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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#include <linux/fs_context.h>
11#include <linux/fs_parser.h>
12
13struct file_kattr;
14
15/*
16 * vfat shortname flags
17 */
18#define VFAT_SFN_DISPLAY_LOWER 0x0001 /* convert to lowercase for display */
19#define VFAT_SFN_DISPLAY_WIN95 0x0002 /* emulate win95 rule for display */
20#define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */
21#define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */
22#define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */
23
24#define FAT_ERRORS_CONT 1 /* ignore error and continue */
25#define FAT_ERRORS_PANIC 2 /* panic on error */
26#define FAT_ERRORS_RO 3 /* remount r/o on error */
27
28#define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */
29#define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */
30
31struct fat_mount_options {
32 kuid_t fs_uid;
33 kgid_t fs_gid;
34 unsigned short fs_fmask;
35 unsigned short fs_dmask;
36 unsigned short codepage; /* Codepage for shortname conversions */
37 int time_offset; /* Offset of timestamps from UTC (in minutes) */
38 char *iocharset; /* Charset used for filename input/display */
39 unsigned short shortname; /* flags for shortname display/create rule */
40 unsigned char name_check; /* r = relaxed, n = normal, s = strict */
41 unsigned char errors; /* On error: continue, panic, remount-ro */
42 unsigned char nfs; /* NFS support: nostale_ro, stale_rw */
43 unsigned short allow_utime;/* permission for setting the [am]time */
44 unsigned quiet:1, /* set = fake successful chmods and chowns */
45 showexec:1, /* set = only set x bit for com/exe/bat */
46 sys_immutable:1, /* set = system files are immutable */
47 dotsOK:1, /* set = hidden and system files are named '.filename' */
48 isvfat:1, /* 0=no vfat long filename support, 1=vfat support */
49 utf8:1, /* Use of UTF-8 character set (Default) */
50 unicode_xlate:1, /* create escape sequences for unhandled Unicode */
51 numtail:1, /* Does first alias have a numeric '~1' type tail? */
52 flush:1, /* write things quickly */
53 nocase:1, /* Does this need case conversion? 0=need case conversion*/
54 usefree:1, /* Use free_clusters for FAT32 */
55 tz_set:1, /* Filesystem timestamps' offset set */
56 rodir:1, /* allow ATTR_RO for directory */
57 discard:1, /* Issue discard requests on deletions */
58 dos1xfloppy:1, /* Assume default BPB for DOS 1.x floppies */
59 debug:1; /* Not currently used */
60};
61
62#define FAT_HASH_BITS 8
63#define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)
64
65/*
66 * MS-DOS file system in-core superblock data
67 */
68struct msdos_sb_info {
69 unsigned short sec_per_clus; /* sectors/cluster */
70 unsigned short cluster_bits; /* log2(cluster_size) */
71 unsigned int cluster_size; /* cluster size */
72 unsigned char fats, fat_bits; /* number of FATs, FAT bits (12,16 or 32) */
73 unsigned short fat_start;
74 unsigned long fat_length; /* FAT start & length (sec.) */
75 unsigned long dir_start;
76 unsigned short dir_entries; /* root dir start & entries */
77 unsigned long data_start; /* first data sector */
78 unsigned long max_cluster; /* maximum cluster number */
79 unsigned long root_cluster; /* first cluster of the root directory */
80 unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
81 struct mutex fat_lock;
82 struct mutex nfs_build_inode_lock;
83 struct mutex s_lock;
84 unsigned int prev_free; /* previously allocated cluster number */
85 unsigned int free_clusters; /* -1 if undefined */
86 unsigned int free_clus_valid; /* is free_clusters valid? */
87 struct fat_mount_options options;
88 struct nls_table *nls_disk; /* Codepage used on disk */
89 struct nls_table *nls_io; /* Charset used for input and display */
90 const void *dir_ops; /* Opaque; default directory operations */
91 int dir_per_block; /* dir entries per block */
92 int dir_per_block_bits; /* log2(dir_per_block) */
93 unsigned int vol_id; /*volume ID*/
94
95 int fatent_shift;
96 const struct fatent_operations *fatent_ops;
97 struct inode *fat_inode;
98 struct inode *fsinfo_inode;
99
100 struct ratelimit_state ratelimit;
101
102 spinlock_t inode_hash_lock;
