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/buffer_head.h> 23 #include <linux/namei.h> 24 #include "fat.h" 25 26 /* 27 * If new entry was created in the parent, it could create the 8.3 28 * alias (the shortname of logname). So, the parent may have the 29 * negative-dentry which matches the created 8.3 alias. 30 * 31 * If it happened, the negative dentry isn't actually negative 32 * anymore. So, drop it. 33 */ 34 static int vfat_revalidate_shortname(struct dentry *dentry) 35 { 36 int ret = 1; 37 spin_lock(&dentry->d_lock); 38 if (dentry->d_time != dentry->d_parent->d_inode->i_version) 39 ret = 0; 40 spin_unlock(&dentry->d_lock); 41 return ret; 42 } 43 44 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) 45 { 46 if (nd && nd->flags & LOOKUP_RCU) 47 return -ECHILD; 48 49 /* This is not negative dentry. Always valid. */ 50 if (dentry->d_inode) 51 return 1; 52 return vfat_revalidate_shortname(dentry); 53 } 54 55 static int vfat_revalidate_ci(struct dentry *dentry, struct nameidata *nd) 56 { 57 if (nd && nd->flags & LOOKUP_RCU) 58 return -ECHILD; 59 60 /* 61 * This is not negative dentry. Always valid. 62 * 63 * Note, rename() to existing directory entry will have ->d_inode, 64 * and will use existing name which isn't specified name by user. 65 * 66 * We may be able to drop this positive dentry here. But dropping 67 * positive dentry isn't good idea. So it's unsupported like 68 * rename("filename", "FILENAME") for now. 69 */ 70 if (dentry->d_inode) 71 return 1; 72 73 /* 74 * This may be nfsd (or something), anyway, we can't see the 75 * intent of this. So, since this can be for creation, drop it. 76 */ 77 if (!nd) 78 return 0; 79 80 /* 81 * Drop the negative dentry, in order to make sure to use the 82 * case sensitive name which is specified by user if this is 83 * for creation. 84 */ 85 if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) { 86 if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 87 return 0; 88 } 89 90 return vfat_revalidate_shortname(dentry); 91 } 92 93 /* returns the length of a struct qstr, ignoring trailing dots */ 94 static unsigned int __vfat_striptail_len(unsigned int len, const char *name) 95 { 96 while (len && name[len - 1] == '.') 97 len--; 98 return len; 99 } 100 101 static unsigned int vfat_striptail_len(const struct qstr *qstr) 102 { 103 return __vfat_striptail_len(qstr->len, qstr->name); 104 } 105 106 /* 107 * Compute the hash for the vfat name corresponding to the dentry. 108 * Note: if the name is invalid, we leave the hash code unchanged so 109 * that the existing dentry can be used. The vfat fs routines will 110 * return ENOENT or EINVAL as appropriate. 111 */ 112 static int vfat_hash(const struct dentry *dentry, const struct inode *inode, 113 struct qstr *qstr) 114 { 115 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); 116 return 0; 117 } 118 119 /* 120 * Compute the hash for the vfat name corresponding to the dentry. 121 * Note: if the name is invalid, we leave the hash code unchanged so 122 * that the existing dentry can be used. The vfat fs routines will 123 * return ENOENT or EINVAL as appropriate. 124 */ 125 static int vfat_hashi(const struct dentry *dentry, const struct inode *inode, 126 struct qstr *qstr) 127 { 128 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 129 const unsigned char *name; 130 unsigned int len; 131 unsigned long hash; 132 133 name = qstr->name; 134 len = vfat_striptail_len(qstr); 135 136 hash = init_name_hash(); 137 while (len--) 138 hash = partial_name_hash(nls_tolower(t, *name++), hash); 139 qstr->hash = end_name_hash(hash); 140 141 return 0; 142 } 143 144 /* 145 * Case insensitive compare of two vfat names. 