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fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / fs / vfat / namei.c
blobc28add2fbe95eebce0ec79de64e8389be793ea26
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 return 0;
189 }
190
191 static int vfat_find_form(struct inode *dir, unsigned char *name)
192 {
193 struct fat_slot_info sinfo;
194 int err = fat_scan(dir, name, &sinfo);
195 if (err)
196 return -ENOENT;
197 brelse(sinfo.bh);
198 return 0;
199 }
200
201 /*
202 * 1) Valid characters for the 8.3 format alias are any combination of
203 * letters, uppercase alphabets, digits, any of the
204 * following special characters:
205 * $ % ' ` - @ { } ~ ! # ( ) & _ ^
206 * In this case Longfilename is not stored in disk.
207 *
208 * WinNT's Extension:
209 * File name and extension name is contain uppercase/lowercase
210 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
211 *
212 * 2) File name is 8.3 format, but it contain the uppercase and
213 * lowercase char, muliti bytes char, etc. In this case numtail is not
214 * added, but Longfilename is stored.
215 *
216 * 3) When the one except for the above, or the following special
217 * character are contained:
218 * . [ ] ; , + =
219 * numtail is added, and Longfilename must be stored in disk .
220 */
221 struct shortname_info {
222 unsigned char lower:1,
223 upper:1,
224 valid:1;
225 };
226 #define INIT_SHORTNAME_INFO(x) do { \
227 (x)->lower = 1; \
228 (x)->upper = 1; \
229 (x)->valid = 1; \
230 } while (0)
231
232 static inline int to_shortname_char(struct nls_table *nls,
233 unsigned char *buf, int buf_size,
234 wchar_t *src, struct shortname_info *info)
235 {
236 int len;
237
238 if (vfat_skip_char(*src)) {
239 info->valid = 0;
240 return 0;
241 }
242 if (vfat_replace_char(*src)) {
243 info->valid = 0;
244 buf[0] = '_';
245 return 1;
246 }
247
248 len = nls->uni2char(*src, buf, buf_size);
249 if (len <= 0) {
250 info->valid = 0;
251 buf[0] = '_';
252 len = 1;
253 } else if (len == 1) {
254 unsigned char prev = buf[0];
255
256 if (buf[0] >= 0x7F) {
257 info->lower = 0;
258 info->upper = 0;
259 }
260
261 buf[0] = nls_toupper(nls, buf[0]);
262 if (isalpha(buf[0])) {
263 if (buf[0] == prev)
264 info->lower = 0;
265 else
266 info->upper = 0;
267 }
268 } else {
269 info->lower = 0;
270 info->upper = 0;
271 }
272
273 return len;
274 }
275
276 /*
277 * Given a valid longname, create a unique shortname. Make sure the
278 * shortname does not exist
279 * Returns negative number on error, 0 for a normal
280 * return, and 1 for valid shortname
281 */
282 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
283 wchar_t *uname, int ulen,
284 unsigned char *name_res, unsigned char *lcase)
285 {
286 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
287 wchar_t *ip, *ext_start, *end, *name_start;
288 unsigned char base[9], ext[4], buf[8], *p;
289 unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
290 int chl, chi;
291 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
292 int is_shortname;
293 struct shortname_info base_info, ext_info;
294
295 is_shortname = 1;
296 INIT_SHORTNAME_INFO(&base_info);
297 INIT_SHORTNAME_INFO(&ext_info);
298
299 /* Now, we need to create a shortname from the long name */
300 ext_start = end = &uname[ulen];
301 while (--ext_start >= uname) {
302 if (*ext_start == 0x002E) { /* is `.' */
303 if (ext_start == end - 1) {
304 sz = ulen;
305 ext_start = NULL;
306 }
307 break;
308 }
309 }
310
311 if (ext_start == uname - 1) {
312 sz = ulen;
313 ext_start = NULL;
314 } else if (ext_start) {
315 /*
316 * Names which start with a dot could be just
317 * an extension eg. "...test". In this case Win95
318 * uses the extension as the name and sets no extension.
