fat.h

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#ifndef _FAT_H
#define _FAT_H

#include <linux/buffer_head.h>
#include <linux/string.h>
#include <linux/nls.h>
#include <linux/fs.h>
#include <linux/hash.h>
#include <linux/mutex.h>
#include <linux/ratelimit.h>
#include <linux/msdos_fs.h>

/*
 * vfat shortname flags
 */
#define VFAT_SFN_DISPLAY_LOWER  0x0001 /* convert to lowercase for display */
#define VFAT_SFN_DISPLAY_WIN95  0x0002 /* emulate win95 rule for display */
#define VFAT_SFN_DISPLAY_WINNT  0x0004 /* emulate winnt rule for display */
#define VFAT_SFN_CREATE_WIN95   0x0100 /* emulate win95 rule for create */
#define VFAT_SFN_CREATE_WINNT   0x0200 /* emulate winnt rule for create */

#define FAT_ERRORS_CONT     1      /* ignore error and continue */
#define FAT_ERRORS_PANIC    2      /* panic on error */
#define FAT_ERRORS_RO       3      /* remount r/o on error */

struct fat_mount_options {
    kuid_t fs_uid;
    kgid_t fs_gid;
    unsigned short fs_fmask;
    unsigned short fs_dmask;
    unsigned short codepage;   /* Codepage for shortname conversions */
    char *iocharset;           /* Charset used for filename input/display */
    unsigned short shortname;  /* flags for shortname display/create rule */
    unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
    unsigned char errors;      /* On error: continue, panic, remount-ro */
    unsigned short allow_utime;/* permission for setting the [am]time */
    unsigned quiet:1,          /* set = fake successful chmods and chowns */
         showexec:1,       /* set = only set x bit for com/exe/bat */
         sys_immutable:1,  /* set = system files are immutable */
         dotsOK:1,         /* set = hidden and system files are named '.filename' */
         isvfat:1,         /* 0=no vfat long filename support, 1=vfat support */
         utf8:1,       /* Use of UTF-8 character set (Default) */
         unicode_xlate:1,  /* create escape sequences for unhandled Unicode */
         numtail:1,        /* Does first alias have a numeric '~1' type tail? */
         flush:1,      /* write things quickly */
         nocase:1,     /* Does this need case conversion? 0=need case conversion*/
         usefree:1,    /* Use free_clusters for FAT32 */
         tz_utc:1,     /* Filesystem timestamps are in UTC */
         rodir:1,      /* allow ATTR_RO for directory */
         discard:1,    /* Issue discard requests on deletions */
         nfs:1;        /* Do extra work needed for NFS export */
};

#define FAT_HASH_BITS   8
#define FAT_HASH_SIZE   (1UL << FAT_HASH_BITS)

/*
 * MS-DOS file system in-core superblock data
 */
struct msdos_sb_info {
    unsigned short sec_per_clus;  /* sectors/cluster */
    unsigned short cluster_bits;  /* log2(cluster_size) */
    unsigned int cluster_size;    /* cluster size */
    unsigned char fats, fat_bits; /* number of FATs, FAT bits (12 or 16) */
    unsigned short fat_start;
    unsigned long fat_length;     /* FAT start & length (sec.) */
    unsigned long dir_start;
    unsigned short dir_entries;   /* root dir start & entries */
    unsigned long data_start;     /* first data sector */
    unsigned long max_cluster;    /* maximum cluster number */
    unsigned long root_cluster;   /* first cluster of the root directory */
    unsigned long fsinfo_sector;  /* sector number of FAT32 fsinfo */
    struct mutex fat_lock;
    struct mutex s_lock;
    unsigned int prev_free;      /* previously allocated cluster number */
    unsigned int free_clusters;  /* -1 if undefined */
    unsigned int free_clus_valid; /* is free_clusters valid? */
    struct fat_mount_options options;
    struct nls_table *nls_disk;   /* Codepage used on disk */
    struct nls_table *nls_io;     /* Charset used for input and display */
    const void *dir_ops;          /* Opaque; default directory operations */
    int dir_per_block;        /* dir entries per block */
    int dir_per_block_bits;       /* log2(dir_per_block) */

    int fatent_shift;
    struct fatent_operations *fatent_ops;
    struct inode *fat_inode;
    struct inode *fsinfo_inode;

    struct ratelimit_state ratelimit;

    spinlock_t inode_hash_lock;
    struct hlist_head inode_hashtable[FAT_HASH_SIZE];

    spinlock_t dir_hash_lock;
    struct hlist_head dir_hashtable[FAT_HASH_SIZE];
};

