1 /*
2 * linux/fs/vfat/namei.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 *
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.
11 *
12 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
13 *
14 * Support Multibyte characters and cleanup by
15 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
16 */
17
18 #include <linux/module.h>
19
20 #include <linux/jiffies.h>
21 #include <linux/msdos_fs.h>
22 #include <linux/ctype.h>
23 #include <linux/slab.h>
24 #include <linux/smp_lock.h>
25 #include <linux/buffer_head.h>
26 #include <linux/namei.h>
27
28 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd)
29 {
30 int ret = 1;
31
32 if (!dentry->d_inode &&
33 nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE))
34 /*
35 * negative dentry is dropped, in order to make sure
36 * to use the name which a user desires if this is
37 * create path.
38 */
39 ret = 0;
40 else {
41 spin_lock(&dentry->d_lock);
42 if (dentry->d_time != dentry->d_parent->d_inode->i_version)
43 ret = 0;
44 spin_unlock(&dentry->d_lock);
45 }
46 return ret;
47 }
48
49 /* returns the length of a struct qstr, ignoring trailing dots */
50 static unsigned int vfat_striptail_len(struct qstr *qstr)
51 {
52 unsigned int len = qstr->len;
53
54 while (len && qstr->name[len - 1] == '.')
55 len--;
56 return len;
57 }
58
59 /*
60 * Compute the hash for the vfat name corresponding to the dentry.
61 * Note: if the name is invalid, we leave the hash code unchanged so
62 * that the existing dentry can be used. The vfat fs routines will
63 * return ENOENT or EINVAL as appropriate.
64 */
65 static int vfat_hash(struct dentry *dentry, struct qstr *qstr)
66 {
67 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
68 return 0;
69 }
70
71 /*
72 * Compute the hash for the vfat name corresponding to the dentry.
73 * Note: if the name is invalid, we leave the hash code unchanged so
74 * that the existing dentry can be used. The vfat fs routines will
75 * return ENOENT or EINVAL as appropriate.
76 */
77 static int vfat_hashi(struct dentry *dentry, struct qstr *qstr)
78 {
79 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
80 const unsigned char *name;
81 unsigned int len;
82 unsigned long hash;
83
84 name = qstr->name;
85 len = vfat_striptail_len(qstr);
86
87 hash = init_name_hash();
88 while (len--)
89 hash = partial_name_hash(nls_tolower(t, *name++), hash);
90 qstr->hash = end_name_hash(hash);
91
92 return 0;
93 }
94
95 /*
96 * Case insensitive compare of two vfat names.
97 */
98 static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b)
99 {
100 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
101 unsigned int alen, blen;
102
103 /* A filename cannot end in '.' or we treat it like it has none */
104 alen = vfat_striptail_len(a);
105 blen = vfat_striptail_len(b);
106 if (alen == blen) {
107 if (nls_strnicmp(t, a->name, b->name, alen) == 0)
108 return 0;
109 }
110 return 1;
111 }
112
113 /*
114 * Case sensitive compare of two vfat names.