319 */
320 name_start = &uname[0];
321 while (name_start < ext_start) {
322 if (!vfat_skip_char(*name_start))
323 break;
324 name_start++;
325 }
326 if (name_start != ext_start) {
327 sz = ext_start - uname;
328 ext_start++;
329 } else {
330 sz = ulen;
331 ext_start = NULL;
332 }
333 }
334
335 numtail_baselen = 6;
336 numtail2_baselen = 2;
337 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
338 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
339 ip, &base_info);
340 if (chl == 0)
341 continue;
342
343 if (baselen < 2 && (baselen + chl) > 2)
344 numtail2_baselen = baselen;
345 if (baselen < 6 && (baselen + chl) > 6)
346 numtail_baselen = baselen;
347 for (chi = 0; chi < chl; chi++) {
348 *p++ = charbuf[chi];
349 baselen++;
350 if (baselen >= 8)
351 break;
352 }
353 if (baselen >= 8) {
354 if ((chi < chl - 1) || (ip + 1) - uname < sz)
355 is_shortname = 0;
356 break;
357 }
358 }
359 if (baselen == 0) {
360 return -EINVAL;
361 }
362
363 extlen = 0;
364 if (ext_start) {
365 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
366 chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
367 ip, &ext_info);
368 if (chl == 0)
369 continue;
370
371 if ((extlen + chl) > 3) {
372 is_shortname = 0;
373 break;
374 }
375 for (chi = 0; chi < chl; chi++) {
376 *p++ = charbuf[chi];
377 extlen++;
378 }
379 if (extlen >= 3) {
380 if (ip + 1 != end)
381 is_shortname = 0;
382 break;
383 }
384 }
385 }
386 ext[extlen] = '\0';
387 base[baselen] = '\0';
388
389 /* Yes, it can happen. ".\xe5" would do it. */
390 if (base[0] == DELETED_FLAG)
391 base[0] = 0x05;
392
393 /* OK, at this point we know that base is not longer than 8 symbols,
394 * ext is not longer than 3, base is nonempty, both don't contain
395 * any bad symbols (lowercase transformed to uppercase).
396 */
397
398 memset(name_res, ' ', MSDOS_NAME);
399 memcpy(name_res, base, baselen);
400 memcpy(name_res + 8, ext, extlen);
401 *lcase = 0;
402 if (is_shortname && base_info.valid && ext_info.valid) {
403 if (vfat_find_form(dir, name_res) == 0)
404 return -EEXIST;
405
406 if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
407 return (base_info.upper && ext_info.upper);
408 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
409 if ((base_info.upper || base_info.lower) &&
410 (ext_info.upper || ext_info.lower)) {
411 if (!base_info.upper && base_info.lower)
412 *lcase |= CASE_LOWER_BASE;
413 if (!ext_info.upper && ext_info.lower)
414 *lcase |= CASE_LOWER_EXT;
415 return 1;
416 }
417 return 0;
418 } else {
419 BUG();
420 }
421 }
422
423 if (opts->numtail == 0)
424 if (vfat_find_form(dir, name_res) < 0)
425 return 0;
426
427 /*
428 * Try to find a unique extension. This used to
429 * iterate through all possibilities sequentially,
430 * but that gave extremely bad performance. Windows
431 * only tries a few cases before using random
432 * values for part of the base.
