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