115 */
116 static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
117 {
118 unsigned int alen, blen;
119
120 /* A filename cannot end in '.' or we treat it like it has none */
121 alen = vfat_striptail_len(a);
122 blen = vfat_striptail_len(b);
123 if (alen == blen) {
124 if (strncmp(a->name, b->name, alen) == 0)
125 return 0;
126 }
127 return 1;
128 }
129
130 static struct dentry_operations vfat_dentry_ops[4] = {
131 {
132 .d_hash = vfat_hashi,
133 .d_compare = vfat_cmpi,
134 },
135 {
136 .d_revalidate = vfat_revalidate,
137 .d_hash = vfat_hashi,
138 .d_compare = vfat_cmpi,
139 },
140 {
141 .d_hash = vfat_hash,
142 .d_compare = vfat_cmp,
143 },
144 {
145 .d_revalidate = vfat_revalidate,
146 .d_hash = vfat_hash,
147 .d_compare = vfat_cmp,
148 }
149 };
150
151 /* Characters that are undesirable in an MS-DOS file name */
152
153 static inline wchar_t vfat_bad_char(wchar_t w)
154 {
155 return (w < 0x0020)
156 || (w == '*') || (w == '?') || (w == '<') || (w == '>')
157 || (w == '|') || (w == '"') || (w == ':') || (w == '/')
158 || (w == '\\');
159 }
160
161 static inline wchar_t vfat_replace_char(wchar_t w)
162 {
163 return (w == '[') || (w == ']') || (w == ';') || (w == ',')
164 || (w == '+') || (w == '=');
165 }
166
167 static wchar_t vfat_skip_char(wchar_t w)
168 {
169 return (w == '.') || (w == ' ');
170 }
171
172 static inline int vfat_is_used_badchars(const wchar_t *s, int len)
173 {
174 int i;
175
176 for (i = 0; i < len; i++)
177 if (vfat_bad_char(s[i]))
178 return -EINVAL;
179 return 0;
180 }
181
182 static int vfat_valid_longname(const unsigned char *name, unsigned int len)
183 {
184 if (name[len - 1] == ' ')
185 return -EINVAL;
186 if (len >= 256)
187 return -ENAMETOOLONG;
188
189 /* MS-DOS "device special files" */
190 if (len == 3 || (len > 3 && name[3] == '.')) { /* basename == 3 */
191 if (!strnicmp(name, "aux", 3) ||
192 !strnicmp(name, "con", 3) ||
193 !strnicmp(name, "nul", 3) ||
194 !strnicmp(name, "prn", 3))
195 return -EINVAL;
196 }
197 if (len == 4 || (len > 4 && name[4] == '.')) { /* basename == 4 */
198 /* "com1", "com2", ... */
199 if ('1' <= name[3] && name[3] <= '9') {
200 if (!strnicmp(name, "com", 3) ||
201 !strnicmp(name, "lpt", 3))
202 return -EINVAL;
203 }
204 }
205
206 return 0;
207 }
208
209 static int vfat_find_form(struct inode *dir, unsigned char *name)
210 {
211 struct msdos_dir_entry *de;
212 struct buffer_head *bh = NULL;
213 loff_t i_pos;
214 int res;
215
216 res = fat_scan(dir, name, &bh, &de, &i_pos);
217 brelse(bh);
218 if (res < 0)
219 return -ENOENT;
220 return 0;
221 }
222
223 /*
224 * 1) Valid characters for the 8.3 format alias are any combination of
225 * letters, uppercase alphabets, digits, any of the
226 * following special characters:
227 * $ % ' ` - @ { } ~ ! # ( ) & _ ^
228 * In this case Longfilename is not stored in disk.
229 *
230 * WinNT's Extension:
231 * File name and extension name is contain uppercase/lowercase
232 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
233 *
234 * 2) File name is 8.3 format, but it contain the uppercase and
235 * lowercase char, muliti bytes char, etc. In this case numtail is not
236 * added, but Longfilename is stored.
237 *
238 * 3) When the one except for the above, or the following special
239 * character are contained:
240 * . [ ] ; , + =
241 * numtail is added, and Longfilename must be stored in disk .
242 */
243 struct shortname_info {
244 unsigned char lower:1,
245 upper:1,
246 valid:1;
247 };
248 #define INIT_SHORTNAME_INFO(x) do { \
249 (x)->lower = 1; \
250 (x)->upper = 1; \
251 (x)->valid = 1; \
252 } while (0)
253
254 static inline int to_shortname_char(struct nls_table *nls,
255 unsigned char *buf, int buf_size,
256 wchar_t *src, struct shortname_info *info)
257 {
258 int len;
259
260 if (vfat_skip_char(*src)) {
261 info->valid = 0;
262 return 0;
263 }
264 if (vfat_replace_char(*src)) {
265 info->valid = 0;
266 buf[0] = '_';
267 return 1;
268 }
269
270 len = nls->uni2char(*src, buf, buf_size);
271 if (len <= 0) {
272 info->valid = 0;
273 buf[0] = '_';
274 len = 1;
275 } else if (len == 1) {
276 unsigned char prev = buf[0];
277
278 if (buf[0] >= 0x7F) {
279 info->lower = 0;
280 info->upper = 0;
281 }
282
283 buf[0] = nls_toupper(nls, buf[0]);
284 if (isalpha(buf[0])) {
285 if (buf[0] == prev)
286 info->lower = 0;
287 else
288 info->upper = 0;
289 }
290 } else {
