1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * linux/fs/vfat/namei.c 4 * 5 * Written 1992,1993 by Werner Almesberger 6 * 7 * Windows95/Windows NT compatible extended MSDOS filesystem 8 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the 9 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify 10 * what file operation caused you trouble and if you can duplicate 11 * the problem, send a script that demonstrates it. 12 * 13 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> 14 * 15 * Support Multibyte characters and cleanup by 16 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> 17 */ 18 19#include <linux/module.h> 20#include <linux/ctype.h> 21#include <linux/slab.h> 22#include <linux/namei.h> 23#include <linux/kernel.h> 24#include <linux/iversion.h> 25#include "fat.h" 26 27static inline unsigned long vfat_d_version(struct dentry *dentry) 28{ 29 return (unsigned long) dentry->d_fsdata; 30} 31 32static inline void vfat_d_version_set(struct dentry *dentry, 33 unsigned long version) 34{ 35 dentry->d_fsdata = (void *) version; 36} 37 38/* 39 * If new entry was created in the parent, it could create the 8.3 40 * alias (the shortname of logname). So, the parent may have the 41 * negative-dentry which matches the created 8.3 alias. 42 * 43 * If it happened, the negative dentry isn't actually negative 44 * anymore. So, drop it. 45 */ 46static int vfat_revalidate_shortname(struct dentry *dentry) 47{ 48 int ret = 1; 49 spin_lock(&dentry->d_lock); 50 if (!inode_eq_iversion(d_inode(dentry->d_parent), vfat_d_version(dentry))) 51 ret = 0; 52 spin_unlock(&dentry->d_lock); 53 return ret; 54} 55 56static int vfat_revalidate(struct dentry *dentry, unsigned int flags) 57{ 58 if (flags & LOOKUP_RCU) 59 return -ECHILD; 60 61 /* This is not negative dentry. Always valid. */ 62 if (d_really_is_positive(dentry)) 63 return 1; 64 return vfat_revalidate_shortname(dentry); 65} 66 67static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags) 68{ 69 if (flags & LOOKUP_RCU) 70 return -ECHILD; 71 72 /* 73 * This is not negative dentry. Always valid. 74 * 75 * Note, rename() to existing directory entry will have ->d_inode, 76 * and will use existing name which isn't specified name by user. 77 * 78 * We may be able to drop this positive dentry here. But dropping 79 * positive dentry isn't good idea. So it's unsupported like 80 * rename("filename", "FILENAME") for now. 81 */ 82 if (d_really_is_positive(dentry)) 83 return 1; 84 85 /* 86 * This may be nfsd (or something), anyway, we can't see the 87 * intent of this. So, since this can be for creation, drop it. 88 */ 89 if (!flags) 90 return 0; 91 92 /* 93 * Drop the negative dentry, in order to make sure to use the 94 * case sensitive name which is specified by user if this is 95 * for creation. 96 */ 97 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 98 return 0; 99 100 return vfat_revalidate_shortname(dentry); 101} 102 103/* returns the length of a struct qstr, ignoring trailing dots */ 104static unsigned int __vfat_striptail_len(unsigned int len, const char *name) 105{ 106 while (len && name[len - 1] == '.') 107 len--; 108 return len; 109} 110 111static unsigned int vfat_striptail_len(const struct qstr *qstr) 112{ 113 return __vfat_striptail_len(qstr->len, qstr->name); 114} 115 116/* 117 * Compute the hash for the vfat name corresponding to the dentry. 118 * Note: if the name is invalid, we leave the hash code unchanged so 119 * that the existing dentry can be used. The vfat fs routines will 120 * return ENOENT or EINVAL as appropriate. 121 */ 122static int vfat_hash(const struct dentry *dentry, struct qstr *qstr) 123{ 124 qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr)); 125 return 0; 126} 127 128/* 129 * Compute the hash for the vfat name corresponding to the dentry. 130 * Note: if the name is invalid, we leave the hash code unchanged so 131 * that the existing dentry can be used. The vfat fs routines will 132 * return ENOENT or EINVAL as appropriate. 