103 struct hlist_head inode_hashtable[FAT_HASH_SIZE];
104
105 spinlock_t dir_hash_lock;
106 struct hlist_head dir_hashtable[FAT_HASH_SIZE];
107
108 unsigned int dirty; /* fs state before mount */
109 struct rcu_head rcu;
110};
111
112#define FAT_CACHE_VALID 0 /* special case for valid cache */
113
114/*
115 * MS-DOS file system inode data in memory
116 */
117struct msdos_inode_info {
118 spinlock_t cache_lru_lock;
119 struct list_head cache_lru;
120 int nr_caches;
121 /* for avoiding the race between fat_free() and fat_get_cluster() */
122 unsigned int cache_valid_id;
123
124 /* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
125 loff_t mmu_private; /* physically allocated size */
126
127 int i_start; /* first cluster or 0 */
128 int i_logstart; /* logical first cluster */
129 int i_attrs; /* unused attribute bits */
130 loff_t i_pos; /* on-disk position of directory entry or 0 */
131 struct hlist_node i_fat_hash; /* hash by i_location */
132 struct hlist_node i_dir_hash; /* hash by i_logstart */
133 struct rw_semaphore truncate_lock; /* protect bmap against truncate */
134 struct timespec64 i_crtime; /* File creation (birth) time */
135 struct mapping_metadata_bhs i_metadata_bhs;
136 struct inode vfs_inode;
137};
138
139struct fat_slot_info {
140 loff_t i_pos; /* on-disk position of directory entry */
141 loff_t slot_off; /* offset for slot or de start */
142 int nr_slots; /* number of slots + 1(de) in filename */
143 struct msdos_dir_entry *de;
144 struct buffer_head *bh;
145};
146
147static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
148{
149 return sb->s_fs_info;
150}
151
152/*
153 * Functions that determine the variant of the FAT file system (i.e.,
154 * whether this is FAT12, FAT16 or FAT32.
155 */
156static inline bool is_fat12(const struct msdos_sb_info *sbi)
157{
158 return sbi->fat_bits == 12;
159}
160
161static inline bool is_fat16(const struct msdos_sb_info *sbi)
162{
163 return sbi->fat_bits == 16;
164}
165
166static inline bool is_fat32(const struct msdos_sb_info *sbi)
167{
168 return sbi->fat_bits == 32;
169}
170
171/* Maximum number of clusters */
172static inline u32 max_fat(struct super_block *sb)
173{
174 struct msdos_sb_info *sbi = MSDOS_SB(sb);
175
176 return is_fat32(sbi) ? MAX_FAT32 :
177 is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
178}
179
180static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
181{
182 return container_of(inode, struct msdos_inode_info, vfs_inode);
183}
184
185/*
186 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
187 * save ATTR_RO instead of ->i_mode.
188 *
189 * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
190 * bit, it's just used as flag for app.
191 */
192static inline int fat_mode_can_hold_ro(struct inode *inode)
193{
194 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
195 umode_t mask;
196
197 if (S_ISDIR(inode->i_mode)) {
198 if (!sbi->options.rodir)
199 return 0;
200 mask = ~sbi->options.fs_dmask;
201 } else
202 mask = ~sbi->options.fs_fmask;
203
204 if (!(mask & S_IWUGO))
205 return 0;
206 return 1;
207}
208
209/* Convert attribute bits and a mask to the UNIX mode. */
210static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
211 u8 attrs, umode_t mode)
212{
213 if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
214 mode &= ~S_IWUGO;
215
216 if (attrs & ATTR_DIR)
217 return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
218 else
219 return (mode & ~sbi->options.fs_fmask) | S_IFREG;
220}
221
222/* Return the FAT attribute byte for this inode */
223static inline u8 fat_make_attrs(struct inode *inode)
224{
225 u8 attrs = MSDOS_I(inode)->i_attrs;
226 if (S_ISDIR(inode->i_mode))
227 attrs |= ATTR_DIR;
228 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
229 attrs |= ATTR_RO;
230 return attrs;
231}
232
233static inline void fat_save_attrs(struct inode *inode, u8 attrs)
234{
235 if (fat_mode_can_hold_ro(inode))
236 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
237 else
238 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
239}
240
241static inline unsigned char fat_checksum(const __u8 *name)
242{
243 unsigned char s = name[0];
244 s = (s<<7) + (s>>1) + name[1]; s = (s<<7) + (s>>1) + name[2];
