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/ufs_fs.h> 22 #include <linux/smp_lock.h> 23 24 #include "swab.h" 25 #include "util.h" 26 27 /* 28 * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure. 29 * 30 * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller. 31 */ 32 static inline int ufs_match(struct super_block *sb, int len, 33 const char * const name, struct ufs_dir_entry * de) 34 { 35 if (len != ufs_get_de_namlen(sb, de)) 36 return 0; 37 if (!de->d_ino) 38 return 0; 39 return !memcmp(name, de->d_name, len); 40 } 41 42 static int ufs_commit_chunk(struct page *page, unsigned from, unsigned to) 43 { 44 struct inode *dir = page->mapping->host; 45 int err = 0; 46 dir->i_version++; 47 page->mapping->a_ops->commit_write(NULL, page, from, to); 48 if (IS_DIRSYNC(dir)) 49 err = write_one_page(page, 1); 50 else 51 unlock_page(page); 52 return err; 53 } 54 55 static inline void ufs_put_page(struct page *page) 56 { 57 kunmap(page); 58 page_cache_release(page); 59 } 60 61 static inline unsigned long ufs_dir_pages(struct inode *inode) 62 { 63 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; 64 } 65 66 ino_t ufs_inode_by_name(struct inode *dir, struct dentry *dentry) 67 { 68 ino_t res = 0; 69 struct ufs_dir_entry *de; 70 struct page *page; 71 72 de = ufs_find_entry(dir, dentry, &page); 73 if (de) { 74 res = fs32_to_cpu(dir->i_sb, de->d_ino); 75 ufs_put_page(page); 76 } 77 return res; 78 } 79 80 81 /* Releases the page */ 82 void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de, 83 struct page *page, struct inode *inode) 84 { 85 unsigned from = (char *) de - (char *) page_address(page); 86 unsigned to = from + fs16_to_cpu(dir->i_sb, de->d_reclen); 87 int err; 88 89 lock_page(page); 90 err = page->mapping->a_ops->prepare_write(NULL, page, from, to); 91 BUG_ON(err); 92 de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino); 93 ufs_set_de_type(dir->i_sb, de, inode->i_mode); 94 err = ufs_commit_chunk(page, from, to); 95 ufs_put_page(page); 96 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 97 mark_inode_dirty(dir); 98 } 99 100 101 static void ufs_check_page(struct page *page) 102 { 103 struct inode *dir = page->mapping->host; 104 struct super_block *sb = dir->i_sb; 105 char *kaddr = page_address(page); 106 unsigned offs, rec_len; 107 unsigned limit = PAGE_CACHE_SIZE; 108 const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1; 109 struct ufs_dir_entry *p; 110 char *error; 111 112 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { 113 limit = dir->i_size & ~PAGE_CACHE_MASK; 114 if (limit & chunk_mask) 115 goto Ebadsize; 116 if (!limit) 117 goto out; 118 } 119 for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) { 120 p = (struct ufs_dir_entry *)(kaddr + offs); 121 rec_len = fs16_to_cpu(sb, p->d_reclen); 122 123 if (rec_len < UFS_DIR_REC_LEN(1)) 124 goto Eshort; 125 if (rec_len & 3) 126 goto Ealign; 127 if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p))) 128 goto Enamelen; 129 if (((offs + rec_len - 1) ^ offs) & ~chunk_mask) 130 goto Espan; 131 if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg * 132 UFS_SB(sb)->s_uspi->s_ncg)) 133 goto Einumber; 134 } 135 if (offs != limit) 136 goto Eend; 137 out: 138 SetPageChecked(page); 139 return; 140 141 /* Too bad, we had an error */ 142 143 Ebadsize: 144 ufs_error(sb, "ufs_check_page", 145 "size of directory #%lu is not a multiple of chunk size", 146 dir->i_ino 147 ); 148 goto