291 info->lower = 0;
292 info->upper = 0;
293 }
294
295 return len;
296 }
297
298 /*
299 * Given a valid longname, create a unique shortname. Make sure the
300 * shortname does not exist
301 * Returns negative number on error, 0 for a normal
302 * return, and 1 for valid shortname
303 */
304 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
305 wchar_t *uname, int ulen,
306 unsigned char *name_res, unsigned char *lcase)
307 {
308 wchar_t *ip, *ext_start, *end, *name_start;
309 unsigned char base[9], ext[4], buf[8], *p;
310 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
311 int chl, chi;
312 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
313 int is_shortname;
314 struct shortname_info base_info, ext_info;
315 unsigned short opt_shortname = MSDOS_SB(dir->i_sb)->options.shortname;
316
317 is_shortname = 1;
318 INIT_SHORTNAME_INFO(&base_info);
319 INIT_SHORTNAME_INFO(&ext_info);
320
321 /* Now, we need to create a shortname from the long name */
322 ext_start = end = &uname[ulen];
323 while (--ext_start >= uname) {
324 if (*ext_start == 0x002E) { /* is `.' */
325 if (ext_start == end - 1) {
326 sz = ulen;
327 ext_start = NULL;
328 }
329 break;
330 }
331 }
332
333 if (ext_start == uname - 1) {
334 sz = ulen;
335 ext_start = NULL;
336 } else if (ext_start) {
337 /*
338 * Names which start with a dot could be just
339 * an extension eg. "...test". In this case Win95
340 * uses the extension as the name and sets no extension.
341 */
342 name_start = &uname[0];
343 while (name_start < ext_start) {
344 if (!vfat_skip_char(*name_start))
345 break;
346 name_start++;
347 }
348 if (name_start != ext_start) {
349 sz = ext_start - uname;
350 ext_start++;
351 } else {
352 sz = ulen;
353 ext_start = NULL;
354 }
355 }
356
357 numtail_baselen = 6;
358 numtail2_baselen = 2;
359 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
360 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
361 ip, &base_info);
362 if (chl == 0)
363 continue;
364
365 if (baselen < 2 && (baselen + chl) > 2)
366 numtail2_baselen = baselen;
367 if (baselen < 6 && (baselen + chl) > 6)
368 numtail_baselen = baselen;
369 for (chi = 0; chi < chl; chi++) {
370 *p++ = charbuf[chi];
371 baselen++;
372 if (baselen >= 8)
373 break;
374 }
375 if (baselen >= 8) {
376 if ((chi < chl - 1) || (ip + 1) - uname < sz)
377 is_shortname = 0;
378 break;
379 }
380 }
381 if (baselen == 0) {
382 return -EINVAL;
383 }
384
385 extlen = 0;
386 if (ext_start) {
387 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
388 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
389 ip, &ext_info);
390 if (chl == 0)
391 continue;
392
393 if ((extlen + chl) > 3) {
394 is_shortname = 0;
395 break;
396 }
397 for (chi = 0; chi < chl; chi++) {
398 *p++ = charbuf[chi];
399 extlen++;
400 }
401 if (extlen >= 3) {
402 if (ip + 1 != end)
403 is_shortname = 0;
404 break;
405 }
406 }
407 }
408 ext[extlen] = '\0';
409 base[baselen] = '\0';
410
411 /* Yes, it can happen. ".\xe5" would do it. */
412 if (base[0] == DELETED_FLAG)
413 base[0] = 0x05;
414
415 /* OK, at this point we know that base is not longer than 8 symbols,
416 * ext is not longer than 3, base is nonempty, both don't contain
417 * any bad symbols (lowercase transformed to uppercase).
418 */
419
420 memset(name_res, ' ', MSDOS_NAME);
421 memcpy(name_res, base, baselen);
422 memcpy(name_res + 8, ext, extlen);
423 *lcase = 0;
424 if (is_shortname && base_info.valid && ext_info.valid) {
425 if (vfat_find_form(dir, name_res) == 0)
426 return -EEXIST;
427
428 if (opt_shortname & VFAT_SFN_CREATE_WIN95) {
429 return (base_info.upper && ext_info.upper);
430 } else if (opt_shortname & VFAT_SFN_CREATE_WINNT) {
431 if ((base_info.upper || base_info.lower) &&
432 (ext_info.upper || ext_info.lower)) {
433 if (!base_info.upper && base_info.lower)
434 *lcase |= CASE_LOWER_BASE;
435 if (!ext_info.upper && ext_info.lower)
436 *lcase |= CASE_LOWER_EXT;
437 return 1;
438 }
439 return 0;
440 } else {
441 BUG();
442 }
443 }
444
445 if (MSDOS_SB(dir->i_sb)->options.numtail == 0)
446 if (vfat_find_form(dir, name_res) < 0)
447 return 0;
448
449 /*
450 * Try to find a unique extension. This used to
451 * iterate through all possibilities sequentially,
452 * but that gave extremely bad performance. Windows
453 * only tries a few cases before using random
454 * values for part of the base.