133 */ 134static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr) 135{ 136 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 137 const unsigned char *name; 138 unsigned int len; 139 unsigned long hash; 140 141 name = qstr->name; 142 len = vfat_striptail_len(qstr); 143 144 hash = init_name_hash(dentry); 145 while (len--) 146 hash = partial_name_hash(nls_tolower(t, *name++), hash); 147 qstr->hash = end_name_hash(hash); 148 149 return 0; 150} 151 152/* 153 * Case insensitive compare of two vfat names. 154 */ 155static int vfat_cmpi(const struct dentry *dentry, 156 unsigned int len, const char *str, const struct qstr *name) 157{ 158 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 159 unsigned int alen, blen; 160 161 /* A filename cannot end in '.' or we treat it like it has none */ 162 alen = vfat_striptail_len(name); 163 blen = __vfat_striptail_len(len, str); 164 if (alen == blen) { 165 if (nls_strnicmp(t, name->name, str, alen) == 0) 166 return 0; 167 } 168 return 1; 169} 170 171/* 172 * Case sensitive compare of two vfat names. 173 */ 174static int vfat_cmp(const struct dentry *dentry, 175 unsigned int len, const char *str, const struct qstr *name) 176{ 177 unsigned int alen, blen; 178 179 /* A filename cannot end in '.' or we treat it like it has none */ 180 alen = vfat_striptail_len(name); 181 blen = __vfat_striptail_len(len, str); 182 if (alen == blen) { 183 if (strncmp(name->name, str, alen) == 0) 184 return 0; 185 } 186 return 1; 187} 188 189static const struct dentry_operations vfat_ci_dentry_ops = { 190 .d_revalidate = vfat_revalidate_ci, 191 .d_hash = vfat_hashi, 192 .d_compare = vfat_cmpi, 193}; 194 195static const struct dentry_operations vfat_dentry_ops = { 196 .d_revalidate = vfat_revalidate, 197 .d_hash = vfat_hash, 198 .d_compare = vfat_cmp, 199}; 200 201/* Characters that are undesirable in an MS-DOS file name */ 202 203static inline bool vfat_bad_char(wchar_t w) 204{ 205 return (w < 0x0020) 206 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 207 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 208 || (w == '\\'); 209} 210 211static inline bool vfat_replace_char(wchar_t w) 212{ 213 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 214 || (w == '+') || (w == '='); 215} 216 217static wchar_t vfat_skip_char(wchar_t w) 218{ 219 return (w == '.') || (w == ' '); 220} 221 222static inline int vfat_is_used_badchars(const wchar_t *s, int len) 223{ 224 int i; 225 226 for (i = 0; i < len; i++) 227 if (vfat_bad_char(s[i])) 228 return -EINVAL; 229 230 if (s[i - 1] == ' ') /* last character cannot be space */ 231 return -EINVAL; 232 233 return 0; 234} 235 236static int vfat_find_form(struct inode *dir, unsigned char *name) 237{ 238 struct fat_slot_info sinfo; 239 int err = fat_scan(dir, name, &sinfo); 240 if (err) 241 return -ENOENT; 242 brelse(sinfo.bh); 243 return 0; 244} 245 246/* 247 * 1) Valid characters for the 8.3 format alias are any combination of 248 * letters, uppercase alphabets, digits, any of the 249 * following special characters: 250 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 251 * In this case Longfilename is not stored in disk. 252 * 253 * WinNT's Extension: 254 * File name and extension name is contain uppercase/lowercase 255 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 256 * 257 * 2) File name is 8.3 format, but it contain the uppercase and 258 * lowercase char, muliti bytes char, etc. In this case numtail is not 259 * added, but Longfilename is stored. 260 * 261 * 3) When the one except for the above, or the following special 262 * character are contained: 263 * . [ ] ; , + = 264 * numtail is added, and Longfilename must be stored in disk . 