LXR linux/fs/fat/fat.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _FAT_H
   3#define _FAT_H
   4
   5#include <linux/buffer_head.h>
   6#include <linux/nls.h>
   7#include <linux/hash.h>
   8#include <linux/ratelimit.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
  24#define FAT_NFS_STALE_RW        1      /* NFS RW support, can cause ESTALE */
  25#define FAT_NFS_NOSTALE_RO      2      /* NFS RO support, no ESTALE issue */
  26
  27struct fat_mount_options {
  28        kuid_t fs_uid;
  29        kgid_t fs_gid;
  30        unsigned short fs_fmask;
  31        unsigned short fs_dmask;
  32        unsigned short codepage;   /* Codepage for shortname conversions */
  33        int time_offset;           /* Offset of timestamps from UTC (in minutes) */
  34        char *iocharset;           /* Charset used for filename input/display */
  35        unsigned short shortname;  /* flags for shortname display/create rule */
  36        unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
  37        unsigned char errors;      /* On error: continue, panic, remount-ro */
  38        unsigned char nfs;        /* NFS support: nostale_ro, stale_rw */
  39        unsigned short allow_utime;/* permission for setting the [am]time */
  40        unsigned quiet:1,          /* set = fake successful chmods and chowns */
  41                 showexec:1,       /* set = only set x bit for com/exe/bat */
  42                 sys_immutable:1,  /* set = system files are immutable */
  43                 dotsOK:1,         /* set = hidden and system files are named '.filename' */
  44                 isvfat:1,         /* 0=no vfat long filename support, 1=vfat support */
  45                 utf8:1,           /* Use of UTF-8 character set (Default) */
  46                 unicode_xlate:1,  /* create escape sequences for unhandled Unicode */
  47                 numtail:1,        /* Does first alias have a numeric '~1' type tail? */
  48                 flush:1,          /* write things quickly */
  49                 nocase:1,         /* Does this need case conversion? 0=need case conversion*/
  50                 usefree:1,        /* Use free_clusters for FAT32 */
  51                 tz_set:1,         /* Filesystem timestamps' offset set */
  52                 rodir:1,          /* allow ATTR_RO for directory */
  53                 discard:1,        /* Issue discard requests on deletions */
  54                 dos1xfloppy:1;    /* Assume default BPB for DOS 1.x floppies */
  55};
  56
  57#define FAT_HASH_BITS   8
  58#define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)
  59
  60/*
  61 * MS-DOS file system in-core superblock data
  62 */
  63struct msdos_sb_info {
  64        unsigned short sec_per_clus;  /* sectors/cluster */
  65        unsigned short cluster_bits;  /* log2(cluster_size) */
  66        unsigned int cluster_size;    /* cluster size */
  67        unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */
  68        unsigned short fat_start;
  69        unsigned long fat_length;     /* FAT start & length (sec.) */
  70        unsigned long dir_start;
  71        unsigned short dir_entries;   /* root dir start & entries */
  72        unsigned long data_start;     /* first data sector */
  73        unsigned long max_cluster;    /* maximum cluster number */
  74        unsigned long root_cluster;   /* first cluster of the root directory */
  75        unsigned long fsinfo_sector;  /* sector number of FAT32 fsinfo */
  76        struct mutex fat_lock;
  77        struct mutex nfs_build_inode_lock;
  78        struct mutex s_lock;
  79        unsigned int prev_free;      /* previously allocated cluster number */
  80        unsigned int free_clusters;  /* -1 if undefined */
  81        unsigned int free_clus_valid; /* is free_clusters valid? */
  82        struct fat_mount_options options;
  83        struct nls_table *nls_disk;   /* Codepage used on disk */
  84        struct nls_table *nls_io;     /* Charset used for input and display */
  85        const void *dir_ops;          /* Opaque; default directory operations */
  86        int dir_per_block;            /* dir entries per block */
  87        int dir_per_block_bits;       /* log2(dir_per_block) */
  88        unsigned int vol_id;            /*volume ID*/
  89
  90        int fatent_shift;
  91        const struct fatent_operations *fatent_ops;
  92        struct inode *fat_inode;
  93        struct inode *fsinfo_inode;
  94
  95        struct ratelimit_state ratelimit;
  96
  97        spinlock_t inode_hash_lock;
  98        struct hlist_head inode_hashtable[FAT_HASH_SIZE];
  99
 100        spinlock_t dir_hash_lock;
 101        struct hlist_head dir_hashtable[FAT_HASH_SIZE];
 102
 103        unsigned int dirty;           /* fs state before mount */
 104        struct rcu_head rcu;
 105};
 106
 107#define FAT_CACHE_VALID 0       /* special case for valid cache */
 108
 109/*
 110 * MS-DOS file system inode data in memory
 111 */
 112struct msdos_inode_info {
 113        spinlock_t cache_lru_lock;
 114        struct list_head cache_lru;
 115        int nr_caches;
 116        /* for avoiding the race between fat_free() and fat_get_cluster() */
 117        unsigned int cache_valid_id;
 118
 119        /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
 120        loff_t mmu_private;     /* physically allocated size */
 121
 122        int i_start;            /* first cluster or 0 */
 123        int i_logstart;         /* logical first cluster */
 124        int i_attrs;            /* unused attribute bits */
 125        loff_t i_pos;           /* on-disk position of directory entry or 0 */
 126        struct hlist_node i_fat_hash;   /* hash by i_location */
 127        struct hlist_node i_dir_hash;   /* hash by i_logstart */
 128        struct rw_semaphore truncate_lock; /* protect bmap against truncate */
 129        struct inode vfs_inode;
 130};
 131
 132struct fat_slot_info {
 133        loff_t i_pos;           /* on-disk position of directory entry */
 134        loff_t slot_off;        /* offset for slot or de start */
 135        int nr_slots;           /* number of slots + 1(de) in filename */
 136        struct msdos_dir_entry *de;
 137        struct buffer_head *bh;
 138};
 139
 140static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
 141{
 142        return sb->s_fs_info;
 143}
 144
 145static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
 146{
 147        return container_of(inode, struct msdos_inode_info, vfs_inode);
 148}
 149
 150/*
 151 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 152 * save ATTR_RO instead of ->i_mode.
