xref: /linux/fs/exfat/exfat_fs.h (revision 962fad301c33dec69324dc2d9320fd84a119a24c)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4  */
5 
6 #ifndef _EXFAT_FS_H
7 #define _EXFAT_FS_H
8 
9 #include <linux/fs.h>
10 #include <linux/ratelimit.h>
11 #include <linux/nls.h>
12 
13 #define EXFAT_SUPER_MAGIC       0x2011BAB0UL
14 #define EXFAT_ROOT_INO		1
15 
16 #define EXFAT_CLUSTERS_UNTRACKED (~0u)
17 
18 /*
19  * exfat error flags
20  */
21 enum exfat_error_mode {
22 	EXFAT_ERRORS_CONT,	/* ignore error and continue */
23 	EXFAT_ERRORS_PANIC,	/* panic on error */
24 	EXFAT_ERRORS_RO,	/* remount r/o on error */
25 };
26 
27 /*
28  * exfat nls lossy flag
29  */
30 enum {
31 	NLS_NAME_NO_LOSSY,	/* no lossy */
32 	NLS_NAME_LOSSY,		/* just detected incorrect filename(s) */
33 	NLS_NAME_OVERLEN,	/* the length is over than its limit */
34 };
35 
36 #define EXFAT_HASH_BITS		8
37 #define EXFAT_HASH_SIZE		(1UL << EXFAT_HASH_BITS)
38 
39 /*
40  * Type Definitions
41  */
42 #define ES_2_ENTRIES		2
43 #define ES_ALL_ENTRIES		0
44 
45 #define DIR_DELETED		0xFFFF0321
46 
47 /* type values */
48 #define TYPE_UNUSED		0x0000
49 #define TYPE_DELETED		0x0001
50 #define TYPE_INVALID		0x0002
51 #define TYPE_CRITICAL_PRI	0x0100
52 #define TYPE_BITMAP		0x0101
53 #define TYPE_UPCASE		0x0102
54 #define TYPE_VOLUME		0x0103
55 #define TYPE_DIR		0x0104
56 #define TYPE_FILE		0x011F
57 #define TYPE_CRITICAL_SEC	0x0200
58 #define TYPE_STREAM		0x0201
59 #define TYPE_EXTEND		0x0202
60 #define TYPE_ACL		0x0203
61 #define TYPE_BENIGN_PRI		0x0400
62 #define TYPE_GUID		0x0401
63 #define TYPE_PADDING		0x0402
64 #define TYPE_ACLTAB		0x0403
65 #define TYPE_BENIGN_SEC		0x0800
66 #define TYPE_ALL		0x0FFF
67 
68 #define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
69 #define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
70 #define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
71 
72 /* Enough size to hold 256 dentry (even 512 Byte sector) */
73 #define DIR_CACHE_SIZE		(256*sizeof(struct exfat_dentry)/512+1)
74 
75 #define EXFAT_HINT_NONE		-1
76 #define EXFAT_MIN_SUBDIR	2
77 
78 /*
79  * helpers for cluster size to byte conversion.
80  */
81 #define EXFAT_CLU_TO_B(b, sbi)		((b) << (sbi)->cluster_size_bits)
82 #define EXFAT_B_TO_CLU(b, sbi)		((b) >> (sbi)->cluster_size_bits)
83 #define EXFAT_B_TO_CLU_ROUND_UP(b, sbi)	\
84 	(((b - 1) >> (sbi)->cluster_size_bits) + 1)
85 #define EXFAT_CLU_OFFSET(off, sbi)	((off) & ((sbi)->cluster_size - 1))
86 
87 /*
88  * helpers for block size to byte conversion.
89  */
90 #define EXFAT_BLK_TO_B(b, sb)		((b) << (sb)->s_blocksize_bits)
91 #define EXFAT_B_TO_BLK(b, sb)		((b) >> (sb)->s_blocksize_bits)
92 #define EXFAT_B_TO_BLK_ROUND_UP(b, sb)	\
93 	(((b - 1) >> (sb)->s_blocksize_bits) + 1)
94 #define EXFAT_BLK_OFFSET(off, sb)	((off) & ((sb)->s_blocksize - 1))
95 
96 /*
97  * helpers for block size to dentry size conversion.