265 */ 266struct shortname_info { 267 unsigned char lower:1, 268 upper:1, 269 valid:1; 270}; 271#define INIT_SHORTNAME_INFO(x) do { \ 272 (x)->lower = 1; \ 273 (x)->upper = 1; \ 274 (x)->valid = 1; \ 275} while (0) 276 277static inline int to_shortname_char(struct nls_table *nls, 278 unsigned char *buf, int buf_size, 279 wchar_t *src, struct shortname_info *info) 280{ 281 int len; 282 283 if (vfat_skip_char(*src)) { 284 info->valid = 0; 285 return 0; 286 } 287 if (vfat_replace_char(*src)) { 288 info->valid = 0; 289 buf[0] = '_'; 290 return 1; 291 } 292 293 len = nls->uni2char(*src, buf, buf_size); 294 if (len <= 0) { 295 info->valid = 0; 296 buf[0] = '_'; 297 len = 1; 298 } else if (len == 1) { 299 unsigned char prev = buf[0]; 300 301 if (buf[0] >= 0x7F) { 302 info->lower = 0; 303 info->upper = 0; 304 } 305 306 buf[0] = nls_toupper(nls, buf[0]); 307 if (isalpha(buf[0])) { 308 if (buf[0] == prev) 309 info->lower = 0; 310 else 311 info->upper = 0; 312 } 313 } else { 314 info->lower = 0; 315 info->upper = 0; 316 } 317 318 return len; 319} 320 321/* 322 * Given a valid longname, create a unique shortname. Make sure the 323 * shortname does not exist 324 * Returns negative number on error, 0 for a normal 325 * return, and 1 for valid shortname 326 */ 327static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 328 wchar_t *uname, int ulen, 329 unsigned char *name_res, unsigned char *lcase) 330{ 331 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 332 wchar_t *ip, *ext_start, *end, *name_start; 333 unsigned char base[9], ext[4], buf[5], *p; 334 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 335 int chl, chi; 336 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 337 int is_shortname; 338 struct shortname_info base_info, ext_info; 339 340 is_shortname = 1; 341 INIT_SHORTNAME_INFO(&base_info); 342 INIT_SHORTNAME_INFO(&ext_info); 343 344 /* Now, we need to create a shortname from the long name */ 345 ext_start = end = &uname[ulen]; 346 while (--ext_start >= uname) { 347 if (*ext_start == 0x002E) { /* is `.' */ 348 if (ext_start == end - 1) { 349 sz = ulen; 350 ext_start = NULL; 351 } 352 break; 353 } 354 } 355 356 if (ext_start == uname - 1) { 357 sz = ulen; 358 ext_start = NULL; 359 } else if (ext_start) { 360 /* 361 * Names which start with a dot could be just 362 * an extension eg. "...test". In this case Win95 363 * uses the extension as the name and sets no extension. 364 */ 365 name_start = &uname[0]; 366 while (name_start < ext_start) { 367 if (!vfat_skip_char(*name_start)) 368 break; 369 name_start++; 370 } 371 if (name_start != ext_start) { 372 sz = ext_start - uname; 373 ext_start++; 374 } else { 375 sz = ulen; 376 ext_start = NULL; 377 } 378 } 379 380 numtail_baselen = 6; 381 numtail2_baselen = 2; 382 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 383 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 384 ip, &base_info); 385 if (chl == 0) 386 continue; 387 388 if (baselen < 2 && (baselen + chl) > 2) 389 numtail2_baselen = baselen; 390 if (baselen < 6 && (baselen + chl) > 6) 391 numtail_baselen = baselen; 392 for (chi = 0; chi < chl; chi++) { 393 *p++ = charbuf[chi]; 394 baselen++; 395 if (baselen >= 8) 396 break; 397 } 398 if (baselen >= 8) { 399 if ((chi < chl - 1) || (ip + 1) - uname < sz) 400 is_shortname = 0; 401 break; 402 } 403 } 404 if (baselen == 0) { 405 return -EINVAL; 406 } 407 408 extlen = 0; 409 if (ext_start) { 410 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 411 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 412 ip, &ext_info); 413 if (chl == 0) 414 continue; 415 416 if ((extlen + chl) > 3) { 417 is_shortname = 0; 418 break; 419 } 420 for (chi = 0; chi < chl; chi++) { 421 *p++ = charbuf[chi]; 422 extlen++; 423 } 424 if (extlen >= 3) { 425 if (ip + 1 != end) 426 is_shortname = 0; 427 break; 428 } 429 } 430 } 431 ext[extlen] = '\0'; 432 base[baselen] = '\0'; 433 434 /* Yes, it can happen. ".\xe5" would do it. */ 435 if (base[0] == DELETED_FLAG) 436 base[0] = 0x05; 437 438 /* OK, at this point we know that base is not longer than 8 symbols, 439 * ext is not longer than 3, base is nonempty, both don't contain 440 * any bad symbols (lowercase transformed to uppercase). 