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