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 #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> 25 #include "fat.h" 26 27 /* 28 * If new entry was created in the parent, it could create the 8.3 29 * alias (the shortname of logname). So, the parent may have the 30 * negative-dentry which matches the created 8.3 alias. 31 * 32 * If it happened, the negative dentry isn't actually negative 33 * anymore. So, drop it. 34 */ 35 static int vfat_revalidate_shortname(struct dentry *dentry) 36 { 37 int ret = 1; 38 spin_lock(&dentry->d_lock); 39 if (dentry->d_time != dentry->d_parent->d_inode->i_version) 40 ret = 0; 41 spin_unlock(&dentry->d_lock); 42 return ret; 43 } 44 45 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) 46 { 47 /* This is not negative dentry. Always valid. */ 48 if (dentry->d_inode) 49 return 1; 50 return vfat_revalidate_shortname(dentry); 51 } 52 53 static int vfat_revalidate_ci(struct dentry *dentry, struct nameidata *nd) 54 { 55 /* 56 * This is not negative dentry. Always valid. 57 * 58 * Note, rename() to existing directory entry will have ->d_inode, 59 * and will use existing name which isn't specified name by user. 60 * 61 * We may be able to drop this positive dentry here. But dropping 62 * positive dentry isn't good idea. So it's unsupported like 63 * rename("filename", "FILENAME") for now. 64 */ 65 if (dentry->d_inode) 66 return 1; 67 68 /* 69 * This may be nfsd (or something), anyway, we can't see the 70 * intent of this. So, since this can be for creation, drop it. 71 */ 72 if (!nd) 73 return 0; 74 75 /* 76 * Drop the negative dentry, in order to make sure to use the 77 * case sensitive name which is specified by user if this is 78 * for creation. 79 */ 80 if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) { 81 if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 82 return 0; 83 } 84 85 return vfat_revalidate_shortname(dentry); 86 } 87 88 /* returns the length of a struct qstr, ignoring trailing dots */ 89 static unsigned int vfat_striptail_len(struct qstr *qstr) 90 { 91 unsigned int len = qstr->len; 92 93 while (len && qstr->name[len - 1] == '.') 94 len--; 95 return len; 96 } 97 98 /* 99 * Compute the hash for the vfat name corresponding to the dentry. 100 * Note: if the name is invalid, we leave the hash code unchanged so 101 * that the existing dentry can be used. The vfat fs routines will 102 * return ENOENT or EINVAL as appropriate. 103 */ 104 static int vfat_hash(struct dentry *dentry, struct qstr *qstr) 105 { 106 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); 107 return 0; 108 } 109 110 /* 111 * Compute the hash for the vfat name corresponding to the dentry. 112 * Note: if the name is invalid, we leave the hash code unchanged so 113 * that the existing dentry can be used. The vfat fs routines will 114 * return ENOENT or EINVAL as appropriate. 115 */ 116 static int vfat_hashi(struct dentry *dentry, struct qstr *qstr) 117 { 118 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 119 const unsigned char *name; 120 unsigned int len; 121 unsigned long hash; 122 123 name = qstr->name; 124 len = vfat_striptail_len(qstr); 125 126 hash = init_name_hash(); 127 while (len--) 128 hash = partial_name_hash(nls_tolower(t, *name++), hash); 129 qstr->hash = end_name_hash(hash); 130 131 return 0; 132 } 133 134 /* 135 * Case insensitive compare of two vfat names. 