1 /* 2 * linux/fs/ext2/dir.c 3 * 4 * Copyright (C) 1992, 1993, 1994, 1995 5 * Remy Card (card@masi.ibp.fr) 6 * Laboratoire MASI - Institut Blaise Pascal 7 * Universite Pierre et Marie Curie (Paris VI) 8 * 9 * from 10 * 11 * linux/fs/minix/dir.c 12 * 13 * Copyright (C) 1991, 1992 Linus Torvalds 14 * 15 * ext2 directory handling functions 16 * 17 * Big-endian to little-endian byte-swapping/bitmaps by 18 * David S. Miller (davem@caip.rutgers.edu), 1995 19 * 20 * All code that works with directory layout had been switched to pagecache 21 * and moved here. AV 22 */ 23 24 #include "ext2.h" 25 #include <linux/buffer_head.h> 26 #include <linux/pagemap.h> 27 #include <linux/swap.h> 28 29 typedef struct ext2_dir_entry_2 ext2_dirent; 30 31 /* 32 * Tests against MAX_REC_LEN etc were put in place for 64k block 33 * sizes; if that is not possible on this arch, we can skip 34 * those tests and speed things up. 35 */ 36 static inline unsigned ext2_rec_len_from_disk(__le16 dlen) 37 { 38 unsigned len = le16_to_cpu(dlen); 39 40 #if (PAGE_SIZE >= 65536) 41 if (len == EXT2_MAX_REC_LEN) 42 return 1 << 16; 43 #endif 44 return len; 45 } 46 47 static inline __le16 ext2_rec_len_to_disk(unsigned len) 48 { 49 #if (PAGE_SIZE >= 65536) 50 if (len == (1 << 16)) 51 return cpu_to_le16(EXT2_MAX_REC_LEN); 52 else 53 BUG_ON(len > (1 << 16)); 54 #endif 55 return cpu_to_le16(len); 56 } 57 58 /* 59 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be 60 * more robust, but we have what we have 61 */ 62 static inline unsigned ext2_chunk_size(struct inode *inode) 63 { 64 return inode->i_sb->s_blocksize; 65 } 66 67 static inline void ext2_put_page(struct page *page) 68 { 69 kunmap(page); 70 put_page(page); 71 } 72 73 /* 74 * Return the offset into page `page_nr' of the last valid 75 * byte in that page, plus one. 76 */ 77 static unsigned 78 ext2_last_byte(struct inode *inode, unsigned long page_nr) 79 { 80 unsigned last_byte = inode->i_size; 81 82 last_byte -= page_nr << PAGE_SHIFT; 83 if (last_byte > PAGE_SIZE) 84 last_byte = PAGE_SIZE; 85 return last_byte; 86 } 87 88 static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) 89 { 90 struct address_space *mapping = page->mapping; 91 struct inode *dir = mapping->host; 92 int err = 0; 93 94 dir->i_version++; 95 block_write_end(NULL, mapping, pos, len, len, page, NULL); 96 97 if (pos+len > dir->i_size) { 98 i_size_write(dir, pos+len); 99 mark_inode_dirty(dir); 100 } 101 102 if (IS_DIRSYNC(dir)) { 103 err = write_one_page(page, 1); 104 if (!err) 105 err = sync_inode_metadata(dir, 1); 106 } else { 107 unlock_page(page); 108 } 109 110 return err; 111 } 112 113 static bool ext2_check_page(struct page *page, int quiet) 114 { 115 struct inode *dir = page->mapping->host; 116 struct super_block *sb = dir->i_sb; 117 unsigned chunk_size = ext2_chunk_size(dir); 118 char *kaddr = page_address(page); 119 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); 120 unsigned offs, rec_len; 121 unsigned limit = PAGE_SIZE; 122 ext2_dirent *p; 123 char *error; 124 125 if ((dir->i_size >> PAGE_SHIFT) == page->index) { 126 limit = dir->i_size & ~PAGE_MASK; 127 if (limit & (chunk_size - 1)) 128 goto Ebadsize; 129 if (!limit) 130 goto out; 131 } 132 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { 133 p = (ext2_dirent *)(kaddr + offs); 134 rec_len = ext2_rec_len_from_disk(p->rec_len); 135 136 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1))) 137 goto Eshort; 138 if (unlikely(rec_len & 3)) 139 goto Ealign; 140 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len))) 141 goto Enamelen; 142 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))) 143 goto Espan; 144 if (unlikely(le32_to_cpu(p->inode) > max_inumber)) 145 goto Einumber; 146 } 147 if (offs != limit) 148 goto Eend; 149 out: 150 SetPageChecked(page); 151 return true; 152 153 /* Too bad, we had an error */ 154 155 Ebadsize: 156 if (!quiet) 157 ext2_error(sb, __func__, 158 "size