xref: /linux/fs/fat/fat.h (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
1 #ifndef _FAT_H
2 #define _FAT_H
3 
4 #include <linux/buffer_head.h>
5 #include <linux/string.h>
6 #include <linux/nls.h>
7 #include <linux/fs.h>
8 #include <linux/mutex.h>
9 #include <linux/ratelimit.h>
10 #include <linux/msdos_fs.h>
11 
12 /*
13  * vfat shortname flags
14  */
15 #define VFAT_SFN_DISPLAY_LOWER	0x0001 /* convert to lowercase for display */
16 #define VFAT_SFN_DISPLAY_WIN95	0x0002 /* emulate win95 rule for display */
17 #define VFAT_SFN_DISPLAY_WINNT	0x0004 /* emulate winnt rule for display */
18 #define VFAT_SFN_CREATE_WIN95	0x0100 /* emulate win95 rule for create */
19 #define VFAT_SFN_CREATE_WINNT	0x0200 /* emulate winnt rule for create */
20 
21 #define FAT_ERRORS_CONT		1      /* ignore error and continue */
22 #define FAT_ERRORS_PANIC	2      /* panic on error */
23 #define FAT_ERRORS_RO		3      /* remount r/o on error */
24 
25 struct fat_mount_options {
26 	uid_t fs_uid;
27 	gid_t fs_gid;
28 	unsigned short fs_fmask;
29 	unsigned short fs_dmask;
30 	unsigned short codepage;  /* Codepage for shortname conversions */
31 	char *iocharset;          /* Charset used for filename input/display */
32 	unsigned short shortname; /* flags for shortname display/create rule */
33 	unsigned char name_check; /* r = relaxed, n = normal, s = strict */
34 	unsigned char errors;	  /* On error: continue, panic, remount-ro */
35 	unsigned short allow_utime;/* permission for setting the [am]time */
36 	unsigned quiet:1,         /* set = fake successful chmods and chowns */
37 		 showexec:1,      /* set = only set x bit for com/exe/bat */
38 		 sys_immutable:1, /* set = system files are immutable */
39 		 dotsOK:1,        /* set = hidden and system files are named '.filename' */
40 		 isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
41 		 utf8:1,	  /* Use of UTF-8 character set (Default) */
42 		 unicode_xlate:1, /* create escape sequences for unhandled Unicode */
43 		 numtail:1,       /* Does first alias have a numeric '~1' type tail? */
44 		 flush:1,	  /* write things quickly */
45 		 nocase:1,	  /* Does this need case conversion? 0=need case conversion*/
46 		 usefree:1,	  /* Use free_clusters for FAT32 */
47 		 tz_utc:1,	  /* Filesystem timestamps are in UTC */
48 		 rodir:1,	  /* allow ATTR_RO for directory */
49 		 discard:1;	  /* Issue discard requests on deletions */
50 };
51 
52 #define FAT_HASH_BITS	8
53 #define FAT_HASH_SIZE	(1UL << FAT_HASH_BITS)
54 
55 /*
56  * MS-DOS file system in-core superblock data
57  */
58 struct msdos_sb_info {
59 	unsigned short sec_per_clus; /* sectors/cluster */
60 	unsigned short cluster_bits; /* log2(cluster_size) */
61 	unsigned int cluster_size;   /* cluster size */
62 	unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
63 	unsigned short fat_start;
64 	unsigned long fat_length;    /* FAT start & length (sec.) */
65 	unsigned long dir_start;
66 	unsigned short dir_entries;  /* root dir start & entries */
67 	unsigned long data_start;    /* first data sector */
68 	unsigned long max_cluster;   /* maximum cluster number */
69 	unsigned long root_cluster;  /* first cluster of the root directory */
70 	unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
71 	struct mutex fat_lock;
72 	unsigned int prev_free;      /* previously allocated cluster number */
73 	unsigned int free_clusters;  /* -1 if undefined */
74 	unsigned int free_clus_valid; /* is free_clusters valid? */
75 	struct fat_mount_options options;
76 	struct nls_table *nls_disk;  /* Codepage used on disk */
77 	struct nls_table *nls_io;    /* Charset used for input and display */
78 	const void *dir_ops;		     /* Opaque; default directory operations */
79 	int dir_per_block;	     /* dir entries per block */
80 	int dir_per_block_bits;	     /* log2(dir_per_block) */
81 
82 	int fatent_shift;
83 	struct fatent_operations *fatent_ops;
84 	struct inode *fat_inode;
85 	struct inode *fsinfo_inode;
86 
87 	struct ratelimit_state ratelimit;
88 
89 	spinlock_t inode_hash_lock;
90 	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
91 };
92 
93 #define FAT_CACHE_VALID	0	/* special case for valid cache */
94 
95 /*
96  * MS-DOS file system inode data in memory
97  */
98 struct msdos_inode_info {
99 	spinlock_t cache_lru_lock;
100 	struct list_head cache_lru;
101 	int nr_caches;
102 	/* for avoiding the race between fat_free() and fat_get_cluster() */
103 	unsigned int cache_valid_id;
104 
105 	/* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
