summaryrefslogtreecommitdiff
path: root/fs/fat/fat.h
blob: e3b690b48e3eb1ea7ffc5b36e6f00600da0aad66 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FAT_H
#define _FAT_H

#include <linux/buffer_head.h>
#include <linux/nls.h>
#include <linux/hash.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 */

#define FAT_NFS_STALE_RW	1      /* NFS RW support, can cause ESTALE */
#define FAT_NFS_NOSTALE_RO	2      /* NFS RO support, no ESTALE issue */

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 */
	int time_offset;	   /* Offset of timestamps from UTC (in minutes) */
	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 char nfs;	  /* NFS support: nostale_ro, stale_rw */
	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_set:1,	   /* Filesystem timestamps' offset set */
		 rodir:1,	   /* allow ATTR_RO for directory */
		 discard:1,	   /* Issue discard requests on deletions */
		 dos1xfloppy:1;	   /* Assume default BPB for DOS 1.x floppies */
};

#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 (12,16 or 32) */
	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 nfs_build_inode_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) */
	unsigned int vol_id;		/*volume ID*/

	int fatent_shift;
	const 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];

	unsigned int dirty;           /* fs state before mount */
	struct rcu_head rcu;
};

#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 timespec64 i_crtime;	/* File creation (birth) time */
	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;
}

/*
 * Functions that determine the variant of the FAT file system (i.e.,
 * whether this is FAT12, FAT16 or FAT32.
 */
static inline bool is_fat12(const struct msdos_sb_info *sbi)
{
	return sbi->fat_bits == 12;
}

static inline bool is_fat16(const struct msdos_sb_info *sbi)
{
	return sbi->fat_bits == 16;
}

static inline bool is_fat32(const struct msdos_sb_info *sbi)
{
	return sbi->fat_bits == 32;
}

/* Maximum number of clusters */
static inline u32 max_fat(struct super_block *sb)
{
	struct msdos_sb_info *sbi = MSDOS_SB(sb);

	return is_fat32(sbi) ? MAX_FAT32 :
		is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
}

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 fat_get_blknr_offset(struct msdos_sb_info *sbi,
				loff_t i_pos, sector_t *blknr, int *offset)
{
	*blknr = i_pos >> sbi->dir_per_block_bits;
	*offset = i_pos & (sbi->dir_per_block - 1);
}

static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
					struct inode *inode)
{
	loff_t i_pos;
#if BITS_PER_LONG == 32
	spin_lock(&sbi->inode_hash_lock);
#endif
	i_pos = MSDOS_I(inode)->i_pos;
#if BITS_PER_LONG == 32
	spin_unlock(&sbi->inode_hash_lock);
#endif
	return i_pos;
}

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 (is_fat32(sbi))
		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_get_mapped_cluster(struct inode *inode, sector_t sector,
				  sector_t last_block,
				  unsigned long *mapped_blocks, sector_t *bmap);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
		    unsigned long *mapped_blocks, int create, bool from_bmap);

/* 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_scan_logstart(struct inode *dir, int i_logstart,
			     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 timespec64 *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;
}

static inline bool fat_valid_entry(struct msdos_sb_info *sbi, int entry)
{
	return FAT_START_ENT <= entry && entry < sbi->max_cluster;
}

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);
extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range);

/* 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 mnt_idmap *idmap, struct dentry *dentry,
		       struct iattr *attr);
extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
extern int fat_getattr(struct mnt_idmap *idmap,
		       const struct path *path, struct kstat *stat,
		       u32 request_mask, unsigned int flags);
extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
			  int datasync);

/* fat/inode.c */
extern int fat_block_truncate_page(struct inode *inode, loff_t from);
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_fill_inode(struct inode *inode, struct msdos_dir_entry *de);

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);
}
extern int fat_add_cluster(struct inode *inode);

/* 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)

#define FAT_PRINTK_PREFIX "%sFAT-fs (%s): "
#define fat_msg(sb, level, fmt, args...)				\
do {									\
	printk_index_subsys_emit(FAT_PRINTK_PREFIX, level, fmt, ##args);\
	_fat_msg(sb, level, fmt, ##args);				\
} while (0)
__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 timespec64 *ts,
			      __le16 __time, __le16 __date, u8 time_cs);
extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
			      __le16 *time, __le16 *date, u8 *time_cs);
extern struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,
					    const struct timespec64 *ts);
extern struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi,
					    const struct timespec64 *ts);
extern int fat_truncate_time(struct inode *inode, struct timespec64 *now,
			     int flags);
extern int fat_update_time(struct inode *inode, struct timespec64 *now,
			   int flags);
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 */
extern const struct export_operations fat_export_ops;
extern const struct export_operations fat_export_ops_nostale;

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

#endif /* !_FAT_H */