2 * linux/fs/vfat/namei.c
4 * Written 1992,1993 by Werner Almesberger
6 * Windows95/Windows NT compatible extended MSDOS filesystem
7 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the
8 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify
9 * what file operation caused you trouble and if you can duplicate
10 * the problem, send a script that demonstrates it.
12 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
14 * Support Multibyte characters and cleanup by
15 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
18 #include <linux/module.h>
19 #include <linux/jiffies.h>
20 #include <linux/ctype.h>
21 #include <linux/slab.h>
22 #include <linux/smp_lock.h>
23 #include <linux/buffer_head.h>
24 #include <linux/namei.h>
27 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd)
31 if (!dentry->d_inode &&
32 nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE))
34 * negative dentry is dropped, in order to make sure
35 * to use the name which a user desires if this is
40 spin_lock(&dentry->d_lock);
41 if (dentry->d_time != dentry->d_parent->d_inode->i_version)
43 spin_unlock(&dentry->d_lock);
48 /* returns the length of a struct qstr, ignoring trailing dots */
49 static unsigned int vfat_striptail_len(struct qstr *qstr)
51 unsigned int len = qstr->len;
53 while (len && qstr->name[len - 1] == '.')
59 * Compute the hash for the vfat name corresponding to the dentry.
60 * Note: if the name is invalid, we leave the hash code unchanged so
61 * that the existing dentry can be used. The vfat fs routines will
62 * return ENOENT or EINVAL as appropriate.
64 static int vfat_hash(struct dentry *dentry, struct qstr *qstr)
66 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
71 * Compute the hash for the vfat name corresponding to the dentry.
72 * Note: if the name is invalid, we leave the hash code unchanged so
73 * that the existing dentry can be used. The vfat fs routines will
74 * return ENOENT or EINVAL as appropriate.
76 static int vfat_hashi(struct dentry *dentry, struct qstr *qstr)
78 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
79 const unsigned char *name;
84 len = vfat_striptail_len(qstr);
86 hash = init_name_hash();
88 hash = partial_name_hash(nls_tolower(t, *name++), hash);
89 qstr->hash = end_name_hash(hash);
95 * Case insensitive compare of two vfat names.
97 static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b)
99 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
100 unsigned int alen, blen;
102 /* A filename cannot end in '.' or we treat it like it has none */
103 alen = vfat_striptail_len(a);
104 blen = vfat_striptail_len(b);
106 if (nls_strnicmp(t, a->name, b->name, alen) == 0)
113 * Case sensitive compare of two vfat names.
115 static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
117 unsigned int alen, blen;
119 /* A filename cannot end in '.' or we treat it like it has none */
120 alen = vfat_striptail_len(a);
121 blen = vfat_striptail_len(b);
123 if (strncmp(a->name, b->name, alen) == 0)
129 static struct dentry_operations vfat_dentry_ops[4] = {
131 .d_hash = vfat_hashi,
132 .d_compare = vfat_cmpi,
135 .d_revalidate = vfat_revalidate,
136 .d_hash = vfat_hashi,
137 .d_compare = vfat_cmpi,
141 .d_compare = vfat_cmp,
144 .d_revalidate = vfat_revalidate,
146 .d_compare = vfat_cmp,
150 /* Characters that are undesirable in an MS-DOS file name */
152 static inline wchar_t vfat_bad_char(wchar_t w)
155 || (w == '*') || (w == '?') || (w == '<') || (w == '>')
156 || (w == '|') || (w == '"') || (w == ':') || (w == '/')
160 static inline wchar_t vfat_replace_char(wchar_t w)
162 return (w == '[') || (w == ']') || (w == ';') || (w == ',')
163 || (w == '+') || (w == '=');
166 static wchar_t vfat_skip_char(wchar_t w)
168 return (w == '.') || (w == ' ');
171 static inline int vfat_is_used_badchars(const wchar_t *s, int len)
175 for (i = 0; i < len; i++)
176 if (vfat_bad_char(s[i]))
179 if (s[i - 1] == ' ') /* last character cannot be space */
185 static int vfat_find_form(struct inode *dir, unsigned char *name)
187 struct fat_slot_info sinfo;
188 int err = fat_scan(dir, name, &sinfo);
196 * 1) Valid characters for the 8.3 format alias are any combination of
197 * letters, uppercase alphabets, digits, any of the
198 * following special characters:
199 * $ % ' ` - @ { } ~ ! # ( ) & _ ^
200 * In this case Longfilename is not stored in disk.
