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 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) 28 { 29 int ret = 1; 30 31 if (!dentry->d_inode && 32 nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE)) 33 /* 34 * negative dentry is dropped, in order to make sure 35 * to use the name which a user desires if this is 36 * create path. 37 */ 38 ret = 0; 39 else { 40 spin_lock(&dentry->d_lock); 41 if (dentry->d_time != dentry->d_parent->d_inode->i_version) 42 ret = 0; 43 spin_unlock(&dentry->d_lock); 44 } 45 return ret; 46 } 47 48 /* returns the length of a struct qstr, ignoring trailing dots */ 49 static unsigned int vfat_striptail_len(struct qstr *qstr) 50 { 51 unsigned int len = qstr->len; 52 53 while (len && qstr->name[len - 1] == '.') 54 len--; 55 return len; 56 } 57 58 /* 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. 63 */ 64 static int vfat_hash(struct dentry *dentry, struct qstr *qstr) 65 { 66 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); 67 return 0; 68 } 69 70 /* 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. 75 */ 76 static int vfat_hashi(struct dentry *dentry, struct qstr *qstr) 77 { 78 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 79 const unsigned char *name; 80 unsigned int len; 81 unsigned long hash; 82 83 name = qstr->name; 84 len = vfat_striptail_len(qstr); 85 86 hash = init_name_hash(); 87 while (len--) 88 hash = partial_name_hash(nls_tolower(t, *name++), hash); 89 qstr->hash = end_name_hash(hash); 90 91 return 0; 92 } 93 94 /* 95 * Case insensitive compare of two vfat names. 96 */ 97 static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b) 98 { 99 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 100 unsigned int alen, blen; 101 102 /* 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); 105 if (alen == blen) { 106 if (nls_strnicmp(t, a->name, b->name, alen) == 0) 107 return 0; 108 } 109 return 1; 110 } 111 112 /* 113 * Case sensitive compare of two vfat names. 114 */ 115 static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b) 116 { 117 unsigned int alen, blen; 118 119 /* 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); 122 if (alen == blen) { 123 if (strncmp(a->name, b->name, alen) == 0) 124 return 0; 125 } 126 return 1; 127 } 128 129 static struct dentry_operations vfat_dentry_ops[4] = { 130 { 131 .d_hash = vfat_hashi, 132 .d_compare = vfat_cmpi, 133 }, 134 { 135 .d_revalidate = vfat_revalidate, 136 .d_hash = vfat_hashi, 137 .d_compare = vfat_cmpi, 138 }, 139 { 140 .d_hash = vfat_hash, 141 .d_compare = vfat_cmp, 142 }, 143 { 144 .d_revalidate = vfat_revalidate, 145 .d_hash = vfat_hash, 146 .d_compare = vfat_cmp, 147 } 148 }; 149 150 /* Characters that are undesirable in an MS-DOS file name */ 151 152 static inline wchar_t vfat_bad_char(wchar_t w) 153 { 154 return (w < 0x0020) 155 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 156 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 157 || (w == '\\'); 158 } 159 160 static inline wchar_t vfat_replace_char(wchar_t w) 161 { 162 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 163 || (w == '+') || (w == '='); 164 } 165 166 static wchar_t vfat_skip_char(wchar_t w) 167 { 168 return (w == '.') || (w == ' '); 169 } 170 171 static inline int vfat_is_used_badchars(const wchar_t *s, int len) 172 { 173 int i; 174 175 for (i = 0; i < len; i++) 176 if (vfat_bad_char(s[i])) 177 return -EINVAL; 178 179 if (s[i - 1] == ' ') /* last character cannot be space */ 180 return -EINVAL; 181 182 return 0; 183 } 184 185 static int vfat_find_form(struct inode *dir, unsigned char *name) 186 { 187 struct fat_slot_info sinfo; 188 int err = fat_scan(dir, name, &sinfo); 189 if (err) 190 return -ENOENT; 191 brelse(sinfo.bh); 192 return 0; 193 } 194 195 /* 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. 