98  */
99 #define EXFAT_B_TO_DEN_IDX(b, sbi)	\
100 	((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
101 #define EXFAT_B_TO_DEN(b)		((b) >> DENTRY_SIZE_BITS)
102 #define EXFAT_DEN_TO_B(b)		((b) << DENTRY_SIZE_BITS)
103 
104 /*
105  * helpers for fat entry.
106  */
107 #define FAT_ENT_SIZE (4)
108 #define FAT_ENT_SIZE_BITS (2)
109 #define FAT_ENT_OFFSET_SECTOR(sb, loc) (EXFAT_SB(sb)->FAT1_start_sector + \
110 	(((u64)loc << FAT_ENT_SIZE_BITS) >> sb->s_blocksize_bits))
111 #define FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc)	\
112 	((loc << FAT_ENT_SIZE_BITS) & (sb->s_blocksize - 1))
113 
114 /*
115  * helpers for bitmap.
116  */
117 #define CLUSTER_TO_BITMAP_ENT(clu) ((clu) - EXFAT_RESERVED_CLUSTERS)
118 #define BITMAP_ENT_TO_CLUSTER(ent) ((ent) + EXFAT_RESERVED_CLUSTERS)
119 #define BITS_PER_SECTOR(sb) ((sb)->s_blocksize * BITS_PER_BYTE)
120 #define BITS_PER_SECTOR_MASK(sb) (BITS_PER_SECTOR(sb) - 1)
121 #define BITMAP_OFFSET_SECTOR_INDEX(sb, ent) \
122 	((ent / BITS_PER_BYTE) >> (sb)->s_blocksize_bits)
123 #define BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent) (ent & BITS_PER_SECTOR_MASK(sb))
124 #define BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent) \
125 	((ent / BITS_PER_BYTE) & ((sb)->s_blocksize - 1))
126 #define BITS_PER_BYTE_MASK	0x7
127 #define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1)
128 
129 struct exfat_dentry_namebuf {
130 	char *lfn;
131 	int lfnbuf_len; /* usally MAX_UNINAME_BUF_SIZE */
132 };
133 
134 /* unicode name structure */
135 struct exfat_uni_name {
136 	/* +3 for null and for converting */
137 	unsigned short name[MAX_NAME_LENGTH + 3];
138 	u16 name_hash;
139 	unsigned char name_len;
140 };
141 
142 /* directory structure */
143 struct exfat_chain {
144 	unsigned int dir;
145 	unsigned int size;
146 	unsigned char flags;
147 };
148 
149 /* first empty entry hint information */
150 struct exfat_hint_femp {
151 	/* entry index of a directory */
152 	int eidx;
153 	/* count of continuous empty entry */
154 	int count;
155 	/* the cluster that first empty slot exists in */
156 	struct exfat_chain cur;
157 };
158 
159 /* hint structure */
160 struct exfat_hint {
161 	unsigned int clu;
162 	union {
163 		unsigned int off; /* cluster offset */
164 		int eidx; /* entry index */
165 	};
166 };
167 
168 struct exfat_entry_set_cache {
169 	struct super_block *sb;
170 	bool modified;
171 	unsigned int start_off;
172 	int num_bh;
173 	struct buffer_head *bh[DIR_CACHE_SIZE];
174 	unsigned int num_entries;
175 };
176 
177 struct exfat_dir_entry {
178 	struct exfat_chain dir;
179 	int entry;
180 	unsigned int type;
181 	unsigned int start_clu;
182 	unsigned char flags;
183 	unsigned short attr;
184 	loff_t size;
185 	unsigned int num_subdirs;
186 	struct timespec64 atime;
187 	struct timespec64 mtime;
188 	struct timespec64 crtime;
189 	struct exfat_dentry_namebuf namebuf;
190 };
191 
192 /*
193  * exfat mount in-memory data
194  */
195 struct exfat_mount_options {
196 	kuid_t fs_uid;
197 	kgid_t fs_gid;
198 	unsigned short fs_fmask;
199 	unsigned short fs_dmask;
200 	/* permission for setting the [am]time */