146 */ 147 static int vfat_cmpi(const struct dentry *parent, const struct inode *pinode, 148 const struct dentry *dentry, const struct inode *inode, 149 unsigned int len, const char *str, const struct qstr *name) 150 { 151 struct nls_table *t = MSDOS_SB(parent->d_sb)->nls_io; 152 unsigned int alen, blen; 153 154 /* A filename cannot end in '.' or we treat it like it has none */ 155 alen = vfat_striptail_len(name); 156 blen = __vfat_striptail_len(len, str); 157 if (alen == blen) { 158 if (nls_strnicmp(t, name->name, str, alen) == 0) 159 return 0; 160 } 161 return 1; 162 } 163 164 /* 165 * Case sensitive compare of two vfat names. 166 */ 167 static int vfat_cmp(const struct dentry *parent, const struct inode *pinode, 168 const struct dentry *dentry, const struct inode *inode, 169 unsigned int len, const char *str, const struct qstr *name) 170 { 171 unsigned int alen, blen; 172 173 /* A filename cannot end in '.' or we treat it like it has none */ 174 alen = vfat_striptail_len(name); 175 blen = __vfat_striptail_len(len, str); 176 if (alen == blen) { 177 if (strncmp(name->name, str, alen) == 0) 178 return 0; 179 } 180 return 1; 181 } 182 183 static const struct dentry_operations vfat_ci_dentry_ops = { 184 .d_revalidate = vfat_revalidate_ci, 185 .d_hash = vfat_hashi, 186 .d_compare = vfat_cmpi, 187 }; 188 189 static const struct dentry_operations vfat_dentry_ops = { 190 .d_revalidate = vfat_revalidate, 191 .d_hash = vfat_hash, 192 .d_compare = vfat_cmp, 193 }; 194 195 /* Characters that are undesirable in an MS-DOS file name */ 196 197 static inline wchar_t vfat_bad_char(wchar_t w) 198 { 199 return (w < 0x0020) 200 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 201 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 202 || (w == '\\'); 203 } 204 205 static inline wchar_t vfat_replace_char(wchar_t w) 206 { 207 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 208 || (w == '+') || (w == '='); 209 } 210 211 static wchar_t vfat_skip_char(wchar_t w) 212 { 213 return (w == '.') || (w == ' '); 214 } 215 216 static inline int vfat_is_used_badchars(const wchar_t *s, int len) 217 { 218 int i; 219 220 for (i = 0; i < len; i++) 221 if (vfat_bad_char(s[i])) 222 return -EINVAL; 223 224 if (s[i - 1] == ' ') /* last character cannot be space */ 225 return -EINVAL; 226 227 return 0; 228 } 229 230 static int vfat_find_form(struct inode *dir, unsigned char *name) 231 { 232 struct fat_slot_info sinfo; 233 int err = fat_scan(dir, name, &sinfo); 234 if (err) 235 return -ENOENT; 236 brelse(sinfo.bh); 237 return 0; 238 } 239 240 /* 241 * 1) Valid characters for the 8.3 format alias are any combination of 242 * letters, uppercase alphabets, digits, any of the 243 * following special characters: 244 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 245 * In this case Longfilename is not stored in disk. 246 * 247 * WinNT's Extension: 248 * File name and extension name is contain uppercase/lowercase 249 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 250 * 251 * 2) File name is 8.3 format, but it contain the uppercase and 252 * lowercase char, muliti bytes char, etc. In this case numtail is not 253 * added, but Longfilename is stored. 254 * 255 * 3) When the one except for the above, or the following special 256 * character are contained: 257 * . [ ] ; , + = 258 * numtail is added, and Longfilename must be stored in disk . 