 153 *
 154 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 155 * bit, it's just used as flag for app.
 156 */
 157static inline int fat_mode_can_hold_ro(struct inode *inode)
 158{
 159        struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 160        umode_t mask;
 161
 162        if (S_ISDIR(inode->i_mode)) {
 163                if (!sbi->options.rodir)
 164                        return 0;
 165                mask = ~sbi->options.fs_dmask;
 166        } else
 167                mask = ~sbi->options.fs_fmask;
 168
 169        if (!(mask & S_IWUGO))
 170                return 0;
 171        return 1;
 172}
 173
 174/* Convert attribute bits and a mask to the UNIX mode. */
 175static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
 176                                   u8 attrs, umode_t mode)
 177{
 178        if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
 179                mode &= ~S_IWUGO;
 180
 181        if (attrs & ATTR_DIR)
 182                return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
 183        else
 184                return (mode & ~sbi->options.fs_fmask) | S_IFREG;
 185}
 186
 187/* Return the FAT attribute byte for this inode */
 188static inline u8 fat_make_attrs(struct inode *inode)
 189{
 190        u8 attrs = MSDOS_I(inode)->i_attrs;
 191        if (S_ISDIR(inode->i_mode))
 192                attrs |= ATTR_DIR;
 193        if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
 194                attrs |= ATTR_RO;
 195        return attrs;
 196}
 197
 198static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 199{
 200        if (fat_mode_can_hold_ro(inode))
 201                MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
 202        else
 203                MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 204}
 205
 206static inline unsigned char fat_checksum(const __u8 *name)
 207{
 208        unsigned char s = name[0];
 209        s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
 210        s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
 211        s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
 212        s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
 213        s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
 214        return s;
 215}
 216
 217static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
 218{
 219        return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
 220                + sbi->data_start;
 221}
 222
 223static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,
 224                                loff_t i_pos, sector_t *blknr, int *offset)
 225{
 226        *blknr = i_pos >> sbi->dir_per_block_bits;
 227        *offset = i_pos & (sbi->dir_per_block - 1);
 228}
 229
 230static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
 231                                        struct inode *inode)
 232{
 233        loff_t i_pos;
 234#if BITS_PER_LONG == 32
 235        spin_lock(&sbi->inode_hash_lock);
 236#endif
 237        i_pos = MSDOS_I(inode)->i_pos;
 238#if BITS_PER_LONG == 32
 239        spin_unlock(&sbi->inode_hash_lock);
 240#endif
 241        return i_pos;
 242}
 243
 244static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
 245{
 246#ifdef __BIG_ENDIAN
 247        while (len--) {
 248                *dst++ = src[0] | (src[1] << 8);
 249                src += 2;
 250        }
 251#else
 252        memcpy(dst, src, len * 2);
 253#endif
 254}
 255
 256static inline int fat_get_start(const struct msdos_sb_info *sbi,
 257                                const struct msdos_dir_entry *de)
 258{
 259        int cluster = le16_to_cpu(de->start);
 260        if (sbi->fat_bits == 32)
 261                cluster |= (le16_to_cpu(de->starthi) << 16);
 262        return cluster;
 263}
 264
 265static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
 266{
 267        de->start   = cpu_to_le16(cluster);
 268        de->starthi = cpu_to_le16(cluster >> 16);
 269}
 270
 271static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
 272{
 273#ifdef __BIG_ENDIAN
 274        while (len--) {
 275                dst[0] = *src & 0x00FF;
 276                dst[1] = (*src & 0xFF00) >> 8;
 277                dst += 2;
 278                src++;
 279        }
 280#else
 281        memcpy(dst, src, len * 2);
 282#endif
 283}
 284
 285/* fat/cache.c */
 286extern void fat_cache_inval_inode(struct inode *inode);
 287extern int fat_get_cluster(struct inode *inode, int cluster,
 288                           int *fclus, int *dclus);
 289extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
 290                                  sector_t last_block,
 291                                  unsigned long *mapped_blocks, sector_t *bmap);
 292extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
 293                    unsigned long *mapped_blocks, int create, bool from_bmap);
 294
 295/* fat/dir.c */
 296extern const struct file_operations fat_dir_operations;
 297extern int fat_search_long(struct inode *inode, const unsigned char *name,
 298                           int name_len, struct fat_slot_info *sinfo);
 299extern int fat_dir_empty(struct inode *dir);
 300extern int fat_subdirs(struct inode *dir);
 301extern int fat_scan(struct inode *dir, const unsigned char *name,
 302                    struct fat_slot_info *sinfo);
 303extern int fat_scan_logstart(struct inode *dir, int i_logstart,
