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/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
  25struct 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 */
  58struct 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        struct inode *fsinfo_inode;
  86
  87        struct ratelimit_state ratelimit;
  88
  89        spinlock_t inode_hash_lock;
  90        struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  91};
  92
  93#define FAT_CACHE_VALID 0       /* special case for valid cache */
  94
  95/*
  96 * MS-DOS file system inode data in memory
  97 */
  98struct msdos_inode_info {
  99        spinlock_t cache_lru_lock;
 100        struct list_head cache_lru;
 101        int nr_caches;
 102        /* for avoiding the race between fat_free() and fat_get_cluster() */
 103        unsigned int cache_valid_id;
 104
 105        /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
 106        loff_t mmu_private;     /* physically allocated size */
 107
 108        int i_start;            /* first cluster or 0 */
 109        int i_logstart;         /* logical first cluster */
 110        int i_attrs;            /* unused attribute bits */
 111        loff_t i_pos;           /* on-disk position of directory entry or 0 */
 112        struct hlist_node i_fat_hash;   /* hash by i_location */
 113        struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 114        struct inode vfs_inode;
 115};
 116
 117struct fat_slot_info {
 118        loff_t i_pos;           /* on-disk position of directory entry */
 119        loff_t slot_off;        /* offset for slot or de start */
 120        int nr_slots;           /* number of slots + 1(de) in filename */
 121        struct msdos_dir_entry *de;
 122        struct buffer_head *bh;
 123};
 124
 125static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 126{
 127        return sb->s_fs_info;
 128}
 129
 130static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 131{
 132        return container_of(inode, struct msdos_inode_info, vfs_inode);
 133}
 134
 135/*
 136 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 137 * save ATTR_RO instead of ->i_mode.
 138 *
 139 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 140 * bit, it's just used as flag for app.
 141 */
 142static inline int fat_mode_can_hold_ro(struct inode *inode)
 143{
 144        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 145        umode_t mask;
 146
 147        if (S_ISDIR(inode->i_mode)) {
 148                if (!sbi->options.rodir)
 149                        return 0;
 150                mask = ~sbi->options.fs_dmask;
 151        } else
 152                mask = ~sbi->options.fs_fmask;
 153
 154        if (!(mask & S_IWUGO))
 155                return 0;
 156        return 1;
 157}
 158
 159/* Convert attribute bits and a mask to the UNIX mode. */
 160static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
 161                                   u8 attrs, umode_t mode)
 162{
 163        if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
 164                mode &= ~S_IWUGO;
 165
 166        if (attrs & ATTR_DIR)
 167                return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 168        else
 169                return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 170}
 171
 172/* Return the FAT attribute byte for this inode */
 173static inline u8 fat_make_attrs(struct inode *inode)
 174{
 175        u8 attrs = MSDOS_I(inode)->i_attrs;
 176        if (S_ISDIR(inode->i_mode))
 177                attrs |= ATTR_DIR;
 178        if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
 179                attrs |= ATTR_RO;
 180        return attrs;
 181}
 182
 183static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 184{
 185        if (fat_mode_can_hold_ro(inode))
 186                MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
 187        else
 188                MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 189}
 190
 191static inline unsigned char fat_checksum(const __u8 *name)
 192{
 193        unsigned char s = name[0];
 194        s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 195        s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 196        s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 197        s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 198        s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 199        return s;
 200}
 201
 202static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 203{
 204        return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 205                + sbi->data_start;
 206}
 207
 208static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 209{
 210#ifdef __BIG_ENDIAN
 211        while (len--) {
 212                *dst++ = src[0] | (src[1] << 8);
 213                src += 2;
 214        }
 215#else
 216        memcpy(dst, src, len * 2);
 217#endif
 218}
 219
 220static inline int fat_get_start(const struct msdos_sb_info *sbi,
 221                                const struct msdos_dir_entry *de)
 222{
 223        int cluster = le16_to_cpu(de->start);
 224        if (sbi->fat_bits == 32)
 225                cluster |= (le16_to_cpu(de->starthi) << 16);
 226        return cluster;
 227}
 228
 229static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
 230{
 231        de->start   = cpu_to_le16(cluster);
 232        de->starthi = cpu_to_le16(cluster >> 16);
 233}
 234
 235static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 236{
 237#ifdef __BIG_ENDIAN
 238        while (len--) {
 239                dst[0] = *src & 0x00FF;
