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(dir); 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 (ufs_match(sb, namelen, name, de)) 283 goto found; 284 de = ufs_next_entry(sb, de); 285 } 286 ufs_put_page(page); 287 } 288 if (++n >= npages) 289 n = 0; 290 } while (n != start); 291 out: 292 return NULL; 293 294 found: 295 *res_page = page; 296 ui->i_dir_start_lookup = n; 297 return de; 298 } 299 300 /* 301 * Parent is locked. 302 */ 303 int ufs_add_link(struct dentry *dentry, struct inode *inode) 304 { 305 struct inode *dir = d_inode(dentry->d_parent); 306 const unsigned char *name = dentry->d_name.name; 307 int namelen = dentry->d_name.len; 308 struct super_block *sb = dir->i_sb; 309 unsigned reclen = UFS_DIR_REC_LEN(namelen); 310 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 311 unsigned short rec_len, name_len; 312 struct page *page = NULL; 313 struct ufs_dir_entry *de; 314 unsigned long npages = dir_pages(dir); 315 unsigned long n; 316 char *kaddr; 317 loff_t pos; 318 int err; 319 320 UFSD("ENTER, name %s, namelen %u\n", name, namelen); 321 322 /* 323 * We take care of directory expansion in the same loop. 324 * This code plays outside i_size, so it locks the page 325 * to protect that region. 326 */ 327 for (n = 0; n <= npages; n++) { 328 char *dir_end; 329 330 page = ufs_get_page(dir, n); 331 err = PTR_ERR(page); 332 if (IS_ERR(page)) 333 goto out; 334 lock_page(page); 335 kaddr = page_address(page); 336 dir_end = kaddr + ufs_last_byte(dir, n); 337 de = (struct ufs_dir_entry *)kaddr; 338 kaddr += PAGE_SIZE - reclen; 339 while ((char *)de <= kaddr) { 340 if ((char *)de == dir_end) { 341 /* We hit i_size */ 342 name_len = 0; 343 rec_len = chunk_size; 344 de->d_reclen = cpu_to_fs16(sb, chunk_size); 345 de->d_ino = 0; 346 goto got_it; 347 } 348 if (de->d_reclen == 0) { 349 ufs_error(dir->i_sb, __func__, 350 "zero-length directory entry"); 351 err = -EIO; 352 goto out_unlock; 353 } 354 err = -EEXIST; 355 if (ufs_match(sb, namelen, name, de)) 356 goto out_unlock; 357 name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)); 358 rec_len = fs16_to_cpu(sb, de->d_reclen); 359 if (!de->d_ino && rec_len >= reclen) 360 goto got_it; 361 if (rec_len >= name_len + reclen) 362 goto got_it; 363 de = (struct ufs_dir_entry *) ((char *) de + rec_len); 364 } 365 unlock_page(page); 366 ufs_put_page(page); 367 } 368 BUG(); 369 return -EINVAL; 370 371 got_it: 372 pos = page_offset(page) + 373 (char*)de - (char*)page_address(page); 374 err = ufs_prepare_chunk(page, pos, rec_len); 375 if (err) 376 goto out_unlock; 377 if (de->d_ino) { 378 struct ufs_dir_entry *de1 = 379 (struct ufs_dir_entry *) ((char *) de + name_len); 380 de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len); 381 de->d_reclen = cpu_to_fs16(sb, name_len); 382 383 de = de1; 384 } 385 386 ufs_set_de_namlen(sb, de, namelen); 387 memcpy(de->d_name, name, namelen + 1); 388 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 389 ufs_set_de_type(sb, de, inode->i_mode); 390 391 err = ufs_commit_chunk(page, pos, rec_len); 392 dir->i_mtime = dir->i_ctime = current_time(dir); 393 394 mark_inode_dirty(dir); 395 /* OFFSET_CACHE */ 396 out_put: 397 ufs_put_page(page); 398 out: 399 return err; 400 out_unlock: 401 unlock_page(page); 402 goto