136 */ 137 static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b) 138 { 139 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 140 unsigned int alen, blen; 141 142 /* A filename cannot end in '.' or we treat it like it has none */ 143 alen = vfat_striptail_len(a); 144 blen = vfat_striptail_len(b); 145 if (alen == blen) { 146 if (nls_strnicmp(t, a->name, b->name, alen) == 0) 147 return 0; 148 } 149 return 1; 150 } 151 152 /* 153 * Case sensitive compare of two vfat names. 154 */ 155 static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b) 156 { 157 unsigned int alen, blen; 158 159 /* A filename cannot end in '.' or we treat it like it has none */ 160 alen = vfat_striptail_len(a); 161 blen = vfat_striptail_len(b); 162 if (alen == blen) { 163 if (strncmp(a->name, b->name, alen) == 0) 164 return 0; 165 } 166 return 1; 167 } 168 169 static const struct dentry_operations vfat_ci_dentry_ops = { 170 .d_revalidate = vfat_revalidate_ci, 171 .d_hash = vfat_hashi, 172 .d_compare = vfat_cmpi, 173 }; 174 175 static const struct dentry_operations vfat_dentry_ops = { 176 .d_revalidate = vfat_revalidate, 177 .d_hash = vfat_hash, 178 .d_compare = vfat_cmp, 179 }; 180 181 /* Characters that are undesirable in an MS-DOS file name */ 182 183 static inline wchar_t vfat_bad_char(wchar_t w) 184 { 185 return (w < 0x0020) 186 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 187 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 188 || (w == '\\'); 189 } 190 191 static inline wchar_t vfat_replace_char(wchar_t w) 192 { 193 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 194 || (w == '+') || (w == '='); 195 } 196 197 static wchar_t vfat_skip_char(wchar_t w) 198 { 199 return (w == '.') || (w == ' '); 200 } 201 202 static inline int vfat_is_used_badchars(const wchar_t *s, int len) 203 { 204 int i; 205 206 for (i = 0; i < len; i++) 207 if (vfat_bad_char(s[i])) 208 return -EINVAL; 209 210 if (s[i - 1] == ' ') /* last character cannot be space */ 211 return -EINVAL; 212 213 return 0; 214 } 215 216 static int vfat_find_form(struct inode *dir, unsigned char *name) 217 { 218 struct fat_slot_info sinfo; 219 int err = fat_scan(dir, name, &sinfo); 220 if (err) 221 return -ENOENT; 222 brelse(sinfo.bh); 223 return 0; 224 } 225 226 /* 227 * 1) Valid characters for the 8.3 format alias are any combination of 228 * letters, uppercase alphabets, digits, any of the 229 * following special characters: 230 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 231 * In this case Longfilename is not stored in disk. 232 * 233 * WinNT's Extension: 234 * File name and extension name is contain uppercase/lowercase 235 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 236 * 237 * 2) File name is 8.3 format, but it contain the uppercase and 238 * lowercase char, muliti bytes char, etc. In this case numtail is not 239 * added, but Longfilename is stored. 240 * 241 * 3) When the one except for the above, or the following special 242 * character are contained: 243 * . [ ] ; , + = 244 * numtail is added, and Longfilename must be stored in disk . 