245 s = (s<<7) + (s>>1) + name[3]; s = (s<<7) + (s>>1) + name[4];
246 s = (s<<7) + (s>>1) + name[5]; s = (s<<7) + (s>>1) + name[6];
247 s = (s<<7) + (s>>1) + name[7]; s = (s<<7) + (s>>1) + name[8];
248 s = (s<<7) + (s>>1) + name[9]; s = (s<<7) + (s>>1) + name[10];
249 return s;
250}
251
252static inline sector_t fat_clus_to_blknr(const struct msdos_sb_info *sbi, int clus)
253{
254 return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
255 + sbi->data_start;
256}
257
258static inline void fat_get_blknr_offset(const struct msdos_sb_info *sbi,
259 loff_t i_pos, sector_t *blknr, int *offset)
260{
261 *blknr = i_pos >> sbi->dir_per_block_bits;
262 *offset = i_pos & (sbi->dir_per_block - 1);
263}
264
265static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
266 struct inode *inode)
267{
268 loff_t i_pos;
269#if BITS_PER_LONG == 32
270 spin_lock(&sbi->inode_hash_lock);
271#endif
272 i_pos = MSDOS_I(inode)->i_pos;
273#if BITS_PER_LONG == 32
274 spin_unlock(&sbi->inode_hash_lock);
275#endif
276 return i_pos;
277}
278
279static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
280{
281#ifdef __BIG_ENDIAN
282 while (len--) {
283 *dst++ = src[0] | (src[1] << 8);
284 src += 2;
285 }
286#else
287 memcpy(dst, src, len * 2);
288#endif
289}
290
291static inline int fat_get_start(const struct msdos_sb_info *sbi,
292 const struct msdos_dir_entry *de)
293{
294 int cluster = le16_to_cpu(de->start);
295 if (is_fat32(sbi))
296 cluster |= (le16_to_cpu(de->starthi) << 16);
297 return cluster;
298}
299
300static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
301{
302 de->start = cpu_to_le16(cluster);
303 de->starthi = cpu_to_le16(cluster >> 16);
304}
305
306static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
307{
308#ifdef __BIG_ENDIAN
309 while (len--) {
310 dst[0] = *src & 0x00FF;
311 dst[1] = (*src & 0xFF00) >> 8;
312 dst += 2;
313 src++;
314 }
315#else
316 memcpy(dst, src, len * 2);
317#endif
318}
319
320/* fat/cache.c */
321extern void fat_cache_inval_inode(struct inode *inode);
322extern int fat_get_cluster(struct inode *inode, int cluster,
323 int *fclus, int *dclus);
324extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
325 sector_t last_block,
326 unsigned long *mapped_blocks, sector_t *bmap);
327extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
328 unsigned long *mapped_blocks, int create, bool from_bmap);
329
330/* fat/dir.c */
331extern const struct file_operations fat_dir_operations;
332extern int fat_search_long(struct inode *inode, const unsigned char *name,
333 int name_len, struct fat_slot_info *sinfo);
334extern int fat_dir_empty(struct inode *dir);
335extern int fat_subdirs(struct inode *dir);
336extern int fat_scan(struct inode *dir, const unsigned char *name,
337 struct fat_slot_info *sinfo);
338extern int fat_scan_logstart(struct inode *dir, int i_logstart,
339 struct fat_slot_info *sinfo);
340extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
341 struct msdos_dir_entry **de);
342extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
343extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
344 struct fat_slot_info *sinfo);
345extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
346
347/* fat/fatent.c */
348struct fat_entry {
349 int entry;
350 union {
351 u8 *ent12_p[2];
352 __le16 *ent16_p;
353 __le32 *ent32_p;
354 } u;
355 int nr_bhs;
356 struct buffer_head *bhs[2];
357 struct inode *fat_inode;
358};
359
360static inline void fatent_init(struct fat_entry *fatent)
361{
362 fatent->nr_bhs = 0;
363 fatent->entry = 0;
364 fatent->u.ent32_p = NULL;
365 fatent->bhs[0] = fatent->bhs[1] = NULL;
366 fatent->fat_inode = NULL;
367}
368
369static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
370{
371 fatent->entry = entry;
372 fatent->u.ent32_p = NULL;
373}
374
375static inline void fatent_brelse(struct fat_entry *fatent)
376{
377 int i;
378 fatent->u.ent32_p = NULL;
379 for (i = 0; i < fatent->nr_bhs; i++)
380 brelse(fatent->bhs[i]);
381 fatent->nr_bhs = 0;
382 fatent->bhs[0] = fatent->bhs[1] = NULL;
383 fatent->fat_inode = NULL;
384}
385
386static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)
387{
388 return FAT_START_ENT <= entry && entry < sbi->max_cluster;