259 */ 260 struct shortname_info { 261 unsigned char lower:1, 262 upper:1, 263 valid:1; 264 }; 265 #define INIT_SHORTNAME_INFO(x) do { \ 266 (x)->lower = 1; \ 267 (x)->upper = 1; \ 268 (x)->valid = 1; \ 269 } while (0) 270 271 static inline int to_shortname_char(struct nls_table *nls, 272 unsigned char *buf, int buf_size, 273 wchar_t *src, struct shortname_info *info) 274 { 275 int len; 276 277 if (vfat_skip_char(*src)) { 278 info->valid = 0; 279 return 0; 280 } 281 if (vfat_replace_char(*src)) { 282 info->valid = 0; 283 buf[0] = '_'; 284 return 1; 285 } 286 287 len = nls->uni2char(*src, buf, buf_size); 288 if (len <= 0) { 289 info->valid = 0; 290 buf[0] = '_'; 291 len = 1; 292 } else if (len == 1) { 293 unsigned char prev = buf[0]; 294 295 if (buf[0] >= 0x7F) { 296 info->lower = 0; 297 info->upper = 0; 298 } 299 300 buf[0] = nls_toupper(nls, buf[0]); 301 if (isalpha(buf[0])) { 302 if (buf[0] == prev) 303 info->lower = 0; 304 else 305 info->upper = 0; 306 } 307 } else { 308 info->lower = 0; 309 info->upper = 0; 310 } 311 312 return len; 313 } 314 315 /* 316 * Given a valid longname, create a unique shortname. Make sure the 317 * shortname does not exist 318 * Returns negative number on error, 0 for a normal 319 * return, and 1 for valid shortname 320 */ 321 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 322 wchar_t *uname, int ulen, 323 unsigned char *name_res, unsigned char *lcase) 324 { 325 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 326 wchar_t *ip, *ext_start, *end, *name_start; 327 unsigned char base[9], ext[4], buf[5], *p; 328 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 329 int chl, chi; 330 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 331 int is_shortname; 332 struct shortname_info base_info, ext_info; 333 334 is_shortname = 1; 335 INIT_SHORTNAME_INFO(&base_info); 336 INIT_SHORTNAME_INFO(&ext_info); 337 338 /* Now, we need to create a shortname from the long name */ 339 ext_start = end = &uname[ulen]; 340 while (--ext_start >= uname) { 341 if (*ext_start == 0x002E) { /* is `.' */ 342 if (ext_start == end - 1) { 343 sz = ulen; 344 ext_start = NULL; 345 } 346 break; 347 } 348 } 349 350 if (ext_start == uname - 1) { 351 sz = ulen; 352 ext_start = NULL; 353 } else if (ext_start) { 354 /* 355 * Names which start with a dot could be just 356 * an extension eg. "...test". In this case Win95 357 * uses the extension as the name and sets no extension. 358 */ 359 name_start = &uname[0]; 360 while (name_start < ext_start) { 361 if (!vfat_skip_char(*name_start)) 362 break; 363 name_start++; 364 } 365 if (name_start != ext_start) { 366 sz = ext_start - uname; 367 ext_start++; 368 } else { 369 sz = ulen; 370 ext_start = NULL; 371 } 372 } 373 374 numtail_baselen = 6; 375 numtail2_baselen = 2; 376 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 377 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 378 ip, &base_info); 379 if (chl == 0) 380 continue; 381 382 if (baselen < 2 && (baselen + chl) > 2) 383 numtail2_baselen = baselen; 384 if (baselen < 6 && (baselen + chl) > 6) 385 numtail_baselen = baselen; 386 for (chi = 0; chi < chl; chi++) { 387 *p++ = charbuf[chi]; 388 baselen++; 389 if (baselen >= 8) 390 break; 391 } 392 if (baselen >= 8) { 393 if ((chi < chl - 1) || (ip + 1) - uname < sz) 394 is_shortname = 0; 395 break; 396 } 397 } 398 if (baselen == 0) { 399 return -EINVAL; 400 } 401 402 extlen = 0; 403 if (ext_start) { 404 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 405 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 406 ip, &ext_info); 407 if (chl == 0) 408 continue; 409 410 if ((extlen + chl) > 3) { 411 is_shortname = 0; 412 break; 413 } 414 for (chi = 0; chi < chl; chi++) { 415 *p++ = charbuf[chi]; 416 extlen++; 417 } 418 if (extlen >= 3) { 419 if (ip + 1 != end) 420 is_shortname = 0; 421 break; 422 } 423 } 424 } 425 ext[extlen] = '\0'; 426 base[baselen] = '\0'; 427 428 /* Yes, it can happen. ".