201 	unsigned short allow_utime;
202 	/* charset for filename input/display */
203 	char *iocharset;
204 	/* on error: continue, panic, remount-ro */
205 	enum exfat_error_mode errors;
206 	unsigned utf8:1, /* Use of UTF-8 character set */
207 		 discard:1; /* Issue discard requests on deletions */
208 	int time_offset; /* Offset of timestamps from UTC (in minutes) */
209 };
210 
211 /*
212  * EXFAT file system superblock in-memory data
213  */
214 struct exfat_sb_info {
215 	unsigned long long num_sectors; /* num of sectors in volume */
216 	unsigned int num_clusters; /* num of clusters in volume */
217 	unsigned int cluster_size; /* cluster size in bytes */
218 	unsigned int cluster_size_bits;
219 	unsigned int sect_per_clus; /* cluster size in sectors */
220 	unsigned int sect_per_clus_bits;
221 	unsigned long long FAT1_start_sector; /* FAT1 start sector */
222 	unsigned long long FAT2_start_sector; /* FAT2 start sector */
223 	unsigned long long data_start_sector; /* data area start sector */
224 	unsigned int num_FAT_sectors; /* num of FAT sectors */
225 	unsigned int root_dir; /* root dir cluster */
226 	unsigned int dentries_per_clu; /* num of dentries per cluster */
227 	unsigned int vol_flags; /* volume flags */
228 	unsigned int vol_flags_persistent; /* volume flags to retain */
229 	struct buffer_head *boot_bh; /* buffer_head of BOOT sector */
230 
231 	unsigned int map_clu; /* allocation bitmap start cluster */
232 	unsigned int map_sectors; /* num of allocation bitmap sectors */
233 	struct buffer_head **vol_amap; /* allocation bitmap */
234 
235 	unsigned short *vol_utbl; /* upcase table */
236 
237 	unsigned int clu_srch_ptr; /* cluster search pointer */
238 	unsigned int used_clusters; /* number of used clusters */
239 
240 	struct mutex s_lock; /* superblock lock */
241 	struct exfat_mount_options options;
242 	struct nls_table *nls_io; /* Charset used for input and display */
243 	struct ratelimit_state ratelimit;
244 
245 	spinlock_t inode_hash_lock;
246 	struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
247 
248 	struct rcu_head rcu;
249 };
250 
251 /*
252  * EXFAT file system inode in-memory data
253  */
254 struct exfat_inode_info {
255 	struct exfat_chain dir;
256 	int entry;
257 	unsigned int type;
258 	unsigned short attr;
259 	unsigned int start_clu;
260 	unsigned char flags;
261 	/*
262 	 * the copy of low 32bit of i_version to check
263 	 * the validation of hint_stat.
264 	 */
265 	unsigned int version;
266 	/* file offset or dentry index for readdir */
267 	loff_t rwoffset;
268 
269 	/* hint for cluster last accessed */
270 	struct exfat_hint hint_bmap;
271 	/* hint for entry index we try to lookup next time */
272 	struct exfat_hint hint_stat;
273 	/* hint for first empty entry */
274 	struct exfat_hint_femp hint_femp;
275 
276 	spinlock_t cache_lru_lock;
277 	struct list_head cache_lru;
278 	int nr_caches;
279 	/* for avoiding the race between alloc and free */
280 	unsigned int cache_valid_id;
281 
282 	/*
283 	 * NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
284 	 * physically allocated size.
