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