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