455 */
456
457 if (baselen > 6) {
458 baselen = numtail_baselen;
459 name_res[7] = ' ';
460 }
461 name_res[baselen] = '~';
462 for (i = 1; i < 10; i++) {
463 name_res[baselen + 1] = i + '';
464 if (vfat_find_form(dir, name_res) < 0)
465 return 0;
466 }
467
468 i = jiffies & 0xffff;
469 sz = (jiffies >> 16) & 0x7;
470 if (baselen > 2) {
471 baselen = numtail2_baselen;
472 name_res[7] = ' ';
473 }
474 name_res[baselen + 4] = '~';
475 name_res[baselen + 5] = '1' + sz;
476 while (1) {
477 sprintf(buf, "%04X", i);
478 memcpy(&name_res[baselen], buf, 4);
479 if (vfat_find_form(dir, name_res) < 0)
480 break;
481 i -= 11;
482 }
483 return 0;
484 }
485
486 /* Translate a string, including coded sequences into Unicode */
487 static int
488 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
489 int *longlen, int *outlen, int escape, int utf8,
490 struct nls_table *nls)
491 {
492 const unsigned char *ip;
493 unsigned char nc;
494 unsigned char *op;
495 unsigned int ec;
496 int i, k, fill;
497 int charlen;
498
499 if (utf8) {
500 int name_len = strlen(name);
501
502 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PAGE_SIZE);
503
504 /*
505 * We stripped '.'s before and set len appropriately,
506 * but utf8_mbstowcs doesn't care about len
507 */
508 *outlen -= (name_len - len);
509
510 op = &outname[*outlen * sizeof(wchar_t)];
511 } else {
512 if (nls) {
513 for (i = 0, ip = name, op = outname, *outlen = 0;
514 i < len && *outlen <= 260;
515 *outlen += 1)
516 {
517 if (escape && (*ip == ':')) {
518 if (i > len - 5)
519 return -EINVAL;
520 ec = 0;
521 for (k = 1; k < 5; k++) {
522 nc = ip[k];
523 ec <<= 4;
524 if (nc >= '' && nc <= '9') {
525 ec |= nc - '';
526 continue;
527 }
528 if (nc >= 'a' && nc <= 'f') {
529 ec |= nc - ('a' - 10);
530 continue;
531 }
532 if (nc >= 'A' && nc <= 'F') {
533 ec |= nc - ('A' - 10);
534 continue;
535 }
536 return -EINVAL;
537 }
538 *op++ = ec & 0xFF;
539 *op++ = ec >> 8;
540 ip += 5;
541 i += 5;
542 } else {
543 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0)
544 return -EINVAL;
545 ip += charlen;
546 i += charlen;
547 op += 2;
548 }
549 }
550 } else {
551 for (i = 0, ip = name, op = outname, *outlen = 0;
552 i < len && *outlen <= 260;
553 i++, *outlen += 1)
554 {
555 *op++ = *ip++;
556 *op++ = 0;
557 }
558 }
559 }
560 if (*outlen > 260)
561 return -ENAMETOOLONG;
562
563 *longlen = *outlen;
564 if (*outlen % 13) {
565 *op++ = 0;
566 *op++ = 0;
567 *outlen += 1;
568 if (*outlen % 13) {
569 fill = 13 - (*outlen % 13);
570 for (i = 0; i < fill; i++) {
571 *op++ = 0xff;
572 *op++ = 0xff;
573 }
574 *outlen += fill;
575 }
576 }
577
578 return 0;
579 }
580
581 static int vfat_build_slots(struct inode *dir, const unsigned char *name,
582 int len, struct msdos_dir_slot *ds,
583 int *slots, int is_dir)
584 {
585 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
586 struct fat_mount_options *opts = &sbi->options;
587 struct msdos_dir_slot *ps;
588 struct msdos_dir_entry *de;
589 unsigned long page;
590 unsigned char cksum, lcase;
591 unsigned char msdos_name[MSDOS_NAME];
592 wchar_t *uname;
593 int res, slot, ulen, usize, i;
594 loff_t offset;
595
596 *slots = 0;
597 res = vfat_valid_longname(name, len);
598 if (res)
599 return res;
600
601 page = __get_free_page(GFP_KERNEL);
602 if (!page)
603 return -ENOMEM;