433 */
434
435 if (baselen > 6) {
436 baselen = numtail_baselen;
437 name_res[7] = ' ';
438 }
439 name_res[baselen] = '~';
440 for (i = 1; i < 10; i++) {
441 name_res[baselen + 1] = i + '0';
442 if (vfat_find_form(dir, name_res) < 0)
443 return 0;
444 }
445
446 i = jiffies & 0xffff;
447 sz = (jiffies >> 16) & 0x7;
448 if (baselen > 2) {
449 baselen = numtail2_baselen;
450 name_res[7] = ' ';
451 }
452 name_res[baselen + 4] = '~';
453 name_res[baselen + 5] = '1' + sz;
454 while (1) {
455 sprintf(buf, "%04X", i);
456 memcpy(&name_res[baselen], buf, 4);
457 if (vfat_find_form(dir, name_res) < 0)
458 break;
459 i -= 11;
460 }
461 return 0;
462 }
463
464 /* Translate a string, including coded sequences into Unicode */
465 static int
466 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
467 int *longlen, int *outlen, int escape, int utf8,
468 struct nls_table *nls)
469 {
470 const unsigned char *ip;
471 unsigned char nc;
472 unsigned char *op;
473 unsigned int ec;
474 int i, k, fill;
475 int charlen;
476
477 if (utf8) {
478 int name_len = strlen(name);
479
480 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PAGE_SIZE);
481
482 /*
483 * We stripped '.'s before and set len appropriately,
484 * but utf8_mbstowcs doesn't care about len
485 */
486 *outlen -= (name_len - len);
487
488 op = &outname[*outlen * sizeof(wchar_t)];
489 } else {
490 if (nls) {
491 for (i = 0, ip = name, op = outname, *outlen = 0;
492 i < len && *outlen <= 260;
493 *outlen += 1)
494 {
495 if (escape && (*ip == ':')) {
496 if (i > len - 5)
497 return -EINVAL;
498 ec = 0;
499 for (k = 1; k < 5; k++) {
500 nc = ip[k];
501 ec <<= 4;
502 if (nc >= '0' && nc <= '9') {
503 ec |= nc - '0';
504 continue;
505 }
506 if (nc >= 'a' && nc <= 'f') {
507 ec |= nc - ('a' - 10);
508 continue;
509 }
510 if (nc >= 'A' && nc <= 'F') {
511 ec |= nc - ('A' - 10);
512 continue;
513 }
514 return -EINVAL;
515 }
516 *op++ = ec & 0xFF;
517 *op++ = ec >> 8;
518 ip += 5;
519 i += 5;
520 } else {
521 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0)
522 return -EINVAL;
523 ip += charlen;
524 i += charlen;
525 op += 2;
526 }
527 }
528 } else {
529 for (i = 0, ip = name, op = outname, *outlen = 0;
530 i < len && *outlen <= 260;
531 i++, *outlen += 1)
532 {
533 *op++ = *ip++;
534 *op++ = 0;
535 }
536 }
537 }
538 if (*outlen > 260)
539 return -ENAMETOOLONG;
540
541 *longlen = *outlen;
542 if (*outlen % 13) {
543 *op++ = 0;
544 *op++ = 0;
545 *outlen += 1;
546 if (*outlen % 13) {
547 fill = 13 - (*outlen % 13);
548 for (i = 0; i < fill; i++) {
549 *op++ = 0xff;
550 *op++ = 0xff;
551 }
552 *outlen += fill;
553 }
554 }
555
556 return 0;
557 }
558
559 static int vfat_build_slots(struct inode *dir, const unsigned char *name,
560 int len, int is_dir, int cluster,
561 struct timespec *ts,
562 struct msdos_dir_slot *slots, int *nr_slots)
563 {
564 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
565 struct fat_mount_options *opts = &sbi->options;
566 struct msdos_dir_slot *ps;
567 struct msdos_dir_entry *de;
568 unsigned long page;
569 unsigned char cksum, lcase;
570 unsigned char msdos_name[MSDOS_NAME];
571 wchar_t *uname;
572 __le16 time, date;
573 int err, ulen, usize, i;
574 loff_t offset;
575
576 *nr_slots = 0;
577 err = vfat_valid_longname(name, len);
578 if (err)
579 return err;
580
581 page = __get_free_page(GFP_KERNEL);
582 if (!page)
583 return -ENOMEM;
584
585 uname = (wchar_t *)page;
586 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
587 opts->unicode_xlate, opts->utf8, sbi->nls_io);
588 if (err)
589 goto out_free;
590
591 err = vfat_is_used_badchars(uname, ulen);
592 if (err)
593 goto out_free;
594
595 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
596 msdos_name, &lcase);
597 if (err < 0)
598 goto out_free;
599 else if (err == 1) {
600 de = (struct msdos_dir_entry *)slots;
