1 /* 2 * linux/fs/ufs/ufs_dir.c 3 * 4 * Copyright (C) 1996 5 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu) 6 * Laboratory for Computer Science Research Computing Facility 7 * Rutgers, The State University of New Jersey 8 * 9 * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406 10 * 11 * 4.4BSD (FreeBSD) support added on February 1st 1998 by 12 * Niels Kristian Bech Jensen <nkbj@image.dk> partially based 13 * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>. 14 * 15 * Migration to usage of "page cache" on May 2006 by 16 * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base. 17 */ 18 19 #include <linux/time.h> 20 #include <linux/fs.h> 21 #include <linux/swap.h> 22 23 #include "ufs_fs.h" 24 #include "ufs.h" 25 #include "swab.h" 26 #include "util.h" 27 28 /* 29 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure. 30 * 31 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller. 32 */ 33 static inline int ufs_match(struct super_block *sb, int len, 34 const unsigned char *name, struct ufs_dir_entry *de) 35 { 36 if (len != ufs_get_de_namlen(sb, de)) 37 return 0; 38 if (!de->d_ino) 39 return 0; 40 return !memcmp(name, de->d_name, len); 41 } 42 43 static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len) 44 { 45 struct address_space *mapping = page->mapping; 46 struct inode *dir = mapping->host; 47 int err = 0; 48 49 dir->i_version++; 50 block_write_end(NULL, mapping, pos, len, len, page, NULL); 51 if (pos+len > dir->i_size) { 52 i_size_write(dir, pos+len); 53 mark_inode_dirty(dir); 54 } 55 if (IS_DIRSYNC(dir)) 56 err = write_one_page(page, 1); 57 else 58 unlock_page(page); 59 return err; 60 } 61 62 static inline void ufs_put_page(struct page *page) 63 { 64 kunmap(page); 65 put_page(page); 66 } 67 68 ino_t ufs_inode_by_name(struct inode *dir, const struct qstr *qstr) 69 { 70 ino_t res = 0; 71 struct ufs_dir_entry *de; 72 struct page *page; 73 74 de = ufs_find_entry(dir, qstr, &page); 75 if (de) { 76 res = fs32_to_cpu(dir->i_sb, de->d_ino); 77 ufs_put_page(page); 78 } 79 return res; 80 } 81 82 83 /* Releases the page */ 84 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de, 85 struct page *page, struct inode *inode, 86 bool update_times) 87 { 88 loff_t pos = page_offset(page) + 89 (char *) de - (char *) page_address(page); 90 unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen); 91 int err; 92 93 lock_page(page); 94 err = ufs_prepare_chunk(page, pos, len); 95 BUG_ON(err); 96 97 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino); 98 ufs_set_de_type(dir->i_sb, de, inode->i_mode); 99 100 err = ufs_commit_chunk(page, pos, len); 101 ufs_put_page(page); 102 if (update_times) 103 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 104 mark_inode_dirty(dir); 105 } 106 107 108 static bool ufs_check_page(struct page *page) 109 { 110 struct inode *dir = page->mapping->host; 111 struct super_block *sb = dir->i_sb; 112 char *kaddr = page_address(page); 113 unsigned offs, rec_len; 114 unsigned limit = PAGE_SIZE; 115 const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1; 116 struct ufs_dir_entry *p; 117 char *error; 118 119 if ((dir->i_size >> PAGE_SHIFT) == page->index) { 120 limit = dir->i_size & ~PAGE_MASK; 121 if (limit & chunk_mask) 122 goto Ebadsize; 123 if (!limit) 124 goto out; 125 } 126 for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) { 127 p = (struct ufs_dir_entry *)(kaddr + offs); 128 rec_len = fs16_to_cpu(sb, p->d_reclen); 129 130 if (rec_len < UFS_DIR_REC_LEN(1)) 131 goto Eshort; 132 if (rec_len & 3) 133 goto Ealign; 134 if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p))) 135 goto Enamelen; 136 if (((offs + rec_len - 1) ^ offs) & ~chunk_mask) 137 goto Espan; 138 if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg * 139 UFS_SB(sb)->s_uspi->s_ncg)) 140 goto Einumber; 141 } 142 if (offs != limit) 143 goto Eend; 144 out: 145 SetPageChecked(page); 146 return true; 147 148 /* Too bad, we had an error */ 149 150 Ebadsize: 151 ufs_error(sb, "ufs_check_page", 152 "size of directory #%lu is not a multiple of chunk size", 153 dir->i_ino 154 ); 155 goto fail; 156 Eshort: 157 error = "rec_len is smaller than minimal"; 158 goto bad_entry; 159 Ealign: 160 error = "unaligned directory entry"; 161 goto bad_entry; 162 Enamelen: 163 error = "rec_len is too small for name_len"; 164 goto bad_entry; 165 Espan: 166 error = "directory entry across blocks"; 167 goto bad_entry; 168 Einumber: 169 error = "inode out of bounds"; 170 bad_entry: 171 ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - " 172 "offset=%lu, rec_len=%d, name_len=%d", 173 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs, 174 rec_len, ufs_get_de_namlen(sb, p)); 175 goto fail; 176 Eend: 177 p = (struct ufs_dir_entry *)(kaddr + offs); 178 ufs_error(sb, __func__, 179 "entry in directory #%lu spans the page boundary" 180 "offset=%lu", 181 dir->i_ino, (page->index<<PAGE_SHIFT)+offs); 182 fail: 183 SetPageError(page); 184 return false; 185 } 186 187 static struct page *ufs_get_page(struct inode *dir, unsigned long n) 188 { 189 struct address_space *mapping = dir->i_mapping; 190 struct page *page = read_mapping_page(mapping, n, NULL); 191 if (!IS_ERR(page)) { 192 kmap(page); 193 if (unlikely(!PageChecked(page))) { 194 if (PageError(page) || !ufs_check_page(page)) 195 goto fail; 196 } 197 } 198 return page; 199 200 fail: 201 ufs_put_page(page); 202 return ERR_PTR(-EIO); 203 } 204 205 /* 206 * Return the offset into page `page_nr' of the last valid 207 * byte in that page, plus one. 208 */ 209 static unsigned 210 ufs_last_byte(struct inode *inode, unsigned long page_nr) 211 { 212 unsigned last_byte = inode->i_size; 213 214 last_byte -= page_nr << PAGE_SHIFT; 215 if (last_byte > PAGE_SIZE) 216 last_byte = PAGE_SIZE; 217 return last_byte; 218 } 219 220 static inline struct ufs_dir_entry * 221 ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p) 222 { 223 return (struct ufs_dir_entry *)((char *)p + 224 fs16_to_cpu(sb, p->d_reclen)); 225 } 226 227 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p) 228 { 229 struct page *page = ufs_get_page(dir, 0); 230 struct ufs_dir_entry *de = NULL; 231 232 if (!IS_ERR(page)) { 233 de = ufs_next_entry(dir->i_sb, 234 (struct ufs_dir_entry *)page_address(page)); 235 *p = page; 236 } 237 return de; 238 } 239 240 /* 241 * ufs_find_entry() 242 * 243 * finds an entry in the specified directory with the wanted name. It 244 * returns the page in which the entry was found, and the entry itself 245 * (as a parameter - res_dir). Page is returned mapped and unlocked. 246 * Entry is guaranteed to be valid. 