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