 240                dst[1] = (*src & 0xFF00) >> 8;
 241                dst += 2;
 242                src++;
 243        }
 244#else
 245        memcpy(dst, src, len * 2);
 246#endif
 247}
 248
 249/* fat/cache.c */
 250extern void fat_cache_inval_inode(struct inode *inode);
 251extern int fat_get_cluster(struct inode *inode, int cluster,
 252                           int *fclus, int *dclus);
 253extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 254                    unsigned long *mapped_blocks, int create);
 255
 256/* fat/dir.c */
 257extern const struct file_operations fat_dir_operations;
 258extern int fat_search_long(struct inode *inode, const unsigned char *name,
 259                           int name_len, struct fat_slot_info *sinfo);
 260extern int fat_dir_empty(struct inode *dir);
 261extern int fat_subdirs(struct inode *dir);
 262extern int fat_scan(struct inode *dir, const unsigned char *name,
 263                    struct fat_slot_info *sinfo);
 264extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 265                                struct msdos_dir_entry **de, loff_t *i_pos);
 266extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
 267extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 268                           struct fat_slot_info *sinfo);
 269extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 270
 271/* fat/fatent.c */
 272struct fat_entry {
 273        int entry;
 274        union {
 275                u8 *ent12_p[2];
 276                __le16 *ent16_p;
 277                __le32 *ent32_p;
 278        } u;
 279        int nr_bhs;
 280        struct buffer_head *bhs[2];
 281        struct inode *fat_inode;
 282};
 283
 284static inline void fatent_init(struct fat_entry *fatent)
 285{
 286        fatent->nr_bhs = 0;
 287        fatent->entry = 0;
 288        fatent->u.ent32_p = NULL;
 289        fatent->bhs[0] = fatent->bhs[1] = NULL;
 290        fatent->fat_inode = NULL;
 291}
 292
 293static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 294{
 295        fatent->entry = entry;
 296        fatent->u.ent32_p = NULL;
 297}
 298
 299static inline void fatent_brelse(struct fat_entry *fatent)
 300{
 301        int i;
 302        fatent->u.ent32_p = NULL;
 303        for (i = 0; i < fatent->nr_bhs; i++)
 304                brelse(fatent->bhs[i]);
 305        fatent->nr_bhs = 0;
 306        fatent->bhs[0] = fatent->bhs[1] = NULL;
 307        fatent->fat_inode = NULL;
 308}
 309
 310extern void fat_ent_access_init(struct super_block *sb);
 311extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 312                        int entry);
 313extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 314                         int new, int wait);
 315extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 316                              int nr_cluster);
 317extern int fat_free_clusters(struct inode *inode, int cluster);
 318extern int fat_count_free_clusters(struct super_block *sb);
 319
 320/* fat/file.c */
 321extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 322                              unsigned long arg);
 323extern const struct file_operations fat_file_operations;
 324extern const struct inode_operations fat_file_inode_operations;
 325extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
 326extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 327extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 328                       struct kstat *stat);
 329extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
 330                          int datasync);
 331
 332/* fat/inode.c */
 333extern void fat_attach(struct inode *inode, loff_t i_pos);
 334extern void fat_detach(struct inode *inode);
 335extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 336extern struct inode *fat_build_inode(struct super_block *sb,
 337                        struct msdos_dir_entry *de, loff_t i_pos);
 338extern int fat_sync_inode(struct inode *inode);
 339extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 340                          int isvfat, void (*setup)(struct super_block *));
 341
 342extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 343                            struct inode *i2);
 344/* fat/misc.c */
 345extern __printf(3, 4) __cold
 346void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
 347#define fat_fs_error(sb, fmt, args...)          \
 348        __fat_fs_error(sb, 1, fmt , ## args)
 349#define fat_fs_error_ratelimit(sb, fmt, args...) \
 350        __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 351__printf(3, 4) __cold
 352void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
 353#define fat_msg_ratelimit(sb, level, fmt, args...)      \
 354        do {    \
 355                        if (__ratelimit(&MSDOS_SB(sb)->ratelimit))      \
 356                                fat_msg(sb, level, fmt, ## args);       \
 357         } while (0)
 358extern int fat_clusters_flush(struct super_block *sb);
 359extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 360extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 361                              __le16 __time, __le16 __date, u8 time_cs);
 362extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 363                              __le16 *time, __le16 *date, u8 *time_cs);
 364extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 365
 366int fat_cache_init(void);
 367void fat_cache_destroy(void);
 368
 369/* helper for printk */
 370typedef unsigned long long      llu;
 371
 372#endif /* !_FAT_H */
 373
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