203 * File name and extension name is contain uppercase/lowercase
204 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
206 * 2) File name is 8.3 format, but it contain the uppercase and
207 * lowercase char, muliti bytes char, etc. In this case numtail is not
208 * added, but Longfilename is stored.
210 * 3) When the one except for the above, or the following special
211 * character are contained:
213 * numtail is added, and Longfilename must be stored in disk .
215 struct shortname_info {
216 unsigned char lower:1,
220 #define INIT_SHORTNAME_INFO(x) do { \
226 static inline int to_shortname_char(struct nls_table *nls,
227 unsigned char *buf, int buf_size,
228 wchar_t *src, struct shortname_info *info)
232 if (vfat_skip_char(*src)) {
236 if (vfat_replace_char(*src)) {
242 len = nls->uni2char(*src, buf, buf_size);
247 } else if (len == 1) {
248 unsigned char prev = buf[0];
250 if (buf[0] >= 0x7F) {
255 buf[0] = nls_toupper(nls, buf[0]);
256 if (isalpha(buf[0])) {
271 * Given a valid longname, create a unique shortname. Make sure the
272 * shortname does not exist
273 * Returns negative number on error, 0 for a normal
274 * return, and 1 for valid shortname
276 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
277 wchar_t *uname, int ulen,
278 unsigned char *name_res, unsigned char *lcase)
280 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
281 wchar_t *ip, *ext_start, *end, *name_start;
282 unsigned char base[9], ext[4], buf[8], *p;
283 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
285 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
287 struct shortname_info base_info, ext_info;
290 INIT_SHORTNAME_INFO(&base_info);
291 INIT_SHORTNAME_INFO(&ext_info);
293 /* Now, we need to create a shortname from the long name */
294 ext_start = end = &uname[ulen];
295 while (--ext_start >= uname) {
296 if (*ext_start == 0x002E) { /* is `.' */
297 if (ext_start == end - 1) {
305 if (ext_start == uname - 1) {
308 } else if (ext_start) {
310 * Names which start with a dot could be just
311 * an extension eg. "...test". In this case Win95
312 * uses the extension as the name and sets no extension.
314 name_start = &uname[0];
315 while (name_start < ext_start) {
316 if (!vfat_skip_char(*name_start))
320 if (name_start != ext_start) {
321 sz = ext_start - uname;
330 numtail2_baselen = 2;
331 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
332 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
337 if (baselen < 2 && (baselen + chl) > 2)
338 numtail2_baselen = baselen;
339 if (baselen < 6 && (baselen + chl) > 6)
340 numtail_baselen = baselen;
341 for (chi = 0; chi < chl; chi++) {
348 if ((chi < chl - 1) || (ip + 1) - uname < sz)
359 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
360 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
365 if ((extlen + chl) > 3) {
369 for (chi = 0; chi < chl; chi++) {
381 base[baselen] = '\0';
383 /* Yes, it can happen. ".\xe5" would do it. */
384 if (base[0] == DELETED_FLAG)
387 /* OK, at this point we know that base is not longer than 8 symbols,
388 * ext is not longer than 3, base is nonempty, both don't contain
389 * any bad symbols (lowercase transformed to uppercase).