441 */ 442 443 memset(name_res, ' ', MSDOS_NAME); 444 memcpy(name_res, base, baselen); 445 memcpy(name_res + 8, ext, extlen); 446 *lcase = 0; 447 if (is_shortname && base_info.valid && ext_info.valid) { 448 if (vfat_find_form(dir, name_res) == 0) 449 return -EEXIST; 450 451 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 452 return (base_info.upper && ext_info.upper); 453 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 454 if ((base_info.upper || base_info.lower) && 455 (ext_info.upper || ext_info.lower)) { 456 if (!base_info.upper && base_info.lower) 457 *lcase |= CASE_LOWER_BASE; 458 if (!ext_info.upper && ext_info.lower) 459 *lcase |= CASE_LOWER_EXT; 460 return 1; 461 } 462 return 0; 463 } else { 464 BUG(); 465 } 466 } 467 468 if (opts->numtail == 0) 469 if (vfat_find_form(dir, name_res) < 0) 470 return 0; 471 472 /* 473 * Try to find a unique extension. This used to 474 * iterate through all possibilities sequentially, 475 * but that gave extremely bad performance. Windows 476 * only tries a few cases before using random 477 * values for part of the base. 478 */ 479 480 if (baselen > 6) { 481 baselen = numtail_baselen; 482 name_res[7] = ' '; 483 } 484 name_res[baselen] = '~'; 485 for (i = 1; i < 10; i++) { 486 name_res[baselen + 1] = i + '0'; 487 if (vfat_find_form(dir, name_res) < 0) 488 return 0; 489 } 490 491 i = jiffies; 492 sz = (jiffies >> 16) & 0x7; 493 if (baselen > 2) { 494 baselen = numtail2_baselen; 495 name_res[7] = ' '; 496 } 497 name_res[baselen + 4] = '~'; 498 name_res[baselen + 5] = '1' + sz; 499 while (1) { 500 snprintf(buf, sizeof(buf), "%04X", i & 0xffff); 501 memcpy(&name_res[baselen], buf, 4); 502 if (vfat_find_form(dir, name_res) < 0) 503 break; 504 i -= 11; 505 } 506 return 0; 507} 508 509/* Translate a string, including coded sequences into Unicode */ 510static int 511xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 512 int *longlen, int *outlen, int escape, int utf8, 513 struct nls_table *nls) 514{ 515 const unsigned char *ip; 516 unsigned char *op; 517 int i, fill; 518 int charlen; 519 520 if (utf8) { 521 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN, 522 (wchar_t *) outname, FAT_LFN_LEN + 2); 523 if (*outlen < 0) 524 return *outlen; 525 else if (*outlen > FAT_LFN_LEN) 526 return -ENAMETOOLONG; 527 528 op = &outname[*outlen * sizeof(wchar_t)]; 529 } else { 530 for (i = 0, ip = name, op = outname, *outlen = 0; 531 i < len && *outlen < FAT_LFN_LEN; 532 *outlen += 1) { 533 if (escape && (*ip == ':')) { 534 u8 uc[2]; 535 536 if (i > len - 5) 537 return -EINVAL; 538 539 if (hex2bin(uc, ip + 1, 2) < 0) 540 return -EINVAL; 541 542 *(wchar_t *)op = uc[0] << 8 | uc[1]; 543 544 op += 2; 545 ip += 5; 546 i += 5; 547 } else { 548 charlen = nls->char2uni(ip, len - i, 549 (wchar_t *)op); 550 if (charlen < 0) 551 return -EINVAL; 552 ip += charlen; 553 i += charlen; 554 op += 2; 555 } 556 } 557 if (i < len) 558 return -ENAMETOOLONG; 559 } 560 561 *longlen = *outlen; 562 if (*outlen % 13) { 563 *op++ = 0; 564 *op++ = 0; 565 *outlen += 1; 566 if (*outlen % 13) { 567 fill = 13 - (*outlen % 13); 568 for (i = 0; i < fill; i++) { 569 *op++ = 0xff; 570 *op++ = 0xff; 571 } 572 *outlen += fill; 573 } 574 } 575 576 return 0; 577} 578 579static int vfat_build_slots(struct inode *dir, const unsigned char *name, 580 int len, int is_dir, int cluster, 581 struct timespec64 *ts, 582 struct msdos_dir_slot *slots, int *nr_slots) 583{ 584 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 585 struct fat_mount_options *opts = &sbi->options; 586 struct msdos_dir_slot *ps; 587 struct msdos_dir_entry *de; 588 unsigned char cksum, lcase; 589 unsigned char msdos_name[MSDOS_NAME]; 590 wchar_t *uname; 591 __le16 time, date; 592 u8 time_cs; 593 int err, ulen, usize, i; 594 loff_t offset; 595 596 *nr_slots = 0; 597 598 uname = __getname(); 599 if (!uname) 600 return -ENOMEM; 601 602 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 603 opts->unicode_xlate, opts->utf8, sbi->nls_io); 604 if (err) 605 goto out_free; 606 607 err = vfat_is_used_badchars(uname, ulen); 608 if (err) 609 goto out_free; 610 611 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 612 msdos_name, &lcase); 613 if (err < 0) 614 goto out_free; 615 else if (err == 1) { 616 