604
605 uname = (wchar_t *)page;
606 res = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
607 opts->unicode_xlate, opts->utf8, sbi->nls_io);
608 if (res < 0)
609 goto out_free;
610
611 res = vfat_is_used_badchars(uname, ulen);
612 if (res < 0)
613 goto out_free;
614
615 res = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
616 msdos_name, &lcase);
617 if (res < 0)
618 goto out_free;
619 else if (res == 1) {
620 de = (struct msdos_dir_entry *)ds;
621 res = 0;
622 goto shortname;
623 }
624
625 /* build the entry of long file name */
626 *slots = usize / 13;
627 for (cksum = i = 0; i < 11; i++)
628 cksum = (((cksum&1)<<7)|((cksum&0xfe)>>1)) + msdos_name[i];
629
630 for (ps = ds, slot = *slots; slot > 0; slot--, ps++) {
631 ps->id = slot;
632 ps->attr = ATTR_EXT;
633 ps->reserved = 0;
634 ps->alias_checksum = cksum;
635 ps->start = 0;
636 offset = (slot - 1) * 13;
637 fatwchar_to16(ps->name0_4, uname + offset, 5);
638 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
639 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
640 }
641 ds[0].id |= 0x40;
642 de = (struct msdos_dir_entry *)ps;
643
644 shortname:
645 /* build the entry of 8.3 alias name */
646 (*slots)++;
647 memcpy(de->name, msdos_name, MSDOS_NAME);
648 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
649 de->lcase = lcase;
650 de->adate = de->cdate = de->date = 0;
651 de->ctime = de->time = 0;
652 de->ctime_ms = 0;
653 de->start = 0;
654 de->starthi = 0;
655 de->size = 0;
656
657 out_free:
658 free_page(page);
659 return res;
660 }
661
662 static int vfat_add_entry(struct inode *dir, struct qstr *qname,
663 int is_dir, struct vfat_slot_info *sinfo_out,
664 struct buffer_head **bh, struct msdos_dir_entry **de)
665 {
666 struct msdos_dir_slot *dir_slots;
667 loff_t offset;
668 int res, slots, slot;
669 unsigned int len;
670 struct msdos_dir_entry *dummy_de;
671 struct buffer_head *dummy_bh;
672 loff_t dummy_i_pos;
673
674 len = vfat_striptail_len(qname);
675 if (len == 0)
676 return -ENOENT;
677
678 dir_slots = kmalloc(sizeof(*dir_slots) * MSDOS_SLOTS, GFP_KERNEL);
679 if (dir_slots == NULL)
680 return -ENOMEM;
681
682 res = vfat_build_slots(dir, qname->name, len,
683 dir_slots, &slots, is_dir);
684 if (res < 0)
685 goto cleanup;
686
687 /* build the empty directory entry of number of slots */
688 offset =
689 fat_add_entries(dir, slots, &dummy_bh, &dummy_de, &dummy_i_pos);
690 if (offset < 0) {
691 res = offset;
692 goto cleanup;
693 }
694 brelse(dummy_bh);
695
696 /* Now create the new entry */
697 *bh = NULL;
698 for (slot = 0; slot < slots; slot++) {
699 if (fat_get_entry(dir, &offset, bh, de, &sinfo_out->i_pos) < 0) {
700 res = -EIO;
701 goto cleanup;
702 }
703 memcpy(*de, dir_slots + slot, sizeof(struct msdos_dir_slot));
704 mark_buffer_dirty(*bh);
705 }
706
707 res = 0;
708 /* update timestamp */
709 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
710 mark_inode_dirty(dir);
711
712 fat_date_unix2dos(dir->i_mtime.tv_sec, &(*de)->time, &(*de)->date);
713 dir->i_mtime.tv_nsec = 0;
714 (*de)->ctime = (*de)->time;
715 (*de)->adate = (*de)->cdate = (*de)->date;
716
717 mark_buffer_dirty(*bh);
718
719 /* slots can't be less than 1 */
720 sinfo_out->long_slots = slots - 1;
721 sinfo_out->longname_offset =
722 offset - sizeof(struct msdos_dir_slot) * slots;
