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/hash.h>
   9 #include <linux/mutex.h>
  10 #include <linux/ratelimit.h>
  11 #include <linux/msdos_fs.h>
  12
  13 /*
  14  * vfat shortname flags
  15  */
  16 #define VFAT_SFN_DISPLAY_LOWER  0x0001 /* convert to lowercase for display */
  17 #define VFAT_SFN_DISPLAY_WIN95  0x0002 /* emulate win95 rule for display */
  18 #define VFAT_SFN_DISPLAY_WINNT  0x0004 /* emulate winnt rule for display */
  19 #define VFAT_SFN_CREATE_WIN95   0x0100 /* emulate win95 rule for create */
  20 #define VFAT_SFN_CREATE_WINNT   0x0200 /* emulate winnt rule for create */
  21
  22 #define FAT_ERRORS_CONT         1      /* ignore error and continue */
  23 #define FAT_ERRORS_PANIC        2      /* panic on error */
  24 #define FAT_ERRORS_RO           3      /* remount r/o on error */
  25
  26 struct fat_mount_options {
  27         kuid_t fs_uid;
  28         kgid_t fs_gid;
  29         unsigned short fs_fmask;
  30         unsigned short fs_dmask;
  31         unsigned short codepage;   /* Codepage for shortname conversions */
  32         int time_offset;           /* Offset of timestamps from UTC (in minutes) */
  33         char *iocharset;           /* Charset used for filename input/display */
  34         unsigned short shortname;  /* flags for shortname display/create rule */
  35         unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
  36         unsigned char errors;      /* On error: continue, panic, remount-ro */
  37         unsigned short allow_utime;/* permission for setting the [am]time */
  38         unsigned quiet:1,          /* set = fake successful chmods and chowns */
  39                  showexec:1,       /* set = only set x bit for com/exe/bat */
  40                  sys_immutable:1,  /* set = system files are immutable */
  41                  dotsOK:1,         /* set = hidden and system files are named '.filename' */
  42                  isvfat:1,         /* 0=no vfat long filename support, 1=vfat support */
  43                  utf8:1,           /* Use of UTF-8 character set (Default) */
  44                  unicode_xlate:1,  /* create escape sequences for unhandled Unicode */
  45                  numtail:1,        /* Does first alias have a numeric '~1' type tail? */
  46                  flush:1,          /* write things quickly */
  47                  nocase:1,         /* Does this need case conversion? 0=need case conversion*/
  48                  usefree:1,        /* Use free_clusters for FAT32 */
  49                  tz_set:1,         /* Filesystem timestamps' offset set */
  50                  rodir:1,          /* allow ATTR_RO for directory */
  51                  discard:1,        /* Issue discard requests on deletions */
  52                  nfs:1;            /* Do extra work needed for NFS export */
  53 };
  54
  55 #define FAT_HASH_BITS   8
  56 #define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)
  57
  58 /*
  59  * MS-DOS file system in-core superblock data
  60  */
  61 struct msdos_sb_info {
  62         unsigned short sec_per_clus;  /* sectors/cluster */
  63         unsigned short cluster_bits;  /* log2(cluster_size) */
  64         unsigned int cluster_size;    /* cluster size */
  65         unsigned char fats, fat_bits; /* number of FATs, FAT bits (12 or 16) */
  66         unsigned short fat_start;
  67         unsigned long fat_length;     /* FAT start & length (sec.) */
  68         unsigned long dir_start;
  69         unsigned short dir_entries;   /* root dir start & entries */
  70         unsigned long data_start;     /* first data sector */
  71         unsigned long max_cluster;    /* maximum cluster number */
  72         unsigned long root_cluster;   /* first cluster of the root directory */
  73         unsigned long fsinfo_sector;  /* sector number of FAT32 fsinfo */
  74         struct mutex fat_lock;
  75         struct mutex s_lock;
  76         unsigned int prev_free;      /* previously allocated cluster number */
  77         unsigned int free_clusters;  /* -1 if undefined */
  78         unsigned int free_clus_valid; /* is free_clusters valid? */
  79         struct fat_mount_options options;
  80         struct nls_table *nls_disk;   /* Codepage used on disk */
  81         struct nls_table *nls_io;     /* Charset used for input and display */
  82         const void *dir_ops;          /* Opaque; default directory operations */
  83         int dir_per_block;            /* dir entries per block */
  84         int dir_per_block_bits;       /* log2(dir_per_block) */
  85
  86         int fatent_shift;
  87         struct fatent_operations *fatent_ops;
  88         struct inode *fat_inode;
  89         struct inode *fsinfo_inode;
  90
  91         struct ratelimit_state ratelimit;
  92
  93         spinlock_t inode_hash_lock;
  94         struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  95
  96         spinlock_t dir_hash_lock;
  97         struct hlist_head dir_hashtable[FAT_HASH_SIZE];
  98
  99         unsigned int dirty;           /* fs state before mount */
 100 };
 101
 102 #define FAT_CACHE_VALID 0       /* special case for valid cache */
 103
 104 /*
 105  * MS-DOS file system inode data in memory
 106  */
 107 struct msdos_inode_info {
 108         spinlock_t cache_lru_lock;
 109         struct list_head cache_lru;
 110         int nr_caches;
 111         /* for avoiding the race between fat_free() and fat_get_cluster() */
 112         unsigned int cache_valid_id;
 113