 304                             struct fat_slot_info *sinfo);
 305extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 306                                struct msdos_dir_entry **de);
 307extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
 308extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
 309                           struct fat_slot_info *sinfo);
 310extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
 311
 312/* fat/fatent.c */
 313struct fat_entry {
 314        int entry;
 315        union {
 316                u8 *ent12_p[2];
 317                __le16 *ent16_p;
 318                __le32 *ent32_p;
 319        } u;
 320        int nr_bhs;
 321        struct buffer_head *bhs[2];
 322        struct inode *fat_inode;
 323};
 324
 325static inline void fatent_init(struct fat_entry *fatent)
 326{
 327        fatent->nr_bhs = 0;
 328        fatent->entry = 0;
 329        fatent->u.ent32_p = NULL;
 330        fatent->bhs[0] = fatent->bhs[1] = NULL;
 331        fatent->fat_inode = NULL;
 332}
 333
 334static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
 335{
 336        fatent->entry = entry;
 337        fatent->u.ent32_p = NULL;
 338}
 339
 340static inline void fatent_brelse(struct fat_entry *fatent)
 341{
 342        int i;
 343        fatent->u.ent32_p = NULL;
 344        for (i = 0; i < fatent->nr_bhs; i++)
 345                brelse(fatent->bhs[i]);
 346        fatent->nr_bhs = 0;
 347        fatent->bhs[0] = fatent->bhs[1] = NULL;
 348        fatent->fat_inode = NULL;
 349}
 350
 351extern void fat_ent_access_init(struct super_block *sb);
 352extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
 353                        int entry);
 354extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
 355                         int new, int wait);
 356extern int fat_alloc_clusters(struct inode *inode, int *cluster,
 357                              int nr_cluster);
 358extern int fat_free_clusters(struct inode *inode, int cluster);
 359extern int fat_count_free_clusters(struct super_block *sb);
 360
 361/* fat/file.c */
 362extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 363                              unsigned long arg);
 364extern const struct file_operations fat_file_operations;
 365extern const struct inode_operations fat_file_inode_operations;
 366extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
 367extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 368extern int fat_getattr(const struct path *path, struct kstat *stat,
 369                       u32 request_mask, unsigned int flags);
 370extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
 371                          int datasync);
 372
 373/* fat/inode.c */
 374extern int fat_block_truncate_page(struct inode *inode, loff_t from);
 375extern void fat_attach(struct inode *inode, loff_t i_pos);
 376extern void fat_detach(struct inode *inode);
 377extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 378extern struct inode *fat_build_inode(struct super_block *sb,
 379                        struct msdos_dir_entry *de, loff_t i_pos);
 380extern int fat_sync_inode(struct inode *inode);
 381extern int fat_fill_super(struct super_block *sb, void *data, int silent,
 382                          int isvfat, void (*setup)(struct super_block *));
 383extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
 384
 385extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 386                            struct inode *i2);
 387static inline unsigned long fat_dir_hash(int logstart)
 388{
 389        return hash_32(logstart, FAT_HASH_BITS);
 390}
 391extern int fat_add_cluster(struct inode *inode);
 392
 393/* fat/misc.c */
 394extern __printf(3, 4) __cold
 395void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
 396#define fat_fs_error(sb, fmt, args...)          \
 397        __fat_fs_error(sb, 1, fmt , ## args)
 398#define fat_fs_error_ratelimit(sb, fmt, args...) \
 399        __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 400__printf(3, 4) __cold
 401void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
 402#define fat_msg_ratelimit(sb, level, fmt, args...)      \
 403        do {    \
 404                        if (__ratelimit(&MSDOS_SB(sb)->ratelimit))      \
 405                                fat_msg(sb, level, fmt, ## args);       \
 406         } while (0)
 407extern int fat_clusters_flush(struct super_block *sb);
 408extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 409extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
 410                              __le16 __time, __le16 __date, u8 time_cs);
 411extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
 412                              __le16 *time, __le16 *date, u8 *time_cs);
 413extern int fat_truncate_time(struct inode *inode, struct timespec64 *now,
 414                             int flags);
 415extern int fat_update_time(struct inode *inode, struct timespec64 *now,
 416                           int flags);
 417extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
 418
 419int fat_cache_init(void);
 420void fat_cache_destroy(void);
 421
 422/* fat/nfs.c */
 423extern const struct export_operations fat_export_ops;
 424extern const struct export_operations fat_export_ops_nostale;
 425
 426/* helper for printk */
 427typedef unsigned long long      llu;
 428
 429#endif /* !_FAT_H */
 430