de = (struct msdos_dir_entry *)slots; 617 err = 0; 618 goto shortname; 619 } 620 621 /* build the entry of long file name */ 622 cksum = fat_checksum(msdos_name); 623 624 *nr_slots = usize / 13; 625 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 626 ps->id = i; 627 ps->attr = ATTR_EXT; 628 ps->reserved = 0; 629 ps->alias_checksum = cksum; 630 ps->start = 0; 631 offset = (i - 1) * 13; 632 fatwchar_to16(ps->name0_4, uname + offset, 5); 633 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 634 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 635 } 636 slots[0].id |= 0x40; 637 de = (struct msdos_dir_entry *)ps; 638 639shortname: 640 /* build the entry of 8.3 alias name */ 641 (*nr_slots)++; 642 memcpy(de->name, msdos_name, MSDOS_NAME); 643 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 644 de->lcase = lcase; 645 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); 646 de->time = de->ctime = time; 647 de->date = de->cdate = de->adate = date; 648 de->ctime_cs = time_cs; 649 fat_set_start(de, cluster); 650 de->size = 0; 651out_free: 652 __putname(uname); 653 return err; 654} 655 656static int vfat_add_entry(struct inode *dir, const struct qstr *qname, 657 int is_dir, int cluster, struct timespec64 *ts, 658 struct fat_slot_info *sinfo) 659{ 660 struct msdos_dir_slot *slots; 661 unsigned int len; 662 int err, nr_slots; 663 664 len = vfat_striptail_len(qname); 665 if (len == 0) 666 return -ENOENT; 667 668 slots = kmalloc_array(MSDOS_SLOTS, sizeof(*slots), GFP_NOFS); 669 if (slots == NULL) 670 return -ENOMEM; 671 672 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 673 slots, &nr_slots); 674 if (err) 675 goto cleanup; 676 677 err = fat_add_entries(dir, slots, nr_slots, sinfo); 678 if (err) 679 goto cleanup; 680 681 /* update timestamp */ 682 fat_truncate_time(dir, ts, S_CTIME|S_MTIME); 683 if (IS_DIRSYNC(dir)) 684 (void)fat_sync_inode(dir); 685 else 686 mark_inode_dirty(dir); 687cleanup: 688 kfree(slots); 689 return err; 690} 691 692static int vfat_find(struct inode *dir, const struct qstr *qname, 693 struct fat_slot_info *sinfo) 694{ 695 unsigned int len = vfat_striptail_len(qname); 696 if (len == 0) 697 return -ENOENT; 698 return fat_search_long(dir, qname->name, len, sinfo); 699} 700 701static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 702 unsigned int flags) 703{ 704 struct super_block *sb = dir->i_sb; 705 struct fat_slot_info sinfo; 706 struct inode *inode; 707 struct dentry *alias; 708 int err; 709 710 mutex_lock(&MSDOS_SB(sb)->s_lock); 711 712 err = vfat_find(dir, &dentry->d_name, &sinfo); 713 if (err) { 714 if (err == -ENOENT) { 715 inode = NULL; 716 goto out; 717 } 718 goto error; 719 } 720 721 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 722 brelse(sinfo.bh); 723 if (IS_ERR(inode)) { 724 err = PTR_ERR(inode); 725 goto error; 726 } 727 728 alias = d_find_alias(inode); 729 /* 730 * Checking "alias->d_parent == dentry->d_parent" to make sure 731 * FS is not corrupted (especially double linked dir). 732 */ 733 if (alias && alias->d_parent == dentry->d_parent) { 734 /* 735 * This inode has non anonymous-DCACHE_DISCONNECTED 736 * dentry. This means, the user did ->lookup() by an 737 * another name (longname vs 8.3 alias of it) in past. 738 * 739 * Switch to new one for reason of locality if possible. 740 */ 741 if (!S_ISDIR(inode->i_mode)) 742 d_move(alias, dentry); 743 iput(inode); 744 mutex_unlock(&MSDOS_SB(sb)->s_lock); 745 return alias; 746 } else 747 dput(alias); 748 749out: 750 mutex_unlock(&MSDOS_SB(sb)->s_lock); 751 if (!inode) 752 vfat_d_version_set(dentry, inode_query_iversion(dir)); 753 return d_splice_alias(inode, dentry); 754error: 755 mutex_unlock(&MSDOS_SB(sb)->s_lock); 756 return ERR_PTR(err); 757} 758 759static int vfat_create(struct mnt_idmap *idmap, struct inode *dir, 760 struct dentry *dentry, umode_t mode, bool excl) 761{ 762 struct super_block *sb = dir->i_sb; 763 struct inode *inode; 764 struct fat_slot_info sinfo; 765 struct timespec64 ts; 766 int err; 767 768 mutex_lock(&MSDOS_SB(sb)->s_lock); 