_SFN_CREATE_WIN95   0x0100 /* emulate win95 rule for create */
  19 #define VFAT_SFN_CREATE_WINNT   0x0200 /* emulate winnt rule for create */
  20
  21 #define FAT_ERRORS_CONT         1      /* ignore error and continue */
  22 #define FAT_ERRORS_PANIC        2      /* panic on error */
  23 #define FAT_ERRORS_RO           3      /* remount r/o on error */
  24
  25 struct fat_mount_options {
  26         uid_t fs_uid;
  27         gid_t fs_gid;
  28         unsigned short fs_fmask;
  29         unsigned short fs_dmask;
  30         unsigned short codepage;  /* Codepage for shortname conversions */
  31         char *iocharset;          /* Charset used for filename input/display */
  32         unsigned short shortname; /* flags for shortname display/create rule */
  33         unsigned char name_check; /* r = relaxed, n = normal, s = strict */
  34         unsigned char errors;     /* On error: continue, panic, remount-ro */
  35         unsigned short allow_utime;/* permission for setting the [am]time */
  36         unsigned quiet:1,         /* set = fake successful chmods and chowns */
  37                  showexec:1,      /* set = only set x bit for com/exe/bat */
  38                  sys_immutable:1, /* set = system files are immutable */
  39                  dotsOK:1,        /* set = hidden and system files are named '.filename' */
  40                  isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
  41                  utf8:1,          /* Use of UTF-8 character set (Default) */
  42                  unicode_xlate:1, /* create escape sequences for unhandled Unicode */
  43                  numtail:1,       /* Does first alias have a numeric '~1' type tail? */
  44                  flush:1,         /* write things quickly */
  45                  nocase:1,        /* Does this need case conversion? 0=need case conversion*/
  46                  usefree:1,       /* Use free_clusters for FAT32 */
  47                  tz_utc:1,        /* Filesystem timestamps are in UTC */
  48                  rodir:1,         /* allow ATTR_RO for directory */
  49                  discard:1;       /* Issue discard requests on deletions */
  50 };
  51
  52 #define FAT_HASH_BITS   8
  53 #define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)
  54
  55 /*
  56  * MS-DOS file system in-core superblock data
  57  */
  58 struct msdos_sb_info {
  59         unsigned short sec_per_clus; /* sectors/cluster */
  60         unsigned short cluster_bits; /* log2(cluster_size) */
  61         unsigned int cluster_size;   /* cluster size */
  62         unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
  63         unsigned short fat_start;
  64         unsigned long fat_length;    /* FAT start & length (sec.) */
  65         unsigned long dir_start;
  66         unsigned short dir_entries;  /* root dir start & entries */
  67         unsigned long data_start;    /* first data sector */
  68         unsigned long max_cluster;   /* maximum cluster number */
  69         unsigned long root_cluster;  /* first cluster of the root directory */
  70         unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
  71         struct mutex fat_lock;
  72         unsigned int prev_free;      /* previously allocated cluster number */
  73         unsigned int free_clusters;  /* -1 if undefined */
  74         unsigned int free_clus_valid; /* is free_clusters valid? */
  75         struct fat_mount_options options;
  76         struct nls_table *nls_disk;  /* Codepage used on disk */
  77         struct nls_table *nls_io;    /* Charset used for input and display */
  78         const void *dir_ops;                 /* Opaque; default directory operations */
  79         int dir_per_block;           /* dir entries per block */
  80         int dir_per_block_bits;      /* log2(dir_per_block) */
  81
  82         int fatent_shift;
  83         struct fatent_operations *fatent_ops;
  84         struct inode *fat_inode;
  85
  86         struct ratelimit_state ratelimit;
  87
  88         spinlock_t inode_hash_lock;
  89         struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  90 };
  91
  92 #define FAT_CACHE_VALID 0       /* special case for valid cache */
  93
  94 /*
  95  * MS-DOS file system inode data in memory
  96  */
  97 struct msdos_inode_info {
  98         spinlock_t cache_lru_lock;
  99         struct list_head cache_lru;
 100         int nr_caches;
 101         /* for avoiding the race between fat_free() and fat_get_cluster() */
 102         unsigned int cache_valid_id;
 103
 104         /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
 105         loff_t mmu_private;     /* physically allocated size */
 106
 107         int i_start;            /* first cluster or 0 */