247 */ 248 struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr, 249 struct page **res_page) 250 { 251 struct super_block *sb = dir->i_sb; 252 const unsigned char *name = qstr->name; 253 int namelen = qstr->len; 254 unsigned reclen = UFS_DIR_REC_LEN(namelen); 255 unsigned long start, n; 256 unsigned long npages = dir_pages(dir); 257 struct page *page = NULL; 258 struct ufs_inode_info *ui = UFS_I(dir); 259 struct ufs_dir_entry *de; 260 261 UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen); 262 263 if (npages == 0 || namelen > UFS_MAXNAMLEN) 264 goto out; 265 266 /* OFFSET_CACHE */ 267 *res_page = NULL; 268 269 start = ui->i_dir_start_lookup; 270 271 if (start >= npages) 272 start = 0; 273 n = start; 274 do { 275 char *kaddr; 276 page = ufs_get_page(dir, n); 277 if (!IS_ERR(page)) { 278 kaddr = page_address(page); 279 de = (struct ufs_dir_entry *) kaddr; 280 kaddr += ufs_last_byte(dir, n) - reclen; 281 while ((char *) de <= kaddr) { 282 if (de->d_reclen == 0) { 283 ufs_error(dir->i_sb, __func__, 284 "zero-length directory entry"); 285 ufs_put_page(page); 286 goto out; 287 } 288 if (ufs_match(sb, namelen, name, de)) 289 goto found; 290 de = ufs_next_entry(sb, de); 291 } 292 ufs_put_page(page); 293 } 294 if (++n >= npages) 295 n = 0; 296 } while (n != start); 297 out: 298 return NULL; 299 300 found: 301 *res_page = page; 302 ui->i_dir_start_lookup = n; 303 return de; 304 } 305 306 /* 307 * Parent is locked. 308 */ 309 int ufs_add_link(struct dentry *dentry, struct inode *inode) 310 { 311 struct inode *dir = d_inode(dentry->d_parent); 312 const unsigned char *name = dentry->d_name.name; 313 int namelen = dentry->d_name.len; 314 struct super_block *sb = dir->i_sb; 315 unsigned reclen = UFS_DIR_REC_LEN(namelen); 316 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 317 unsigned short rec_len, name_len; 318 struct page *page = NULL; 319 struct ufs_dir_entry *de; 320 unsigned long npages = dir_pages(dir); 321 unsigned long n; 322 char *kaddr; 323 loff_t pos; 324 int err; 325 326 UFSD("ENTER, name %s, namelen %u\n", name, namelen); 327 328 /* 329 * We take care of directory expansion in the same loop. 330 * This code plays outside i_size, so it locks the page 331 * to protect that region. 332 */ 333 for (n = 0; n <= npages; n++) { 334 char *dir_end; 335 336 page = ufs_get_page(dir, n); 337 err = PTR_ERR(page); 338 if (IS_ERR(page)) 339 goto out; 340 lock_page(page); 341 kaddr = page_address(page); 342 dir_end = kaddr + ufs_last_byte(dir, n); 343 de = (struct ufs_dir_entry *)kaddr; 344 kaddr += PAGE_SIZE - reclen; 345 while ((char *)de <= kaddr) { 346 if ((char *)de == dir_end) { 347 /* We hit i_size */ 348 name_len = 0; 349 rec_len = chunk_size; 350 de->d_reclen = cpu_to_fs16(sb, chunk_size); 351 de->d_ino = 0; 352 goto got_it; 353 } 354 if (de->d_reclen == 0) { 355 ufs_error(dir->i_sb, __func__, 356 "zero-length directory entry"); 357 err = -EIO; 358 goto out_unlock; 359 } 360 err = -EEXIST; 361 if (ufs_match(sb, namelen, name, de)) 362 goto out_unlock; 363 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)); 364 rec_len = fs16_to_cpu(sb, de->d_reclen); 365 if (!de->d_ino && rec_len >= reclen) 366 goto got_it; 367 if (rec_len >= name_len + reclen) 368 goto got_it; 369 de = (struct ufs_dir_entry *) ((char *) de + rec_len); 370 } 371 unlock_page(page); 372 ufs_put_page(page); 373 } 374 BUG(); 375 return -EINVAL; 376 377 got_it: 378 pos = page_offset(page) + 379 (char*)de - (char*)page_address(page); 380 err = ufs_prepare_chunk(page, pos, rec_len); 381 if (err) 382 goto out_unlock; 383 if (de->d_ino) { 384 struct ufs_dir_entry *de1 = 385 (struct ufs_dir_entry *) ((char *) de + name_len); 386 de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len); 387 de->d_reclen = cpu_to_fs16(sb, name_len); 388 389 de = de1; 390 } 391 392 ufs_set_de_namlen(sb, de, namelen); 393 memcpy(de->d_name, name, namelen + 1); 394 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 395 