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