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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _FAT_H3#define _FAT_H4 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#include <linux/fs_context.h>11#include <linux/fs_parser.h>12 13/*14 * vfat shortname flags15 */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 26#define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */27#define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */28 29struct fat_mount_options {30 kuid_t fs_uid;31 kgid_t fs_gid;32 unsigned short fs_fmask;33 unsigned short fs_dmask;34 unsigned short codepage; /* Codepage for shortname conversions */35 int time_offset; /* Offset of timestamps from UTC (in minutes) */36 char *iocharset; /* Charset used for filename input/display */37 unsigned short shortname; /* flags for shortname display/create rule */38 unsigned char name_check; /* r = relaxed, n = normal, s = strict */39 unsigned char errors; /* On error: continue, panic, remount-ro */40 unsigned char nfs; /* NFS support: nostale_ro, stale_rw */41 unsigned short allow_utime;/* permission for setting the [am]time */42 unsigned quiet:1, /* set = fake successful chmods and chowns */43 showexec:1, /* set = only set x bit for com/exe/bat */44 sys_immutable:1, /* set = system files are immutable */45 dotsOK:1, /* set = hidden and system files are named '.filename' */46 isvfat:1, /* 0=no vfat long filename support, 1=vfat support */47 utf8:1, /* Use of UTF-8 character set (Default) */48 unicode_xlate:1, /* create escape sequences for unhandled Unicode */49 numtail:1, /* Does first alias have a numeric '~1' type tail? */50 flush:1, /* write things quickly */51 nocase:1, /* Does this need case conversion? 0=need case conversion*/52 usefree:1, /* Use free_clusters for FAT32 */53 tz_set:1, /* Filesystem timestamps' offset set */54 rodir:1, /* allow ATTR_RO for directory */55 discard:1, /* Issue discard requests on deletions */56 dos1xfloppy:1, /* Assume default BPB for DOS 1.x floppies */57 debug:1; /* Not currently used */58};59 60#define FAT_HASH_BITS 861#define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)62 63/*64 * MS-DOS file system in-core superblock data65 */66struct msdos_sb_info {67 unsigned short sec_per_clus; /* sectors/cluster */68 unsigned short cluster_bits; /* log2(cluster_size) */69 unsigned int cluster_size; /* cluster size */70 unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */71 unsigned short fat_start;72 unsigned long fat_length; /* FAT start & length (sec.) */73 unsigned long dir_start;74 unsigned short dir_entries; /* root dir start & entries */75 unsigned long data_start; /* first data sector */76 unsigned long max_cluster; /* maximum cluster number */77 unsigned long root_cluster; /* first cluster of the root directory */78 unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */79 struct mutex fat_lock;80 struct mutex nfs_build_inode_lock;81 struct mutex s_lock;82 unsigned int prev_free; /* previously allocated cluster number */83 unsigned int free_clusters; /* -1 if undefined */84 unsigned int free_clus_valid; /* is free_clusters valid? */85 struct fat_mount_options options;86 struct nls_table *nls_disk; /* Codepage used on disk */87 struct nls_table *nls_io; /* Charset used for input and display */88 const void *dir_ops; /* Opaque; default directory operations */89 int dir_per_block; /* dir entries per block */90 int dir_per_block_bits; /* log2(dir_per_block) */91 unsigned int vol_id; /*volume ID*/92 93 int fatent_shift;94 const struct fatent_operations *fatent_ops;95 struct inode *fat_inode;96 struct inode *fsinfo_inode;97 98 struct ratelimit_state ratelimit;99 100 spinlock_t inode_hash_lock;101 struct hlist_head inode_hashtable[FAT_HASH_SIZE];102 103 spinlock_t dir_hash_lock;104 struct hlist_head dir_hashtable[FAT_HASH_SIZE];105 106 unsigned int dirty; /* fs state before mount */107 struct rcu_head rcu;108};109 110#define FAT_CACHE_VALID 0 /* special case for valid cache */111 112/*113 * MS-DOS file system inode data in memory114 */115struct msdos_inode_info {116 spinlock_t cache_lru_lock;117 struct list_head cache_lru;118 int nr_caches;119 /* for avoiding the race between fat_free() and fat_get_cluster() */120 unsigned int cache_valid_id;121 122 /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */123 loff_t mmu_private; /* physically allocated size */124 125 int i_start; /* first cluster or 0 */126 int i_logstart; /* logical first cluster */127 int i_attrs; /* unused attribute bits */128 loff_t i_pos; /* on-disk position of directory entry or 0 */129 struct hlist_node i_fat_hash; /* hash by i_location */130 struct hlist_node i_dir_hash; /* hash by i_logstart */131 struct rw_semaphore truncate_lock; /* protect bmap against truncate */132 struct timespec64 i_crtime; /* File creation (birth) time */133 struct inode vfs_inode;134};135 136struct fat_slot_info {137 loff_t i_pos; /* on-disk position of directory entry */138 loff_t slot_off; /* offset for slot or de start */139 int nr_slots; /* number of slots + 1(de) in filename */140 struct msdos_dir_entry *de;141 struct buffer_head *bh;142};143 144static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)145{146 return sb->s_fs_info;147}148 149/*150 * Functions that determine the variant of the FAT file system (i.e.,151 * whether this is FAT12, FAT16 or FAT32.152 */153static inline bool is_fat12(const struct msdos_sb_info *sbi)154{155 return sbi->fat_bits == 12;156}157 158static inline bool is_fat16(const struct msdos_sb_info *sbi)159{160 return sbi->fat_bits == 16;161}162 163static inline bool is_fat32(const struct msdos_sb_info *sbi)164{165 return sbi->fat_bits == 32;166}167 168/* Maximum number of clusters */169static inline u32 max_fat(struct super_block *sb)170{171 struct msdos_sb_info *sbi = MSDOS_SB(sb);172 173 return is_fat32(sbi) ? MAX_FAT32 :174 is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;175}176 177static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)178{179 return container_of(inode, struct msdos_inode_info, vfs_inode);180}181 182/*183 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to184 * save ATTR_RO instead of ->i_mode.185 *186 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only187 * bit, it's just used as flag for app.188 */189static inline int fat_mode_can_hold_ro(struct inode *inode)190{191 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);192 umode_t mask;193 194 if (S_ISDIR(inode->i_mode)) {195 if (!sbi->options.rodir)196 return 0;197 mask = ~sbi->options.fs_dmask;198 } else199 mask = ~sbi->options.fs_fmask;200 201 if (!(mask & S_IWUGO))202 return 0;203 return 1;204}205 206/* Convert attribute bits and a mask to the UNIX mode. */207static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,208 u8 attrs, umode_t mode)209{210 if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))211 mode &= ~S_IWUGO;212 213 if (attrs & ATTR_DIR)214 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;215 else216 return (mode & ~sbi->options.fs_fmask) | S_IFREG;217}218 219/* Return the FAT attribute byte for this inode */220static inline u8 fat_make_attrs(struct inode *inode)221{222 u8 attrs = MSDOS_I(inode)->i_attrs;223 if (S_ISDIR(inode->i_mode))224 attrs |= ATTR_DIR;225 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))226 attrs |= ATTR_RO;227 return attrs;228}229 230static inline void fat_save_attrs(struct inode *inode, u8 attrs)231{232 if (fat_mode_can_hold_ro(inode))233 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;234 else235 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);236}237 238static inline unsigned char fat_checksum(const __u8 *name)239{240 unsigned char s = name[0];241 s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2];242 s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4];243 s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6];244 s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8];245 s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10];246 return s;247}248 249static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)250{251 return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus252 + sbi->data_start;253}254 255static inline void fat_get_blknr_offset(struct msdos_sb_info *sbi,256 loff_t i_pos, sector_t *blknr, int *offset)257{258 *blknr = i_pos >> sbi->dir_per_block_bits;259 *offset = i_pos & (sbi->dir_per_block - 1);260}261 262static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,263 struct inode *inode)264{265 loff_t i_pos;266#if BITS_PER_LONG == 32267 spin_lock(&sbi->inode_hash_lock);268#endif269 i_pos = MSDOS_I(inode)->i_pos;270#if BITS_PER_LONG == 32271 spin_unlock(&sbi->inode_hash_lock);272#endif273 return i_pos;274}275 276static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)277{278#ifdef __BIG_ENDIAN279 while (len--) {280 *dst++ = src[0] | (src[1] << 8);281 src += 2;282 }283#else284 memcpy(dst, src, len * 2);285#endif286}287 288static inline int fat_get_start(const struct msdos_sb_info *sbi,289 const struct msdos_dir_entry *de)290{291 int cluster = le16_to_cpu(de->start);292 if (is_fat32(sbi))293 cluster |= (le16_to_cpu(de->starthi) << 16);294 return cluster;295}296 297static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)298{299 de->start = cpu_to_le16(cluster);300 de->starthi = cpu_to_le16(cluster >> 16);301}302 303static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)304{305#ifdef __BIG_ENDIAN306 while (len--) {307 dst[0] = *src & 0x00FF;308 dst[1] = (*src & 0xFF00) >> 8;309 dst += 2;310 src++;311 }312#else313 memcpy(dst, src, len * 2);314#endif315}316 317/* fat/cache.c */318extern void fat_cache_inval_inode(struct inode *inode);319extern int fat_get_cluster(struct inode *inode, int cluster,320 int *fclus, int *dclus);321extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,322 sector_t last_block,323 unsigned long *mapped_blocks, sector_t *bmap);324extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,325 unsigned long *mapped_blocks, int create, bool from_bmap);326 327/* fat/dir.c */328extern const struct file_operations fat_dir_operations;329extern int fat_search_long(struct inode *inode, const unsigned char *name,330 int name_len, struct fat_slot_info *sinfo);331extern int fat_dir_empty(struct inode *dir);332extern int fat_subdirs(struct inode *dir);333extern int fat_scan(struct inode *dir, const unsigned char *name,334 struct fat_slot_info *sinfo);335extern int fat_scan_logstart(struct inode *dir, int i_logstart,336 struct fat_slot_info *sinfo);337extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,338 struct msdos_dir_entry **de);339extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);340extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,341 struct fat_slot_info *sinfo);342extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);343 344/* fat/fatent.c */345struct fat_entry {346 int entry;347 union {348 u8 *ent12_p[2];349 __le16 *ent16_p;350 __le32 *ent32_p;351 } u;352 int nr_bhs;353 struct buffer_head *bhs[2];354 struct inode *fat_inode;355};356 357static inline void fatent_init(struct fat_entry *fatent)358{359 fatent->nr_bhs = 0;360 fatent->entry = 0;361 fatent->u.ent32_p = NULL;362 fatent->bhs[0] = fatent->bhs[1] = NULL;363 fatent->fat_inode = NULL;364}365 366static inline void fatent_set_entry(struct fat_entry *fatent, int entry)367{368 fatent->entry = entry;369 fatent->u.ent32_p = NULL;370}371 372static inline void fatent_brelse(struct fat_entry *fatent)373{374 int i;375 fatent->u.ent32_p = NULL;376 for (i = 0; i < fatent->nr_bhs; i++)377 brelse(fatent->bhs[i]);378 fatent->nr_bhs = 0;379 fatent->bhs[0] = fatent->bhs[1] = NULL;380 fatent->fat_inode = NULL;381}382 383static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)384{385 return FAT_START_ENT <= entry && entry < sbi->max_cluster;386}387 388extern void fat_ent_access_init(struct super_block *sb);389extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,390 int entry);391extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,392 int new, int wait);393extern int fat_alloc_clusters(struct inode *inode, int *cluster,394 int nr_cluster);395extern int fat_free_clusters(struct inode *inode, int cluster);396extern int fat_count_free_clusters(struct super_block *sb);397extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);398 399/* fat/file.c */400extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,401 unsigned long arg);402extern const struct file_operations fat_file_operations;403extern const struct inode_operations fat_file_inode_operations;404extern int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,405 struct iattr *attr);406extern void fat_truncate_blocks(struct inode *inode, loff_t offset);407extern int fat_getattr(struct mnt_idmap *idmap,408 const struct path *path, struct kstat *stat,409 u32 request_mask, unsigned int flags);410extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,411 int datasync);412 413/* fat/inode.c */414extern int fat_block_truncate_page(struct inode *inode, loff_t from);415extern void fat_attach(struct inode *inode, loff_t i_pos);416extern void fat_detach(struct inode *inode);417extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);418extern struct inode *fat_build_inode(struct super_block *sb,419 struct msdos_dir_entry *de, loff_t i_pos);420extern int fat_sync_inode(struct inode *inode);421extern int fat_fill_super(struct super_block *sb, struct fs_context *fc,422 void (*setup)(struct super_block *));423extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);424 425extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,426 struct inode *i2);427 428extern const struct fs_parameter_spec fat_param_spec[];429int fat_init_fs_context(struct fs_context *fc, bool is_vfat);430void fat_free_fc(struct fs_context *fc);431 432int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,433 bool is_vfat);434int fat_reconfigure(struct fs_context *fc);435 436static inline unsigned long fat_dir_hash(int logstart)437{438 return hash_32(logstart, FAT_HASH_BITS);439}440extern int fat_add_cluster(struct inode *inode);441 442/* fat/misc.c */443extern __printf(3, 4) __cold444void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);445#define fat_fs_error(sb, fmt, args...) \446 __fat_fs_error(sb, 1, fmt , ## args)447#define fat_fs_error_ratelimit(sb, fmt, args...) \448 __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)449 450#define FAT_PRINTK_PREFIX "%sFAT-fs (%s): "451#define fat_msg(sb, level, fmt, args...) \452do { \453 printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\454 _fat_msg(sb, level, fmt, ##args); \455} while (0)456__printf(3, 4) __cold457void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);458#define fat_msg_ratelimit(sb, level, fmt, args...) \459 do { \460 if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \461 fat_msg(sb, level, fmt, ## args); \462 } while (0)463extern int fat_clusters_flush(struct super_block *sb);464extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);465extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,466 __le16 __time, __le16 __date, u8 time_cs);467extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,468 __le16 *time, __le16 *date, u8 *time_cs);469extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,470 const struct timespec64 *ts);471extern struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi,472 const struct timespec64 *ts);473extern int fat_truncate_time(struct inode *inode, struct timespec64 *now,474 int flags);475extern int fat_update_time(struct inode *inode, int flags);476extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);477 478int fat_cache_init(void);479void fat_cache_destroy(void);480 481/* fat/nfs.c */482extern const struct export_operations fat_export_ops;483extern const struct export_operations fat_export_ops_nostale;484 485/* helper for printk */486typedef unsigned long long llu;487 488#endif /* !_FAT_H */489