601 err = 0;
602 goto shortname;
603 }
604
605 /* build the entry of long file name */
606 cksum = fat_checksum(msdos_name);
607
608 *nr_slots = usize / 13;
609 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
610 ps->id = i;
611 ps->attr = ATTR_EXT;
612 ps->reserved = 0;
613 ps->alias_checksum = cksum;
614 ps->start = 0;
615 offset = (i - 1) * 13;
616 fatwchar_to16(ps->name0_4, uname + offset, 5);
617 fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
618 fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
619 }
620 slots[0].id |= 0x40;
621 de = (struct msdos_dir_entry *)ps;
622
623 shortname:
624 /* build the entry of 8.3 alias name */
625 (*nr_slots)++;
626 memcpy(de->name, msdos_name, MSDOS_NAME);
627 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
628 de->lcase = lcase;
629 fat_date_unix2dos(ts->tv_sec, &time, &date);
630 de->time = de->ctime = time;
631 de->date = de->cdate = de->adate = date;
632 de->ctime_cs = 0;
633 de->start = cpu_to_le16(cluster);
634 de->starthi = cpu_to_le16(cluster >> 16);
635 de->size = 0;
636 out_free:
637 free_page(page);
638 return err;
639 }
640
641 static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
642 int cluster, struct timespec *ts,
643 struct fat_slot_info *sinfo)
644 {
645 struct msdos_dir_slot *slots;
646 unsigned int len;
647 int err, nr_slots;
648
649 len = vfat_striptail_len(qname);
650 if (len == 0)
651 return -ENOENT;
652
653 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_KERNEL);
654 if (slots == NULL)
655 return -ENOMEM;
656
657 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
658 slots, &nr_slots);
659 if (err)
660 goto cleanup;
661
662 err = fat_add_entries(dir, slots, nr_slots, sinfo);
663 if (err)
664 goto cleanup;
665
666 /* update timestamp */
667 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
668 if (IS_DIRSYNC(dir))
669 (void)fat_sync_inode(dir);
670 else
671 mark_inode_dirty(dir);
672 cleanup:
673 kfree(slots);
674 return err;
675 }
676
677 static int vfat_find(struct inode *dir, struct qstr *qname,
678 struct fat_slot_info *sinfo)
679 {
680 unsigned int len = vfat_striptail_len(qname);
681 if (len == 0)
682 return -ENOENT;
683 return fat_search_long(dir, qname->name, len, sinfo);
684 }
685
686 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
687 struct nameidata *nd)
688 {
689 struct super_block *sb = dir->i_sb;
690 struct fat_slot_info sinfo;
691 struct inode *inode = NULL;
692 struct dentry *alias;
693 int err, table;
694
695 lock_kernel();
696 table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0;
697 dentry->d_op = &vfat_dentry_ops[table];
698
699 err = vfat_find(dir, &dentry->d_name, &sinfo);
700 if (err) {
701 table++;
702 goto error;
703 }
704 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
705 brelse(sinfo.bh);
706 if (IS_ERR(inode)) {
707 unlock_kernel();
708 return ERR_PTR(PTR_ERR(inode));
709 }
710 alias = d_find_alias(inode);
711 if (alias) {
712 if (d_invalidate(alias) == 0)
713 dput(alias);
714 else {
715 iput(inode);
716 unlock_kernel();
717 return alias;
718 }
719
720 }
721 error:
722 unlock_kernel();
723 dentry->d_op = &vfat_dentry_ops[table];
724 dentry->d_time = dentry->d_parent->d_inode->i_version;
725 dentry = d_splice_alias(inode, dentry);
726 if (dentry) {
727 dentry->d_op = &vfat_dentry_ops[table];
728 dentry->d_time = dentry->d_parent->d_inode->i_version;
729 }
730 return dentry;
731 }
732
733 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode,
734 struct nameidata *nd)
735 {
736 struct super_block *sb = dir->i_sb;
737 struct inode *inode;
738 struct fat_slot_info sinfo;
739 struct timespec ts;
740 int err;
741
742 lock_kernel();
743
744 ts = CURRENT_TIME_SEC;
745 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
746 if (err)
747 goto out;
748 dir->i_version++;
749
