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 char * const 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 page_cache_release(page); 66 } 67 68 static inline unsigned long ufs_dir_pages(struct inode *inode) 69 { 70 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; 71 } 72 73 ino_t ufs_inode_by_name(struct inode *dir, struct dentry *dentry) 74 { 75 ino_t res = 0; 76 struct ufs_dir_entry *de; 77 struct page *page; 78 79 de = ufs_find_entry(dir, dentry, &page); 80 if (de) { 81 res = fs32_to_cpu(dir->i_sb, de->d_ino); 82 ufs_put_page(page); 83 } 84 return res; 85 } 86 87 88 /* Releases the page */ 89 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de, 90 struct page *page, struct inode *inode) 91 { 92 loff_t pos = page_offset(page) + 93 (char *) de - (char *) page_address(page); 94 unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen); 95 int err; 96 97 lock_page(page); 98 err = __ufs_write_begin(NULL, page->mapping, pos, len, 99 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); 100 BUG_ON(err); 101 102 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino); 103 ufs_set_de_type(dir->i_sb, de, inode->i_mode); 104 105 err = ufs_commit_chunk(page, pos, len); 106 ufs_put_page(page); 107 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 108 mark_inode_dirty(dir); 109 } 110 111 112 static void ufs_check_page(struct page *page) 113 { 114 struct inode *dir = page->mapping->host; 115 struct super_block *sb = dir->i_sb; 116 char *kaddr = page_address(page); 117 unsigned offs, rec_len; 118 unsigned limit = PAGE_CACHE_SIZE; 119 const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1; 120 struct ufs_dir_entry *p; 121 char *error; 122 123 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { 124 limit = dir->i_size & ~PAGE_CACHE_MASK; 125 if (limit & chunk_mask) 126 goto Ebadsize; 127 if (!limit) 128 goto out; 129 } 130 for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) { 131 p = (struct ufs_dir_entry *)(kaddr + offs); 132 rec_len = fs16_to_cpu(sb, p->d_reclen); 133 134 if (rec_len < UFS_DIR_REC_LEN(1)) 135 goto Eshort; 136 if (rec_len & 3) 137 goto Ealign; 138 if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p))) 139 goto Enamelen; 140 if (((offs + rec_len - 1) ^ offs) & ~chunk_mask) 141 goto Espan; 142 if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg * 143 UFS_SB(sb)->s_uspi->s_ncg)) 144 goto Einumber; 145 } 146 if (offs != limit) 147 goto Eend; 148 out: 149 SetPageChecked(page); 150 return; 151 152 /* Too bad, we had an error */ 153 154 Ebadsize: 155 ufs_error(sb, "ufs_check_page", 156 "size of directory #%lu is not a multiple of chunk size", 157 dir->i_ino 158 ); 159 goto fail; 160 Eshort: 161 error = "rec_len is smaller than minimal"; 162 goto bad_entry; 163 Ealign: 164 error = "unaligned directory entry"; 165 goto bad_entry; 166 Enamelen: 167 error = "rec_len is too small for name_len"; 168 goto bad_entry; 169 Espan: 170 error = "directory entry across blocks"; 171 goto bad_entry; 172 Einumber: 173 error = "inode out of bounds"; 174 bad_entry: 175 ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - " 176 "offset=%lu, rec_len=%d, name_len=%d", 177 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, 178 rec_len, ufs_get_de_namlen(sb, p)); 179 goto fail; 180 Eend: 181 p = (struct ufs_dir_entry *)(kaddr + offs); 182 ufs_error(sb, __func__, 183 "entry in directory #%lu spans the page boundary" 184 "offset=%lu", 185 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs); 186 fail: 187 SetPageChecked(page); 188 SetPageError(page); 189 } 190 191 static struct page *ufs_get_page(struct inode *dir, unsigned long n) 192 { 193 struct address_space *mapping = dir->i_mapping; 194 struct page *page = read_mapping_page(mapping, n, NULL); 195 if (!IS_ERR(page)) { 196 kmap(page); 197 if (!PageChecked(page)) 198 ufs_check_page(page); 199 if (PageError(page)) 200 goto fail; 201 } 202 return page; 203 204 fail: 205 ufs_put_page(page); 206 return ERR_PTR(-EIO); 207 } 208 209 /* 210 * Return the offset into page `page_nr' of the last valid 211 * byte in that page, plus one. 212 */ 213 static unsigned 214 ufs_last_byte(struct inode *inode, unsigned