201 * 202 * WinNT's Extension: 203 * File name and extension name is contain uppercase/lowercase 204 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 205 * 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. 209 * 210 * 3) When the one except for the above, or the following special 211 * character are contained: 212 * . [ ] ; , + = 213 * numtail is added, and Longfilename must be stored in disk . 214 */ 215 struct shortname_info { 216 unsigned char lower:1, 217 upper:1, 218 valid:1; 219 }; 220 #define INIT_SHORTNAME_INFO(x) do { \ 221 (x)->lower = 1; \ 222 (x)->upper = 1; \ 223 (x)->valid = 1; \ 224 } while (0) 225 226 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) 229 { 230 int len; 231 232 if (vfat_skip_char(*src)) { 233 info->valid = 0; 234 return 0; 235 } 236 if (vfat_replace_char(*src)) { 237 info->valid = 0; 238 buf[0] = '_'; 239 return 1; 240 } 241 242 len = nls->uni2char(*src, buf, buf_size); 243 if (len <= 0) { 244 info->valid = 0; 245 buf[0] = '_'; 246 len = 1; 247 } else if (len == 1) { 248 unsigned char prev = buf[0]; 249 250 if (buf[0] >= 0x7F) { 251 info->lower = 0; 252 info->upper = 0; 253 } 254 255 buf[0] = nls_toupper(nls, buf[0]); 256 if (isalpha(buf[0])) { 257 if (buf[0] == prev) 258 info->lower = 0; 259 else 260 info->upper = 0; 261 } 262 } else { 263 info->lower = 0; 264 info->upper = 0; 265 } 266 267 return len; 268 } 269 270 /* 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 275 */ 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) 279 { 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]; 284 int chl, chi; 285 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 286 int is_shortname; 287 struct shortname_info base_info, ext_info; 288 289 is_shortname = 1; 290 INIT_SHORTNAME_INFO(&base_info); 291 INIT_SHORTNAME_INFO(&ext_info); 292 293 /* 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) { 298 sz = ulen; 299 ext_start = NULL; 300 } 301 break; 302 } 303 } 304 305 if (ext_start == uname - 1) { 306 sz = ulen; 307 ext_start = NULL; 308 } else if (ext_start) { 309 /* 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. 313 */ 314 name_start = &uname[0]; 315 while (name_start < ext_start) { 316 if (!vfat_skip_char(*name_start)) 317 break; 318 name_start++; 319 } 320 if (name_start != ext_start) { 321 sz = ext_start - uname; 322 ext_start++; 323 } else { 324 sz = ulen; 325 ext_start = NULL; 326 } 327 } 328 329 numtail_baselen = 6; 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), 333 ip, &base_info); 334 if (chl == 0) 335 continue; 336 337 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++) { 342 *p++ = charbuf[chi]; 343 baselen++; 344 if (baselen >= 8) 345 break; 346 } 347 if (baselen >= 8) { 348 if ((chi < chl - 1) || (ip + 1) - uname < sz) 349 is_shortname = 0; 350 break; 351 } 352 } 353 if (baselen == 0) { 354 return -EINVAL; 355 } 356 357 extlen = 0; 358 if (ext_start) { 359 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 360 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 361 ip, &ext_info); 362 if (chl == 0) 363 continue; 364 365 if ((extlen + chl) > 3) { 366 is_shortname = 0; 367 break; 368 } 369 for (chi = 0; chi < chl; chi++) { 370 *p++ = charbuf[chi]; 371 extlen++; 372 } 373 if (extlen >= 3) { 374 if (ip + 1 != end) 375 is_shortname = 0; 376 break; 377 } 378 } 379 } 380 ext[extlen] = '\0'; 381 base[baselen] = '\0'; 382 383 /* Yes, it can happen. ".