392 memset(name_res, ' ', MSDOS_NAME);
393 memcpy(name_res, base, baselen);
394 memcpy(name_res + 8, ext, extlen);
396 if (is_shortname && base_info.valid && ext_info.valid) {
397 if (vfat_find_form(dir, name_res) == 0)
400 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
401 return (base_info.upper && ext_info.upper);
402 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
403 if ((base_info.upper || base_info.lower) &&
404 (ext_info.upper || ext_info.lower)) {
405 if (!base_info.upper && base_info.lower)
406 *lcase |= CASE_LOWER_BASE;
407 if (!ext_info.upper && ext_info.lower)
408 *lcase |= CASE_LOWER_EXT;
417 if (opts->numtail == 0)
418 if (vfat_find_form(dir, name_res) < 0)
422 * Try to find a unique extension. This used to
423 * iterate through all possibilities sequentially,
424 * but that gave extremely bad performance. Windows
425 * only tries a few cases before using random
426 * values for part of the base.
430 baselen = numtail_baselen;
433 name_res[baselen] = '~';
434 for (i = 1; i < 10; i++) {
435 name_res[baselen + 1] = i + '0';
436 if (vfat_find_form(dir, name_res) < 0)
440 i = jiffies & 0xffff;
441 sz = (jiffies >> 16) & 0x7;
443 baselen = numtail2_baselen;
446 name_res[baselen + 4] = '~';
447 name_res[baselen + 5] = '1' + sz;
449 sprintf(buf, "%04X", i);
450 memcpy(&name_res[baselen], buf, 4);
451 if (vfat_find_form(dir, name_res) < 0)
458 /* Translate a string, including coded sequences into Unicode */
460 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
461 int *longlen, int *outlen, int escape, int utf8,
462 struct nls_table *nls)
464 const unsigned char *ip;
472 int name_len = strlen(name);
474 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX);
477 * We stripped '.'s before and set len appropriately,
478 * but utf8_mbstowcs doesn't care about len
480 *outlen -= (name_len - len);
483 return -ENAMETOOLONG;
485 op = &outname[*outlen * sizeof(wchar_t)];
488 for (i = 0, ip = name, op = outname, *outlen = 0;
489 i < len && *outlen <= 255;
492 if (escape && (*ip == ':')) {
496 for (k = 1; k < 5; k++) {
499 if (nc >= '0' && nc <= '9') {
503 if (nc >= 'a' && nc <= 'f') {
504 ec |= nc - ('a' - 10);
507 if (nc >= 'A' && nc <= 'F') {
508 ec |= nc - ('A' - 10);
518 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0)
526 return -ENAMETOOLONG;
528 for (i = 0, ip = name, op = outname, *outlen = 0;
529 i < len && *outlen <= 255;
536 return -ENAMETOOLONG;
546 fill = 13 - (*outlen % 13);
547 for (i = 0; i < fill; i++) {
558 static int vfat_build_slots(struct inode *dir, const unsigned char *name,
559 int len, int is_dir, int cluster,
561 struct msdos_dir_slot *slots, int *nr_slots)
563 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
564 struct fat_mount_options *opts = &sbi->options;
565 struct msdos_dir_slot *ps;
566 struct msdos_dir_entry *de;
567 unsigned char cksum, lcase;
568 unsigned char msdos_name[MSDOS_NAME];
572 int err, ulen, usize, i;
581 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
582 opts->unicode_xlate, opts->utf8, sbi->nls_io);
586 err = vfat_is_used_badchars(uname, ulen);
590 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
595 de = (struct msdos_dir_entry *)slots;
600 /* build the entry of long file name */
601 cksum = fat_checksum(msdos_name);
603 *nr_slots = usize / 13;
604 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
608 ps->alias_checksum = cksum;
610 offset = (i - 1) * 13;
611 fatwchar_to16(ps->name0_4, uname + offset, 5);
612 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
613 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
616 de = (struct msdos_dir_entry *)ps;
619 /* build the entry of 8.3 alias name */
621 memcpy(de->name, msdos_name, MSDOS_NAME);