245 */ 246 struct shortname_info { 247 unsigned char lower:1, 248 upper:1, 249 valid:1; 250 }; 251 #define INIT_SHORTNAME_INFO(x) do { \ 252 (x)->lower = 1; \ 253 (x)->upper = 1; \ 254 (x)->valid = 1; \ 255 } while (0) 256 257 static inline int to_shortname_char(struct nls_table *nls, 258 unsigned char *buf, int buf_size, 259 wchar_t *src, struct shortname_info *info) 260 { 261 int len; 262 263 if (vfat_skip_char(*src)) { 264 info->valid = 0; 265 return 0; 266 } 267 if (vfat_replace_char(*src)) { 268 info->valid = 0; 269 buf[0] = '_'; 270 return 1; 271 } 272 273 len = nls->uni2char(*src, buf, buf_size); 274 if (len <= 0) { 275 info->valid = 0; 276 buf[0] = '_'; 277 len = 1; 278 } else if (len == 1) { 279 unsigned char prev = buf[0]; 280 281 if (buf[0] >= 0x7F) { 282 info->lower = 0; 283 info->upper = 0; 284 } 285 286 buf[0] = nls_toupper(nls, buf[0]); 287 if (isalpha(buf[0])) { 288 if (buf[0] == prev) 289 info->lower = 0; 290 else 291 info->upper = 0; 292 } 293 } else { 294 info->lower = 0; 295 info->upper = 0; 296 } 297 298 return len; 299 } 300 301 /* 302 * Given a valid longname, create a unique shortname. Make sure the 303 * shortname does not exist 304 * Returns negative number on error, 0 for a normal 305 * return, and 1 for valid shortname 306 */ 307 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 308 wchar_t *uname, int ulen, 309 unsigned char *name_res, unsigned char *lcase) 310 { 311 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 312 wchar_t *ip, *ext_start, *end, *name_start; 313 unsigned char base[9], ext[4], buf[8], *p; 314 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 315 int chl, chi; 316 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 317 int is_shortname; 318 struct shortname_info base_info, ext_info; 319 320 is_shortname = 1; 321 INIT_SHORTNAME_INFO(&base_info); 322 INIT_SHORTNAME_INFO(&ext_info); 323 324 /* Now, we need to create a shortname from the long name */ 325 ext_start = end = &uname[ulen]; 326 while (--ext_start >= uname) { 327 if (*ext_start == 0x002E) { /* is `.' */ 328 if (ext_start == end - 1) { 329 sz = ulen; 330 ext_start = NULL; 331 } 332 break; 333 } 334 } 335 336 if (ext_start == uname - 1) { 337 sz = ulen; 338 ext_start = NULL; 339 } else if (ext_start) { 340 /* 341 * Names which start with a dot could be just 342 * an extension eg. "...test". In this case Win95 343 * uses the extension as the name and sets no extension. 344 */ 345 name_start = &uname[0]; 346 while (name_start < ext_start) { 347 if (!vfat_skip_char(*name_start)) 348 break; 349 name_start++; 350 } 351 if (name_start != ext_start) { 352 sz = ext_start - uname; 353 ext_start++; 354 } else { 355 sz = ulen; 356 ext_start = NULL; 357 } 358 } 359 360 numtail_baselen = 6; 361 numtail2_baselen = 2; 362 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 363 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 364 ip, &base_info); 365 if (chl == 0) 366 continue; 367 368 if (baselen < 2 && (baselen + chl) > 2) 369 numtail2_baselen = baselen; 370 if (baselen < 6 && (baselen + chl) > 6) 371 numtail_baselen = baselen; 372 for (chi = 0; chi < chl; chi++) { 373 *p++ = charbuf[chi]; 374 baselen++; 375 if (baselen >= 8) 376 break; 377 } 378 if (baselen >= 8) { 379 if ((chi < chl - 1) || (ip + 1) - uname < sz) 380 is_shortname = 0; 381 break; 382 } 383 } 384 if (baselen == 0) { 385 return -EINVAL; 386 } 387 388 extlen = 0; 389 if (ext_start) { 390 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 391 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 392 ip, &ext_info); 393 if (chl == 0) 394 continue; 395 396 if ((extlen + chl) > 3) { 397 is_shortname = 0; 398 break; 399 } 400 for (chi = 0; chi < chl; chi++) { 401 *p++ = charbuf[chi]; 402 extlen++; 403 } 404 if (extlen >= 3) { 405 if (ip + 1 != end) 406 is_shortname = 0; 407 break; 408 } 409 } 410 } 411 ext[extlen] = '\0'; 412 base[baselen] = '\0'; 413 414 /* Yes, it can happen. ".