723
724 cleanup:
725 kfree(dir_slots);
726 return res;
727 }
728
729 static int vfat_find(struct inode *dir, struct qstr *qname,
730 struct vfat_slot_info *sinfo, struct buffer_head **last_bh,
731 struct msdos_dir_entry **last_de)
732 {
733 struct super_block *sb = dir->i_sb;
734 loff_t offset;
735 unsigned int len;
736 int res;
737
738 len = vfat_striptail_len(qname);
739 if (len == 0)
740 return -ENOENT;
741
742 res = fat_search_long(dir, qname->name, len,
743 (MSDOS_SB(sb)->options.name_check != 's'),
744 &offset, &sinfo->longname_offset);
745 if (res > 0) {
746 sinfo->long_slots = res - 1;
747 if (fat_get_entry(dir, &offset, last_bh, last_de, &sinfo->i_pos) >= 0)
748 return 0;
749 res = -EIO;
750 }
751 return res ? res : -ENOENT;
752 }
753
754 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
755 struct nameidata *nd)
756 {
757 int res;
758 struct vfat_slot_info sinfo;
759 struct inode *inode;
760 struct dentry *alias;
761 struct buffer_head *bh = NULL;
762 struct msdos_dir_entry *de;
763 int table;
764
765 lock_kernel();
766 table = (MSDOS_SB(dir->i_sb)->options.name_check == 's') ? 2 : 0;
767 dentry->d_op = &vfat_dentry_ops[table];
768
769 inode = NULL;
770 res = vfat_find(dir, &dentry->d_name, &sinfo, &bh, &de);
771 if (res < 0) {
772 table++;
773 goto error;
774 }
775 inode = fat_build_inode(dir->i_sb, de, sinfo.i_pos, &res);
776 brelse(bh);
777 if (res) {
778 unlock_kernel();
779 return ERR_PTR(res);
780 }
781 alias = d_find_alias(inode);
782 if (alias) {
783 if (d_invalidate(alias) == 0)
784 dput(alias);
785 else {
786 iput(inode);
787 unlock_kernel();
788 return alias;
789 }
790
791 }
792 error:
793 unlock_kernel();
794 dentry->d_op = &vfat_dentry_ops[table];
795 dentry->d_time = dentry->d_parent->d_inode->i_version;
796 dentry = d_splice_alias(inode, dentry);
797 if (dentry) {
798 dentry->d_op = &vfat_dentry_ops[table];
799 dentry->d_time = dentry->d_parent->d_inode->i_version;
800 }
801 return dentry;
802 }
803
804 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode,
805 struct nameidata *nd)
806 {
807 struct super_block *sb = dir->i_sb;
808 struct inode *inode = NULL;
809 struct buffer_head *bh = NULL;
810 struct msdos_dir_entry *de;
811 struct vfat_slot_info sinfo;
812 int res;
813
814 lock_kernel();
815 res = vfat_add_entry(dir, &dentry->d_name, 0, &sinfo, &bh, &de);
816 if (res < 0)
817 goto out;
818 inode = fat_build_inode(sb, de, sinfo.i_pos, &res);
819 brelse(bh);
820 if (!inode)
821 goto out;
822 res = 0;
823 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
824 mark_inode_dirty(inode);
825 inode->i_version++;
826 dir->i_version++;
827 dentry->d_time = dentry->d_parent->d_inode->i_version;
828 d_instantiate(dentry, inode);
829 out:
830 unlock_kernel();
831 return res;
832 }
833
834 static void vfat_remove_entry(struct inode *dir, struct vfat_slot_info *sinfo,
835 struct buffer_head *bh,
836 struct msdos_dir_entry *de)
837 {
838 loff_t offset, i_pos;
839 int i;
840
841 /* remove the shortname */
842 dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
843 dir->i_version++;
844 mark_inode_dirty(dir);
845 de->name[0] = DELETED_FLAG;
846 mark_buffer_dirty(bh);
847 /* remove the longname */
848 offset = sinfo->longname_offset;
849 de = NULL;
850 for (i = sinfo->long_slots; i > 0; --i) {