ufs_set_de_type(sb, de, inode->i_mode); 396 397 err = ufs_commit_chunk(page, pos, rec_len); 398 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 399 400 mark_inode_dirty(dir); 401 /* OFFSET_CACHE */ 402 out_put: 403 ufs_put_page(page); 404 out: 405 return err; 406 out_unlock: 407 unlock_page(page); 408 goto out_put; 409 } 410 411 static inline unsigned 412 ufs_validate_entry(struct super_block *sb, char *base, 413 unsigned offset, unsigned mask) 414 { 415 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset); 416 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask)); 417 while ((char*)p < (char*)de) { 418 if (p->d_reclen == 0) 419 break; 420 p = ufs_next_entry(sb, p); 421 } 422 return (char *)p - base; 423 } 424 425 426 /* 427 * This is blatantly stolen from ext2fs 428 */ 429 static int 430 ufs_readdir(struct file *file, struct dir_context *ctx) 431 { 432 loff_t pos = ctx->pos; 433 struct inode *inode = file_inode(file); 434 struct super_block *sb = inode->i_sb; 435 unsigned int offset = pos & ~PAGE_MASK; 436 unsigned long n = pos >> PAGE_SHIFT; 437 unsigned long npages = dir_pages(inode); 438 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 439 int need_revalidate = file->f_version != inode->i_version; 440 unsigned flags = UFS_SB(sb)->s_flags; 441 442 UFSD("BEGIN\n"); 443 444 if (pos > inode->i_size - UFS_DIR_REC_LEN(1)) 445 return 0; 446 447 for ( ; n < npages; n++, offset = 0) { 448 char *kaddr, *limit; 449 struct ufs_dir_entry *de; 450 451 struct page *page = ufs_get_page(inode, n); 452 453 if (IS_ERR(page)) { 454 ufs_error(sb, __func__, 455 "bad page in #%lu", 456 inode->i_ino); 457 ctx->pos += PAGE_SIZE - offset; 458 return -EIO; 459 } 460 kaddr = page_address(page); 461 if (unlikely(need_revalidate)) { 462 if (offset) { 463 offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask); 464 ctx->pos = (n<<PAGE_SHIFT) + offset; 465 } 466 file->f_version = inode->i_version; 467 need_revalidate = 0; 468 } 469 de = (struct ufs_dir_entry *)(kaddr+offset); 470 limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1); 471 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) { 472 if (de->d_reclen == 0) { 473 ufs_error(sb, __func__, 474 "zero-length directory entry"); 475 ufs_put_page(page); 476 return -EIO; 477 } 478 if (de->d_ino) { 479 unsigned char d_type = DT_UNKNOWN; 480 481 UFSD("filldir(%s,%u)\n", de->d_name, 482 fs32_to_cpu(sb, de->d_ino)); 483 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de)); 484 485 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) 486 d_type = de->d_u.d_44.d_type; 487 488 if (!dir_emit(ctx, de->d_name, 489 ufs_get_de_namlen(sb, de), 490 fs32_to_cpu(sb, de->d_ino), 491 d_type)) { 492 ufs_put_page(page); 493 return 0; 494 } 495 } 496 ctx->pos += fs16_to_cpu(sb, de->d_reclen); 497 } 498 ufs_put_page(page); 499 } 500 return 0; 501 } 502 503 504 /* 505 * ufs_delete_entry deletes a directory entry by merging it with the 506 * previous entry. 507 */ 508 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir, 509 struct page * page) 510 { 511 struct super_block *sb = inode->i_sb; 512 char *kaddr = page_address(page); 513 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 514 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen); 515 loff_t pos; 516 struct ufs_dir_entry *pde = NULL; 517 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from); 518 int err; 519 520 UFSD("ENTER\n"); 521 522 UFSD("ino %u, reclen %u, namlen %u, name %s\n", 523 fs32_to_cpu(sb, de->d_ino), 524 fs16_to_cpu(sb, de->d_reclen), 