of directory #%lu is not a multiple " 159 "of chunk size", dir->i_ino); 160 goto fail; 161 Eshort: 162 error = "rec_len is smaller than minimal"; 163 goto bad_entry; 164 Ealign: 165 error = "unaligned directory entry"; 166 goto bad_entry; 167 Enamelen: 168 error = "rec_len is too small for name_len"; 169 goto bad_entry; 170 Espan: 171 error = "directory entry across blocks"; 172 goto bad_entry; 173 Einumber: 174 error = "inode out of bounds"; 175 bad_entry: 176 if (!quiet) 177 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - " 178 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", 179 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs, 180 (unsigned long) le32_to_cpu(p->inode), 181 rec_len, p->name_len); 182 goto fail; 183 Eend: 184 if (!quiet) { 185 p = (ext2_dirent *)(kaddr + offs); 186 ext2_error(sb, "ext2_check_page", 187 "entry in directory #%lu spans the page boundary" 188 "offset=%lu, inode=%lu", 189 dir->i_ino, (page->index<<PAGE_SHIFT)+offs, 190 (unsigned long) le32_to_cpu(p->inode)); 191 } 192 fail: 193 SetPageError(page); 194 return false; 195 } 196 197 static struct page * ext2_get_page(struct inode *dir, unsigned long n, 198 int quiet) 199 { 200 struct address_space *mapping = dir->i_mapping; 201 struct page *page = read_mapping_page(mapping, n, NULL); 202 if (!IS_ERR(page)) { 203 kmap(page); 204 if (unlikely(!PageChecked(page))) { 205 if (PageError(page) || !ext2_check_page(page, quiet)) 206 goto fail; 207 } 208 } 209 return page; 210 211 fail: 212 ext2_put_page(page); 213 return ERR_PTR(-EIO); 214 } 215 216 /* 217 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. 218 * 219 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. 220 */ 221 static inline int ext2_match (int len, const char * const name, 222 struct ext2_dir_entry_2 * de) 223 { 224 if (len != de->name_len) 225 return 0; 226 if (!de->inode) 227 return 0; 228 return !memcmp(name, de->name, len); 229 } 230 231 /* 232 * p is at least 6 bytes before the end of page 233 */ 234 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) 235 { 236 return (ext2_dirent *)((char *)p + 237 ext2_rec_len_from_disk(p->rec_len)); 238 } 239 240 static inline unsigned 241 ext2_validate_entry(char *base, unsigned offset, unsigned mask) 242 { 243 ext2_dirent *de = (ext2_dirent*)(base + offset); 244 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); 245 while ((char*)p < (char*)de) { 246 if (p->rec_len == 0) 247 break; 248 p = ext2_next_entry(p); 249 } 250 return (char *)p - base; 251 } 252 253 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { 254 [EXT2_FT_UNKNOWN] = DT_UNKNOWN, 255 [EXT2_FT_REG_FILE] = DT_REG, 256 [EXT2_FT_DIR] = DT_DIR, 257 [EXT2_FT_CHRDEV] = DT_CHR, 258 [EXT2_FT_BLKDEV] = DT_BLK, 259 [EXT2_FT_FIFO] = DT_FIFO, 260 [EXT2_FT_SOCK] = DT_SOCK, 261 [EXT2_FT_SYMLINK] = DT_LNK, 262 }; 263 264 #define S_SHIFT 12 265 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { 266 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, 267 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, 268 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, 269 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, 270 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, 271 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, 272 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, 273 }; 274 275 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) 276 { 277 umode_t mode = inode->i_mode; 278 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 279 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; 280 else 281 de->file_type = 0; 282 } 283 284 static int 285 ext2_readdir(struct file *file, struct dir_context *ctx) 286 { 287 loff_t pos = ctx->pos; 288 struct inode *inode = file_inode(file); 289 struct super_block *sb = inode->i_sb; 290 unsigned int offset = pos & ~PAGE_MASK; 291 unsigned long n = pos >> PAGE_SHIFT; 292 unsigned long npages = dir_pages(inode); 