750 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
751 brelse(sinfo.bh);
752 if (IS_ERR(inode)) {
753 err = PTR_ERR(inode);
754 goto out;
755 }
756 inode->i_version++;
757 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
758 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
759
760 dentry->d_time = dentry->d_parent->d_inode->i_version;
761 d_instantiate(dentry, inode);
762 out:
763 unlock_kernel();
764 return err;
765 }
766
767 static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
768 {
769 struct inode *inode = dentry->d_inode;
770 struct fat_slot_info sinfo;
771 int err;
772
773 lock_kernel();
774
775 err = fat_dir_empty(inode);
776 if (err)
777 goto out;
778 err = vfat_find(dir, &dentry->d_name, &sinfo);
779 if (err)
780 goto out;
781
782 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
783 if (err)
784 goto out;
785 drop_nlink(dir);
786
787 clear_nlink(inode);
788 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
789 fat_detach(inode);
790 out:
791 unlock_kernel();
792
793 return err;
794 }
795
796 static int vfat_unlink(struct inode *dir, struct dentry *dentry)
797 {
798 struct inode *inode = dentry->d_inode;
799 struct fat_slot_info sinfo;
800 int err;
801
802 lock_kernel();
803
804 err = vfat_find(dir, &dentry->d_name, &sinfo);
805 if (err)
806 goto out;
807
808 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
809 if (err)
810 goto out;
811 clear_nlink(inode);
812 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
813 fat_detach(inode);
814 out:
815 unlock_kernel();
816
817 return err;
818 }
819
820 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode)
821 {
822 struct super_block *sb = dir->i_sb;
823 struct inode *inode;
824 struct fat_slot_info sinfo;
825 struct timespec ts;
826 int err, cluster;
827
828 lock_kernel();
829
830 ts = CURRENT_TIME_SEC;
831 cluster = fat_alloc_new_dir(dir, &ts);
832 if (cluster < 0) {
833 err = cluster;
834 goto out;
835 }
836 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
837 if (err)
838 goto out_free;
839 dir->i_version++;
840 inc_nlink(dir);
841
842 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
843 brelse(sinfo.bh);
844 if (IS_ERR(inode)) {
845 err = PTR_ERR(inode);
846 /* the directory was completed, just return a error */
847 goto out;
848 }
849 inode->i_version++;
850 inode->i_nlink = 2;
851 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
852 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
853
854 dentry->d_time = dentry->d_parent->d_inode->i_version;
855 d_instantiate(dentry, inode);
856
857 unlock_kernel();
858 return 0;
859
860 out_free:
861 fat_free_clusters(dir, cluster);
862 out:
863 unlock_kernel();
864 return err;
865 }
866
867 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
868 struct inode *new_dir, struct dentry *new_dentry)
869 {
870 struct buffer_head *dotdot_bh;
871 struct msdos_dir_entry *dotdot_de;
872 struct inode *old_inode, *new_inode;
873 struct fat_slot_info old_sinfo, sinfo;
874 struct timespec ts;
875 loff_t dotdot_i_pos, new_i_pos;
876 int err, is_dir, update_dotdot, corrupt = 0;
877
878 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
879 old_inode = old_dentry->d_inode;
880 new_inode = new_dentry->d_inode;
881 lock_kernel();
882 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
883 if (err)
884 goto out;
885
886 is_dir = S_ISDIR(old_inode->i_mode);
887 update_dotdot = (is_dir && old_dir != new_dir);
888 if (update_dotdot) {
889 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
890 &dotdot_i_pos) < 0) {
891 err = -EIO;
892 goto out;
893 }
894 }
895
896 ts = CURRENT_TIME_SEC;
897 if (new_inode) {
898 if (is_dir) {
899 err = fat_dir_empty(new_inode);
900 if (err)
901 goto out;
902 }
903 new_i_pos = MSDOS_I(new_inode)->i_pos;
904 fat_detach(new_inode);
905 } else {
906 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