 114         /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
 115         loff_t mmu_private;     /* physically allocated size */
 116
 117         int i_start;            /* first cluster or 0 */
 118         int i_logstart;         /* logical first cluster */
 119         int i_attrs;            /* unused attribute bits */
 120         loff_t i_pos;           /* on-disk position of directory entry or 0 */
 121         struct hlist_node i_fat_hash;   /* hash by i_location */
 122         struct hlist_node i_dir_hash;   /* hash by i_logstart */
 123         struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 124         struct inode vfs_inode;
 125 };
 126
 127 struct fat_slot_info {
 128         loff_t i_pos;           /* on-disk position of directory entry */
 129         loff_t slot_off;        /* offset for slot or de start */
 130         int nr_slots;           /* number of slots + 1(de) in filename */
 131         struct msdos_dir_entry *de;
 132         struct buffer_head *bh;
 133 };
 134
 135 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 136 {
 137         return sb->s_fs_info;
 138 }
 139
 140 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 141 {
 142         return container_of(inode, struct msdos_inode_info, vfs_inode);
 143 }
 144
 145 /*
 146  * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 147  * save ATTR_RO instead of ->i_mode.
 148  *
 149  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 150  * bit, it's just used as flag for app.
 151  */
 152 static inline int fat_mode_can_hold_ro(struct inode *inode)
 153 {
 154         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 155         umode_t mask;
 156
 157         if (S_ISDIR(inode->i_mode)) {
 158                 if (!sbi->options.rodir)
 159                         return 0;
 160                 mask = ~sbi->options.fs_dmask;
 161         } else
 162                 mask = ~sbi->options.fs_fmask;
 163
 164         if (!(mask & S_IWUGO))
 165                 return 0;
 166         return 1;
 167 }
 168
 169 /* Convert attribute bits and a mask to the UNIX mode. */
 170 static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
 171                                    u8 attrs, umode_t mode)
 172 {
 173         if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
 174                 mode &= ~S_IWUGO;
 175
 176         if (attrs & ATTR_DIR)
 177                 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 178         else
 179                 return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 180 }
 181
 182 /* Return the FAT attribute byte for this inode */
 183 static inline u8 fat_make_attrs(struct inode *inode)
 184 {
 185         u8 attrs = MSDOS_I(inode)->i_attrs;
 186         if (S_ISDIR(inode->i_mode))
 187                 attrs |= ATTR_DIR;
 188         if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
 189                 attrs |= ATTR_RO;
 190         return attrs;
 191 }
 192
 193 static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 194 {
 195         if (fat_mode_can_hold_ro(inode))
 196                 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
 197         else
 198                 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 199 }
 200
 201 static inline unsigned char fat_checksum(const __u8 *name)
 202 {
 203         unsigned char s = name[0];
 204         s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 205         s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 206         s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 207         s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 208         s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 209         return s;
 210 }
 211
 212 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 213 {
 214         return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 215                 + sbi->data_start;
 216 }
 217
 218 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 219 {
 220 #ifdef __BIG_ENDIAN
 221         while (len--) {
 222                 *dst++ = src[0] | (src[1] << 8);
 223                 src += 2;
 224         }
 225 #else
 226         memcpy(dst, src, len * 2);
 227 #endif
 228 }
 229
 230 static inline int fat_get_start(const struct msdos_sb_info *sbi,
 231                                 const struct msdos_dir_entry *de)
 232 {
 233         int cluster = le16_to_cpu(de->start);
 234         if (sbi->fat_bits == 32)
 235                 cluster |= (le16_to_cpu(de->starthi) << 16);
 236         return cluster;
 237 }
 238
 239 static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
 240 {
 241         de->start   = cpu_to_le16(cluster);
 242         de->starthi = cpu_to_le16(cluster >> 16);
 243 }
 244
 245 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 246 {
 247 #ifdef __BIG_ENDIAN
 248         while (len--) {
 249                 dst[0] = *src & 0x00FF;
 250                 dst[1] = (*src & 0xFF00) >> 8;
 251                 dst += 2;
 252                 src++;
 253         }
 254 #else
 255         memcpy(dst, src, len * 2);
 256 #endif
 257 }
 258
 259 /* fat/cache.c */
 260 extern void fat_cache_inval_inode(struct inode *inode);
 261 extern int fat_get_cluster(struct inode *inode, int cluster,
 262                            int *fclus, int *dclus);
 263 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 264                     unsigned long *mapped_blocks, int create);
 265
 266 /* fat/dir.c */
 267 extern const struct file_operations fat_dir_operations;
