1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext2/dir.c 4 * 5 * Copyright (C) 1992, 1993, 1994, 1995 6 * Remy Card (card@masi.ibp.fr) 7 * Laboratoire MASI - Institut Blaise Pascal 8 * Universite Pierre et Marie Curie (Paris VI) 9 * 10 * from 11 * 12 * linux/fs/minix/dir.c 13 * 14 * Copyright (C) 1991, 1992 Linus Torvalds 15 * 16 * ext2 directory handling functions 17 * 18 * Big-endian to little-endian byte-swapping/bitmaps by 19 * David S. Miller (davem@caip.rutgers.edu), 1995 20 * 21 * All code that works with directory layout had been switched to pagecache 22 * and moved here. AV 23 */ 24 25 #include "ext2.h" 26 #include <linux/buffer_head.h> 27 #include <linux/pagemap.h> 28 #include <linux/swap.h> 29 #include <linux/iversion.h> 30 31 typedef struct ext2_dir_entry_2 ext2_dirent; 32 33 /* 34 * Tests against MAX_REC_LEN etc were put in place for 64k block 35 * sizes; if that is not possible on this arch, we can skip 36 * those tests and speed things up. 37 */ 38 static inline unsigned ext2_rec_len_from_disk(__le16 dlen) 39 { 40 unsigned len = le16_to_cpu(dlen); 41 42 #if (PAGE_SIZE >= 65536) 43 if (len == EXT2_MAX_REC_LEN) 44 return 1 << 16; 45 #endif 46 return len; 47 } 48 49 static inline __le16 ext2_rec_len_to_disk(unsigned len) 50 { 51 #if (PAGE_SIZE >= 65536) 52 if (len == (1 << 16)) 53 return cpu_to_le16(EXT2_MAX_REC_LEN); 54 else 55 BUG_ON(len > (1 << 16)); 56 #endif 57 return cpu_to_le16(len); 58 } 59 60 /* 61 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be 62 * more robust, but we have what we have 63 */ 64 static inline unsigned ext2_chunk_size(struct inode *inode) 65 { 66 return inode->i_sb->s_blocksize; 67 } 68 69 static inline void ext2_put_page(struct page *page) 70 { 71 kunmap(page); 72 put_page(page); 73 } 74 75 /* 76 * Return the offset into page `page_nr' of the last valid 77 * byte in that page, plus one. 78 */ 79 static unsigned 80 ext2_last_byte(struct inode *inode, unsigned long page_nr) 81 { 82 unsigned last_byte = inode->i_size; 83 84 last_byte -= page_nr << PAGE_SHIFT; 85 if (last_byte > PAGE_SIZE) 86 last_byte = PAGE_SIZE; 87 return last_byte; 88 } 89 90 static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) 91 { 92 struct address_space *mapping = page->mapping; 93 struct inode *dir = mapping->host; 94 int err = 0; 95 96 inode_inc_iversion(dir); 97 block_write_end(NULL, mapping, pos, len, len, page, NULL); 98 99 if (pos+len > dir->i_size) { 100 i_size_write(dir, pos+len); 101 mark_inode_dirty(dir); 102 } 103 104 if (IS_DIRSYNC(dir)) { 105 err = write_one_page(page); 106 if (!err) 107 err = sync_inode_metadata(dir, 1); 108 } else { 109 unlock_page(page); 110 } 111 112 return err; 113 } 114 115 static bool ext2_check_page(struct page *page, int quiet) 116 { 117 struct inode *dir = page->mapping->host; 118 struct super_block *sb = dir->i_sb; 119 unsigned chunk_size = ext2_chunk_size(dir); 120 char *kaddr = page_address(page); 121 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); 122 unsigned offs, rec_len; 123 unsigned limit = PAGE_SIZE; 124 ext2_dirent *p; 125 char *error; 126 127 if ((dir->i_size >> PAGE_SHIFT) == page->index) { 128 limit = dir->i_size & ~PAGE_MASK; 129 if (limit & (chunk_size - 1)) 130 goto Ebadsize; 131 if (!limit) 132 goto out; 133 } 134 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { 135 p = (ext2_dirent *)(kaddr + offs); 136 rec_len = ext2_rec_len_from_disk(p->rec_len); 137 138 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1))) 139 goto Eshort; 140 if (unlikely(rec_len & 3)) 141 goto Ealign; 142 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len))) 143 goto Enamelen; 144 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))) 145 goto Espan; 146 if (unlikely(le32_to_cpu(p->inode) > max_inumber)) 147 goto Einumber; 148 } 149 if (offs != limit) 150 goto