622 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
624 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
625 de->time = de->ctime = time;
626 de->date = de->cdate = de->adate = date;
627 de->ctime_cs = time_cs;
628 de->start = cpu_to_le16(cluster);
629 de->starthi = cpu_to_le16(cluster >> 16);
636 static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
637 int cluster, struct timespec *ts,
638 struct fat_slot_info *sinfo)
640 struct msdos_dir_slot *slots;
644 len = vfat_striptail_len(qname);
648 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
652 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
657 err = fat_add_entries(dir, slots, nr_slots, sinfo);
661 /* update timestamp */
662 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
664 (void)fat_sync_inode(dir);
666 mark_inode_dirty(dir);
672 static int vfat_find(struct inode *dir, struct qstr *qname,
673 struct fat_slot_info *sinfo)
675 unsigned int len = vfat_striptail_len(qname);
678 return fat_search_long(dir, qname->name, len, sinfo);
681 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
682 struct nameidata *nd)
684 struct super_block *sb = dir->i_sb;
685 struct fat_slot_info sinfo;
686 struct inode *inode = NULL;
687 struct dentry *alias;
691 table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0;
692 dentry->d_op = &vfat_dentry_ops[table];
694 err = vfat_find(dir, &dentry->d_name, &sinfo);
699 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
703 return ERR_CAST(inode);
705 alias = d_find_alias(inode);
707 if (d_invalidate(alias) == 0)
718 dentry->d_op = &vfat_dentry_ops[table];
719 dentry->d_time = dentry->d_parent->d_inode->i_version;
720 dentry = d_splice_alias(inode, dentry);
722 dentry->d_op = &vfat_dentry_ops[table];
723 dentry->d_time = dentry->d_parent->d_inode->i_version;
728 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode,
729 struct nameidata *nd)
731 struct super_block *sb = dir->i_sb;
733 struct fat_slot_info sinfo;
739 ts = CURRENT_TIME_SEC;
740 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
745 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
748 err = PTR_ERR(inode);
752 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
753 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
755 dentry->d_time = dentry->d_parent->d_inode->i_version;
756 d_instantiate(dentry, inode);
762 static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
764 struct inode *inode = dentry->d_inode;
765 struct super_block *sb = dir->i_sb;
766 struct fat_slot_info sinfo;
771 err = fat_dir_empty(inode);
774 err = vfat_find(dir, &dentry->d_name, &sinfo);
778 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
784 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
792 static int vfat_unlink(struct inode *dir, struct dentry *dentry)
794 struct inode *inode = dentry->d_inode;
795 struct super_block *sb = dir->i_sb;
796 struct fat_slot_info sinfo;
801 err = vfat_find(dir, &dentry->d_name, &sinfo);
805 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
809 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
817 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode)
819 struct super_block *sb = dir->i_sb;
821 struct fat_slot_info sinfo;
827 ts = CURRENT_TIME_SEC;
828 cluster = fat_alloc_new_dir(dir, &ts);
833 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
839 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
842 err = PTR_ERR(inode);
843 /* the directory was completed, just return a error */
848 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
849 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
851 dentry->d_time = dentry->d_parent->d_inode->i_version;
852 d_instantiate(dentry, inode);
858 fat_free_clusters(dir, cluster);