\xe5" would do it. */ 384 if (base[0] == DELETED_FLAG) 385 base[0] = 0x05; 386 387 /* 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). 390 */ 391 392 memset(name_res, ' ', MSDOS_NAME); 393 memcpy(name_res, base, baselen); 394 memcpy(name_res + 8, ext, extlen); 395 *lcase = 0; 396 if (is_shortname && base_info.valid && ext_info.valid) { 397 if (vfat_find_form(dir, name_res) == 0) 398 return -EEXIST; 399 400 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; 409 return 1; 410 } 411 return 0; 412 } else { 413 BUG(); 414 } 415 } 416 417 if (opts->numtail == 0) 418 if (vfat_find_form(dir, name_res) < 0) 419 return 0; 420 421 /* 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. 427 */ 428 429 if (baselen > 6) { 430 baselen = numtail_baselen; 431 name_res[7] = ' '; 432 } 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) 437 return 0; 438 } 439 440 i = jiffies & 0xffff; 441 sz = (jiffies >> 16) & 0x7; 442 if (baselen > 2) { 443 baselen = numtail2_baselen; 444 name_res[7] = ' '; 445 } 446 name_res[baselen + 4] = '~'; 447 name_res[baselen + 5] = '1' + sz; 448 while (1) { 449 sprintf(buf, "%04X", i); 450 memcpy(&name_res[baselen], buf, 4); 451 if (vfat_find_form(dir, name_res) < 0) 452 break; 453 i -= 11; 454 } 455 return 0; 456 } 457 458 /* Translate a string, including coded sequences into Unicode */ 459 static int 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) 463 { 464 const unsigned char *ip; 465 unsigned char nc; 466 unsigned char *op; 467 unsigned int ec; 468 int i, k, fill; 469 int charlen; 470 471 if (utf8) { 472 int name_len = strlen(name); 473 474 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX); 475 476 /* 477 * We stripped '.'s before and set len appropriately, 478 * but utf8_mbstowcs doesn't care about len 479 */ 480 *outlen -= (name_len - len); 481 482 if (*outlen > 255) 483 return -ENAMETOOLONG; 484 485 op = &outname[*outlen * sizeof(wchar_t)]; 486 } else { 487 if (nls) { 488 for (i = 0, ip = name, op = outname, *outlen = 0; 489 i < len && *outlen <= 255; 490 *outlen += 1) 491 { 492 if (escape && (*ip == ':')) { 493 if (i > len - 5) 494 return -EINVAL; 495 ec = 0; 496 for (k = 1; k < 5; k++) { 497 nc = ip[k]; 498 ec <<= 4; 499 if (nc >= '0' && nc <= '9') { 500 ec |= nc - '0'; 501 continue; 502 } 503 if (nc >= 'a' && nc <= 'f') { 504 ec |= nc - ('a' - 10); 505 continue; 506 } 507 if (nc >= 'A' && nc <= 'F') { 508 ec |= nc - ('A' - 10); 509 continue; 510 } 511 return -EINVAL; 512 } 513 *op++ = ec & 0xFF; 514 *op++ = ec >> 8; 515 ip += 5; 516 i += 5; 517 } else { 518 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0) 519 return -EINVAL; 520 ip += charlen; 521 i += charlen; 522 op += 2; 523 } 524 } 525 if (i < len) 526 return -ENAMETOOLONG; 527 } else { 528 for (i = 0, ip = name, op = outname, *outlen = 0; 529 i < len && *outlen <= 255; 530 i++, *outlen += 1) 531 { 532 *op++ = *ip++; 533 *op++ = 0; 534 } 535 if (i < len) 536 return -ENAMETOOLONG; 537 } 538 } 539 540 *longlen = *outlen; 541 if (*outlen % 13) { 542 *op++ = 0; 543 *op++ = 0; 544 *outlen += 1; 545 if (*outlen % 13) { 546 fill = 13 - (*outlen % 13); 547 for (i = 0; i < fill; i++) { 548 *op++ = 0xff; 549 *op++ = 0xff; 550 } 551 *outlen += fill; 552 } 553 } 554 555 return 0; 556 } 557 558 static int vfat_build_slots(struct inode *dir, const unsigned char *name, 559 int len, int is_dir, int cluster, 560 struct timespec *ts, 561 struct msdos_dir_slot *slots, int *nr_slots) 562 { 