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; 179 180 if (s[i - 1] == ' ') /* last character cannot be space */ 181 return -EINVAL; 182 183 return 0; 184 } 185 186 static int vfat_find_form(struct inode *dir, unsigned char *name) 187 { 188 struct fat_slot_info sinfo; 189 int err = fat_scan(dir, name, &sinfo); 190 if (err) 191 return -ENOENT; 192 brelse(sinfo.bh); 193 return 0; 194 } 195 196 /* 197 * 1) Valid characters for the 8.3 format alias are any combination of 198 * letters, uppercase alphabets, digits, any of the 199 * following special characters: 200 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 201 * In this case Longfilename is not stored in disk. 202 * 203 * WinNT's Extension: 204 * File name and extension name is contain uppercase/lowercase 205 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 206 * 207 * 2) File name is 8.3 format, but it contain the uppercase and 208 * lowercase char, muliti bytes char, etc. In this case numtail is not 209 * added, but Longfilename is stored. 210 * 211 * 3) When the one except for the above, or the following special 212 * character are contained: 213 * . [ ] ; , + = 214 * numtail is added, and Longfilename must be stored in disk . 215 */ 216 struct shortname_info { 217 unsigned char lower:1, 218 upper:1, 219 valid:1; 220 }; 221 #define INIT_SHORTNAME_INFO(x) do { \ 222 (x)->lower = 1; \ 223 (x)->upper = 1; \ 224 (x)->valid = 1; \ 225 } while (0) 226 227 static inline int to_shortname_char(struct nls_table *nls, 228 unsigned char *buf, int buf_size, 229 wchar_t *src, struct shortname_info *info) 230 { 231 int len; 232 233 if (vfat_skip_char(*src)) { 234 info->valid = 0; 235 return 0; 236 } 237 if (vfat_replace_char(*src)) { 238 info->valid = 0; 239 buf[0] = '_'; 240 return 1; 241 } 242 243 len = nls->uni2char(*src, buf, buf_size); 244 if (len <= 0) { 245 info->valid = 0; 246 buf[0] = '_'; 247 len = 1; 248 } else if (len == 1) { 249 unsigned char prev = buf[0]; 250 251 if (buf[0] >= 0x7F) { 252 info->lower = 0; 253 info->upper = 0; 254 } 255 256 buf[0] = nls_toupper(nls, buf[0]); 257 if (isalpha(buf[0])) { 258 if (buf[0] == prev) 259 info->lower = 0; 260 else 261 info->upper = 0; 262 } 263 } else { 264 info->lower = 0; 265 info->upper = 0; 266 } 267 268 return len; 269 } 270 271 /* 272 * Given a valid longname, create a unique shortname. Make sure the 273 * shortname does not exist 274 * Returns negative number on error, 0 for a normal 275 * return, and 1 for valid shortname 276 */ 277 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 278 wchar_t *uname, int ulen, 279 unsigned char *name_res, unsigned char *lcase) 280 { 281 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 282 wchar_t *ip, *ext_start, *end, *name_start; 283 unsigned char base[9], ext[4], buf[8], *p; 284 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 285 int chl, chi; 286 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 287 int is_shortname; 288 struct shortname_info base_info, ext_info; 289 290 is_shortname = 1; 291 INIT_SHORTNAME_INFO(&base_info); 292 INIT_SHORTNAME_INFO(&ext_info); 293 294 /* Now, we need to create a shortname from the long name */ 295 ext_start = end = &uname[ulen]; 296 while (--ext_start >= uname) { 297 if (*ext_start == 0x002E) { /* is `.' */ 298 if (ext_start == end - 1) { 299 sz = ulen; 300 ext_start = NULL; 301 } 302 break; 303 } 304 } 305 306 if (ext_start == uname - 1) { 307 sz = ulen; 308 ext_start = NULL; 309 } else if (ext_start) { 310 /* 311 * Names which start with a dot could be just 312 * an extension eg. "...test". In this case Win95 313 * uses the extension as the name and sets no extension. 314 */ 315 name_start = &uname[0]; 316 while (name_start < ext_start) { 317 if (!vfat_skip_char(*name_start)) 318 break; 319 name_start++; 320 } 321 if (name_start != ext_start) { 322 sz = ext_start - uname; 323 ext_start++; 324 } else { 325 sz = ulen; 326 ext_start = NULL; 327 } 328 } 329 330 numtail_baselen = 6; 331 numtail2_baselen = 2; 332 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 333 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 334 ip, &base_info); 335 if (chl == 0) 336 continue; 337 338 if (baselen < 2 && (baselen + chl) > 2) 339 numtail2_baselen = baselen; 340 if (baselen < 6 && (baselen + chl) > 6) 341 numtail_baselen = baselen; 342 for (chi = 0; chi < chl; chi++) { 343 *p++ = charbuf[chi]; 344 baselen++; 345 if (baselen >= 8) 346 break; 347 } 348 if (baselen >= 8) { 349 if ((chi < chl - 1) || (ip + 1) - uname < sz) 350 is_shortname = 0; 351 break; 352 } 353 } 354 if (baselen == 0) { 355 return -EINVAL; 356 } 357 358 extlen = 0; 359 if (ext_start) { 360 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 361 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 362 ip, &ext_info); 363 if (chl == 0) 364 continue; 365 366 if ((extlen + chl) > 3) { 367 is_shortname = 0; 368 break; 369 } 370 for (chi = 0; chi < chl; chi++) { 371 *p++ = charbuf[chi]; 372 extlen++; 373 } 374 if (extlen >= 3) { 375 if (ip + 1 != end) 376 is_shortname = 0; 377 break; 378 } 379 } 380 } 381 ext[extlen] = '\0'; 382 base[baselen] = '\0'; 383 384 /* Yes, it can happen. ".