769 770 ts = current_time(dir); 771 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 772 if (err) 773 goto out; 774 inode_inc_iversion(dir); 775 776 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 777 brelse(sinfo.bh); 778 if (IS_ERR(inode)) { 779 err = PTR_ERR(inode); 780 goto out; 781 } 782 inode_inc_iversion(inode); 783 784 d_instantiate(dentry, inode); 785out: 786 mutex_unlock(&MSDOS_SB(sb)->s_lock); 787 return err; 788} 789 790static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 791{ 792 struct inode *inode = d_inode(dentry); 793 struct super_block *sb = dir->i_sb; 794 struct fat_slot_info sinfo; 795 int err; 796 797 mutex_lock(&MSDOS_SB(sb)->s_lock); 798 799 err = fat_dir_empty(inode); 800 if (err) 801 goto out; 802 err = vfat_find(dir, &dentry->d_name, &sinfo); 803 if (err) 804 goto out; 805 806 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 807 if (err) 808 goto out; 809 drop_nlink(dir); 810 811 clear_nlink(inode); 812 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME); 813 fat_detach(inode); 814 vfat_d_version_set(dentry, inode_query_iversion(dir)); 815out: 816 mutex_unlock(&MSDOS_SB(sb)->s_lock); 817 818 return err; 819} 820 821static int vfat_unlink(struct inode *dir, struct dentry *dentry) 822{ 823 struct inode *inode = d_inode(dentry); 824 struct super_block *sb = dir->i_sb; 825 struct fat_slot_info sinfo; 826 int err; 827 828 mutex_lock(&MSDOS_SB(sb)->s_lock); 829 830 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 clear_nlink(inode); 838 fat_truncate_time(inode, NULL, S_ATIME|S_MTIME); 839 fat_detach(inode); 840 vfat_d_version_set(dentry, inode_query_iversion(dir)); 841out: 842 mutex_unlock(&MSDOS_SB(sb)->s_lock); 843 844 return err; 845} 846 847static int vfat_mkdir(struct mnt_idmap *idmap, struct inode *dir, 848 struct dentry *dentry, umode_t mode) 849{ 850 struct super_block *sb = dir->i_sb; 851 struct inode *inode; 852 struct fat_slot_info sinfo; 853 struct timespec64 ts; 854 int err, cluster; 855 856 mutex_lock(&MSDOS_SB(sb)->s_lock); 857 858 ts = current_time(dir); 859 cluster = fat_alloc_new_dir(dir, &ts); 860 if (cluster < 0) { 861 err = cluster; 862 goto out; 863 } 864 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 865 if (err) 866 goto out_free; 867 inode_inc_iversion(dir); 868 inc_nlink(dir); 869 870 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 871 brelse(sinfo.bh); 872 if (IS_ERR(inode)) { 873 err = PTR_ERR(inode); 874 /* the directory was completed, just return a error */ 875 goto out; 876 } 877 inode_inc_iversion(inode); 878 set_nlink(inode, 2); 879 880 d_instantiate(dentry, inode); 881 882 mutex_unlock(&MSDOS_SB(sb)->s_lock); 883 return 0; 884 885out_free: 886 fat_free_clusters(dir, cluster); 887out: 888 mutex_unlock(&MSDOS_SB(sb)->s_lock); 889 return err; 890} 891 892static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh, 893 struct msdos_dir_entry **de) 894{ 895 if (S_ISDIR(inode->i_mode)) { 896 if (fat_get_dotdot_entry(inode, bh, de)) 897 return -EIO; 898 } 899 return 0; 900} 901 902static int vfat_sync_ipos(struct inode *dir, struct inode *inode) 903{ 904 if (IS_DIRSYNC(dir)) 905 return fat_sync_inode(inode); 906 mark_inode_dirty(inode); 907 return 0; 908} 909 910static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode, 911 struct buffer_head *dotdot_bh, 912 struct msdos_dir_entry *dotdot_de) 913{ 914 fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart); 915 mark_buffer_dirty_inode(dotdot_bh, inode); 916 if (IS_DIRSYNC(dir)) 917 return sync_dirty_buffer(dotdot_bh); 918 return 0; 919} 920 921static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts) 922{ 923 inode_inc_iversion(dir); 924 fat_truncate_time(dir, ts, S_CTIME | S_MTIME); 925 if (IS_DIRSYNC(dir)) 926 (void)fat_sync_inode(dir); 927 else 928 mark_inode_dirty(dir); 929} 930 931static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 932 struct inode *new_dir, struct dentry *new_dentry) 933{ 934 struct buffer_head *dotdot_bh; 935 struct msdos_dir_entry *dotdot_de = NULL; 936 