525 ufs_get_de_namlen(sb, de), de->d_name); 526 527 while ((char*)de < (char*)dir) { 528 if (de->d_reclen == 0) { 529 ufs_error(inode->i_sb, __func__, 530 "zero-length directory entry"); 531 err = -EIO; 532 goto out; 533 } 534 pde = de; 535 de = ufs_next_entry(sb, de); 536 } 537 if (pde) 538 from = (char*)pde - (char*)page_address(page); 539 540 pos = page_offset(page) + from; 541 lock_page(page); 542 err = ufs_prepare_chunk(page, pos, to - from); 543 BUG_ON(err); 544 if (pde) 545 pde->d_reclen = cpu_to_fs16(sb, to - from); 546 dir->d_ino = 0; 547 err = ufs_commit_chunk(page, pos, to - from); 548 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 549 mark_inode_dirty(inode); 550 out: 551 ufs_put_page(page); 552 UFSD("EXIT\n"); 553 return err; 554 } 555 556 int ufs_make_empty(struct inode * inode, struct inode *dir) 557 { 558 struct super_block * sb = dir->i_sb; 559 struct address_space *mapping = inode->i_mapping; 560 struct page *page = grab_cache_page(mapping, 0); 561 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 562 struct ufs_dir_entry * de; 563 char *base; 564 int err; 565 566 if (!page) 567 return -ENOMEM; 568 569 err = ufs_prepare_chunk(page, 0, chunk_size); 570 if (err) { 571 unlock_page(page); 572 goto fail; 573 } 574 575 kmap(page); 576 base = (char*)page_address(page); 577 memset(base, 0, PAGE_SIZE); 578 579 de = (struct ufs_dir_entry *) base; 580 581 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 582 ufs_set_de_type(sb, de, inode->i_mode); 583 ufs_set_de_namlen(sb, de, 1); 584 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); 585 strcpy (de->d_name, "."); 586 de = (struct ufs_dir_entry *) 587 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 588 de->d_ino = cpu_to_fs32(sb, dir->i_ino); 589 ufs_set_de_type(sb, de, dir->i_mode); 590 de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1)); 591 ufs_set_de_namlen(sb, de, 2); 592 strcpy (de->d_name, ".."); 593 kunmap(page); 594 595 err = ufs_commit_chunk(page, 0, chunk_size); 596 fail: 597 put_page(page); 598 return err; 599 } 600 601 /* 602 * routine to check that the specified directory is empty (for rmdir) 603 */ 604 int ufs_empty_dir(struct inode * inode) 605 { 606 struct super_block *sb = inode->i_sb; 607 struct page *page = NULL; 608 unsigned long i, npages = dir_pages(inode); 609 610 for (i = 0; i < npages; i++) { 611 char *kaddr; 612 struct ufs_dir_entry *de; 613 page = ufs_get_page(inode, i); 614 615 if (IS_ERR(page)) 616 continue; 617 618 kaddr = page_address(page); 619 de = (struct ufs_dir_entry *)kaddr; 620 kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1); 621 622 while ((char *)de <= kaddr) { 623 if (de->d_reclen == 0) { 624 ufs_error(inode->i_sb, __func__, 625 "zero-length directory entry: " 626 "kaddr=%p, de=%p\n", kaddr, de); 627 goto not_empty; 628 } 629 if (de->d_ino) { 630 u16 namelen=ufs_get_de_namlen(sb, de); 631 /* check for . and .. */ 632 if (de->d_name[0] != '.') 633 goto not_empty; 634 if (namelen > 2) 635 goto not_empty; 636 if (namelen < 2) { 637 if (inode->i_ino != 638 fs32_to_cpu(sb, de->d_ino)) 639 goto not_empty; 640 } else if (de->d_name[1] != '.') 641 goto not_empty; 642 } 643 de = ufs_next_entry(sb, de); 644 } 645 ufs_put_page(page); 646 } 647 return 1; 648 649 not_empty: 650 ufs_put_page(page); 651 return 0; 652 } 653 654 const struct file_operations ufs_dir_operations = { 655 .read = generic_read_dir, 656 .iterate_shared = ufs_readdir, 657 .fsync = generic_file_fsync, 658 .llseek = generic_file_llseek, 659 }; 660