fail; 149 Eshort: 150 error = "rec_len is smaller than minimal"; 151 goto bad_entry; 152 Ealign: 153 error = "unaligned directory entry"; 154 goto bad_entry; 155 Enamelen: 156 error = "rec_len is too small for name_len"; 157 goto bad_entry; 158 Espan: 159 error = "directory entry across blocks"; 160 goto bad_entry; 161 Einumber: 162 error = "inode out of bounds"; 163 bad_entry: 164 ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - " 165 "offset=%lu, rec_len=%d, name_len=%d", 166 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, 167 rec_len, ufs_get_de_namlen(sb, p)); 168 goto fail; 169 Eend: 170 p = (struct ufs_dir_entry *)(kaddr + offs); 171 ufs_error (sb, "ext2_check_page", 172 "entry in directory #%lu spans the page boundary" 173 "offset=%lu", 174 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs); 175 fail: 176 SetPageChecked(page); 177 SetPageError(page); 178 } 179 180 static struct page *ufs_get_page(struct inode *dir, unsigned long n) 181 { 182 struct address_space *mapping = dir->i_mapping; 183 struct page *page = read_mapping_page(mapping, n, NULL); 184 if (!IS_ERR(page)) { 185 kmap(page); 186 if (!PageChecked(page)) 187 ufs_check_page(page); 188 if (PageError(page)) 189 goto fail; 190 } 191 return page; 192 193 fail: 194 ufs_put_page(page); 195 return ERR_PTR(-EIO); 196 } 197 198 /* 199 * Return the offset into page `page_nr' of the last valid 200 * byte in that page, plus one. 201 */ 202 static unsigned 203 ufs_last_byte(struct inode *inode, unsigned long page_nr) 204 { 205 unsigned last_byte = inode->i_size; 206 207 last_byte -= page_nr << PAGE_CACHE_SHIFT; 208 if (last_byte > PAGE_CACHE_SIZE) 209 last_byte = PAGE_CACHE_SIZE; 210 return last_byte; 211 } 212 213 static inline struct ufs_dir_entry * 214 ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p) 215 { 216 return (struct ufs_dir_entry *)((char *)p + 217 fs16_to_cpu(sb, p->d_reclen)); 218 } 219 220 struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p) 221 { 222 struct page *page = ufs_get_page(dir, 0); 223 struct ufs_dir_entry *de = NULL; 224 225 if (!IS_ERR(page)) { 226 de = ufs_next_entry(dir->i_sb, 227 (struct ufs_dir_entry *)page_address(page)); 228 *p = page; 229 } 230 return de; 231 } 232 233 /* 234 * ufs_find_entry() 235 * 236 * finds an entry in the specified directory with the wanted name. It 237 * returns the page in which the entry was found, and the entry itself 238 * (as a parameter - res_dir). Page is returned mapped and unlocked. 239 * Entry is guaranteed to be valid. 240 */ 241 struct ufs_dir_entry *ufs_find_entry(struct inode *dir, struct dentry *dentry, 242 struct page **res_page) 243 { 244 struct super_block *sb = dir->i_sb; 245 const char *name = dentry->d_name.name; 246 int namelen = dentry->d_name.len; 247 unsigned reclen = UFS_DIR_REC_LEN(namelen); 248 unsigned long start, n; 249 unsigned long npages = ufs_dir_pages(dir); 250 struct page *page = NULL; 251 struct ufs_inode_info *ui = UFS_I(dir); 252 struct ufs_dir_entry *de; 253 254 UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen); 255 256 if (npages == 0 || namelen > UFS_MAXNAMLEN) 257 goto out; 258 259 /* OFFSET_CACHE */ 260 *res_page = NULL; 261 262 start = ui->i_dir_start_lookup; 263 264 if (start >= npages) 265 start = 0; 266 n = start; 267 do { 268 char *kaddr; 269 page = ufs_get_page(dir, n); 270 if (!IS_ERR(page)) { 271 kaddr = page_address(page); 272 de = (struct ufs_dir_entry *) kaddr; 273 