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]; 569 wchar_t *uname; 570 __le16 time, date; 571 u8 time_cs; 572 int err, ulen, usize, i; 573 loff_t offset; 574 575 *nr_slots = 0; 576 577 uname = __getname(); 578 if (!uname) 579 return -ENOMEM; 580 581 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 582 opts->unicode_xlate, opts->utf8, sbi->nls_io); 583 if (err) 584 goto out_free; 585 586 err = vfat_is_used_badchars(uname, ulen); 587 if (err) 588 goto out_free; 589 590 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 591 msdos_name, &lcase); 592 if (err < 0) 593 goto out_free; 594 else if (err == 1) { 595 de = (struct msdos_dir_entry *)slots; 596 err = 0; 597 goto shortname; 598 } 599 600 /* build the entry of long file name */ 601 cksum = fat_checksum(msdos_name); 602 603 *nr_slots = usize / 13; 604 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 605 ps->id = i; 606 ps->attr = ATTR_EXT; 607 ps->reserved = 0; 608 ps->alias_checksum = cksum; 609 ps->start = 0; 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); 614 } 615 slots[0].id |= 0x40; 616 de = (struct msdos_dir_entry *)ps; 617 618 shortname: 619 /* build the entry of 8.3 alias name */ 620 (*nr_slots)++; 621 memcpy(de->name, msdos_name, MSDOS_NAME); 622 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 623 de->lcase = lcase; 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); 630 de->size = 0; 631 out_free: 632 __putname(uname); 633 return err; 634 } 635 636 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) 639 { 640 struct msdos_dir_slot *slots; 641 unsigned int len; 642 int err, nr_slots; 643 644 len = vfat_striptail_len(qname); 645 if (len == 0) 646 return -ENOENT; 647 648 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 649 if (slots == NULL) 650 return -ENOMEM; 651 652 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 653 slots, &nr_slots); 654 if (err) 655 goto cleanup; 656 657 err = fat_add_entries(dir, slots, nr_slots, sinfo); 658 if (err) 659 goto cleanup; 660 661 /* update timestamp */ 662 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 663 if (IS_DIRSYNC(dir)) 664 (void)fat_sync_inode(dir); 665 else 666 mark_inode_dirty(dir); 667 cleanup: 668 kfree(slots); 669 return err; 670 } 671 672 static int vfat_find(struct inode *dir, struct qstr *qname, 673 struct fat_slot_info *sinfo) 674 { 675 unsigned int len = vfat_striptail_len(qname); 676 if (len == 0) 677 return -ENOENT; 678 return fat_search_long(dir, qname->name, len, sinfo); 679 } 680 681 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 682 struct nameidata *nd) 683 { 684 struct super_block *sb = dir->i_sb; 685 struct fat_slot_info sinfo; 686 struct inode *inode = NULL; 687 struct dentry *alias; 688 int err, table; 689 690 lock_super(sb); 691 table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0; 692 dentry->d_op = &vfat_dentry_ops[table]; 693 694 err = vfat_find(dir, &dentry->d_name, &sinfo); 695 if (err) { 696 table++; 697 goto error; 698 } 699 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 700 brelse(sinfo.bh); 701 if (IS_ERR(inode)) { 702 unlock_super(sb); 703 return ERR_CAST(inode); 704 } 705 alias = d_find_alias(inode); 706 if (alias) { 707 if (d_invalidate(alias) == 0) 708 dput(alias); 709 else { 710 iput(inode); 711 unlock_super(sb); 712 return alias; 713 } 714 715 } 716 error: 717 unlock_super(sb); 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); 721 if (dentry) { 722 dentry->d_op = &vfat_dentry_ops[table]; 723 dentry->d_time = dentry->d_parent->d_inode->i_version; 724 } 725 return dentry; 726 } 727 728 