293 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); 294 unsigned char *types = NULL; 295 int need_revalidate = file->f_version != inode->i_version; 296 297 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) 298 return 0; 299 300 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 301 types = ext2_filetype_table; 302 303 for ( ; n < npages; n++, offset = 0) { 304 char *kaddr, *limit; 305 ext2_dirent *de; 306 struct page *page = ext2_get_page(inode, n, 0); 307 308 if (IS_ERR(page)) { 309 ext2_error(sb, __func__, 310 "bad page in #%lu", 311 inode->i_ino); 312 ctx->pos += PAGE_SIZE - offset; 313 return PTR_ERR(page); 314 } 315 kaddr = page_address(page); 316 if (unlikely(need_revalidate)) { 317 if (offset) { 318 offset = ext2_validate_entry(kaddr, offset, chunk_mask); 319 ctx->pos = (n<<PAGE_SHIFT) + offset; 320 } 321 file->f_version = inode->i_version; 322 need_revalidate = 0; 323 } 324 de = (ext2_dirent *)(kaddr+offset); 325 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); 326 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { 327 if (de->rec_len == 0) { 328 ext2_error(sb, __func__, 329 "zero-length directory entry"); 330 ext2_put_page(page); 331 return -EIO; 332 } 333 if (de->inode) { 334 unsigned char d_type = DT_UNKNOWN; 335 336 if (types && de->file_type < EXT2_FT_MAX) 337 d_type = types[de->file_type]; 338 339 if (!dir_emit(ctx, de->name, de->name_len, 340 le32_to_cpu(de->inode), 341 d_type)) { 342 ext2_put_page(page); 343 return 0; 344 } 345 } 346 ctx->pos += ext2_rec_len_from_disk(de->rec_len); 347 } 348 ext2_put_page(page); 349 } 350 return 0; 351 } 352 353 /* 354 * ext2_find_entry() 355 * 356 * finds an entry in the specified directory with the wanted name. It 357 * returns the page in which the entry was found (as a parameter - res_page), 358 * and the entry itself. Page is returned mapped and unlocked. 359 * Entry is guaranteed to be valid. 360 */ 361 struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir, 362 const struct qstr *child, struct page **res_page) 363 { 364 const char *name = child->name; 365 int namelen = child->len; 366 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 367 unsigned long start, n; 368 unsigned long npages = dir_pages(dir); 369 struct page *page = NULL; 370 struct ext2_inode_info *ei = EXT2_I(dir); 371 ext2_dirent * de; 372 int dir_has_error = 0; 373 374 if (npages == 0) 375 goto out; 376 377 /* OFFSET_CACHE */ 378 *res_page = NULL; 379 380 start = ei->i_dir_start_lookup; 381 if (start >= npages) 382 start = 0; 383 n = start; 384 do { 385 char *kaddr; 386 page = ext2_get_page(dir, n, dir_has_error); 387 if (!IS_ERR(page)) { 388 kaddr = page_address(page); 389 de = (ext2_dirent *) kaddr; 390 kaddr += ext2_last_byte(dir, n) - reclen; 391 while ((char *) de <= kaddr) { 392 if (de->rec_len == 0) { 393 ext2_error(dir->i_sb, __func__, 394 "zero-length directory entry"); 395 ext2_put_page(page); 396 goto out; 397 } 398 if (ext2_match (namelen, name, de)) 399 goto found; 400 de = ext2_next_entry(de); 401 } 402 ext2_put_page(page); 403 } else 404 dir_has_error = 1; 405 406 if (++n >= npages) 407 n = 0; 408 /* next page is past the blocks we've got */ 409 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) { 410 ext2_error(dir->i_sb, __func__, 411 "dir %lu size %lld exceeds block count %llu", 412 dir->i_ino, dir->i_size, 413 (unsigned long long)dir->i_blocks); 414 goto out; 415 } 416 } while (n != start); 417 out: 418 return NULL; 419 420 found: 421 *res_page = page; 422 ei->i_dir_start_lookup = n; 423 return de; 424 } 425 426 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) 427 { 428 struct page *page = ext2_get_page(dir, 0, 0); 429 ext2_dirent *de = NULL; 430 431 if (!IS_ERR(page)) { 432 de = ext2_next_entry((ext2_dirent *) page_address(page)); 433 *p = page; 434 } 435 return de; 436 } 437 438 ino_t ext2_inode_by_name(struct inode *dir, const struct qstr *child) 