out_put; 403 } 404 405 static inline unsigned 406 ufs_validate_entry(struct super_block *sb, char *base, 407 unsigned offset, unsigned mask) 408 { 409 struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset); 410 struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask)); 411 while ((char*)p < (char*)de) 412 p = ufs_next_entry(sb, p); 413 return (char *)p - base; 414 } 415 416 417 /* 418 * This is blatantly stolen from ext2fs 419 */ 420 static int 421 ufs_readdir(struct file *file, struct dir_context *ctx) 422 { 423 loff_t pos = ctx->pos; 424 struct inode *inode = file_inode(file); 425 struct super_block *sb = inode->i_sb; 426 unsigned int offset = pos & ~PAGE_MASK; 427 unsigned long n = pos >> PAGE_SHIFT; 428 unsigned long npages = dir_pages(inode); 429 unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 430 int need_revalidate = file->f_version != inode->i_version; 431 unsigned flags = UFS_SB(sb)->s_flags; 432 433 UFSD("BEGIN\n"); 434 435 if (pos > inode->i_size - UFS_DIR_REC_LEN(1)) 436 return 0; 437 438 for ( ; n < npages; n++, offset = 0) { 439 char *kaddr, *limit; 440 struct ufs_dir_entry *de; 441 442 struct page *page = ufs_get_page(inode, n); 443 444 if (IS_ERR(page)) { 445 ufs_error(sb, __func__, 446 "bad page in #%lu", 447 inode->i_ino); 448 ctx->pos += PAGE_SIZE - offset; 449 return -EIO; 450 } 451 kaddr = page_address(page); 452 if (unlikely(need_revalidate)) { 453 if (offset) { 454 offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask); 455 ctx->pos = (n<<PAGE_SHIFT) + offset; 456 } 457 file->f_version = inode->i_version; 458 need_revalidate = 0; 459 } 460 de = (struct ufs_dir_entry *)(kaddr+offset); 461 limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1); 462 for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) { 463 if (de->d_ino) { 464 unsigned char d_type = DT_UNKNOWN; 465 466 UFSD("filldir(%s,%u)\n", de->d_name, 467 fs32_to_cpu(sb, de->d_ino)); 468 UFSD("namlen %u\n", ufs_get_de_namlen(sb, de)); 469 470 if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) 471 d_type = de->d_u.d_44.d_type; 472 473 if (!dir_emit(ctx, de->d_name, 474 ufs_get_de_namlen(sb, de), 475 fs32_to_cpu(sb, de->d_ino), 476 d_type)) { 477 ufs_put_page(page); 478 return 0; 479 } 480 } 481 ctx->pos += fs16_to_cpu(sb, de->d_reclen); 482 } 483 ufs_put_page(page); 484 } 485 return 0; 486 } 487 488 489 /* 490 * ufs_delete_entry deletes a directory entry by merging it with the 491 * previous entry. 492 */ 493 int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir, 494 struct page * page) 495 { 496 struct super_block *sb = inode->i_sb; 497 char *kaddr = page_address(page); 498 unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); 499 unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen); 500 loff_t pos; 501 struct ufs_dir_entry *pde = NULL; 502 struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from); 503 int err; 504 505 UFSD("ENTER\n"); 506 507 UFSD("ino %u, reclen %u, namlen %u, name %s\n", 508 fs32_to_cpu(sb, de->d_ino), 509 fs16_to_cpu(sb, de->d_reclen), 510 ufs_get_de_namlen(sb, de), de->d_name); 511 512 while ((char*)de < (char*)dir) { 513 if (de->d_reclen == 0) { 514 ufs_error(inode->i_sb, __func__, 515 "zero-length directory entry"); 516 err = -EIO; 517 goto out; 518 } 519 