285 	 */
286 	loff_t i_size_ondisk;
287 	/* block-aligned i_size (used in cont_write_begin) */
288 	loff_t i_size_aligned;
289 	/* on-disk position of directory entry or 0 */
290 	loff_t i_pos;
291 	/* hash by i_location */
292 	struct hlist_node i_hash_fat;
293 	/* protect bmap against truncate */
294 	struct rw_semaphore truncate_lock;
295 	struct inode vfs_inode;
296 	/* File creation time */
297 	struct timespec64 i_crtime;
298 };
299 
300 static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
301 {
302 	return sb->s_fs_info;
303 }
304 
305 static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
306 {
307 	return container_of(inode, struct exfat_inode_info, vfs_inode);
308 }
309 
310 /*
311  * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
312  * save ATTR_RO instead of ->i_mode.
313  *
314  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
315  * bit, it's just used as flag for app.
316  */
317 static inline int exfat_mode_can_hold_ro(struct inode *inode)
318 {
319 	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
320 
321 	if (S_ISDIR(inode->i_mode))
322 		return 0;
323 
324 	if ((~sbi->options.fs_fmask) & 0222)
325 		return 1;
326 	return 0;
327 }
328 
329 /* Convert attribute bits and a mask to the UNIX mode. */
330 static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
331 		unsigned short attr, mode_t mode)
332 {
333 	if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
334 		mode &= ~0222;
335 
336 	if (attr & ATTR_SUBDIR)
337 		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
338 
339 	return (mode & ~sbi->options.fs_fmask) | S_IFREG;
340 }
341 
342 /* Return the FAT attribute byte for this inode */
343 static inline unsigned short exfat_make_attr(struct inode *inode)
344 {
345 	unsigned short attr = EXFAT_I(inode)->attr;
346 
347 	if (S_ISDIR(inode->i_mode))
348 		attr |= ATTR_SUBDIR;
349 	if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
350 		attr |= ATTR_READONLY;
351 	return attr;
352 }
353 
354 static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
355 {
356 	if (exfat_mode_can_hold_ro(inode))
357 		EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
358 	else
359 		EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
360 }
361 
362 static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
363 		sector_t sec)
364 {
365 	return ((sec - sbi->data_start_sector + 1) &
366 		((1 << sbi->sect_per_clus_bits) - 1)) == 0;
367 }
368 
369 static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
370 		unsigned int clus)
371 {
372 	return ((sector_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +
373 		sbi->data_start_sector;
374 }
375 
376 static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
377 		sector_t sec)
378 {
379 	return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
380 		EXFAT_RESERVED_CLUSTERS;
381 }
382 
383 /* super.c */
384 int exfat_set_volume_dirty(struct super_block *sb);
385 int exfat_clear_volume_dirty(struct super_block *sb);
386 
387 /* fatent.c */
388 #define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
389 
390 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
391 		struct exfat_chain *p_chain);
392 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
393 int exfat_ent_get(struct super_block *sb, unsigned int loc,
394 		unsigned int *content);
395 int exfat_ent_set(struct super_block *sb, unsigned int loc,
396 		unsigned int content);
397 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
398 		int entry, struct exfat_dentry *p_entry);
399 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
400 		unsigned int len);
401 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
402 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
403 		unsigned int *ret_clu);
404 int exfat_count_num_clusters(struct super_block *sb,
405 		struct exfat_chain *p_chain, unsigned int *ret_count);
406 
407 /* balloc.c */
408 int exfat_load_bitmap(struct super_block *sb);
409 void exfat_free_bitmap(struct exfat_sb_info *sbi);
410 int exfat_set_bitmap(struct inode *inode, unsigned int clu);
411 void exfat_clear_bitmap(struct inode *inode, unsigned int clu);
412 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);
413 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
414 
415 /* file.c */
416 extern const struct file_operations exfat_file_operations;
417 int __exfat_truncate(struct inode *inode, loff_t new_size);
418 void exfat_truncate(struct inode *inode, loff_t size);
419 int exfat_setattr(struct dentry *dentry, struct iattr *attr);
420 int exfat_getattr(const struct path *path, struct kstat *stat,
421 		unsigned int request_mask, unsigned int query_flags);
422 int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
423 
424 /* namei.c */
425 extern const struct dentry_operations exfat_dentry_ops;