389}
390
391extern void fat_ent_access_init(struct super_block *sb);
392extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
393 int entry);
394extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
395 int new, int wait);
396extern int fat_alloc_clusters(struct inode *inode, int *cluster,
397 int nr_cluster);
398extern int fat_free_clusters(struct inode *inode, int cluster);
399extern int fat_count_free_clusters(struct super_block *sb);
400extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);
401
402/* fat/file.c */
403extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
404 unsigned long arg);
405extern const struct file_operations fat_file_operations;
406extern const struct inode_operations fat_file_inode_operations;
407extern int fat_setattr(const struct mnt_idmap *idmap, struct dentry *dentry,
408 struct iattr *attr);
409extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
410extern int fat_getattr(const struct mnt_idmap *idmap,
411 const struct path *path, struct kstat *stat,
412 u32 request_mask, unsigned int flags);
413int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
414extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
415 int datasync);
416
417/* fat/inode.c */
418extern int fat_block_truncate_page(struct inode *inode, loff_t from);
419extern void fat_attach(struct inode *inode, loff_t i_pos);
420extern void fat_detach(struct inode *inode);
421extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
422extern struct inode *fat_build_inode(struct super_block *sb,
423 struct msdos_dir_entry *de, loff_t i_pos);
424extern int fat_fill_super(struct super_block *sb, struct fs_context *fc,
425 void (*setup)(struct super_block *));
426extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
427
428extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
429 struct inode *i2);
430
431extern const struct fs_parameter_spec fat_param_spec[];
432int fat_init_fs_context(struct fs_context *fc, bool is_vfat);
433void fat_free_fc(struct fs_context *fc);
434
435int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,
436 bool is_vfat);
437int fat_reconfigure(struct fs_context *fc);
438
439static inline unsigned long fat_dir_hash(int logstart)
440{
441 return hash_32(logstart, FAT_HASH_BITS);
442}
443extern int fat_add_cluster(struct inode *inode);
444
445/* fat/misc.c */
446extern __printf(3, 4) __cold
447void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
448#define fat_fs_error(sb, fmt, args...) \
449 __fat_fs_error(sb, 1, fmt , ## args)
450#define fat_fs_error_ratelimit(sb, fmt, args...) \
451 __fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
452
453#define FAT_PRINTK_PREFIX "%sFAT-fs (%s): "
454#define fat_msg(sb, level, fmt, args...) \
455do { \
456 printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\
457 _fat_msg(sb, level, fmt, ##args); \
458} while (0)
459__printf(3, 4) __cold
460void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
461#define fat_msg_ratelimit(sb, level, fmt, args...) \
462 do { \
463 if (__ratelimit(&MSDOS_SB(sb)->ratelimit)) \
464 fat_msg(sb, level, fmt, ## args); \
465 } while (0)
466extern int fat_clusters_flush(struct super_block *sb);
467extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
468extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
469 __le16 __time, __le16 __date, u8 time_cs);
470extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
471 __le16 *time, __le16 *date, u8 *time_cs);
472extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,
473 const struct timespec64 *ts);
474#define FAT_UPDATE_ATIME (1u << 0)
475#define FAT_UPDATE_CMTIME (1u << 1)
476void fat_truncate_time(struct inode *inode, struct timespec64 *now,
477 unsigned int flags);
478int fat_update_time(struct inode *inode, enum fs_update_time type,
479 unsigned int flags);
480extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
481
482int fat_cache_init(void);
483void fat_cache_destroy(void);
484
485/* fat/nfs.c */
486extern const struct export_operations fat_export_ops;
487extern const struct export_operations fat_export_ops_nostale;
488
489/* helper for printk */
490typedef unsigned long long llu;
491
492#endif /* !_FAT_H */