106 	loff_t mmu_private;	/* physically allocated size */
107 
108 	int i_start;		/* first cluster or 0 */
109 	int i_logstart;		/* logical first cluster */
110 	int i_attrs;		/* unused attribute bits */
111 	loff_t i_pos;		/* on-disk position of directory entry or 0 */
112 	struct hlist_node i_fat_hash;	/* hash by i_location */
113 	struct rw_semaphore truncate_lock; /* protect bmap against truncate */
114 	struct inode vfs_inode;
115 };
116 
117 struct fat_slot_info {
118 	loff_t i_pos;		/* on-disk position of directory entry */
119 	loff_t slot_off;	/* offset for slot or de start */
120 	int nr_slots;		/* number of slots + 1(de) in filename */
121 	struct msdos_dir_entry *de;
122 	struct buffer_head *bh;
123 };
124 
125 static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
126 {
127 	return sb->s_fs_info;
128 }
129 
130 static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
131 {
132 	return container_of(inode, struct msdos_inode_info, vfs_inode);
133 }
134 
135 /*
136  * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
137  * save ATTR_RO instead of ->i_mode.
138  *
139  * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
140  * bit, it's just used as flag for app.
141  */
142 static inline int fat_mode_can_hold_ro(struct inode *inode)
143 {
144 	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
145 	umode_t mask;
146 
147 	if (S_ISDIR(inode->i_mode)) {
148 		if (!sbi->options.rodir)
149 			return 0;
150 		mask = ~sbi->options.fs_dmask;
151 	} else
152 		mask = ~sbi->options.fs_fmask;
153 
154 	if (!(mask & S_IWUGO))
155 		return 0;
156 	return 1;
157 }
158 
159 /* Convert attribute bits and a mask to the UNIX mode. */
160 static inline umode_t fat_make_mode(struct msdos_sb_info *sbi,
161 				   u8 attrs, umode_t mode)
162 {
163 	if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
164 		mode &= ~S_IWUGO;
165 
166 	if (attrs & ATTR_DIR)
167 		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
168 	else
169 		return (mode & ~sbi->options.fs_fmask) | S_IFREG;
170 }
171 
172 /* Return the FAT attribute byte for this inode */
173 static inline u8 fat_make_attrs(struct inode *inode)
174 {
175 	u8 attrs = MSDOS_I(inode)->i_attrs;
176 	if (S_ISDIR(inode->i_mode))
177 		attrs |= ATTR_DIR;
178 	if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
179 		attrs |= ATTR_RO;
180 	return attrs;
181 }
182 
183 static inline void fat_save_attrs(struct inode *inode, u8 attrs)
184 {
185 	if (fat_mode_can_hold_ro(inode))
186 		MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
187 	else
188 		MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
189 }
190 
191 static inline unsigned char fat_checksum(const __u8 *name)
192 {
193 	unsigned char s = name[0];
194 	s = (s<<7) + (s>>1) + name[1];	s = (s<<7) + (s>>1) + name[2];
195 	s = (s<<7) + (s>>1) + name[3];	s = (s<<7) + (s>>1) + name[4];
196 	s = (s<<7) + (s>>1) + name[5];	s = (s<<7) + (s>>1) + name[6];
197 	s = (s<<7) + (s>>1) + name[7];	s = (s<<7) + (s>>1) + name[8];
198 	s = (s<<7) + (s>>1) + name[9];	s = (s<<7) + (s>>1) + name[10];
199 	return s;
200 }
201 
202 static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
203 {
204 	return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
205 		+ sbi->data_start;
206 }
207 
208 static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
209 {
210 #ifdef __BIG_ENDIAN
211 	while (len--) {
212 		*dst++ = src[0] | (src[1] << 8);
213 		src += 2;
214 	}
215 #else
216 	memcpy(dst, src, len * 2);
217 #endif
218 }
219 
220 static inline int fat_get_start(const struct msdos_sb_info *sbi,
221 				const struct msdos_dir_entry *de)
222 {
223 	int cluster = le16_to_cpu(de->start);
224 	if (sbi->fat_bits == 32)
225 		cluster |= (le16_to_cpu(de->starthi) << 16);
226 	return cluster;
227 }
228 
229 static inline void fat_set_start(struct msdos_dir_entry *de, int cluster)
230 {
231 	de->start   = cpu_to_le16(cluster);
232 	de->starthi = cpu_to_le16(cluster >> 16);
233 }
234 
235 static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
236 {
237 #ifdef __BIG_ENDIAN
238 	while (len--) {
239 		dst[0] = *src & 0x00FF;
240 		dst[1] = (*src & 0xFF00) >> 8;
241 		dst += 2;
242 		src++;
243 	}
244 #else
245 	memcpy(dst, src, len * 2);
246 #endif
247 }
248 
249 /* fat/cache.c */
250 extern void fat_cache_inval_inode(struct inode *inode);
251 extern int fat_get_cluster(struct inode *inode, int cluster,
252 			   int *fclus, int *dclus);
253 extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