long page_nr) 215 { 216 unsigned last_byte = inode->i_size; 217 218 last_byte -= page_nr << PAGE_CACHE_SHIFT; 219 if (last_byte > PAGE_CACHE_SIZE) 220 last_byte = PAGE_CACHE_SIZE; 221 return last_byte; 222 } 223 224 static inline struct ufs_dir_entry * 225 ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p) 226 { 227 return (struct ufs_dir_entry *)((char *)p + 228 fs16_to_cpu(sb, p->d_reclen)); 229 } 230 231 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p) 232 { 233 struct page *page = ufs_get_page(dir, 0); 234 struct ufs_dir_entry *de = NULL; 235 236 if (!IS_ERR(page)) { 237 de = ufs_next_entry(dir->i_sb, 238 (struct ufs_dir_entry *)page_address(page)); 239 *p = page; 240 } 241 return de; 242 } 243 244 /* 245 * ufs_find_entry() 246 * 247 * finds an entry in the specified directory with the wanted name. It 248 * returns the page in which the entry was found, and the entry itself 249 * (as a parameter - res_dir). Page is returned mapped and unlocked. 250 * Entry is guaranteed to be valid. 251 */ 252 struct ufs_dir_entry *ufs_find_entry(struct inode *dir, struct dentry *dentry, 253 struct page **res_page) 254 { 255 struct super_block *sb = dir->i_sb; 256 const char *name = dentry->d_name.name; 257 int namelen = dentry->d_name.len; 258 unsigned reclen = UFS_DIR_REC_LEN(namelen); 259 unsigned long start, n; 260 unsigned long npages = ufs_dir_pages(dir); 261 struct page *page = NULL; 262 struct ufs_inode_info *ui = UFS_I(dir); 263 struct ufs_dir_entry *de; 264 265 UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen); 266 267 if (npages == 0 || namelen > UFS_MAXNAMLEN) 268 goto out; 269 270 /* OFFSET_CACHE */ 271 *res_page = NULL; 272 273 start = ui->i_dir_start_lookup; 274 275 if (start >= npages) 276 start = 0; 277 n = start; 278 do { 279 char *kaddr; 280 page = ufs_get_page(dir, n); 281 if (!IS_ERR(page)) { 282 kaddr = page_address(page); 283 de = (struct ufs_dir_entry *) kaddr; 284 kaddr += ufs_last_byte(dir, n) - reclen; 285 while ((char *) de <= kaddr) { 286 if (de->d_reclen == 0) { 287 ufs_error(dir->i_sb, __func__, 288 "zero-length directory entry"); 289 ufs_put_page(page); 290 goto out; 291 } 292 if (ufs_match(sb, namelen, name, de)) 293 goto found; 294 de = ufs_next_entry(sb, de); 295 } 296 ufs_put_page(page); 297 } 298 if (++n >= npages) 299 n = 0; 300 } while (n != start); 301 out: 302 return NULL; 303 304 found: 305 *res_page = page; 306 ui->i_dir_start_lookup = n; 307 return de; 308 } 309 310 /* 311 * Parent is locked. 312 */ 313 int ufs_add_link(struct dentry *dentry, struct inode *inode) 314 { 315 struct inode *dir = dentry->d_parent->d_inode; 316 const char *name = dentry->d_name.name; 317 int namelen = dentry->d_name.len; 318 struct super_block *sb = dir->i_sb; 319 unsigned reclen = UFS_DIR_REC_LEN(namelen); 320 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 321 unsigned short rec_len, name_len; 322 struct page *page = NULL; 323 struct ufs_dir_entry *de; 324 unsigned long npages = ufs_dir_pages(dir); 325 unsigned long n; 326 char *kaddr; 327 loff_t pos; 328 int err; 329 330 UFSD("ENTER, name %s, namelen %u\n", name, namelen); 331 332 /* 333 * We take care of directory expansion in the same loop. 334 * This code plays outside i_size, so it locks the page 335 * to protect that region. 336 */ 337 for (n = 0; n <= npages; n++) { 338 char *dir_end; 339 340 page = ufs_get_page(dir, n); 341 err = PTR_ERR(page); 342 if (IS_ERR(page)) 343 goto out; 344 lock_page(page); 345 kaddr = page_address(page); 346 dir_end = kaddr + ufs_last_byte(dir, n); 347 de = (struct ufs_dir_entry *)kaddr; 348 kaddr += PAGE_CACHE_SIZE - reclen; 349 while ((char *)de <= kaddr) { 350 if ((char *)de == dir_end) { 351 /* We hit i_size */ 352 name_len = 0; 353 rec_len = chunk_size; 354 de->d_reclen = cpu_to_fs16(sb, chunk_size); 355 de->d_ino = 0; 356 goto got_it; 357 } 358 if (de->d_reclen == 0) { 359 ufs_error(dir->i_sb, __func__, 360 "zero-length directory entry"); 361 err = -EIO; 362 goto out_unlock; 363 } 364 err = -EEXIST; 365 if (ufs_match(sb, namelen, name, de)) 366 goto out_unlock; 367 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)); 368 rec_len = fs16_to_cpu(sb, de->d_reclen); 369 if (!de->d_ino && rec_len >= reclen) 370 goto got_it; 371 if (rec_len >= name_len + reclen) 372 goto got_it; 373 de = (struct ufs_dir_entry *) ((char *) de + rec_len); 374 } 375 unlock_page(page); 376 ufs_put_page(page); 377 } 378 BUG(); 379 return -EINVAL; 380 381 got_it: 382 pos = page_offset(page) + 383 (char*)de - (char*)page_address(page); 384 err = __ufs_write_begin(NULL, page->mapping, pos, rec_len, 385 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); 386 if (err) 387 goto out_unlock; 388 if (de->d_ino) { 389 struct ufs_dir_entry *de1 = 390 (struct ufs_dir_entry *) ((char *) de + name_len); 391 de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len); 392 de->d_reclen = cpu_to_fs16(sb, name_len); 393 394 de = de1; 395 } 396 397 ufs_set_de_namlen(sb, de, namelen); 398 memcpy(de->d_name, name, namelen + 1); 399 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 400 ufs_set_de_type(sb, de, inode->i_mode); 401 402 err = ufs_commit_chunk(page, pos, rec_len); 403 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 404 405 mark_inode_dirty(dir); 406 /* OFFSET_CACHE */ 407 out_put: 408 ufs_put_page(page); 409 out: 410 return err; 411 out_unlock: 412 unlock_page(page); 413 goto out_put; 414 } 415 416 static inline unsigned 417 ufs_validate_entry(struct super_block *sb, char *base, 418 unsigned offset, unsigned mask) 419 { 420 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset); 421 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask)); 422 while ((char*)p < (char*)de) { 423 if (p->d_reclen == 0) 424 break; 425 p = ufs_next_entry(sb, p); 426 } 427 return (char *)p - base; 428 } 429 430 431 /* 432 * This is blatantly stolen from ext2fs 433 */ 434 static int 435 ufs_readdir(struct file *filp, void *dirent, filldir_t filldir) 436 { 437 loff_t pos = filp->f_pos; 438 struct inode *inode = filp->f_path.dentry->d_inode; 439 struct super_block *sb = inode->i_sb; 440 unsigned int offset = pos & ~PAGE_CACHE_MASK; 441 unsigned long n = pos >> PAGE_CACHE_SHIFT; 442 unsigned long npages = ufs_dir_pages(inode); 443 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 444 int need_revalidate = filp->f_version != inode->i_version; 445 unsigned flags = UFS_SB(sb)->s_flags; 446 447 UFSD("BEGIN\n"); 448 449 if (pos > inode->i_size - UFS_DIR_REC_LEN(1)) 450 return 0; 451 452 for ( ; n < npages; n++, offset = 0) { 453 char *kaddr, *limit; 454 struct ufs_dir_entry *de; 455 456 struct page *page = ufs_get_page(inode, n); 457 458 if (IS_ERR(page)) { 459 ufs_error(sb, __func__, 460 "bad page in #%lu", 461 inode->i_ino); 462 filp->f_pos += PAGE_CACHE_SIZE - offset; 463 return -EIO; 464 } 465 kaddr = page_address(page); 466 if (unlikely(need_revalidate)) { 467 if (offset) { 468 offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask); 469 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; 470 } 471 filp->f_version = inode->i_version; 472 need_revalidate = 0; 473 } 474 de = (struct ufs_dir_entry *)(kaddr+offset); 475 limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1); 476 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) { 477 if (de->d_reclen == 0) { 478 ufs_error(sb, __func__, 479 "zero-length directory entry"); 480 ufs_put_page(page); 481 return -EIO; 482 } 483 if (de->d_ino) { 484 int over; 485 unsigned char d_type = DT_UNKNOWN; 486 487 offset = (char *)de - kaddr; 488 489 UFSD("filldir(%s,%u)\n", de->d_name, 490 fs32_to_cpu(sb, de->d_ino)); 491 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de)); 492 493 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) 494 d_type = de->d_u.d_44.d_type; 495 496 over = filldir(dirent, de->d_name, 497 ufs_get_de_namlen(sb, de), 498 (n<<PAGE_CACHE_SHIFT) | offset, 499 fs32_to_cpu(sb, de->d_ino), d_type); 500 if (over) { 501 ufs_put_page(page); 502 return 0; 503 } 504 } 505 filp->f_pos += fs16_to_cpu(sb, de->d_reclen); 506 } 507 ufs_put_page(page); 508 } 509 return 0; 510 } 511 512 513 /* 514 * ufs_delete_entry deletes a directory entry by merging it with the 515 * previous entry. 