\xe5" would do it. */ 429 if (base[0] == DELETED_FLAG) 430 base[0] = 0x05; 431 432 /* OK, at this point we know that base is not longer than 8 symbols, 433 * ext is not longer than 3, base is nonempty, both don't contain 434 * any bad symbols (lowercase transformed to uppercase). 435 */ 436 437 memset(name_res, ' ', MSDOS_NAME); 438 memcpy(name_res, base, baselen); 439 memcpy(name_res + 8, ext, extlen); 440 *lcase = 0; 441 if (is_shortname && base_info.valid && ext_info.valid) { 442 if (vfat_find_form(dir, name_res) == 0) 443 return -EEXIST; 444 445 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 446 return (base_info.upper && ext_info.upper); 447 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 448 if ((base_info.upper || base_info.lower) && 449 (ext_info.upper || ext_info.lower)) { 450 if (!base_info.upper && base_info.lower) 451 *lcase |= CASE_LOWER_BASE; 452 if (!ext_info.upper && ext_info.lower) 453 *lcase |= CASE_LOWER_EXT; 454 return 1; 455 } 456 return 0; 457 } else { 458 BUG(); 459 } 460 } 461 462 if (opts->numtail == 0) 463 if (vfat_find_form(dir, name_res) < 0) 464 return 0; 465 466 /* 467 * Try to find a unique extension. This used to 468 * iterate through all possibilities sequentially, 469 * but that gave extremely bad performance. Windows 470 * only tries a few cases before using random 471 * values for part of the base. 472 */ 473 474 if (baselen > 6) { 475 baselen = numtail_baselen; 476 name_res[7] = ' '; 477 } 478 name_res[baselen] = '~'; 479 for (i = 1; i < 10; i++) { 480 name_res[baselen + 1] = i + '0'; 481 if (vfat_find_form(dir, name_res) < 0) 482 return 0; 483 } 484 485 i = jiffies; 486 sz = (jiffies >> 16) & 0x7; 487 if (baselen > 2) { 488 baselen = numtail2_baselen; 489 name_res[7] = ' '; 490 } 491 name_res[baselen + 4] = '~'; 492 name_res[baselen + 5] = '1' + sz; 493 while (1) { 494 snprintf(buf, sizeof(buf), "%04X", i & 0xffff); 495 memcpy(&name_res[baselen], buf, 4); 496 if (vfat_find_form(dir, name_res) < 0) 497 break; 498 i -= 11; 499 } 500 return 0; 501 } 502 503 /* Translate a string, including coded sequences into Unicode */ 504 static int 505 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 506 int *longlen, int *outlen, int escape, int utf8, 507 struct nls_table *nls) 508 { 509 const unsigned char *ip; 510 unsigned char nc; 511 unsigned char *op; 512 unsigned int ec; 513 int i, k, fill; 514 int charlen; 515 516 if (utf8) { 517 *outlen = utf8s_to_utf16s(name, len, (wchar_t *)outname); 518 if (*outlen < 0) 519 return *outlen; 520 else if (*outlen > FAT_LFN_LEN) 521 return -ENAMETOOLONG; 522 523 op = &outname[*outlen * sizeof(wchar_t)]; 524 } else { 525 if (nls) { 526 for (i = 0, ip = name, op = outname, *outlen = 0; 527 i < len && *outlen <= FAT_LFN_LEN; 528 *outlen += 1) 529 { 530 if (escape && (*ip == ':')) { 531 if (i > len - 5) 532 return -EINVAL; 533 ec = 0; 534 for (k = 1; k < 5; k++) { 535 nc = ip[k]; 536 ec <<= 4; 537 if (nc >= '0' && nc <= '9') { 538 ec |= nc - '0'; 539 continue; 540 } 541 if (nc >= 'a' && nc <= 'f') { 542 ec |= nc - ('a' - 10); 543 continue; 544 } 545 if (nc >= 'A' && nc <= 'F') { 546 ec |= nc - ('A' - 10); 547 continue; 