 268 extern int fat_search_long(struct inode *inode, const unsigned char *name,
 269                            int name_len, struct fat_slot_info *sinfo);
 270 extern int fat_dir_empty(struct inode *dir);
 271 extern int fat_subdirs(struct inode *dir);
 272 extern int fat_scan(struct inode *dir, const unsigned char *name,
 273                     struct fat_slot_info *sinfo);
 274 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 275                                 struct msdos_dir_entry **de);
 276 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 277 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 278                            struct fat_slot_info *sinfo);
 279 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 280
 281 /* fat/fatent.c */
 282 struct fat_entry {
 283         int entry;
 284         union {
 285                 u8 *ent12_p[2];
 286                 __le16 *ent16_p;
 287                 __le32 *ent32_p;
 288         } u;
 289         int nr_bhs;
 290         struct buffer_head *bhs[2];
 291         struct inode *fat_inode;
 292 };
 293
 294 static inline void fatent_init(struct fat_entry *fatent)
 295 {
 296         fatent->nr_bhs = 0;
 297         fatent->entry = 0;
 298         fatent->u.ent32_p = NULL;
 299         fatent->bhs[0] = fatent->bhs[1] = NULL;
 300         fatent->fat_inode = NULL;
 301 }
 302
 303 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 304 {
 305         fatent->entry = entry;
 306         fatent->u.ent32_p = NULL;
 307 }
 308
 309 static inline void fatent_brelse(struct fat_entry *fatent)
 310 {
 311         int i;
 312         fatent->u.ent32_p = NULL;
 313         for (i = 0; i < fatent->nr_bhs; i++)
 314                 brelse(fatent->bhs[i]);
 315         fatent->nr_bhs = 0;
 316         fatent->bhs[0] = fatent->bhs[1] = NULL;
 317         fatent->fat_inode = NULL;
 318 }
 319
 320 extern void fat_ent_access_init(struct super_block *sb);
 321 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 322                         int entry);
 323 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 324                          int new, int wait);
 325 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 326                               int nr_cluster);
 327 extern int fat_free_clusters(struct inode *inode, int cluster);
 328 extern int fat_count_free_clusters(struct super_block *sb);
 329
 330 /* fat/file.c */
 331 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 332                               unsigned long arg);
 333 extern const struct file_operations fat_file_operations;
 334 extern const struct inode_operations fat_file_inode_operations;
 335 extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
 336 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 337 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 338                        struct kstat *stat);
 339 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
 340                           int datasync);
 341
 342 /* fat/inode.c */
 343 extern void fat_attach(struct inode *inode, loff_t i_pos);
 344 extern void fat_detach(struct inode *inode);
 345 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 346 extern struct inode *fat_build_inode(struct super_block *sb,
 347                         struct msdos_dir_entry *de, loff_t i_pos);
 348 extern int fat_sync_inode(struct inode *inode);
 349 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 350                           int isvfat, void (*setup)(struct super_block *));
 351
 352 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 353                             struct inode *i2);
 354 static inline unsigned long fat_dir_hash(int logstart)
 355 {
 356         return hash_32(logstart, FAT_HASH_BITS);
 357 }
 358
 359 /* fat/misc.c */
 360 extern __printf(3, 4) __cold
 361 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
 362 #define fat_fs_error(sb, fmt, args...)          \
 363         __fat_fs_error(sb, 1, fmt , ## args)
 364 #define fat_fs_error_ratelimit(sb, fmt, args...) \
 365         __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 366 __printf(3, 4) __cold
 367 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
 368 #define fat_msg_ratelimit(sb, level, fmt, args...)      \
 369         do {    \
 370                         if (__ratelimit(&MSDOS_SB(sb)->ratelimit))      \
 371                                 fat_msg(sb, level, fmt, ## args);       \
 372          } while (0)
 373 extern int fat_clusters_flush(struct super_block *sb);
 374 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 375 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 376                               __le16 __time, __le16 __date, u8 time_cs);
 377 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 378                               __le16 *time, __le16 *date, u8 *time_cs);
 379 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 380
 381 int fat_cache_init(void);
 382 void fat_cache_destroy(void);
 383
 384 /* fat/nfs.c */
 385 struct fid;
 386 extern struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid,
 387                                        int fh_len, int fh_type);
 388 extern struct dentry *fat_fh_to_parent(struct super_block *sb, struct fid *fid,
 389                                        int fh_len, int fh_type);
 390 extern struct dentry *fat_get_parent(struct dentry *child_dir);
 391
 392 /* helper for printk */
 393 typedef unsigned long long      llu;
 394
 395 #endif /* !_FAT_H */