kaddr += ufs_last_byte(dir, n) - reclen; 274 while ((char *) de <= kaddr) { 275 if (de->d_reclen == 0) { 276 ufs_error(dir->i_sb, __FUNCTION__, 277 "zero-length directory entry"); 278 ufs_put_page(page); 279 goto out; 280 } 281 if (ufs_match(sb, namelen, name, de)) 282 goto found; 283 de = ufs_next_entry(sb, de); 284 } 285 ufs_put_page(page); 286 } 287 if (++n >= npages) 288 n = 0; 289 } while (n != start); 290 out: 291 return NULL; 292 293 found: 294 *res_page = page; 295 ui->i_dir_start_lookup = n; 296 return de; 297 } 298 299 /* 300 * Parent is locked. 301 */ 302 int ufs_add_link(struct dentry *dentry, struct inode *inode) 303 { 304 struct inode *dir = dentry->d_parent->d_inode; 305 const char *name = dentry->d_name.name; 306 int namelen = dentry->d_name.len; 307 struct super_block *sb = dir->i_sb; 308 unsigned reclen = UFS_DIR_REC_LEN(namelen); 309 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 310 unsigned short rec_len, name_len; 311 struct page *page = NULL; 312 struct ufs_dir_entry *de; 313 unsigned long npages = ufs_dir_pages(dir); 314 unsigned long n; 315 char *kaddr; 316 unsigned from, to; 317 int err; 318 319 UFSD("ENTER, name %s, namelen %u\n", name, namelen); 320 321 /* 322 * We take care of directory expansion in the same loop. 323 * This code plays outside i_size, so it locks the page 324 * to protect that region. 325 */ 326 for (n = 0; n <= npages; n++) { 327 char *dir_end; 328 329 page = ufs_get_page(dir, n); 330 err = PTR_ERR(page); 331 if (IS_ERR(page)) 332 goto out; 333 lock_page(page); 334 kaddr = page_address(page); 335 dir_end = kaddr + ufs_last_byte(dir, n); 336 de = (struct ufs_dir_entry *)kaddr; 337 kaddr += PAGE_CACHE_SIZE - reclen; 338 while ((char *)de <= kaddr) { 339 if ((char *)de == dir_end) { 340 /* We hit i_size */ 341 name_len = 0; 342 rec_len = chunk_size; 343 de->d_reclen = cpu_to_fs16(sb, chunk_size); 344 de->d_ino = 0; 345 goto got_it; 346 } 347 if (de->d_reclen == 0) { 348 ufs_error(dir->i_sb, __FUNCTION__, 349 "zero-length directory entry"); 350 err = -EIO; 351 goto out_unlock; 352 } 353 err = -EEXIST; 354 if (ufs_match(sb, namelen, name, de)) 355 goto out_unlock; 356 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)); 357 rec_len = fs16_to_cpu(sb, de->d_reclen); 358 if (!de->d_ino && rec_len >= reclen) 359 goto got_it; 360 if (rec_len >= name_len + reclen) 361 goto got_it; 362 de = (struct ufs_dir_entry *) ((char *) de + rec_len); 363 } 364 unlock_page(page); 365 ufs_put_page(page); 366 } 367 BUG(); 368 return -EINVAL; 369 370 got_it: 371 from = (char*)de - (char*)page_address(page); 372 to = from + rec_len; 373 err = page->mapping->a_ops->prepare_write(NULL, page, from, to); 374 if (err) 375 goto out_unlock; 376 if (de->d_ino) { 377 struct ufs_dir_entry *de1 = 378 (struct ufs_dir_entry *) ((char *) de + name_len); 379 de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len); 380 de->d_reclen = cpu_to_fs16(sb, name_len); 381 382 de = de1; 383 } 384 385 ufs_set_de_namlen(sb, de, namelen); 386 memcpy(de->d_name, name, namelen + 1); 387 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 388 ufs_set_de_type(sb, de, inode->i_mode); 389 390 err = ufs_commit_chunk(page, from, to); 391 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 392 393 mark_inode_dirty(dir); 394 /* OFFSET_CACHE */ 395 out_put: 396 ufs_put_page(page); 397 out: 398 return err; 399 out_unlock: 400 unlock_page(page); 401 goto out_put; 402 } 403 404 