 108         int i_logstart;         /* logical first cluster */
 109         int i_attrs;            /* unused attribute bits */
 110         loff_t i_pos;           /* on-disk position of directory entry or 0 */
 111         struct hlist_node i_fat_hash;   /* hash by i_location */
 112         struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 113         struct inode vfs_inode;
 114 };
 115
 116 struct fat_slot_info {
 117         loff_t i_pos;           /* on-disk position of directory entry */
 118         loff_t slot_off;        /* offset for slot or de start */
 119         int nr_slots;           /* number of slots + 1(de) in filename */
 120         struct msdos_dir_entry *de;
 121         struct buffer_head *bh;
 122 };
 123
 124 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 125 {
 126         return sb->s_fs_info;
 127 }
 128
 129 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 130 {
 131         return container_of(inode, struct msdos_inode_info, vfs_inode);
 132 }
 133
 134 /*
 135  * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 136  * save ATTR_RO instead of ->i_mode.
 137  *
 138  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 139  * bit, it's just used as flag for app.
 140  */
 141 static inline int fat_mode_can_hold_ro(struct inode *inode)
 142 {
 143         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 144         mode_t mask;
 145
 146         if (S_ISDIR(inode->i_mode)) {
 147                 if (!sbi->options.rodir)
 148                         return 0;
 149                 mask = ~sbi->options.fs_dmask;
 150         } else
 151                 mask = ~sbi->options.fs_fmask;
 152
 153         if (!(mask & S_IWUGO))
 154                 return 0;
 155         return 1;
 156 }
 157
 158 /* Convert attribute bits and a mask to the UNIX mode. */
 159 static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
 160                                    u8 attrs, mode_t mode)
 161 {
 162         if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
 163                 mode &= ~S_IWUGO;
 164
 165         if (attrs & ATTR_DIR)
 166                 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 167         else
 168                 return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 169 }
 170
 171 /* Return the FAT attribute byte for this inode */
 172 static inline u8 fat_make_attrs(struct inode *inode)
 173 {
 174         u8 attrs = MSDOS_I(inode)->i_attrs;
 175         if (S_ISDIR(inode->i_mode))
 176                 attrs |= ATTR_DIR;
 177         if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
 178                 attrs |= ATTR_RO;
 179         return attrs;
 180 }
 181
 182 static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 183 {
 184         if (fat_mode_can_hold_ro(inode))
 185                 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
 186         else
 187                 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 188 }
 189
 190 static inline unsigned char fat_checksum(const __u8 *name)
 191 {
 192         unsigned char s = name[0];
 193         s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 194         s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 195         s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 196         s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 197         s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 198         return s;
 199 }
 200
 201 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 202 {
 203         return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 204                 + sbi->data_start;
 205 }
 206
 207 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 208 {
 209 #ifdef __BIG_ENDIAN
 210         while (len--) {
 211                 *dst++ = src[0] | (src[1] << 8);
 212                 src += 2;
 213         }
 214 #else
 215         memcpy(dst, src, len * 2);
 216 #endif
 217 }
 218
 219 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 220 {
 221 #ifdef __BIG_ENDIAN
 222         while (len--) {
 223                 dst[0] = *src & 0x00FF;
 224                 dst[1] = (*src & 0xFF00) >> 8;
 225                 dst += 2;
 226                 src++;
 227         }
 228 #else
 229         memcpy(dst, src, len * 2);
 230 #endif
 231 }
 232
 233 /* fat/cache.c */
 234 extern void fat_cache_inval_inode(struct inode *inode);
 235 extern int fat_get_cluster(struct inode *inode, int cluster,
 236                            int *fclus, int *dclus);
 237 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 238                     unsigned long *mapped_blocks, int create);
 239
 240 /* fat/dir.c */
 241 extern const struct file_operations fat_dir_operations;