439 { 440 ino_t res = 0; 441 struct ext2_dir_entry_2 *de; 442 struct page *page; 443 444 de = ext2_find_entry (dir, child, &page); 445 if (de) { 446 res = le32_to_cpu(de->inode); 447 ext2_put_page(page); 448 } 449 return res; 450 } 451 452 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len) 453 { 454 return __block_write_begin(page, pos, len, ext2_get_block); 455 } 456 457 /* Releases the page */ 458 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, 459 struct page *page, struct inode *inode, int update_times) 460 { 461 loff_t pos = page_offset(page) + 462 (char *) de - (char *) page_address(page); 463 unsigned len = ext2_rec_len_from_disk(de->rec_len); 464 int err; 465 466 lock_page(page); 467 err = ext2_prepare_chunk(page, pos, len); 468 BUG_ON(err); 469 de->inode = cpu_to_le32(inode->i_ino); 470 ext2_set_de_type(de, inode); 471 err = ext2_commit_chunk(page, pos, len); 472 ext2_put_page(page); 473 if (update_times) 474 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 475 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 476 mark_inode_dirty(dir); 477 } 478 479 /* 480 * Parent is locked. 481 */ 482 int ext2_add_link (struct dentry *dentry, struct inode *inode) 483 { 484 struct inode *dir = d_inode(dentry->d_parent); 485 const char *name = dentry->d_name.name; 486 int namelen = dentry->d_name.len; 487 unsigned chunk_size = ext2_chunk_size(dir); 488 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 489 unsigned short rec_len, name_len; 490 struct page *page = NULL; 491 ext2_dirent * de; 492 unsigned long npages = dir_pages(dir); 493 unsigned long n; 494 char *kaddr; 495 loff_t pos; 496 int err; 497 498 /* 499 * We take care of directory expansion in the same loop. 500 * This code plays outside i_size, so it locks the page 501 * to protect that region. 502 */ 503 for (n = 0; n <= npages; n++) { 504 char *dir_end; 505 506 page = ext2_get_page(dir, n, 0); 507 err = PTR_ERR(page); 508 if (IS_ERR(page)) 509 goto out; 510 lock_page(page); 511 kaddr = page_address(page); 512 dir_end = kaddr + ext2_last_byte(dir, n); 513 de = (ext2_dirent *)kaddr; 514 kaddr += PAGE_SIZE - reclen; 515 while ((char *)de <= kaddr) { 516 if ((char *)de == dir_end) { 517 /* We hit i_size */ 518 name_len = 0; 519 rec_len = chunk_size; 520 de->rec_len = ext2_rec_len_to_disk(chunk_size); 521 de->inode = 0; 522 goto got_it; 523 } 524 if (de->rec_len == 0) { 525 ext2_error(dir->i_sb, __func__, 526 "zero-length directory entry"); 527 err = -EIO; 528 goto out_unlock; 529 } 530 err = -EEXIST; 531 if (ext2_match (namelen, name, de)) 532 goto out_unlock; 533 name_len = EXT2_DIR_REC_LEN(de->name_len); 534 rec_len = ext2_rec_len_from_disk(de->rec_len); 535 if (!de->inode && rec_len >= reclen) 536 goto got_it; 537 if (rec_len >= name_len + reclen) 538 goto got_it; 539 de = (ext2_dirent *) ((char *) de + rec_len); 540 } 541 unlock_page(page); 542 ext2_put_page(page); 543 } 544 BUG(); 545 return -EINVAL; 546 547 got_it: 548 pos = page_offset(page) + 549 (char*)de - (char*)page_address(page); 550 err = ext2_prepare_chunk(page, pos, rec_len); 551 if (err) 552 goto out_unlock; 553 if (de->inode) { 554 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); 555 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); 556 de->rec_len = ext2_rec_len_to_disk(name_len); 557 de = de1; 558 } 559 de->name_len = namelen; 560 memcpy(de->name, name, namelen); 561 de->inode = cpu_to_le32(inode->i_ino); 562 ext2_set_de_type (de, inode); 563 err = ext2_commit_chunk(page, pos, rec_len); 564 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 565 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 566 mark_inode_dirty(dir); 567 /* OFFSET_CACHE */ 568 out_put: 569 ext2_put_page(page); 570 out: 571 return err; 572 out_unlock: 573 unlock_page(page); 574 goto out_put; 575 } 576 577 /* 578 * ext2_delete_entry deletes a directory entry by merging it with the 579 * previous entry. Page