254 		    unsigned long *mapped_blocks, int create);
255 
256 /* fat/dir.c */
257 extern const struct file_operations fat_dir_operations;
258 extern int fat_search_long(struct inode *inode, const unsigned char *name,
259 			   int name_len, struct fat_slot_info *sinfo);
260 extern int fat_dir_empty(struct inode *dir);
261 extern int fat_subdirs(struct inode *dir);
262 extern int fat_scan(struct inode *dir, const unsigned char *name,
263 		    struct fat_slot_info *sinfo);
264 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
265 				struct msdos_dir_entry **de, loff_t *i_pos);
266 extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
267 extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
268 			   struct fat_slot_info *sinfo);
269 extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
270 
271 /* fat/fatent.c */
272 struct fat_entry {
273 	int entry;
274 	union {
275 		u8 *ent12_p[2];
276 		__le16 *ent16_p;
277 		__le32 *ent32_p;
278 	} u;
279 	int nr_bhs;
280 	struct buffer_head *bhs[2];
281 	struct inode *fat_inode;
282 };
283 
284 static inline void fatent_init(struct fat_entry *fatent)
285 {
286 	fatent->nr_bhs = 0;
287 	fatent->entry = 0;
288 	fatent->u.ent32_p = NULL;
289 	fatent->bhs[0] = fatent->bhs[1] = NULL;
290 	fatent->fat_inode = NULL;
291 }
292 
293 static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
294 {
295 	fatent->entry = entry;
296 	fatent->u.ent32_p = NULL;
297 }
298 
299 static inline void fatent_brelse(struct fat_entry *fatent)
300 {
301 	int i;
302 	fatent->u.ent32_p = NULL;
303 	for (i = 0; i < fatent->nr_bhs; i++)
304 		brelse(fatent->bhs[i]);
305 	fatent->nr_bhs = 0;
306 	fatent->bhs[0] = fatent->bhs[1] = NULL;
307 	fatent->fat_inode = NULL;
308 }
309 
310 extern void fat_ent_access_init(struct super_block *sb);
311 extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
312 			int entry);
313 extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
314 			 int new, int wait);
315 extern int fat_alloc_clusters(struct inode *inode, int *cluster,
316 			      int nr_cluster);
317 extern int fat_free_clusters(struct inode *inode, int cluster);
318 extern int fat_count_free_clusters(struct super_block *sb);
319 
320 /* fat/file.c */
321 extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
322 			      unsigned long arg);
323 extern const struct file_operations fat_file_operations;
324 extern const struct inode_operations fat_file_inode_operations;
325 extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
326 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
327 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
328 		       struct kstat *stat);
329 extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
330 			  int datasync);
331 
332 /* fat/inode.c */
333 extern void fat_attach(struct inode *inode, loff_t i_pos);
334 extern void fat_detach(struct inode *inode);
335 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
336 extern struct inode *fat_build_inode(struct super_block *sb,
337 			struct msdos_dir_entry *de, loff_t i_pos);
338 extern int fat_sync_inode(struct inode *inode);
339 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
340 			  int isvfat, void (*setup)(struct super_block *));
341 
342 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
343 		            struct inode *i2);
344 /* fat/misc.c */
345 extern __printf(3, 4) __cold
346 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
347 #define fat_fs_error(sb, fmt, args...)		\
348 	__fat_fs_error(sb, 1, fmt , ## args)
349 #define fat_fs_error_ratelimit(sb, fmt, args...) \
350 	__fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
351 __printf(3, 4) __cold
352 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
353 #define fat_msg_ratelimit(sb, level, fmt, args...)	\
354 	do {	\
355 			if (__ratelimit(&MSDOS_SB(sb)->ratelimit))	\
356 				fat_msg(sb, level, fmt, ## args);	\
357 	 } while (0)
358 extern int fat_clusters_flush(struct super_block *sb);
359 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
360 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
361 			      __le16 __time, __le16 __date, u8 time_cs);
362 extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
363 			      __le16 *time, __le16 *date, u8 *time_cs);
364 extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
365 
366 int fat_cache_init(void);
367 void fat_cache_destroy(void);
368 
369 /* helper for printk */
370 typedef unsigned long long	llu;
371 
372 #endif /* !_FAT_H */
373