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode, 729 struct nameidata *nd) 730 { 731 struct super_block *sb = dir->i_sb; 732 struct inode *inode; 733 struct fat_slot_info sinfo; 734 struct timespec ts; 735 int err; 736 737 lock_super(sb); 738 739 ts = CURRENT_TIME_SEC; 740 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 741 if (err) 742 goto out; 743 dir->i_version++; 744 745 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 746 brelse(sinfo.bh); 747 if (IS_ERR(inode)) { 748 err = PTR_ERR(inode); 749 goto out; 750 } 751 inode->i_version++; 752 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 753 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 754 755 dentry->d_time = dentry->d_parent->d_inode->i_version; 756 d_instantiate(dentry, inode); 757 out: 758 unlock_super(sb); 759 return err; 760 } 761 762 static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 763 { 764 struct inode *inode = dentry->d_inode; 765 struct super_block *sb = dir->i_sb; 766 struct fat_slot_info sinfo; 767 int err; 768 769 lock_super(sb); 770 771 err = fat_dir_empty(inode); 772 if (err) 773 goto out; 774 err = vfat_find(dir, &dentry->d_name, &sinfo); 775 if (err) 776 goto out; 777 778 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 779 if (err) 780 goto out; 781 drop_nlink(dir); 782 783 clear_nlink(inode); 784 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 785 fat_detach(inode); 786 out: 787 unlock_super(sb); 788 789 return err; 790 } 791 792 static int vfat_unlink(struct inode *dir, struct dentry *dentry) 793 { 794 struct inode *inode = dentry->d_inode; 795 struct super_block *sb = dir->i_sb; 796 struct fat_slot_info sinfo; 797 int err; 798 799 lock_super(sb); 800 801 err = vfat_find(dir, &dentry->d_name, &sinfo); 802 if (err) 803 goto out; 804 805 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 806 if (err) 807 goto out; 808 clear_nlink(inode); 809 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 810 fat_detach(inode); 811 out: 812 unlock_super(sb); 813 814 return err; 815 } 816 817 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode) 818 { 819 struct super_block *sb = dir->i_sb; 820 struct inode *inode; 821 struct fat_slot_info sinfo; 822 struct timespec ts; 823 int err, cluster; 824 825 lock_super(sb); 826 827 ts = CURRENT_TIME_SEC; 828 cluster = fat_alloc_new_dir(dir, &ts); 829 if (cluster < 0) { 830 err = cluster; 831 goto out; 832 } 833 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 834 if (err) 835 goto out_free; 836 dir->i_version++; 837 inc_nlink(dir); 838 839 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 840 brelse(sinfo.bh); 841 if (IS_ERR(inode)) { 842 err = PTR_ERR(inode); 843 /* the directory was completed, just return a error */ 844 goto out; 845 } 846 inode->i_version++; 847 inode->i_nlink = 2; 848 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 849 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 850 851 dentry->d_time = dentry->d_parent->d_inode->i_version; 852 d_instantiate(dentry, inode); 853 854 unlock_super(sb); 855 return 0; 856 857 out_free: 858 fat_free_clusters(dir, cluster); 859 out: 860 unlock_super(sb); 861 return err; 862 } 863 864 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 865 struct inode *new_dir, struct dentry *new_dentry) 866 { 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; 871 struct timespec ts; 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; 875 876 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 877 old_inode = old_dentry->d_inode; 878 new_inode = new_dentry->d_inode; 