\xe5" would do it. */ 415 if (base[0] == DELETED_FLAG) 416 base[0] = 0x05; 417 418 /* OK, at this point we know that base is not longer than 8 symbols, 419 * ext is not longer than 3, base is nonempty, both don't contain 420 * any bad symbols (lowercase transformed to uppercase). 421 */ 422 423 memset(name_res, ' ', MSDOS_NAME); 424 memcpy(name_res, base, baselen); 425 memcpy(name_res + 8, ext, extlen); 426 *lcase = 0; 427 if (is_shortname && base_info.valid && ext_info.valid) { 428 if (vfat_find_form(dir, name_res) == 0) 429 return -EEXIST; 430 431 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 432 return (base_info.upper && ext_info.upper); 433 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 434 if ((base_info.upper || base_info.lower) && 435 (ext_info.upper || ext_info.lower)) { 436 if (!base_info.upper && base_info.lower) 437 *lcase |= CASE_LOWER_BASE; 438 if (!ext_info.upper && ext_info.lower) 439 *lcase |= CASE_LOWER_EXT; 440 return 1; 441 } 442 return 0; 443 } else { 444 BUG(); 445 } 446 } 447 448 if (opts->numtail == 0) 449 if (vfat_find_form(dir, name_res) < 0) 450 return 0; 451 452 /* 453 * Try to find a unique extension. This used to 454 * iterate through all possibilities sequentially, 455 * but that gave extremely bad performance. Windows 456 * only tries a few cases before using random 457 * values for part of the base. 458 */ 459 460 if (baselen > 6) { 461 baselen = numtail_baselen; 462 name_res[7] = ' '; 463 } 464 name_res[baselen] = '~'; 465 for (i = 1; i < 10; i++) { 466 name_res[baselen + 1] = i + '0'; 467 if (vfat_find_form(dir, name_res) < 0) 468 return 0; 469 } 470 471 i = jiffies & 0xffff; 472 sz = (jiffies >> 16) & 0x7; 473 if (baselen > 2) { 474 baselen = numtail2_baselen; 475 name_res[7] = ' '; 476 } 477 name_res[baselen + 4] = '~'; 478 name_res[baselen + 5] = '1' + sz; 479 while (1) { 480 sprintf(buf, "%04X", i); 481 memcpy(&name_res[baselen], buf, 4); 482 if (vfat_find_form(dir, name_res) < 0) 483 break; 484 i -= 11; 485 } 486 return 0; 487 } 488 489 /* Translate a string, including coded sequences into Unicode */ 490 static int 491 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 492 int *longlen, int *outlen, int escape, int utf8, 493 struct nls_table *nls) 494 { 495 const unsigned char *ip; 496 unsigned char nc; 497 unsigned char *op; 498 unsigned int ec; 499 int i, k, fill; 500 int charlen; 501 502 if (utf8) { 503 int name_len = strlen(name); 504 505 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX); 506 507 /* 508 * We stripped '.'s before and set len appropriately, 509 * but utf8_mbstowcs doesn't care about len 510 */ 511 *outlen -= (name_len - len); 512 513 if (*outlen > 255) 514 return -ENAMETOOLONG; 515 516 op = &outname[*outlen * sizeof(wchar_t)]; 517 } else { 518 if (nls) { 519 for (i = 0, ip = name, op = outname, *outlen = 0; 520 i < len && *outlen <= 255; 521 *outlen += 1) 522 { 523 if (escape && (*ip == ':')) { 524 if (i > len - 5) 525 return -EINVAL; 526 ec = 0; 527 for (k = 1; k < 5; k++) { 528 nc = ip[k]; 529 ec <<= 4; 530 if (nc >= '0' && nc <= '9') { 531 ec |= nc - '0'; 532 continue; 533 } 534 if (nc >= 'a' && nc <= 'f') { 535 ec |= nc - ('a' - 10); 536 continue; 537 } 538 if (nc >= 'A' && nc <= 'F') { 539 ec |= nc - ('A' - 10); 540 continue; 541 } 542 return -EINVAL; 543 } 544 *op++ = ec & 0xFF; 545 *op++ = ec >> 8; 546 ip += 5; 547 i += 5; 548 } else { 549 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0) 550 return -EINVAL; 551 ip += charlen; 552 i += charlen; 553 op += 2; 554 } 555 } 556 if (i < len) 557 return -ENAMETOOLONG; 558 } else { 559 for (i = 0, ip = name, op = outname, *outlen = 0; 560 i < len && *outlen <= 255; 561 i++, *outlen += 1) 562 { 563 *op++ = *ip++; 564 *op++ = 0; 565 } 566 if (i < len) 567 return -ENAMETOOLONG; 568 } 569 } 570 571 *longlen = *outlen; 572 if (*outlen % 13) { 573 *op++ = 0; 574 *op++ = 0; 575 *outlen += 1; 576 if (*outlen % 13) { 577 fill = 13 - (*outlen % 13); 578 for (i = 0; i < fill; i++) { 579 *op++ = 0xff; 580 *op++ = 0xff; 581 } 582 *outlen += fill; 583 } 584 } 585 586 return 0; 587 } 588 589 static int vfat_build_slots(struct inode *dir, const unsigned char *name, 590 int len, int is_dir, int cluster, 591 struct timespec *ts, 592 struct msdos_dir_slot *slots, int *nr_slots) 593 { 594 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 595 struct fat_mount_options *opts = &sbi->options; 596 struct msdos_dir_slot *ps; 597 struct msdos_dir_entry *de; 598 unsigned char cksum, lcase; 599 unsigned char msdos_name[MSDOS_NAME]; 600 wchar_t *uname; 601 __le16 time, date; 602 u8 time_cs; 603 int err, ulen, usize, i; 604 loff_t offset; 605 606 *nr_slots = 0; 607 608 uname = __getname(); 609 if (!uname) 610 return -ENOMEM; 611 612 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 613 opts->unicode_xlate, opts->utf8, sbi->nls_io); 614 if (err) 615 goto out_free; 616 617 err = vfat_is_used_badchars(uname, ulen); 618 if (err) 619 goto out_free; 620 621 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 622 msdos_name, &lcase); 623 if (err < 0) 624 goto out_free; 625 else if (err == 1) { 626 de = (struct msdos_dir_entry *)slots; 627 err = 0; 628 goto shortname; 629 } 630 631 /* build the entry of long file name */ 632 cksum = fat_checksum(msdos_name); 633 634 *nr_slots = usize / 13; 635 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 636 ps->id = i; 637 ps->attr = ATTR_EXT; 638 ps->reserved = 0; 639 ps->alias_checksum = cksum; 640 ps->start = 0; 641 offset = (i - 1) * 13; 642 fatwchar_to16(ps->name0_4, uname + offset, 5); 643 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 644 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 645 } 646 slots[0].id |= 0x40; 647 de = (struct msdos_dir_entry *)ps; 648 649 shortname: 650 /* build the entry of 8.3 alias name */ 651 (*nr_slots)++; 652 memcpy(de->name, msdos_name, MSDOS_NAME); 653 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 654 de->lcase = lcase; 655 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); 656 de->time = de->ctime = time; 657 de->date = de->cdate = de->adate = date; 658 de->ctime_cs = time_cs; 659 de->start = cpu_to_le16(cluster); 660 de->starthi = cpu_to_le16(cluster >> 16); 661 de->size = 0; 662 out_free: 663 __putname(uname); 664 return err; 665 } 666 667 static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir, 668 int cluster, struct timespec *ts, 669 struct fat_slot_info *sinfo) 670 { 671 struct msdos_dir_slot *slots; 672 unsigned int len; 673 int err, nr_slots; 674 675 len = vfat_striptail_len(qname); 676 if (len == 0) 677 return -ENOENT; 678 679 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 680 if (slots == NULL) 681 return -ENOMEM; 682 683 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 