struct inode *old_inode, *new_inode; 937 struct fat_slot_info old_sinfo, sinfo; 938 struct timespec64 ts; 939 loff_t new_i_pos; 940 int err, is_dir, corrupt = 0; 941 struct super_block *sb = old_dir->i_sb; 942 943 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 944 old_inode = d_inode(old_dentry); 945 new_inode = d_inode(new_dentry); 946 mutex_lock(&MSDOS_SB(sb)->s_lock); 947 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 948 if (err) 949 goto out; 950 951 if (old_dir != new_dir) { 952 err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de); 953 if (err) 954 goto out; 955 } 956 957 is_dir = S_ISDIR(old_inode->i_mode); 958 ts = current_time(old_dir); 959 if (new_inode) { 960 if (is_dir) { 961 err = fat_dir_empty(new_inode); 962 if (err) 963 goto out; 964 } 965 new_i_pos = MSDOS_I(new_inode)->i_pos; 966 fat_detach(new_inode); 967 } else { 968 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 969 &ts, &sinfo); 970 if (err) 971 goto out; 972 new_i_pos = sinfo.i_pos; 973 } 974 inode_inc_iversion(new_dir); 975 976 fat_detach(old_inode); 977 fat_attach(old_inode, new_i_pos); 978 err = vfat_sync_ipos(new_dir, old_inode); 979 if (err) 980 goto error_inode; 981 982 if (dotdot_de) { 983 err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh, 984 dotdot_de); 985 if (err) 986 goto error_dotdot; 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 vfat_update_dir_metadata(old_dir, &ts); 997 998 if (new_inode) { 999 drop_nlink(new_inode); 1000 if (is_dir) 1001 drop_nlink(new_inode); 1002 fat_truncate_time(new_inode, &ts, S_CTIME); 1003 } 1004out: 1005 brelse(sinfo.bh); 1006 brelse(dotdot_bh); 1007 brelse(old_sinfo.bh); 1008 mutex_unlock(&MSDOS_SB(sb)->s_lock); 1009 1010 return err; 1011 1012error_dotdot: 1013 /* data cluster is shared, serious corruption */ 1014 corrupt = 1; 1015 1016 if (dotdot_de) { 1017 corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh, 1018 dotdot_de); 1019 } 1020error_inode: 1021 fat_detach(old_inode); 1022 fat_attach(old_inode, old_sinfo.i_pos); 1023 if (new_inode) { 1024 fat_attach(new_inode, new_i_pos); 1025 if (corrupt) 1026 corrupt |= fat_sync_inode(new_inode); 1027 } else { 1028 /* 1029 * If new entry was not sharing the data cluster, it 1030 * shouldn't be serious corruption. 1031 */ 1032 int err2 = fat_remove_entries(new_dir, &sinfo); 1033 if (corrupt) 1034 corrupt |= err2; 1035 sinfo.bh = NULL; 1036 } 1037 if (corrupt < 0) { 1038 fat_fs_error(new_dir->i_sb, 1039 "%s: Filesystem corrupted (i_pos %lld)", 1040 __func__, sinfo.i_pos); 1041 } 1042 goto out; 1043} 1044 1045static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode, 1046 loff_t old_i_pos, loff_t new_i_pos) 1047{ 1048 fat_detach(old_inode); 1049 fat_detach(new_inode); 1050 fat_attach(old_inode, new_i_pos); 1051 fat_attach(new_inode, old_i_pos); 1052} 1053 1054static void vfat_move_nlink(struct inode *src, struct inode *dst) 1055{ 1056 drop_nlink(src); 1057 inc_nlink(dst); 1058} 1059 1060static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, 1061 struct inode *new_dir, struct dentry *new_dentry) 1062{ 1063 struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL; 1064 struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL; 1065 struct inode *old_inode, *new_inode; 1066 struct timespec64 ts = current_time(old_dir); 1067 loff_t old_i_pos, new_i_pos; 1068 int err, corrupt = 0; 1069 struct super_block *sb = old_dir->i_sb; 1070 1071 old_inode = d_inode(old_dentry); 1072 new_inode = d_inode(new_dentry); 1073 1074 /* Acquire super block lock for the operation to be atomic */ 1075 mutex_lock(&MSDOS_SB(sb)->s_lock); 1076 1077 /* if directories are not the same, get ".." info to update */ 1078 if (old_dir != new_dir) { 1079 err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh, 1080 &old_dotdot_de); 1081 if (err) 1082 goto out; 1083 1084 err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh, 1085 &new_dotdot_de); 1086 if (err) 1087 goto out; 1088 } 1089 1090 old_i_pos = MSDOS_I(old_inode)->i_pos; 1091 new_i_pos = MSDOS_I(new_inode)->i_pos; 