is up-to-date. Releases the page. 580 */ 581 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) 582 { 583 struct inode *inode = page->mapping->host; 584 char *kaddr = page_address(page); 585 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); 586 unsigned to = ((char *)dir - kaddr) + 587 ext2_rec_len_from_disk(dir->rec_len); 588 loff_t pos; 589 ext2_dirent * pde = NULL; 590 ext2_dirent * de = (ext2_dirent *) (kaddr + from); 591 int err; 592 593 while ((char*)de < (char*)dir) { 594 if (de->rec_len == 0) { 595 ext2_error(inode->i_sb, __func__, 596 "zero-length directory entry"); 597 err = -EIO; 598 goto out; 599 } 600 pde = de; 601 de = ext2_next_entry(de); 602 } 603 if (pde) 604 from = (char*)pde - (char*)page_address(page); 605 pos = page_offset(page) + from; 606 lock_page(page); 607 err = ext2_prepare_chunk(page, pos, to - from); 608 BUG_ON(err); 609 if (pde) 610 pde->rec_len = ext2_rec_len_to_disk(to - from); 611 dir->inode = 0; 612 err = ext2_commit_chunk(page, pos, to - from); 613 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 614 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; 615 mark_inode_dirty(inode); 616 out: 617 ext2_put_page(page); 618 return err; 619 } 620 621 /* 622 * Set the first fragment of directory. 623 */ 624 int ext2_make_empty(struct inode *inode, struct inode *parent) 625 { 626 struct page *page = grab_cache_page(inode->i_mapping, 0); 627 unsigned chunk_size = ext2_chunk_size(inode); 628 struct ext2_dir_entry_2 * de; 629 int err; 630 void *kaddr; 631 632 if (!page) 633 return -ENOMEM; 634 635 err = ext2_prepare_chunk(page, 0, chunk_size); 636 if (err) { 637 unlock_page(page); 638 goto fail; 639 } 640 kaddr = kmap_atomic(page); 641 memset(kaddr, 0, chunk_size); 642 de = (struct ext2_dir_entry_2 *)kaddr; 643 de->name_len = 1; 644 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1)); 645 memcpy (de->name, ".\0\0", 4); 646 de->inode = cpu_to_le32(inode->i_ino); 647 ext2_set_de_type (de, inode); 648 649 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); 650 de->name_len = 2; 651 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1)); 652 de->inode = cpu_to_le32(parent->i_ino); 653 memcpy (de->name, "..\0", 4); 654 ext2_set_de_type (de, inode); 655 kunmap_atomic(kaddr); 656 err = ext2_commit_chunk(page, 0, chunk_size); 657 fail: 658 put_page(page); 659 return err; 660 } 661 662 /* 663 * routine to check that the specified directory is empty (for rmdir) 664 */ 665 int ext2_empty_dir (struct inode * inode) 666 { 667 struct page *page = NULL; 668 unsigned long i, npages = dir_pages(inode); 669 int dir_has_error = 0; 670 671 for (i = 0; i < npages; i++) { 672 char *kaddr; 673 ext2_dirent * de; 674 page = ext2_get_page(inode, i, dir_has_error); 675 676 if (IS_ERR(page)) { 677 dir_has_error = 1; 678 continue; 679 } 680 681 kaddr = page_address(page); 682 de = (ext2_dirent *)kaddr; 683 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); 684 685 while ((char *)de <= kaddr) { 686 if (de->rec_len == 0) { 687 ext2_error(inode->i_sb, __func__, 688 "zero-length directory entry"); 689 printk("kaddr=%p, de=%p\n", kaddr, de); 690 goto not_empty; 691 } 692 if (de->inode != 0) { 693 /* check for . and .. */ 694 if (de->name[0] != '.') 695 goto not_empty; 696 if (de->name_len > 2) 697 goto not_empty; 698 if (de->name_len < 2) { 699 if (de->inode != 700 cpu_to_le32(inode->i_ino)) 701 goto not_empty; 702 } else if (de->name[1] != '.') 703 goto not_empty; 704 } 705 de = ext2_next_entry(de); 706 } 707 ext2_put_page(page); 708 } 709 return 1; 710 711 not_empty: 712 ext2_put_page(page); 713 return 0; 714 } 715 716 const struct file_operations ext2_dir_operations = { 717 .llseek = generic_file_llseek, 718 .read = generic_read_dir, 719 .iterate_shared = ext2_readdir, 720 .unlocked_ioctl = ext2_ioctl, 721 #ifdef CONFIG_COMPAT 722 .compat_ioctl = ext2_compat_ioctl, 723 #endif 724 .fsync = ext2_fsync, 725 }; 726