426 extern const struct dentry_operations exfat_utf8_dentry_ops;
427 
428 /* cache.c */
429 int exfat_cache_init(void);
430 void exfat_cache_shutdown(void);
431 void exfat_cache_init_inode(struct inode *inode);
432 void exfat_cache_inval_inode(struct inode *inode);
433 int exfat_get_cluster(struct inode *inode, unsigned int cluster,
434 		unsigned int *fclus, unsigned int *dclus,
435 		unsigned int *last_dclus, int allow_eof);
436 
437 /* dir.c */
438 extern const struct inode_operations exfat_dir_inode_operations;
439 extern const struct file_operations exfat_dir_operations;
440 unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
441 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
442 		int entry, unsigned int type, unsigned int start_clu,
443 		unsigned long long size);
444 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
445 		int entry, int num_entries, struct exfat_uni_name *p_uniname);
446 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
447 		int entry, int order, int num_entries);
448 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
449 		int entry);
450 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
451 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
452 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
453 		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
454 		int num_entries, unsigned int type);
455 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
456 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
457 		int entry, sector_t *sector, int *offset);
458 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
459 		struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
460 		sector_t *sector);
461 struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
462 		int num);
463 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
464 		struct exfat_chain *p_dir, int entry, unsigned int type);
465 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
466 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
467 
468 /* inode.c */
469 extern const struct inode_operations exfat_file_inode_operations;
470 void exfat_sync_inode(struct inode *inode);
471 struct inode *exfat_build_inode(struct super_block *sb,
472 		struct exfat_dir_entry *info, loff_t i_pos);
473 void exfat_hash_inode(struct inode *inode, loff_t i_pos);
474 void exfat_unhash_inode(struct inode *inode);
475 struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
476 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
477 void exfat_evict_inode(struct inode *inode);
478 int exfat_block_truncate_page(struct inode *inode, loff_t from);
479 
480 /* exfat/nls.c */
481 unsigned short exfat_toupper(struct super_block *sb, unsigned short a);
482 int exfat_uniname_ncmp(struct super_block *sb, unsigned short *a,
483 		unsigned short *b, unsigned int len);
484 int exfat_utf16_to_nls(struct super_block *sb,
485 		struct exfat_uni_name *uniname, unsigned char *p_cstring,
486 		int len);
487 int exfat_nls_to_utf16(struct super_block *sb,
488 		const unsigned char *p_cstring, const int len,
489 		struct exfat_uni_name *uniname, int *p_lossy);
490 int exfat_create_upcase_table(struct super_block *sb);
491 void exfat_free_upcase_table(struct exfat_sb_info *sbi);
492 
493 /* exfat/misc.c */
494 void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
495 		__printf(3, 4) __cold;
496 #define exfat_fs_error(sb, fmt, args...)          \
497 		__exfat_fs_error(sb, 1, fmt, ## args)
498 #define exfat_fs_error_ratelimit(sb, fmt, args...) \
499 		__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
500 		fmt, ## args)
501 void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
502 		__printf(3, 4) __cold;
503 #define exfat_err(sb, fmt, ...)						\
504 	exfat_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
505 #define exfat_warn(sb, fmt, ...)					\
506 	exfat_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
507 #define exfat_info(sb, fmt, ...)					\
508 	exfat_msg(sb, KERN_INFO, fmt, ##__VA_ARGS__)
509 
510 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
511 		u8 tz, __le16 time, __le16 date, u8 time_cs);
512 void exfat_truncate_atime(struct timespec64 *ts);
513 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
514 		u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
515 u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
516 u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type);
517 void exfat_update_bh(struct buffer_head *bh, int sync);
518 int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync);
519 void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
520 		unsigned int size, unsigned char flags);
521 void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec);
522 
523 #endif /* !_EXFAT_FS_H */
524