\xe5" would do it. */ 385 if (base[0] == DELETED_FLAG) 386 base[0] = 0x05; 387 388 /* OK, at this point we know that base is not longer than 8 symbols, 389 * ext is not longer than 3, base is nonempty, both don't contain 390 * any bad symbols (lowercase transformed to uppercase). 391 */ 392 393 memset(name_res, ' ', MSDOS_NAME); 394 memcpy(name_res, base, baselen); 395 memcpy(name_res + 8, ext, extlen); 396 *lcase = 0; 397 if (is_shortname && base_info.valid && ext_info.valid) { 398 if (vfat_find_form(dir, name_res) == 0) 399 return -EEXIST; 400 401 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 402 return (base_info.upper && ext_info.upper); 403 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 404 if ((base_info.upper || base_info.lower) && 405 (ext_info.upper || ext_info.lower)) { 406 if (!base_info.upper && base_info.lower) 407 *lcase |= CASE_LOWER_BASE; 408 if (!ext_info.upper && ext_info.lower) 409 *lcase |= CASE_LOWER_EXT; 410 return 1; 411 } 412 return 0; 413 } else { 414 BUG(); 415 } 416 } 417 418 if (opts->numtail == 0) 419 if (vfat_find_form(dir, name_res) < 0) 420 return 0; 421 422 /* 423 * Try to find a unique extension. This used to 424 * iterate through all possibilities sequentially, 425 * but that gave extremely bad performance. Windows 426 * only tries a few cases before using random 427 * values for part of the base. 428 */ 429 430 if (baselen > 6) { 431 baselen = numtail_baselen; 432 name_res[7] = ' '; 433 } 434 name_res[baselen] = '~'; 435 for (i = 1; i < 10; i++) { 436 name_res[baselen + 1] = i + '0'; 437 if (vfat_find_form(dir, name_res) < 0) 438 return 0; 439 } 440 441 i = jiffies & 0xffff; 442 sz = (jiffies >> 16) & 0x7; 443 if (baselen > 2) { 444 baselen = numtail2_baselen; 445 name_res[7] = ' '; 446 } 447 name_res[baselen + 4] = '~'; 448 name_res[baselen + 5] = '1' + sz; 449 while (1) { 450 sprintf(buf, "%04X", i); 451 memcpy(&name_res[baselen], buf, 4); 452 if (vfat_find_form(dir, name_res) < 0) 453 break; 454 i -= 11; 455 } 456 return 0; 457 } 458 459 /* Translate a string, including coded sequences into Unicode */ 460 static int 461 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 462 int *longlen, int *outlen, int escape, int utf8, 463 struct nls_table *nls) 464 { 465 const unsigned char *ip; 466 unsigned char nc; 467 unsigned char *op; 468 unsigned int ec; 469 int i, k, fill; 470 int charlen; 471 472 if (utf8) { 473 int name_len = strlen(name); 474 475 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX); 476 477 /* 478 * We stripped '.'s before and set len appropriately, 479 * but utf8_mbstowcs doesn't care about len 480 */ 481 *outlen -= (name_len - len); 482 483 if (*outlen > 255) 484 return -ENAMETOOLONG; 485 486 op = &outname[*outlen * sizeof(wchar_t)]; 487 } else { 488 if (nls) { 489 for (i = 0, ip = name, op = outname, *outlen = 0; 490 i < len && *outlen <= 255; 491 *outlen += 1) 492 { 493 if (escape && (*ip == ':')) { 494 if (i > len - 5) 495 return -EINVAL; 496 ec = 0; 497 for (k = 1; k < 5; k++) { 498 nc = ip[k]; 499 ec <<= 4; 500 if (nc >= '0' && nc <= '9') { 501 ec |= nc - '0'; 502 continue; 503 } 504 if (nc >= 'a' && nc <= 'f') { 505 ec |= nc - ('a' - 10); 506 continue; 507 } 508 if (nc >= 'A' && nc <= 'F') { 509 ec |= nc - ('A' - 10); 510 continue; 511 } 512 return -EINVAL; 513 } 514 *op++ = ec & 0xFF; 515 *op++ = ec >> 8; 516 ip += 5; 517 i += 5; 518 } else { 519 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0) 520 return -EINVAL; 521 ip += charlen; 522 i += charlen; 523 op += 2; 524 } 525 } 526 if (i < len) 527 return -ENAMETOOLONG; 528 } else { 529 for (i = 0, ip = name, op = outname, *outlen = 0; 530 i < len && *outlen <= 255; 531 i++, *outlen += 1) 532 { 533 *op++ = *ip++; 534 *op++ = 0; 535 } 536 if (i < len) 537 return -ENAMETOOLONG; 538 } 539 } 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 char cksum, lcase; 569 unsigned char msdos_name[MSDOS_NAME]; 570 wchar_t *uname; 571 __le16 time, date; 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_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.tz_utc); 625 de->time = de->ctime = time; 626 de->date = de->cdate = de->adate = date; 627 de->ctime_cs = 0; 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