864 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
865 struct inode *new_dir, struct dentry *new_dentry)
867 struct buffer_head *dotdot_bh;
868 struct msdos_dir_entry *dotdot_de;
869 struct inode *old_inode, *new_inode;
870 struct fat_slot_info old_sinfo, sinfo;
872 loff_t dotdot_i_pos, new_i_pos;
873 int err, is_dir, update_dotdot, corrupt = 0;
874 struct super_block *sb = old_dir->i_sb;
876 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
877 old_inode = old_dentry->d_inode;
878 new_inode = new_dentry->d_inode;
880 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
884 is_dir = S_ISDIR(old_inode->i_mode);
885 update_dotdot = (is_dir && old_dir != new_dir);
887 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
888 &dotdot_i_pos) < 0) {
894 ts = CURRENT_TIME_SEC;
897 err = fat_dir_empty(new_inode);
901 new_i_pos = MSDOS_I(new_inode)->i_pos;
902 fat_detach(new_inode);
904 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
908 new_i_pos = sinfo.i_pos;
910 new_dir->i_version++;
912 fat_detach(old_inode);
913 fat_attach(old_inode, new_i_pos);
914 if (IS_DIRSYNC(new_dir)) {
915 err = fat_sync_inode(old_inode);
919 mark_inode_dirty(old_inode);
922 int start = MSDOS_I(new_dir)->i_logstart;
923 dotdot_de->start = cpu_to_le16(start);
924 dotdot_de->starthi = cpu_to_le16(start >> 16);
925 mark_buffer_dirty(dotdot_bh);
926 if (IS_DIRSYNC(new_dir)) {
927 err = sync_dirty_buffer(dotdot_bh);
936 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
940 old_dir->i_version++;
941 old_dir->i_ctime = old_dir->i_mtime = ts;
942 if (IS_DIRSYNC(old_dir))
943 (void)fat_sync_inode(old_dir);
945 mark_inode_dirty(old_dir);
948 drop_nlink(new_inode);
950 drop_nlink(new_inode);
951 new_inode->i_ctime = ts;
956 brelse(old_sinfo.bh);
962 /* data cluster is shared, serious corruption */
966 int start = MSDOS_I(old_dir)->i_logstart;
967 dotdot_de->start = cpu_to_le16(start);
968 dotdot_de->starthi = cpu_to_le16(start >> 16);
969 mark_buffer_dirty(dotdot_bh);
970 corrupt |= sync_dirty_buffer(dotdot_bh);
973 fat_detach(old_inode);
974 fat_attach(old_inode, old_sinfo.i_pos);
976 fat_attach(new_inode, new_i_pos);
978 corrupt |= fat_sync_inode(new_inode);
981 * If new entry was not sharing the data cluster, it
982 * shouldn't be serious corruption.
984 int err2 = fat_remove_entries(new_dir, &sinfo);
990 fat_fs_panic(new_dir->i_sb,
991 "%s: Filesystem corrupted (i_pos %lld)",
992 __func__, sinfo.i_pos);
997 static const struct inode_operations vfat_dir_inode_operations = {
998 .create = vfat_create,
999 .lookup = vfat_lookup,
1000 .unlink = vfat_unlink,
1001 .mkdir = vfat_mkdir,
1002 .rmdir = vfat_rmdir,
1003 .rename = vfat_rename,
1004 .setattr = fat_setattr,
1005 .getattr = fat_getattr,
1008 static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1012 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
1016 if (MSDOS_SB(sb)->options.name_check != 's')
1017 sb->s_root->d_op = &vfat_dentry_ops[0];
1019 sb->s_root->d_op = &vfat_dentry_ops[2];
1024 static int vfat_get_sb(struct file_system_type *fs_type,
1025 int flags, const char *dev_name,
1026 void *data, struct vfsmount *mnt)
1028 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super,
1032 static struct file_system_type vfat_fs_type = {
1033 .owner = THIS_MODULE,
1035 .get_sb = vfat_get_sb,
1036 .kill_sb = kill_block_super,
1037 .fs_flags = FS_REQUIRES_DEV,
1040 static int __init init_vfat_fs(void)
1042 return register_filesystem(&vfat_fs_type);
1045 static void __exit exit_vfat_fs(void)
1047 unregister_filesystem(&vfat_fs_type);
1050 MODULE_LICENSE("GPL");
1051 MODULE_DESCRIPTION("VFAT filesystem support");
1052 MODULE_AUTHOR("Gordon Chaffee");
1054 module_init(init_vfat_fs)
1055 module_exit(exit_vfat_fs)