851 if (fat_get_entry(dir, &offset, &bh, &de, &i_pos) < 0)
852 continue;
853 de->name[0] = DELETED_FLAG;
854 de->attr = ATTR_NONE;
855 mark_buffer_dirty(bh);
856 }
857 brelse(bh);
858 }
859
860 static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
861 {
862 struct inode *inode = dentry->d_inode;
863 struct vfat_slot_info sinfo;
864 struct buffer_head *bh = NULL;
865 struct msdos_dir_entry *de;
866 int res;
867
868 lock_kernel();
869 res = fat_dir_empty(inode);
870 if (res)
871 goto out;
872
873 res = vfat_find(dir, &dentry->d_name, &sinfo, &bh, &de);
874 if (res < 0)
875 goto out;
876
877 res = 0;
878 inode->i_nlink = 0;
879 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
880 fat_detach(inode);
881 mark_inode_dirty(inode);
882 /* releases bh */
883 vfat_remove_entry(dir, &sinfo, bh, de);
884 dir->i_nlink--;
885 out:
886 unlock_kernel();
887 return res;
888 }
889
890 static int vfat_unlink(struct inode *dir, struct dentry *dentry)
891 {
892 struct inode *inode = dentry->d_inode;
893 struct vfat_slot_info sinfo;
894 struct buffer_head *bh = NULL;
895 struct msdos_dir_entry *de;
896 int res;
897
898 lock_kernel();
899 res = vfat_find(dir, &dentry->d_name, &sinfo, &bh, &de);
900 if (res < 0)
901 goto out;
902 inode->i_nlink = 0;
903 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
904 fat_detach(inode);
905 mark_inode_dirty(inode);
906 /* releases bh */
907 vfat_remove_entry(dir, &sinfo, bh, de);
908 out:
909 unlock_kernel();
910
911 return res;
912 }
913
914 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode)
915 {
916 struct super_block *sb = dir->i_sb;
917 struct inode *inode = NULL;
918 struct vfat_slot_info sinfo;
919 struct buffer_head *bh = NULL;
920 struct msdos_dir_entry *de;
921 int res;
922
923 lock_kernel();
924 res = vfat_add_entry(dir, &dentry->d_name, 1, &sinfo, &bh, &de);
925 if (res < 0)
926 goto out;
927 inode = fat_build_inode(sb, de, sinfo.i_pos, &res);
928 if (!inode)
929 goto out_brelse;
930 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
931 mark_inode_dirty(inode);
932 inode->i_version++;
933 dir->i_version++;
934 dir->i_nlink++;
935 inode->i_nlink = 2; /* no need to mark them dirty */
936 res = fat_new_dir(inode, dir, 1);
937 if (res < 0)
938 goto mkdir_failed;
939 dentry->d_time = dentry->d_parent->d_inode->i_version;
940 d_instantiate(dentry, inode);
941 out_brelse:
942 brelse(bh);
943 out:
944 unlock_kernel();
945 return res;
946
947 mkdir_failed:
948 inode->i_nlink = 0;
949 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
950 fat_detach(inode);
951 mark_inode_dirty(inode);
952 /* releases bh */
953 vfat_remove_entry(dir, &sinfo, bh, de);
954 iput(inode);
955 dir->i_nlink--;
956 goto out;
957 }
958
959 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
960 struct inode *new_dir, struct dentry *new_dentry)
961 {
962 struct buffer_head *old_bh, *new_bh, *dotdot_bh;
963 struct msdos_dir_entry *old_de, *new_de, *dotdot_de;
964 loff_t dotdot_i_pos;
965 struct inode *old_inode, *new_inode;
966 int res, is_dir;
967 struct vfat_slot_info old_sinfo, sinfo;
968
969 old_bh = new_bh = dotdot_bh = NULL;
970 old_inode = old_dentry->d_inode;
971 new_inode = new_dentry->d_inode;
972 lock_kernel();
973 res = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo, &old_bh,
974 &old_de);
975 if (res < 0)
