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