548 } 549 return -EINVAL; 550 } 551 *op++ = ec & 0xFF; 552 *op++ = ec >> 8; 553 ip += 5; 554 i += 5; 555 } else { 556 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0) 557 return -EINVAL; 558 ip += charlen; 559 i += charlen; 560 op += 2; 561 } 562 } 563 if (i < len) 564 return -ENAMETOOLONG; 565 } else { 566 for (i = 0, ip = name, op = outname, *outlen = 0; 567 i < len && *outlen <= FAT_LFN_LEN; 568 i++, *outlen += 1) 569 { 570 *op++ = *ip++; 571 *op++ = 0; 572 } 573 if (i < len) 574 return -ENAMETOOLONG; 575 } 576 } 577 578 *longlen = *outlen; 579 if (*outlen % 13) { 580 *op++ = 0; 581 *op++ = 0; 582 *outlen += 1; 583 if (*outlen % 13) { 584 fill = 13 - (*outlen % 13); 585 for (i = 0; i < fill; i++) { 586 *op++ = 0xff; 587 *op++ = 0xff; 588 } 589 *outlen += fill; 590 } 591 } 592 593 return 0; 594 } 595 596 static int vfat_build_slots(struct inode *dir, const unsigned char *name, 597 int len, int is_dir, int cluster, 598 struct timespec *ts, 599 struct msdos_dir_slot *slots, int *nr_slots) 600 { 601 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 602 struct fat_mount_options *opts = &sbi->options; 603 struct msdos_dir_slot *ps; 604 struct msdos_dir_entry *de; 605 unsigned char cksum, lcase; 606 unsigned char msdos_name[MSDOS_NAME]; 607 wchar_t *uname; 608 __le16 time, date; 609 u8 time_cs; 610 int err, ulen, usize, i; 611 loff_t offset; 612 613 *nr_slots = 0; 614 615 uname = __getname(); 616 if (!uname) 617 return -ENOMEM; 618 619 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 620 opts->unicode_xlate, opts->utf8, sbi->nls_io); 621 if (err) 622 goto out_free; 623 624 err = vfat_is_used_badchars(uname, ulen); 625 if (err) 626 goto out_free; 627 628 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 629 msdos_name, &lcase); 630 if (err < 0) 631 goto out_free; 632 else if (err == 1) { 633 de = (struct msdos_dir_entry *)slots; 634 err = 0; 635 goto shortname; 636 } 637 638 /* build the entry of long file name */ 639 cksum = fat_checksum(msdos_name); 640 641 *nr_slots = usize / 13; 642 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 643 ps->id = i; 644 ps->attr = ATTR_EXT; 645 ps->reserved = 0; 646 ps->alias_checksum = cksum; 647 ps->start = 0; 648 offset = (i - 1) * 13; 649 fatwchar_to16(ps->name0_4, uname + offset, 5); 650 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 651 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 652 } 653 slots[0].id |= 0x40; 654 de = (struct msdos_dir_entry *)ps; 655 656 shortname: 657 /* build the entry of 8.3 alias name */ 658 (*nr_slots)++; 659 memcpy(de->name, msdos_name, MSDOS_NAME); 660 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 661 de->lcase = lcase; 662 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); 663 de->time = de->ctime = time; 664 de->date = de->cdate = de->adate = date; 665 de->ctime_cs = time_cs; 666 de->start = cpu_to_le16(cluster); 667 de->starthi = cpu_to_le16(cluster >> 16); 668 de->size = 0; 669 out_free: 670 __putname(uname); 671 return err; 672 } 673 674 static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir, 675 int cluster, struct timespec *ts, 676 struct fat_slot_info *sinfo) 677 { 678 struct msdos_dir_slot *slots; 679 unsigned int len; 680 int err, nr_slots; 681 682 len = vfat_striptail_len(qname); 683 if (len == 0) 684 return -ENOENT; 685 686 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 687 if (slots == NULL) 688 return -ENOMEM; 689 690 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 691 slots, &nr_slots); 692 if (err) 693 goto cleanup; 