684 slots, &nr_slots); 685 if (err) 686 goto cleanup; 687 688 err = fat_add_entries(dir, slots, nr_slots, sinfo); 689 if (err) 690 goto cleanup; 691 692 /* update timestamp */ 693 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 694 if (IS_DIRSYNC(dir)) 695 (void)fat_sync_inode(dir); 696 else 697 mark_inode_dirty(dir); 698 cleanup: 699 kfree(slots); 700 return err; 701 } 702 703 static int vfat_find(struct inode *dir, struct qstr *qname, 704 struct fat_slot_info *sinfo) 705 { 706 unsigned int len = vfat_striptail_len(qname); 707 if (len == 0) 708 return -ENOENT; 709 return fat_search_long(dir, qname->name, len, sinfo); 710 } 711 712 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 713 struct nameidata *nd) 714 { 715 struct super_block *sb = dir->i_sb; 716 struct fat_slot_info sinfo; 717 struct inode *inode; 718 struct dentry *alias; 719 int err; 720 721 lock_super(sb); 722 723 err = vfat_find(dir, &dentry->d_name, &sinfo); 724 if (err) { 725 if (err == -ENOENT) { 726 inode = NULL; 727 goto out; 728 } 729 goto error; 730 } 731 732 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 733 brelse(sinfo.bh); 734 if (IS_ERR(inode)) { 735 err = PTR_ERR(inode); 736 goto error; 737 } 738 739 alias = d_find_alias(inode); 740 if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) { 741 /* 742 * This inode has non DCACHE_DISCONNECTED dentry. This 743 * means, the user did ->lookup() by an another name 744 * (longname vs 8.3 alias of it) in past. 745 * 746 * Switch to new one for reason of locality if possible. 747 */ 748 BUG_ON(d_unhashed(alias)); 749 if (!S_ISDIR(inode->i_mode)) 750 d_move(alias, dentry); 751 iput(inode); 752 unlock_super(sb); 753 return alias; 754 } 755 out: 756 unlock_super(sb); 757 dentry->d_op = sb->s_root->d_op; 758 dentry->d_time = dentry->d_parent->d_inode->i_version; 759 dentry = d_splice_alias(inode, dentry); 760 if (dentry) { 761 dentry->d_op = sb->s_root->d_op; 762 dentry->d_time = dentry->d_parent->d_inode->i_version; 763 } 764 return dentry; 765 766 error: 767 unlock_super(sb); 768 return ERR_PTR(err); 769 } 770 771 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode, 772 struct nameidata *nd) 773 { 774 struct super_block *sb = dir->i_sb; 775 struct inode *inode; 776 struct fat_slot_info sinfo; 777 struct timespec ts; 778 int err; 779 780 lock_super(sb); 781 782 ts = CURRENT_TIME_SEC; 783 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 784 if (err) 785 goto out; 786 dir->i_version++; 787 788 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 789 brelse(sinfo.bh); 790 if (IS_ERR(inode)) { 791 err = PTR_ERR(inode); 792 goto out; 793 } 794 inode->i_version++; 795 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 796 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 797 798 dentry->d_time = dentry->d_parent->d_inode->i_version; 799 d_instantiate(dentry, inode); 800 out: 801 unlock_super(sb); 802 return err; 803 } 804 805 static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 806 { 807 struct inode *inode = dentry->d_inode; 808 struct super_block *sb = dir->i_sb; 809 struct fat_slot_info sinfo; 810 int err; 811 812 lock_super(sb); 813 814 err = fat_dir_empty(inode); 815 if (err) 816 goto out; 817 err = vfat_find(dir, &dentry->d_name, &sinfo); 818 if (err) 819 goto out; 820 821 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 822 if (err) 823 goto out; 824 drop_nlink(dir); 825 826 clear_nlink(inode); 