1092 1093 vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos); 1094 1095 err = vfat_sync_ipos(old_dir, new_inode); 1096 if (err) 1097 goto error_exchange; 1098 err = vfat_sync_ipos(new_dir, old_inode); 1099 if (err) 1100 goto error_exchange; 1101 1102 /* update ".." directory entry info */ 1103 if (old_dotdot_de) { 1104 err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh, 1105 old_dotdot_de); 1106 if (err) 1107 goto error_old_dotdot; 1108 } 1109 if (new_dotdot_de) { 1110 err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh, 1111 new_dotdot_de); 1112 if (err) 1113 goto error_new_dotdot; 1114 } 1115 1116 /* if cross directory and only one is a directory, adjust nlink */ 1117 if (!old_dotdot_de != !new_dotdot_de) { 1118 if (old_dotdot_de) 1119 vfat_move_nlink(old_dir, new_dir); 1120 else 1121 vfat_move_nlink(new_dir, old_dir); 1122 } 1123 1124 vfat_update_dir_metadata(old_dir, &ts); 1125 /* if directories are not the same, update new_dir as well */ 1126 if (old_dir != new_dir) 1127 vfat_update_dir_metadata(new_dir, &ts); 1128 1129out: 1130 brelse(old_dotdot_bh); 1131 brelse(new_dotdot_bh); 1132 mutex_unlock(&MSDOS_SB(sb)->s_lock); 1133 1134 return err; 1135 1136error_new_dotdot: 1137 if (new_dotdot_de) { 1138 corrupt |= vfat_update_dotdot_de(new_dir, new_inode, 1139 new_dotdot_bh, new_dotdot_de); 1140 } 1141 1142error_old_dotdot: 1143 if (old_dotdot_de) { 1144 corrupt |= vfat_update_dotdot_de(old_dir, old_inode, 1145 old_dotdot_bh, old_dotdot_de); 1146 } 1147 1148error_exchange: 1149 vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos); 1150 corrupt |= vfat_sync_ipos(new_dir, new_inode); 1151 corrupt |= vfat_sync_ipos(old_dir, old_inode); 1152 1153 if (corrupt < 0) { 1154 fat_fs_error(new_dir->i_sb, 1155 "%s: Filesystem corrupted (i_pos %lld, %lld)", 1156 __func__, old_i_pos, new_i_pos); 1157 } 1158 goto out; 1159} 1160 1161static int vfat_rename2(struct mnt_idmap *idmap, struct inode *old_dir, 1162 struct dentry *old_dentry, struct inode *new_dir, 1163 struct dentry *new_dentry, unsigned int flags) 1164{ 1165 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 1166 return -EINVAL; 1167 1168 if (flags & RENAME_EXCHANGE) { 1169 return vfat_rename_exchange(old_dir, old_dentry, 1170 new_dir, new_dentry); 1171 } 1172 1173 /* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */ 1174 return vfat_rename(old_dir, old_dentry, new_dir, new_dentry); 1175} 1176 1177static const struct inode_operations vfat_dir_inode_operations = { 1178 .create = vfat_create, 1179 .lookup = vfat_lookup, 1180 .unlink = vfat_unlink, 1181 .mkdir = vfat_mkdir, 1182 .rmdir = vfat_rmdir, 1183 .rename = vfat_rename2, 1184 .setattr = fat_setattr, 1185 .getattr = fat_getattr, 1186 .update_time = fat_update_time, 1187}; 1188 1189static void setup(struct super_block *sb) 1190{ 1191 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations; 1192 if (MSDOS_SB(sb)->options.name_check != 's') 1193 sb->s_d_op = &vfat_ci_dentry_ops; 1194 else 1195 sb->s_d_op = &vfat_dentry_ops; 1196} 1197 1198static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1199{ 1200 return fat_fill_super(sb, data, silent, 1, setup); 1201} 1202 1203static struct dentry *vfat_mount(struct file_system_type *fs_type, 1204 int flags, const char *dev_name, 1205 void *data) 1206{ 1207 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super); 1208} 1209 1210static struct file_system_type vfat_fs_type = { 1211 .owner = THIS_MODULE, 1212 .name = "vfat", 1213 .mount = vfat_mount, 1214 .kill_sb = kill_block_super, 1215 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, 1216}; 1217MODULE_ALIAS_FS("vfat"); 1218 1219static int __init init_vfat_fs(void) 1220{ 1221 return register_filesystem(&vfat_fs_type); 1222} 1223 1224static void __exit exit_vfat_fs(void) 1225{ 1226 unregister_filesystem(&vfat_fs_type); 1227} 1228 1229MODULE_LICENSE("GPL"); 1230MODULE_DESCRIPTION("VFAT filesystem support"); 1231MODULE_AUTHOR("Gordon Chaffee"); 1232 1233module_init(init_vfat_fs) 1234module_exit(exit_vfat_fs) 1235