694 695 err = fat_add_entries(dir, slots, nr_slots, sinfo); 696 if (err) 697 goto cleanup; 698 699 /* update timestamp */ 700 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 701 if (IS_DIRSYNC(dir)) 702 (void)fat_sync_inode(dir); 703 else 704 mark_inode_dirty(dir); 705 cleanup: 706 kfree(slots); 707 return err; 708 } 709 710 static int vfat_find(struct inode *dir, struct qstr *qname, 711 struct fat_slot_info *sinfo) 712 { 713 unsigned int len = vfat_striptail_len(qname); 714 if (len == 0) 715 return -ENOENT; 716 return fat_search_long(dir, qname->name, len, sinfo); 717 } 718 719 /* 720 * (nfsd's) anonymous disconnected dentry? 721 * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job). 722 */ 723 static int vfat_d_anon_disconn(struct dentry *dentry) 724 { 725 return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED); 726 } 727 728 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 729 struct nameidata *nd) 730 { 731 struct super_block *sb = dir->i_sb; 732 struct fat_slot_info sinfo; 733 struct inode *inode; 734 struct dentry *alias; 735 int err; 736 737 lock_super(sb); 738 739 err = vfat_find(dir, &dentry->d_name, &sinfo); 740 if (err) { 741 if (err == -ENOENT) { 742 inode = NULL; 743 goto out; 744 } 745 goto error; 746 } 747 748 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 749 brelse(sinfo.bh); 750 if (IS_ERR(inode)) { 751 err = PTR_ERR(inode); 752 goto error; 753 } 754 755 alias = d_find_alias(inode); 756 if (alias && !vfat_d_anon_disconn(alias)) { 757 /* 758 * This inode has non anonymous-DCACHE_DISCONNECTED 759 * dentry. This means, the user did ->lookup() by an 760 * another name (longname vs 8.3 alias of it) in past. 761 * 762 * Switch to new one for reason of locality if possible. 763 */ 764 BUG_ON(d_unhashed(alias)); 765 if (!S_ISDIR(inode->i_mode)) 766 d_move(alias, dentry); 767 iput(inode); 768 unlock_super(sb); 769 return alias; 770 } else 771 dput(alias); 772 773 out: 774 unlock_super(sb); 775 dentry->d_time = dentry->d_parent->d_inode->i_version; 776 dentry = d_splice_alias(inode, dentry); 777 if (dentry) 778 dentry->d_time = dentry->d_parent->d_inode->i_version; 779 return dentry; 780 781 error: 782 unlock_super(sb); 783 return ERR_PTR(err); 784 } 785 786 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode, 787 struct nameidata *nd) 788 { 789 struct super_block *sb = dir->i_sb; 790 struct inode *inode; 791 struct fat_slot_info sinfo; 792 struct timespec ts; 793 int err; 794 795 lock_super(sb); 796 797 ts = CURRENT_TIME_SEC; 798 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 799 if (err) 800 goto out; 801 dir->i_version++; 802 803 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 804 brelse(sinfo.bh); 805 if (IS_ERR(inode)) { 806 err = PTR_ERR(inode); 807 goto out; 808 } 809 inode->i_version++; 810 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 811 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 812 813 dentry->d_time = dentry->d_parent->d_inode->i_version; 814 d_instantiate(dentry, inode); 815 out: 816 unlock_super(sb); 817 return err; 818 } 819 820 static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 821 { 822 struct inode *inode = dentry->d_inode; 823 struct super_block *sb = dir->i_sb; 824 struct fat_slot_info sinfo; 825 int err; 826 827 dentry_unhash(dentry); 828 829 lock_super(sb); 830 831 err = fat_dir_empty(inode); 832 if (err) 833 goto out; 834 err = vfat_find(dir, &dentry->d_name, &sinfo); 835 if (err) 836 goto out; 837 838 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 