static inline unsigned 405 ufs_validate_entry(struct super_block *sb, char *base, 406 unsigned offset, unsigned mask) 407 { 408 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset); 409 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask)); 410 while ((char*)p < (char*)de) { 411 if (p->d_reclen == 0) 412 break; 413 p = ufs_next_entry(sb, p); 414 } 415 return (char *)p - base; 416 } 417 418 419 /* 420 * This is blatantly stolen from ext2fs 421 */ 422 static int 423 ufs_readdir(struct file *filp, void *dirent, filldir_t filldir) 424 { 425 loff_t pos = filp->f_pos; 426 struct inode *inode = filp->f_path.dentry->d_inode; 427 struct super_block *sb = inode->i_sb; 428 unsigned int offset = pos & ~PAGE_CACHE_MASK; 429 unsigned long n = pos >> PAGE_CACHE_SHIFT; 430 unsigned long npages = ufs_dir_pages(inode); 431 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 432 int need_revalidate = filp->f_version != inode->i_version; 433 unsigned flags = UFS_SB(sb)->s_flags; 434 435 UFSD("BEGIN\n"); 436 437 if (pos > inode->i_size - UFS_DIR_REC_LEN(1)) 438 return 0; 439 440 for ( ; n < npages; n++, offset = 0) { 441 char *kaddr, *limit; 442 struct ufs_dir_entry *de; 443 444 struct page *page = ufs_get_page(inode, n); 445 446 if (IS_ERR(page)) { 447 ufs_error(sb, __FUNCTION__, 448 "bad page in #%lu", 449 inode->i_ino); 450 filp->f_pos += PAGE_CACHE_SIZE - offset; 451 return -EIO; 452 } 453 kaddr = page_address(page); 454 if (unlikely(need_revalidate)) { 455 if (offset) { 456 offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask); 457 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; 458 } 459 filp->f_version = inode->i_version; 460 need_revalidate = 0; 461 } 462 de = (struct ufs_dir_entry *)(kaddr+offset); 463 limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1); 464 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) { 465 if (de->d_reclen == 0) { 466 ufs_error(sb, __FUNCTION__, 467 "zero-length directory entry"); 468 ufs_put_page(page); 469 return -EIO; 470 } 471 if (de->d_ino) { 472 int over; 473 unsigned char d_type = DT_UNKNOWN; 474 475 offset = (char *)de - kaddr; 476 477 UFSD("filldir(%s,%u)\n", de->d_name, 478 fs32_to_cpu(sb, de->d_ino)); 479 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de)); 480 481 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) 482 d_type = de->d_u.d_44.d_type; 483 484 over = filldir(dirent, de->d_name, 485 ufs_get_de_namlen(sb, de), 486 (n<<PAGE_CACHE_SHIFT) | offset, 487 fs32_to_cpu(sb, de->d_ino), d_type); 488 if (over) { 489 ufs_put_page(page); 490 return 0; 491 } 492 } 493 filp->f_pos += fs16_to_cpu(sb, de->d_reclen); 494 } 495 ufs_put_page(page); 496 } 497 return 0; 498 } 499 500 501 /* 502 * ufs_delete_entry deletes a directory entry by merging it with the 503 * previous entry. 504 */ 505 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir, 506 struct page * page) 507 { 508 struct super_block *sb = inode->i_sb; 509 struct address_space *mapping = page->mapping; 510 char *kaddr = page_address(page); 511 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 512 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen); 513 struct ufs_dir_entry *pde = NULL; 514 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from); 515 int err; 516 517 UFSD("ENTER\n"); 518 519 UFSD("ino %u, reclen %u, namlen %u, name %s\n", 520 fs32_to_cpu(sb, de->d_ino), 521 fs16_to_cpu(sb, de->d_reclen), 522 ufs_get_de_namlen(sb, de), de->d_name); 