827 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 828 fat_detach(inode); 829 out: 830 unlock_super(sb); 831 832 return err; 833 } 834 835 static int vfat_unlink(struct inode *dir, struct dentry *dentry) 836 { 837 struct inode *inode = dentry->d_inode; 838 struct super_block *sb = dir->i_sb; 839 struct fat_slot_info sinfo; 840 int err; 841 842 lock_super(sb); 843 844 err = vfat_find(dir, &dentry->d_name, &sinfo); 845 if (err) 846 goto out; 847 848 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 849 if (err) 850 goto out; 851 clear_nlink(inode); 852 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 853 fat_detach(inode); 854 out: 855 unlock_super(sb); 856 857 return err; 858 } 859 860 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode) 861 { 862 struct super_block *sb = dir->i_sb; 863 struct inode *inode; 864 struct fat_slot_info sinfo; 865 struct timespec ts; 866 int err, cluster; 867 868 lock_super(sb); 869 870 ts = CURRENT_TIME_SEC; 871 cluster = fat_alloc_new_dir(dir, &ts); 872 if (cluster < 0) { 873 err = cluster; 874 goto out; 875 } 876 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 877 if (err) 878 goto out_free; 879 dir->i_version++; 880 inc_nlink(dir); 881 882 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 883 brelse(sinfo.bh); 884 if (IS_ERR(inode)) { 885 err = PTR_ERR(inode); 886 /* the directory was completed, just return a error */ 887 goto out; 888 } 889 inode->i_version++; 890 inode->i_nlink = 2; 891 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 892 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 893 894 dentry->d_time = dentry->d_parent->d_inode->i_version; 895 d_instantiate(dentry, inode); 896 897 unlock_super(sb); 898 return 0; 899 900 out_free: 901 fat_free_clusters(dir, cluster); 902 out: 903 unlock_super(sb); 904 return err; 905 } 906 907 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 908 struct inode *new_dir, struct dentry *new_dentry) 909 { 910 struct buffer_head *dotdot_bh; 911 struct msdos_dir_entry *dotdot_de; 912 struct inode *old_inode, *new_inode; 913 struct fat_slot_info old_sinfo, sinfo; 914 struct timespec ts; 915 loff_t dotdot_i_pos, new_i_pos; 916 int err, is_dir, update_dotdot, corrupt = 0; 917 struct super_block *sb = old_dir->i_sb; 918 919 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 920 old_inode = old_dentry->d_inode; 921 new_inode = new_dentry->d_inode; 922 lock_super(sb); 923 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 924 if (err) 925 goto out; 926 927 is_dir = S_ISDIR(old_inode->i_mode); 928 update_dotdot = (is_dir && old_dir != new_dir); 929 if (update_dotdot) { 930 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de, 931 &dotdot_i_pos) < 0) { 932 err = -EIO; 933 goto out; 934 } 935 } 936 937 ts = CURRENT_TIME_SEC; 938 if (new_inode) { 939 if (is_dir) { 940 err = fat_dir_empty(new_inode); 941 if (err) 942 goto out; 943 } 944 new_i_pos = MSDOS_I(new_inode)->i_pos; 945 fat_detach(new_inode); 946 } else { 947 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 948 &ts, &sinfo); 949 if (err) 950 goto out; 951 new_i_pos = sinfo.i_pos; 952 } 953 new_dir->i_version++; 954 955 fat_detach(old_inode); 956 fat_attach(old_inode, new_i_pos); 957 if (IS_DIRSYNC(new_dir)) { 958 err = fat_sync_inode(old_inode); 959 if (err) 960 goto error_inode; 961 } else 962 mark_inode_dirty(old_inode); 963 964 if (update_dotdot) { 965 int start = MSDOS_I(new_dir)->i_logstart; 