976 goto rename_done;
977
978 is_dir = S_ISDIR(old_inode->i_mode);
979
980 if (is_dir) {
981 if (fat_scan(old_inode, MSDOS_DOTDOT, &dotdot_bh,
982 &dotdot_de, &dotdot_i_pos) < 0) {
983 res = -EIO;
984 goto rename_done;
985 }
986 }
987
988 if (new_dentry->d_inode) {
989 res = vfat_find(new_dir, &new_dentry->d_name, &sinfo, &new_bh,
990 &new_de);
991 if (res < 0 || MSDOS_I(new_inode)->i_pos != sinfo.i_pos) {
992 /* WTF??? Cry and fail. */
993 printk(KERN_WARNING "vfat_rename: fs corrupted\n");
994 goto rename_done;
995 }
996
997 if (is_dir) {
998 res = fat_dir_empty(new_inode);
999 if (res)
1000 goto rename_done;
1001 }
1002 fat_detach(new_inode);
1003 } else {
1004 res = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir,
1005 &sinfo, &new_bh, &new_de);
1006 if (res < 0)
1007 goto rename_done;
1008 }
1009
1010 new_dir->i_version++;
1011
1012 /* releases old_bh */
1013 vfat_remove_entry(old_dir, &old_sinfo, old_bh, old_de);
1014 old_bh = NULL;
1015 fat_detach(old_inode);
1016 fat_attach(old_inode, sinfo.i_pos);
1017 mark_inode_dirty(old_inode);
1018
1019 old_dir->i_version++;
1020 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
1021 mark_inode_dirty(old_dir);
1022 if (new_inode) {
1023 new_inode->i_nlink--;
1024 new_inode->i_ctime = CURRENT_TIME_SEC;
1025 }
1026
1027 if (is_dir) {
1028 int start = MSDOS_I(new_dir)->i_logstart;
1029 dotdot_de->start = cpu_to_le16(start);
1030 dotdot_de->starthi = cpu_to_le16(start>>16);
1031 mark_buffer_dirty(dotdot_bh);
1032 old_dir->i_nlink--;
1033 if (new_inode) {
1034 new_inode->i_nlink--;
1035 } else {
1036 new_dir->i_nlink++;
1037 mark_inode_dirty(new_dir);
1038 }
1039 }
1040
1041 rename_done:
1042 brelse(dotdot_bh);
1043 brelse(old_bh);
1044 brelse(new_bh);
1045 unlock_kernel();
1046 return res;
1047 }
1048
1049 static struct inode_operations vfat_dir_inode_operations = {
1050 .create = vfat_create,
1051 .lookup = vfat_lookup,
1052 .unlink = vfat_unlink,
1053 .mkdir = vfat_mkdir,
1054 .rmdir = vfat_rmdir,
1055 .rename = vfat_rename,
1056 .setattr = fat_notify_change,
1057 };
1058
1059 static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1060 {
1061 int res;
1062
1063 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
1064 if (res)
1065 return res;
1066
1067 if (MSDOS_SB(sb)->options.name_check != 's')
1068 sb->s_root->d_op = &vfat_dentry_ops[0];
1069 else
1070 sb->s_root->d_op = &vfat_dentry_ops[2];
1071
1072 return 0;
1073 }
1074
1075 static struct super_block *vfat_get_sb(struct file_system_type *fs_type,
1076 int flags, const char *dev_name,
1077 void *data)
1078 {
1079 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
1080 }
1081
1082 static struct file_system_type vfat_fs_type = {
1083 .owner = THIS_MODULE,
1084 .name = "vfat",
1085 .get_sb = vfat_get_sb,
1086 .kill_sb = kill_block_super,
1087 .fs_flags = FS_REQUIRES_DEV,
1088 };
1089
1090 static int __init init_vfat_fs(void)
1091 {
1092 return register_filesystem(&vfat_fs_type);
1093 }
1094
1095 static void __exit exit_vfat_fs(void)
1096 {
1097 unregister_filesystem(&vfat_fs_type);
1098 }
1099
1100 MODULE_LICENSE("GPL");
1101 MODULE_DESCRIPTION("VFAT filesystem support");
1102 MODULE_AUTHOR("Gordon Chaffee");
1103
1104 module_init(init_vfat_fs)
1105 module_exit(exit_vfat_fs)
1106
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