pde = de; 520 de = ufs_next_entry(sb, de); 521 } 522 if (pde) 523 from = (char*)pde - (char*)page_address(page); 524 525 pos = page_offset(page) + from; 526 lock_page(page); 527 err = ufs_prepare_chunk(page, pos, to - from); 528 BUG_ON(err); 529 if (pde) 530 pde->d_reclen = cpu_to_fs16(sb, to - from); 531 dir->d_ino = 0; 532 err = ufs_commit_chunk(page, pos, to - from); 533 inode->i_ctime = inode->i_mtime = current_time(inode); 534 mark_inode_dirty(inode); 535 out: 536 ufs_put_page(page); 537 UFSD("EXIT\n"); 538 return err; 539 } 540 541 int ufs_make_empty(struct inode * inode, struct inode *dir) 542 { 543 struct super_block * sb = dir->i_sb; 544 struct address_space *mapping = inode->i_mapping; 545 struct page *page = grab_cache_page(mapping, 0); 546 const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; 547 struct ufs_dir_entry * de; 548 char *base; 549 int err; 550 551 if (!page) 552 return -ENOMEM; 553 554 err = ufs_prepare_chunk(page, 0, chunk_size); 555 if (err) { 556 unlock_page(page); 557 goto fail; 558 } 559 560 kmap(page); 561 base = (char*)page_address(page); 562 memset(base, 0, PAGE_SIZE); 563 564 de = (struct ufs_dir_entry *) base; 565 566 de->d_ino = cpu_to_fs32(sb, inode->i_ino); 567 ufs_set_de_type(sb, de, inode->i_mode); 568 ufs_set_de_namlen(sb, de, 1); 569 de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); 570 strcpy (de->d_name, "."); 571 de = (struct ufs_dir_entry *) 572 ((char *)de + fs16_to_cpu(sb, de->d_reclen)); 573 de->d_ino = cpu_to_fs32(sb, dir->i_ino); 574 ufs_set_de_type(sb, de, dir->i_mode); 575 de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1)); 576 ufs_set_de_namlen(sb, de, 2); 577 strcpy (de->d_name, ".."); 578 kunmap(page); 579 580 err = ufs_commit_chunk(page, 0, chunk_size); 581 fail: 582 put_page(page); 583 return err; 584 } 585 586 /* 587 * routine to check that the specified directory is empty (for rmdir) 588 */ 589 int ufs_empty_dir(struct inode * inode) 590 { 591 struct super_block *sb = inode->i_sb; 592 struct page *page = NULL; 593 unsigned long i, npages = dir_pages(inode); 594 595 for (i = 0; i < npages; i++) { 596 char *kaddr; 597 struct ufs_dir_entry *de; 598 page = ufs_get_page(inode, i); 599 600 if (IS_ERR(page)) 601 continue; 602 603 kaddr = page_address(page); 604 de = (struct ufs_dir_entry *)kaddr; 605 kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1); 606 607 while ((char *)de <= kaddr) { 608 if (de->d_reclen == 0) { 609 ufs_error(inode->i_sb, __func__, 610 "zero-length directory entry: " 611 "kaddr=%p, de=%p\n", kaddr, de); 612 goto not_empty; 613 } 614 if (de->d_ino) { 615 u16 namelen=ufs_get_de_namlen(sb, de); 616 /* check for . and .. */ 617 if (de->d_name[0] != '.') 618 goto not_empty; 619 if (namelen > 2) 620 goto not_empty; 621 if (namelen < 2) { 622 if (inode->i_ino != 623 fs32_to_cpu(sb, de->d_ino)) 624 goto not_empty; 625 } else if (de->d_name[1] != '.') 626 goto not_empty; 627 } 628 de = ufs_next_entry(sb, de); 629 } 630 ufs_put_page(page); 631 } 632 return 1; 633 634 not_empty: 635 ufs_put_page(page); 636 return 0; 637 } 638 639 const struct file_operations ufs_dir_operations = { 640 .read = generic_read_dir, 641 .iterate_shared = ufs_readdir, 642 .fsync = generic_file_fsync, 643 .llseek = generic_file_llseek, 644 }; 645