 242 extern int fat_search_long(struct inode *inode, const unsigned char *name,
 243                            int name_len, struct fat_slot_info *sinfo);
 244 extern int fat_dir_empty(struct inode *dir);
 245 extern int fat_subdirs(struct inode *dir);
 246 extern int fat_scan(struct inode *dir, const unsigned char *name,
 247                     struct fat_slot_info *sinfo);
 248 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 249                                 struct msdos_dir_entry **de, loff_t *i_pos);
 250 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 251 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 252                            struct fat_slot_info *sinfo);
 253 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 254
 255 /* fat/fatent.c */
 256 struct fat_entry {
 257         int entry;
 258         union {
 259                 u8 *ent12_p[2];
 260                 __le16 *ent16_p;
 261                 __le32 *ent32_p;
 262         } u;
 263         int nr_bhs;
 264         struct buffer_head *bhs[2];
 265         struct inode *fat_inode;
 266 };
 267
 268 static inline void fatent_init(struct fat_entry *fatent)
 269 {
 270         fatent->nr_bhs = 0;
 271         fatent->entry = 0;
 272         fatent->u.ent32_p = NULL;
 273         fatent->bhs[0] = fatent->bhs[1] = NULL;
 274         fatent->fat_inode = NULL;
 275 }
 276
 277 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 278 {
 279         fatent->entry = entry;
 280         fatent->u.ent32_p = NULL;
 281 }
 282
 283 static inline void fatent_brelse(struct fat_entry *fatent)
 284 {
 285         int i;
 286         fatent->u.ent32_p = NULL;
 287         for (i = 0; i < fatent->nr_bhs; i++)
 288                 brelse(fatent->bhs[i]);
 289         fatent->nr_bhs = 0;
 290         fatent->bhs[0] = fatent->bhs[1] = NULL;
 291         fatent->fat_inode = NULL;
 292 }
 293
 294 extern void fat_ent_access_init(struct super_block *sb);
 295 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 296                         int entry);
 297 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 298                          int new, int wait);
 299 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 300                               int nr_cluster);
 301 extern int fat_free_clusters(struct inode *inode, int cluster);
 302 extern int fat_count_free_clusters(struct super_block *sb);
 303
 304 /* fat/file.c */
 305 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 306                               unsigned long arg);
 307 extern const struct file_operations fat_file_operations;
 308 extern const struct inode_operations fat_file_inode_operations;
 309 extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
 310 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 311 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 312                        struct kstat *stat);
 313 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
 314                           int datasync);
 315
 316 /* fat/inode.c */
 317 extern void fat_attach(struct inode *inode, loff_t i_pos);
 318 extern void fat_detach(struct inode *inode);
 319 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 320 extern struct inode *fat_build_inode(struct super_block *sb,
 321                         struct msdos_dir_entry *de, loff_t i_pos);
 322 extern int fat_sync_inode(struct inode *inode);
 323 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 324                           int isvfat, void (*setup)(struct super_block *));
 325
 326 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 327                             struct inode *i2);
 328 /* fat/misc.c */
 329 extern void
 330 __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 331         __attribute__ ((format (printf, 3, 4))) __cold;
 332 #define fat_fs_error(sb, fmt, args...)          \
 333         __fat_fs_error(sb, 1, fmt , ## args)
 334 #define fat_fs_error_ratelimit(sb, fmt, args...) \
 335         __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 336 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
 337         __attribute__ ((format (printf, 3, 4))) __cold;
 338 extern int fat_clusters_flush(struct super_block *sb);
 339 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 340 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 341                               __le16 __time, __le16 __date, u8 time_cs);
 342 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 343                               __le16 *time, __le16 *date, u8 *time_cs);
 344 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 345
 346 int fat_cache_init(void);
 347 void fat_cache_destroy(void);
 348
 349 /* helper for printk */
 350 typedef unsigned long long      llu;
 351
 352 #endif /* !_FAT_H */