839 if (err) 840 goto out; 841 drop_nlink(dir); 842 843 clear_nlink(inode); 844 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 845 fat_detach(inode); 846 out: 847 unlock_super(sb); 848 849 return err; 850 } 851 852 static int vfat_unlink(struct inode *dir, struct dentry *dentry) 853 { 854 struct inode *inode = dentry->d_inode; 855 struct super_block *sb = dir->i_sb; 856 struct fat_slot_info sinfo; 857 int err; 858 859 lock_super(sb); 860 861 err = vfat_find(dir, &dentry->d_name, &sinfo); 862 if (err) 863 goto out; 864 865 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 866 if (err) 867 goto out; 868 clear_nlink(inode); 869 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 870 fat_detach(inode); 871 out: 872 unlock_super(sb); 873 874 return err; 875 } 876 877 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode) 878 { 879 struct super_block *sb = dir->i_sb; 880 struct inode *inode; 881 struct fat_slot_info sinfo; 882 struct timespec ts; 883 int err, cluster; 884 885 lock_super(sb); 886 887 ts = CURRENT_TIME_SEC; 888 cluster = fat_alloc_new_dir(dir, &ts); 889 if (cluster < 0) { 890 err = cluster; 891 goto out; 892 } 893 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 894 if (err) 895 goto out_free; 896 dir->i_version++; 897 inc_nlink(dir); 898 899 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 900 brelse(sinfo.bh); 901 if (IS_ERR(inode)) { 902 err = PTR_ERR(inode); 903 /* the directory was completed, just return a error */ 904 goto out; 905 } 906 inode->i_version++; 907 inode->i_nlink = 2; 908 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 909 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 910 911 dentry->d_time = dentry->d_parent->d_inode->i_version; 912 d_instantiate(dentry, inode); 913 914 unlock_super(sb); 915 return 0; 916 917 out_free: 918 fat_free_clusters(dir, cluster); 919 out: 920 unlock_super(sb); 921 return err; 922 } 923 924 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 925 struct inode *new_dir, struct dentry *new_dentry) 926 { 927 struct buffer_head *dotdot_bh; 928 struct msdos_dir_entry *dotdot_de; 929 struct inode *old_inode, *new_inode; 930 struct fat_slot_info old_sinfo, sinfo; 931 struct timespec ts; 932 loff_t dotdot_i_pos, new_i_pos; 933 int err, is_dir, update_dotdot, corrupt = 0; 934 struct super_block *sb = old_dir->i_sb; 935 936 if (new_dentry->d_inode && S_ISDIR(new_dentry->d_inode->i_mode)) 937 dentry_unhash(new_dentry); 938 939 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 940 old_inode = old_dentry->d_inode; 941 new_inode = new_dentry->d_inode; 942 lock_super(sb); 943 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 944 if (err) 945 goto out; 946 947 is_dir = S_ISDIR(old_inode->i_mode); 948 update_dotdot = (is_dir && old_dir != new_dir); 949 if (update_dotdot) { 950 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de, 951 &dotdot_i_pos) < 0) { 952 err = -EIO; 953 goto out; 954 } 955 } 956 957 ts = CURRENT_TIME_SEC; 958 if (new_inode) { 959 if (is_dir) { 960 err = fat_dir_empty(new_inode); 961 if (err) 962 goto out; 963 } 964 new_i_pos = MSDOS_I(new_inode)->i_pos; 965 fat_detach(new_inode); 966 } else { 967 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 968 &ts, &sinfo); 969 if (err) 970 goto out; 971 new_i_pos = sinfo.i_pos; 972 } 973 new_dir->i_version++; 974 975 fat_detach(old_inode); 976 fat_attach(old_inode, new_i_pos); 977 if (IS_DIRSYNC(new_dir)) { 978 err = fat_sync_inode(old_inode); 979 if (err) 980 goto error_inode; 981 } else 982 mark_inode_dirty(old_inode); 