516 */ 517 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir, 518 struct page * page) 519 { 520 struct super_block *sb = inode->i_sb; 521 struct address_space *mapping = page->mapping; 522 char *kaddr = page_address(page); 523 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 524 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen); 525 loff_t pos; 526 struct ufs_dir_entry *pde = NULL; 527 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from); 528 int err; 529 530 UFSD("ENTER\n"); 531 532 UFSD("ino %u, reclen %u, namlen %u, name %s\n", 533 fs32_to_cpu(sb, de->d_ino), 534 fs16_to_cpu(sb, de->d_reclen), 535 ufs_get_de_namlen(sb, de), de->d_name); 536 537 while ((char*)de < (char*)dir) { 538 if (de->d_reclen == 0) { 539 ufs_error(inode->i_sb, __func__, 540 "zero-length directory entry"); 541 err = -EIO; 542 goto out; 543 } 544 pde = de; 545 de = ufs_next_entry(sb, de); 546 } 547 if (pde) 548 from = (char*)pde - (char*)page_address(page); 549 550 pos = page_offset(page) + from; 551 lock_page(page); 552 err = __ufs_write_begin(NULL, mapping, pos, to - from, 553 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); 554 BUG_ON(err); 555 if (pde) 556 pde->d_reclen = cpu_to_fs16(sb, to - from); 557 dir->d_ino = 0; 558 err = ufs_commit_chunk(page, pos, to - from); 559 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 560 mark_inode_dirty(inode); 561 out: 562 ufs_put_page(page); 563 UFSD("EXIT\n"); 564 return err; 565 } 566 567 int ufs_make_empty(struct inode * inode, struct inode *dir) 568 { 569 struct super_block * sb = dir->i_sb; 570 struct address_space *mapping = inode->i_mapping; 571 struct page *page = grab_cache_page(mapping, 0); 572 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 573 struct ufs_dir_entry * de; 574 char *base; 575 int err; 576 577 if (!page) 578 return -ENOMEM; 579 580 err = __ufs_write_begin(NULL, mapping, 0, chunk_size, 581 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); 582 if (err) { 583 unlock_page(page); 584 goto fail; 585 } 586 587 kmap(page); 588 base = (char*)page_address(page); 589 memset(base, 0, PAGE_CACHE_SIZE); 590 591 de = (struct ufs_dir_entry *) base; 592 593 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 594 ufs_set_de_type(sb, de, inode->i_mode); 595 ufs_set_de_namlen(sb, de, 1); 596 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); 597 strcpy (de->d_name, "."); 598 de = (struct ufs_dir_entry *) 599 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 600 de->d_ino = cpu_to_fs32(sb, dir->i_ino); 601 ufs_set_de_type(sb, de, dir->i_mode); 602 de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1)); 603 ufs_set_de_namlen(sb, de, 2); 604 strcpy (de->d_name, ".."); 605 kunmap(page); 606 607 err = ufs_commit_chunk(page, 0, chunk_size); 608 fail: 609 page_cache_release(page); 610 return err; 611 } 612 613 /* 614 * routine to check that the specified directory is empty (for rmdir) 615 */ 616 int ufs_empty_dir(struct inode * inode) 617 { 618 struct super_block *sb = inode->i_sb; 619 struct page *page = NULL; 620 unsigned long i, npages = ufs_dir_pages(inode); 621 622 for (i = 0; i < npages; i++) { 623 char *kaddr; 624 struct ufs_dir_entry *de; 625 page = ufs_get_page(inode, i); 626 627 if (IS_ERR(page)) 628 continue; 629 630 kaddr = page_address(page); 631 de = (struct ufs_dir_entry *)kaddr; 632 kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1); 633 634 while ((char *)de <= kaddr) { 635 if (de->d_reclen == 0) { 636 ufs_error(inode->i_sb, __func__, 637 "zero-length directory entry: " 638 "kaddr=%p, de=%p\n", kaddr, de); 639 goto not_empty; 640 } 641 if (de->d_ino) { 642 u16 namelen=ufs_get_de_namlen(sb, de); 643 /* check for . and .. */ 644 if (de->d_name[0] != '.') 645 goto not_empty; 646 if (namelen > 2) 647 goto not_empty; 648 if (namelen < 2) { 649 if (inode->i_ino != 650 fs32_to_cpu(sb, de->d_ino)) 651 goto not_empty; 652 } else if (de->d_name[1] != '.') 653 goto not_empty; 654 } 655 de = ufs_next_entry(sb, de); 656 } 657 ufs_put_page(page); 658 } 659 return 1; 660 661 not_empty: 662 ufs_put_page(page); 663 return 0; 664 } 665 666 const struct file_operations ufs_dir_operations = { 667 .read = generic_read_dir, 668 .readdir = ufs_readdir, 669 .fsync = simple_fsync, 670 .llseek = generic_file_llseek, 671 }; 672