879 lock_super(sb); 880 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 881 if (err) 882 goto out; 883 884 is_dir = S_ISDIR(old_inode->i_mode); 885 update_dotdot = (is_dir && old_dir != new_dir); 886 if (update_dotdot) { 887 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de, 888 &dotdot_i_pos) < 0) { 889 err = -EIO; 890 goto out; 891 } 892 } 893 894 ts = CURRENT_TIME_SEC; 895 if (new_inode) { 896 if (is_dir) { 897 err = fat_dir_empty(new_inode); 898 if (err) 899 goto out; 900 } 901 new_i_pos = MSDOS_I(new_inode)->i_pos; 902 fat_detach(new_inode); 903 } else { 904 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 905 &ts, &sinfo); 906 if (err) 907 goto out; 908 new_i_pos = sinfo.i_pos; 909 } 910 new_dir->i_version++; 911 912 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); 916 if (err) 917 goto error_inode; 918 } else 919 mark_inode_dirty(old_inode); 920 921 if (update_dotdot) { 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); 928 if (err) 929 goto error_dotdot; 930 } 931 drop_nlink(old_dir); 932 if (!new_inode) 933 inc_nlink(new_dir); 934 } 935 936 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 937 old_sinfo.bh = NULL; 938 if (err) 939 goto error_dotdot; 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); 944 else 945 mark_inode_dirty(old_dir); 946 947 if (new_inode) { 948 drop_nlink(new_inode); 949 if (is_dir) 950 drop_nlink(new_inode); 951 new_inode->i_ctime = ts; 952 } 953 out: 954 brelse(sinfo.bh); 955 brelse(dotdot_bh); 956 brelse(old_sinfo.bh); 957 unlock_super(sb); 958 959 return err; 960 961 error_dotdot: 962 /* data cluster is shared, serious corruption */ 963 corrupt = 1; 964 965 if (update_dotdot) { 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); 971 } 972 error_inode: 973 fat_detach(old_inode); 974 fat_attach(old_inode, old_sinfo.i_pos); 975 if (new_inode) { 976 fat_attach(new_inode, new_i_pos); 977 if (corrupt) 978 corrupt |= fat_sync_inode(new_inode); 979 } else { 980 /* 981 * If new entry was not sharing the data cluster, it 982 * shouldn't be serious corruption. 983 */ 984 int err2 = fat_remove_entries(new_dir, &sinfo); 985 if (corrupt) 986 corrupt |= err2; 987 sinfo.bh = NULL; 988 } 989 if (corrupt < 0) { 990 fat_fs_panic(new_dir->i_sb, 991 "%s: Filesystem corrupted (i_pos %lld)", 992 __func__, sinfo.i_pos); 993 } 994 goto out; 995 } 996 997 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, 1006 }; 1007 1008 static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1009 { 1010 int res; 1011 1012 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1); 1013 if (res) 1014 return res; 1015 1016 if (MSDOS_SB(sb)->options.name_check != 's') 1017 sb->s_root->d_op = &vfat_dentry_ops[0]; 1018 else 1019 sb->s_root->d_op = &vfat_dentry_ops[2]; 1020 1021 return 0; 1022 } 1023 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) 1027 { 1028 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super, 1029 mnt); 1030 } 1031 1032 static struct file_system_type vfat_fs_type = { 1033 .owner = THIS_MODULE, 1034 .name = "vfat", 1035 .get_sb = vfat_get_sb, 1036 .kill_sb = kill_block_super, 1037 .fs_flags = FS_REQUIRES_DEV, 1038 }; 1039 1040 static int __init init_vfat_fs(void) 1041 { 1042 return register_filesystem(&vfat_fs_type); 1043 } 1044 1045 static void __exit exit_vfat_fs(void) 1046 { 1047 unregister_filesystem(&vfat_fs_type); 1048 } 1049 1050 MODULE_LICENSE("GPL"); 1051 MODULE_DESCRIPTION("VFAT filesystem support"); 1052 MODULE_AUTHOR("Gordon Chaffee"); 1053 1054 module_init(init_vfat_fs) 1055 module_exit(exit_vfat_fs) 1056