#define FAT_CACHE_VALID 0   /* special case for valid cache */

/*
 * MS-DOS file system inode data in memory
 */
struct msdos_inode_info {
    spinlock_t cache_lru_lock;
    struct list_head cache_lru;
    int nr_caches;
    /* for avoiding the race between fat_free() and fat_get_cluster() */
    unsigned int cache_valid_id;

    /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
    loff_t mmu_private; /* physically allocated size */

    int i_start;        /* first cluster or 0 */
    int i_logstart;     /* logical first cluster */
    int i_attrs;        /* unused attribute bits */
    loff_t i_pos;       /* on-disk position of directory entry or 0 */
    struct hlist_node i_fat_hash;   /* hash by i_location */
    struct hlist_node i_dir_hash;   /* hash by i_logstart */
    struct rw_semaphore truncate_lock; /* protect bmap against truncate */
    struct inode vfs_inode;
};

struct fat_slot_info {
    loff_t i_pos;       /* on-disk position of directory entry */
    loff_t slot_off;    /* offset for slot or de start */
    int nr_slots;       /* number of slots + 1(de) in filename */
    struct msdos_dir_entry *de;
    struct buffer_head *bh;
};

static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
{
    return sb->s_fs_info;
}

static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
{
    return container_of(inode, struct msdos_inode_info, vfs_inode);
}

/*
 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
 * save ATTR_RO instead of ->i_mode.
 *
 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
 * bit, it's just used as flag for app.
 */
static inline int fat_mode_can_hold_ro(struct inode *inode)
{
    struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
    umode_t mask;

    if (S_ISDIR(inode->i_mode)) {
        if (!sbi->options.rodir)
            return 0;
        mask = ~sbi->options.fs_dmask;
    } else
        mask = ~sbi->options.fs_fmask;

    if (!(mask & S_IWUGO))
        return 0;
    return 1;
}

/* Convert attribute bits and a mask to the UNIX mode. */
static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
                   u8 attrs, umode_t mode)
{
    if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
        mode &= ~S_IWUGO;

    if (attrs & ATTR_DIR)
        return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
    else
        return (mode & ~sbi->options.fs_fmask) | S_IFREG;
}

/* Return the FAT attribute byte for this inode */
static inline u8 fat_make_attrs(struct inode *inode)
{
    u8 attrs = MSDOS_I(inode)->i_attrs;
    if (S_ISDIR(inode->i_mode))
        attrs |= ATTR_DIR;
    if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
        attrs |= ATTR_RO;
    return attrs;
}

static inline void fat_save_attrs(struct inode *inode, u8 attrs)
{
    if (fat_mode_can_hold_ro(inode))
        MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
    else
        MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
}

static inline unsigned char fat_checksum(const __u8 *name)
{
    unsigned char s = name[0];
    s = (s<<7) + (s>>1) + name[1];  s = (s<<7) + (s>>1) + name[2];
    s = (s<<7) + (s>>1) + name[3];  s = (s<<7) + (s>>1) + name[4];
    s = (s<<7) + (s>>1) + name[5];  s = (s<<7) + (s>>1) + name[6];
    s = (s<<7) + (s>>1) + name[7];  s = (s<<7) + (s>>1) + name[8];
    s = (s<<7) + (s>>1) + name[9];  s = (s<<7) + (s>>1) + name[10];
    return s;
}

static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
{
    return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
        + sbi->data_start;
}

static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
{
#ifdef __BIG_ENDIAN
    while (len--) {
        *dst++ = src[0] | (src[1] << 8);
        src += 2;
    }
#else
    memcpy(dst, src, len * 2);
#endif
}

static inline int fat_get_start(const struct msdos_sb_info *sbi,
                const struct msdos_dir_entry *de)
{
    int cluster = le16_to_cpu(de->start);
    if (sbi->fat_bits == 32)
        cluster |= (le16_to_cpu(de->starthi) << 16);
    return cluster;
}

static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
{
    de->start   = cpu_to_le16(cluster);
    de->starthi = cpu_to_le16(cluster >> 16);
}

static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
{
#ifdef __BIG_ENDIAN
    while (len--) {
        dst[0] = *src & 0x00FF;
        dst[1] = (*src & 0xFF00) >> 8;
        dst += 2;
        src++;
    }
#else
    memcpy(dst, src, len * 2);
#endif
}