983 984 if (update_dotdot) { 985 int start = MSDOS_I(new_dir)->i_logstart; 986 dotdot_de->start = cpu_to_le16(start); 987 dotdot_de->starthi = cpu_to_le16(start >> 16); 988 mark_buffer_dirty_inode(dotdot_bh, old_inode); 989 if (IS_DIRSYNC(new_dir)) { 990 err = sync_dirty_buffer(dotdot_bh); 991 if (err) 992 goto error_dotdot; 993 } 994 drop_nlink(old_dir); 995 if (!new_inode) 996 inc_nlink(new_dir); 997 } 998 999 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 1000 old_sinfo.bh = NULL; 1001 if (err) 1002 goto error_dotdot; 1003 old_dir->i_version++; 1004 old_dir->i_ctime = old_dir->i_mtime = ts; 1005 if (IS_DIRSYNC(old_dir)) 1006 (void)fat_sync_inode(old_dir); 1007 else 1008 mark_inode_dirty(old_dir); 1009 1010 if (new_inode) { 1011 drop_nlink(new_inode); 1012 if (is_dir) 1013 drop_nlink(new_inode); 1014 new_inode->i_ctime = ts; 1015 } 1016 out: 1017 brelse(sinfo.bh); 1018 brelse(dotdot_bh); 1019 brelse(old_sinfo.bh); 1020 unlock_super(sb); 1021 1022 return err; 1023 1024 error_dotdot: 1025 /* data cluster is shared, serious corruption */ 1026 corrupt = 1; 1027 1028 if (update_dotdot) { 1029 int start = MSDOS_I(old_dir)->i_logstart; 1030 dotdot_de->start = cpu_to_le16(start); 1031 dotdot_de->starthi = cpu_to_le16(start >> 16); 1032 mark_buffer_dirty_inode(dotdot_bh, old_inode); 1033 corrupt |= sync_dirty_buffer(dotdot_bh); 1034 } 1035 error_inode: 1036 fat_detach(old_inode); 1037 fat_attach(old_inode, old_sinfo.i_pos); 1038 if (new_inode) { 1039 fat_attach(new_inode, new_i_pos); 1040 if (corrupt) 1041 corrupt |= fat_sync_inode(new_inode); 1042 } else { 1043 /* 1044 * If new entry was not sharing the data cluster, it 1045 * shouldn't be serious corruption. 1046 */ 1047 int err2 = fat_remove_entries(new_dir, &sinfo); 1048 if (corrupt) 1049 corrupt |= err2; 1050 sinfo.bh = NULL; 1051 } 1052 if (corrupt < 0) { 1053 fat_fs_error(new_dir->i_sb, 1054 "%s: Filesystem corrupted (i_pos %lld)", 1055 __func__, sinfo.i_pos); 1056 } 1057 goto out; 1058 } 1059 1060 static const struct inode_operations vfat_dir_inode_operations = { 1061 .create = vfat_create, 1062 .lookup = vfat_lookup, 1063 .unlink = vfat_unlink, 1064 .mkdir = vfat_mkdir, 1065 .rmdir = vfat_rmdir, 1066 .rename = vfat_rename, 1067 .setattr = fat_setattr, 1068 .getattr = fat_getattr, 1069 }; 1070 1071 static void setup(struct super_block *sb) 1072 { 1073 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations; 1074 if (MSDOS_SB(sb)->options.name_check != 's') 1075 sb->s_d_op = &vfat_ci_dentry_ops; 1076 else 1077 sb->s_d_op = &vfat_dentry_ops; 1078 } 1079 1080 static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1081 { 1082 return fat_fill_super(sb, data, silent, 1, setup); 1083 } 1084 1085 static struct dentry *vfat_mount(struct file_system_type *fs_type, 1086 int flags, const char *dev_name, 1087 void *data) 1088 { 1089 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super); 1090 } 1091 1092 static struct file_system_type vfat_fs_type = { 1093 .owner = THIS_MODULE, 1094 .name = "vfat", 1095 .mount = vfat_mount, 1096 .kill_sb = kill_block_super, 1097 .fs_flags = FS_REQUIRES_DEV, 1098 }; 1099 1100 static int __init init_vfat_fs(void) 1101 { 1102 return register_filesystem(&vfat_fs_type); 1103 } 1104 1105 static void __exit exit_vfat_fs(void) 1106 { 1107 unregister_filesystem(&vfat_fs_type); 1108 } 1109 1110 MODULE_LICENSE("GPL"); 1111 MODULE_DESCRIPTION("VFAT filesystem support"); 1112 MODULE_AUTHOR("Gordon Chaffee"); 1113 1114 module_init(init_vfat_fs) 1115 module_exit(exit_vfat_fs) 1116