523 524 while ((char*)de < (char*)dir) { 525 if (de->d_reclen == 0) { 526 ufs_error(inode->i_sb, __FUNCTION__, 527 "zero-length directory entry"); 528 err = -EIO; 529 goto out; 530 } 531 pde = de; 532 de = ufs_next_entry(sb, de); 533 } 534 if (pde) 535 from = (char*)pde - (char*)page_address(page); 536 lock_page(page); 537 err = mapping->a_ops->prepare_write(NULL, page, from, to); 538 BUG_ON(err); 539 if (pde) 540 pde->d_reclen = cpu_to_fs16(sb, to-from); 541 dir->d_ino = 0; 542 err = ufs_commit_chunk(page, from, to); 543 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 544 mark_inode_dirty(inode); 545 out: 546 ufs_put_page(page); 547 UFSD("EXIT\n"); 548 return err; 549 } 550 551 int ufs_make_empty(struct inode * inode, struct inode *dir) 552 { 553 struct super_block * sb = dir->i_sb; 554 struct address_space *mapping = inode->i_mapping; 555 struct page *page = grab_cache_page(mapping, 0); 556 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 557 struct ufs_dir_entry * de; 558 char *base; 559 int err; 560 561 if (!page) 562 return -ENOMEM; 563 kmap(page); 564 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size); 565 if (err) { 566 unlock_page(page); 567 goto fail; 568 } 569 570 571 base = (char*)page_address(page); 572 memset(base, 0, PAGE_CACHE_SIZE); 573 574 de = (struct ufs_dir_entry *) base; 575 576 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 577 ufs_set_de_type(sb, de, inode->i_mode); 578 ufs_set_de_namlen(sb, de, 1); 579 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); 580 strcpy (de->d_name, "."); 581 de = (struct ufs_dir_entry *) 582 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 583 de->d_ino = cpu_to_fs32(sb, dir->i_ino); 584 ufs_set_de_type(sb, de, dir->i_mode); 585 de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1)); 586 ufs_set_de_namlen(sb, de, 2); 587 strcpy (de->d_name, ".."); 588 589 err = ufs_commit_chunk(page, 0, chunk_size); 590 fail: 591 kunmap(page); 592 page_cache_release(page); 593 return err; 594 } 595 596 /* 597 * routine to check that the specified directory is empty (for rmdir) 598 */ 599 int ufs_empty_dir(struct inode * inode) 600 { 601 struct super_block *sb = inode->i_sb; 602 struct page *page = NULL; 603 unsigned long i, npages = ufs_dir_pages(inode); 604 605 for (i = 0; i < npages; i++) { 606 char *kaddr; 607 struct ufs_dir_entry *de; 608 page = ufs_get_page(inode, i); 609 610 if (IS_ERR(page)) 611 continue; 612 613 kaddr = page_address(page); 614 de = (struct ufs_dir_entry *)kaddr; 615 kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1); 616 617 while ((char *)de <= kaddr) { 618 if (de->d_reclen == 0) { 619 ufs_error(inode->i_sb, __FUNCTION__, 620 "zero-length directory entry: " 621 "kaddr=%p, de=%p\n", kaddr, de); 622 goto not_empty; 623 } 624 if (de->d_ino) { 625 u16 namelen=ufs_get_de_namlen(sb, de); 626 /* check for . and .. */ 627 if (de->d_name[0] != '.') 628 goto not_empty; 629 if (namelen > 2) 630 goto not_empty; 631 if (namelen < 2) { 632 if (inode->i_ino != 633 fs32_to_cpu(sb, de->d_ino)) 634 goto not_empty; 635 } else if (de->d_name[1] != '.') 636 goto not_empty; 637 } 638 de = ufs_next_entry(sb, de); 639 } 640 ufs_put_page(page); 641 } 642 return 1; 643 644 not_empty: 645 ufs_put_page(page); 646 return 0; 647 } 648 649 const struct file_operations ufs_dir_operations = { 650 .read = generic_read_dir, 651 .readdir = ufs_readdir, 652 .fsync = file_fsync, 653 }; 654