/* fat/cache.c */
extern void fat_cache_inval_inode(struct inode *inode);
extern int fat_get_cluster(struct inode *inode, int cluster,
               int *fclus, int *dclus);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
            unsigned long *mapped_blocks, int create);

/* fat/dir.c */
extern const struct file_operations fat_dir_operations;
extern int fat_search_long(struct inode *inode, const unsigned char *name,
               int name_len, struct fat_slot_info *sinfo);
extern int fat_dir_empty(struct inode *dir);
extern int fat_subdirs(struct inode *dir);
extern int fat_scan(struct inode *dir, const unsigned char *name,
            struct fat_slot_info *sinfo);
extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
                struct msdos_dir_entry **de);
extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
               struct fat_slot_info *sinfo);
extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);

/* fat/fatent.c */
struct fat_entry {
    int entry;
    union {
        u8 *ent12_p[2];
        __le16 *ent16_p;
        __le32 *ent32_p;
    } u;
    int nr_bhs;
    struct buffer_head *bhs[2];
    struct inode *fat_inode;
};

static inline void fatent_init(struct fat_entry *fatent)
{
    fatent->nr_bhs = 0;
    fatent->entry = 0;
    fatent->u.ent32_p = NULL;
    fatent->bhs[0] = fatent->bhs[1] = NULL;
    fatent->fat_inode = NULL;
}

static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
{
    fatent->entry = entry;
    fatent->u.ent32_p = NULL;
}

static inline void fatent_brelse(struct fat_entry *fatent)
{
    int i;
    fatent->u.ent32_p = NULL;
    for (i = 0; i < fatent->nr_bhs; i++)
        brelse(fatent->bhs[i]);
    fatent->nr_bhs = 0;
    fatent->bhs[0] = fatent->bhs[1] = NULL;
    fatent->fat_inode = NULL;
}

extern void fat_ent_access_init(struct super_block *sb);
extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
            int entry);
extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
             int new, int wait);
extern int fat_alloc_clusters(struct inode *inode, int *cluster,
                  int nr_cluster);
extern int fat_free_clusters(struct inode *inode, int cluster);
extern int fat_count_free_clusters(struct super_block *sb);

/* fat/file.c */
extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
                  unsigned long arg);
extern const struct file_operations fat_file_operations;
extern const struct inode_operations fat_file_inode_operations;
extern int fat_setattr(struct dentry *dentry, struct iattr *attr);
extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
               struct kstat *stat);
extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
              int datasync);

/* fat/inode.c */
extern void fat_attach(struct inode *inode, loff_t i_pos);
extern void fat_detach(struct inode *inode);
extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
extern struct inode *fat_build_inode(struct super_block *sb,
            struct msdos_dir_entry *de, loff_t i_pos);
extern int fat_sync_inode(struct inode *inode);
extern int fat_fill_super(struct super_block *sb, void *data, int silent,
              int isvfat, void (*setup)(struct super_block *));

extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
                struct inode *i2);
static inline unsigned long fat_dir_hash(int logstart)
{
    return hash_32(logstart, FAT_HASH_BITS);
}

/* fat/misc.c */
extern __printf(3, 4) __cold
void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
#define fat_fs_error(sb, fmt, args...)      \
    __fat_fs_error(sb, 1, fmt , ## args)
#define fat_fs_error_ratelimit(sb, fmt, args...) \
    __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
__printf(3, 4) __cold
void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
#define fat_msg_ratelimit(sb, level, fmt, args...)  \
    do {    \
            if (__ratelimit(&MSDOS_SB(sb)->ratelimit))  \
                fat_msg(sb, level, fmt, ## args);   \
     } while (0)
extern int fat_clusters_flush(struct super_block *sb);
extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
                  __le16 __time, __le16 __date, u8 time_cs);
extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
                  __le16 *time, __le16 *date, u8 *time_cs);
extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);

int fat_cache_init(void);
void fat_cache_destroy(void);

/* fat/nfs.c */
struct fid;
extern struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid,
                       int fh_len, int fh_type);
extern struct dentry *fat_fh_to_parent(struct super_block *sb, struct fid *fid,
                       int fh_len, int fh_type);
extern struct dentry *fat_get_parent(struct dentry *child_dir);

/* helper for printk */
typedef unsigned long long  llu;

#endif /* !_FAT_H */