966 dotdot_de->start = cpu_to_le16(start); 967 dotdot_de->starthi = cpu_to_le16(start >> 16); 968 mark_buffer_dirty_inode(dotdot_bh, old_inode); 969 if (IS_DIRSYNC(new_dir)) { 970 err = sync_dirty_buffer(dotdot_bh); 971 if (err) 972 goto error_dotdot; 973 } 974 drop_nlink(old_dir); 975 if (!new_inode) 976 inc_nlink(new_dir); 977 } 978 979 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 980 old_sinfo.bh = NULL; 981 if (err) 982 goto error_dotdot; 983 old_dir->i_version++; 984 old_dir->i_ctime = old_dir->i_mtime = ts; 985 if (IS_DIRSYNC(old_dir)) 986 (void)fat_sync_inode(old_dir); 987 else 988 mark_inode_dirty(old_dir); 989 990 if (new_inode) { 991 drop_nlink(new_inode); 992 if (is_dir) 993 drop_nlink(new_inode); 994 new_inode->i_ctime = ts; 995 } 996 out: 997 brelse(sinfo.bh); 998 brelse(dotdot_bh); 999 brelse(old_sinfo.bh); 1000 unlock_super(sb); 1001 1002 return err; 1003 1004 error_dotdot: 1005 /* data cluster is shared, serious corruption */ 1006 corrupt = 1; 1007 1008 if (update_dotdot) { 1009 int start = MSDOS_I(old_dir)->i_logstart; 1010 dotdot_de->start = cpu_to_le16(start); 1011 dotdot_de->starthi = cpu_to_le16(start >> 16); 1012 mark_buffer_dirty_inode(dotdot_bh, old_inode); 1013 corrupt |= sync_dirty_buffer(dotdot_bh); 1014 } 1015 error_inode: 1016 fat_detach(old_inode); 1017 fat_attach(old_inode, old_sinfo.i_pos); 1018 if (new_inode) { 1019 fat_attach(new_inode, new_i_pos); 1020 if (corrupt) 1021 corrupt |= fat_sync_inode(new_inode); 1022 } else { 1023 /* 1024 * If new entry was not sharing the data cluster, it 1025 * shouldn't be serious corruption. 1026 */ 1027 int err2 = fat_remove_entries(new_dir, &sinfo); 1028 if (corrupt) 1029 corrupt |= err2; 1030 sinfo.bh = NULL; 1031 } 1032 if (corrupt < 0) { 1033 fat_fs_error(new_dir->i_sb, 1034 "%s: Filesystem corrupted (i_pos %lld)", 1035 __func__, sinfo.i_pos); 1036 } 1037 goto out; 1038 } 1039 1040 static const struct inode_operations vfat_dir_inode_operations = { 1041 .create = vfat_create, 1042 .lookup = vfat_lookup, 1043 .unlink = vfat_unlink, 1044 .mkdir = vfat_mkdir, 1045 .rmdir = vfat_rmdir, 1046 .rename = vfat_rename, 1047 .setattr = fat_setattr, 1048 .getattr = fat_getattr, 1049 }; 1050 1051 static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1052 { 1053 int res; 1054 1055 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1); 1056 if (res) 1057 return res; 1058 1059 if (MSDOS_SB(sb)->options.name_check != 's') 1060 sb->s_root->d_op = &vfat_ci_dentry_ops; 1061 else 1062 sb->s_root->d_op = &vfat_dentry_ops; 1063 1064 return 0; 1065 } 1066 1067 static int vfat_get_sb(struct file_system_type *fs_type, 1068 int flags, const char *dev_name, 1069 void *data, struct vfsmount *mnt) 1070 { 1071 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super, 1072 mnt); 1073 } 1074 1075 static struct file_system_type vfat_fs_type = { 1076 .owner = THIS_MODULE, 1077 .name = "vfat", 1078 .get_sb = vfat_get_sb, 1079 .kill_sb = kill_block_super, 1080 .fs_flags = FS_REQUIRES_DEV, 1081 }; 1082 1083 static int __init init_vfat_fs(void) 1084 { 1085 return register_filesystem(&vfat_fs_type); 1086 } 1087 1088 static void __exit exit_vfat_fs(void) 1089 { 1090 unregister_filesystem(&vfat_fs_type); 1091 } 1092 1093 MODULE_LICENSE("GPL"); 1094 MODULE_DESCRIPTION("VFAT filesystem support"); 1095 MODULE_AUTHOR("Gordon Chaffee"); 1096 1097 module_init(init_vfat_fs) 1098 module_exit(exit_vfat_fs) 1099