907 &ts, &sinfo);
908 if (err)
909 goto out;
910 new_i_pos = sinfo.i_pos;
911 }
912 new_dir->i_version++;
913
914 fat_detach(old_inode);
915 fat_attach(old_inode, new_i_pos);
916 if (IS_DIRSYNC(new_dir)) {
917 err = fat_sync_inode(old_inode);
918 if (err)
919 goto error_inode;
920 } else
921 mark_inode_dirty(old_inode);
922
923 if (update_dotdot) {
924 int start = MSDOS_I(new_dir)->i_logstart;
925 dotdot_de->start = cpu_to_le16(start);
926 dotdot_de->starthi = cpu_to_le16(start >> 16);
927 mark_buffer_dirty(dotdot_bh);
928 if (IS_DIRSYNC(new_dir)) {
929 err = sync_dirty_buffer(dotdot_bh);
930 if (err)
931 goto error_dotdot;
932 }
933 drop_nlink(old_dir);
934 if (!new_inode)
935 inc_nlink(new_dir);
936 }
937
938 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
939 old_sinfo.bh = NULL;
940 if (err)
941 goto error_dotdot;
942 old_dir->i_version++;
943 old_dir->i_ctime = old_dir->i_mtime = ts;
944 if (IS_DIRSYNC(old_dir))
945 (void)fat_sync_inode(old_dir);
946 else
947 mark_inode_dirty(old_dir);
948
949 if (new_inode) {
950 drop_nlink(new_inode);
951 if (is_dir)
952 drop_nlink(new_inode);
953 new_inode->i_ctime = ts;
954 }
955 out:
956 brelse(sinfo.bh);
957 brelse(dotdot_bh);
958 brelse(old_sinfo.bh);
959 unlock_kernel();
960
961 return err;
962
963 error_dotdot:
964 /* data cluster is shared, serious corruption */
965 corrupt = 1;
966
967 if (update_dotdot) {
968 int start = MSDOS_I(old_dir)->i_logstart;
969 dotdot_de->start = cpu_to_le16(start);
970 dotdot_de->starthi = cpu_to_le16(start >> 16);
971 mark_buffer_dirty(dotdot_bh);
972 corrupt |= sync_dirty_buffer(dotdot_bh);
973 }
974 error_inode:
975 fat_detach(old_inode);
976 fat_attach(old_inode, old_sinfo.i_pos);
977 if (new_inode) {
978 fat_attach(new_inode, new_i_pos);
979 if (corrupt)
980 corrupt |= fat_sync_inode(new_inode);
981 } else {
982 /*
983 * If new entry was not sharing the data cluster, it
984 * shouldn't be serious corruption.
985 */
986 int err2 = fat_remove_entries(new_dir, &sinfo);
987 if (corrupt)
988 corrupt |= err2;
989 sinfo.bh = NULL;
990 }
991 if (corrupt < 0) {
992 fat_fs_panic(new_dir->i_sb,
993 "%s: Filesystem corrupted (i_pos %lld)",
994 __FUNCTION__, sinfo.i_pos);
995 }
996 goto out;
997 }
998
999 static const struct inode_operations vfat_dir_inode_operations = {
1000 .create = vfat_create,
1001 .lookup = vfat_lookup,
1002 .unlink = vfat_unlink,
1003 .mkdir = vfat_mkdir,
1004 .rmdir = vfat_rmdir,
1005 .rename = vfat_rename,
1006 .setattr = fat_notify_change,
1007 .getattr = fat_getattr,
1008 };
1009
1010 static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1011 {
1012 int res;
1013
1014 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
1015 if (res)
1016 return res;
1017
1018 if (MSDOS_SB(sb)->options.name_check != 's')
1019 sb->s_root->d_op = &vfat_dentry_ops[0];
1020 else
1021 sb->s_root->d_op = &vfat_dentry_ops[2];
1022
1023 return 0;
1024 }
1025
1026 static int vfat_get_sb(struct file_system_type *fs_type,
1027 int flags, const char *dev_name,
1028 void *data, struct vfsmount *mnt)
1029 {
1030 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super,
1031 mnt);
1032 }
1033
1034 static struct file_system_type vfat_fs_type = {
1035 .owner = THIS_MODULE,
1036 .name = "vfat",
1037 .get_sb = vfat_get_sb,
1038 .kill_sb = kill_block_super,
1039 .fs_flags = FS_REQUIRES_DEV,
1040 };
1041
1042 static int __init init_vfat_fs(void)
1043 {
1044 return register_filesystem(&vfat_fs_type);
1045 }
1046
1047 static void __exit exit_vfat_fs(void)
1048 {
1049 unregister_filesystem(&vfat_fs_type);
1050 }
1051
1052 MODULE_LICENSE("GPL");
1053 MODULE_DESCRIPTION("VFAT filesystem support");
1054 MODULE_AUTHOR("Gordon Chaffee");
1055
1056 module_init(init_vfat_fs)
1057 module_exit(exit_vfat_fs)
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