Eend; 151 out: 152 SetPageChecked(page); 153 return true; 154 155 /* Too bad, we had an error */ 156 157 Ebadsize: 158 if (!quiet) 159 ext2_error(sb, __func__, 160 "size of directory #%lu is not a multiple " 161 "of chunk size", dir->i_ino); 162 goto fail; 163 Eshort: 164 error = "rec_len is smaller than minimal"; 165 goto bad_entry; 166 Ealign: 167 error = "unaligned directory entry"; 168 goto bad_entry; 169 Enamelen: 170 error = "rec_len is too small for name_len"; 171 goto bad_entry; 172 Espan: 173 error = "directory entry across blocks"; 174 goto bad_entry; 175 Einumber: 176 error = "inode out of bounds"; 177 bad_entry: 178 if (!quiet) 179 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - " 180 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", 181 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs, 182 (unsigned long) le32_to_cpu(p->inode), 183 rec_len, p->name_len); 184 goto fail; 185 Eend: 186 if (!quiet) { 187 p = (ext2_dirent *)(kaddr + offs); 188 ext2_error(sb, "ext2_check_page", 189 "entry in directory #%lu spans the page boundary" 190 "offset=%lu, inode=%lu", 191 dir->i_ino, (page->index<<PAGE_SHIFT)+offs, 192 (unsigned long) le32_to_cpu(p->inode)); 193 } 194 fail: 195 SetPageError(page); 196 return false; 197 } 198 199 static struct page * ext2_get_page(struct inode *dir, unsigned long n, 200 int quiet) 201 { 202 struct address_space *mapping = dir->i_mapping; 203 struct page *page = read_mapping_page(mapping, n, NULL); 204 if (!IS_ERR(page)) { 205 kmap(page); 206 if (unlikely(!PageChecked(page))) { 207 if (PageError(page) || !ext2_check_page(page, quiet)) 208 goto fail; 209 } 210 } 211 return page; 212 213 fail: 214 ext2_put_page(page); 215 return ERR_PTR(-EIO); 216 } 217 218 /* 219 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. 220 * 221 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. 222 */ 223 static inline int ext2_match (int len, const char * const name, 224 struct ext2_dir_entry_2 * de) 225 { 226 if (len != de->name_len) 227 return 0; 228 if (!de->inode) 229 return 0; 230 return !memcmp(name, de->name, len); 231 } 232 233 /* 234 * p is at least 6 bytes before the end of page 235 */ 236 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) 237 { 238 return (ext2_dirent *)((char *)p + 239 ext2_rec_len_from_disk(p->rec_len)); 240 } 241 242 static inline unsigned 243 ext2_validate_entry(char *base, unsigned offset, unsigned mask) 244 { 245 ext2_dirent *de = (ext2_dirent*)(base + offset); 246 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); 247 while ((char*)p < (char*)de) { 248 if (p->rec_len == 0) 249 break; 250 p = ext2_next_entry(p); 251 } 252 return (char *)p - base; 253 } 254 255 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { 256 [EXT2_FT_UNKNOWN] = DT_UNKNOWN, 257 [EXT2_FT_REG_FILE] = DT_REG, 258 [EXT2_FT_DIR] = DT_DIR, 259 [EXT2_FT_CHRDEV] = DT_CHR, 260 [EXT2_FT_BLKDEV] = DT_BLK, 261 [EXT2_FT_FIFO] = DT_FIFO, 262 [EXT2_FT_SOCK] = DT_SOCK, 263 [EXT2_FT_SYMLINK] = DT_LNK, 264 }; 265 266 #define S_SHIFT 12 267 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { 268 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, 269 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, 270 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, 271 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, 272 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, 273 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, 274 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, 275 }; 276 277 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) 278 { 279 umode_t mode = inode->i_mode; 280 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 281 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; 282 else 283 de->file_type = 0; 284 } 285 286 static int 287 ext2_readdir(struct file *file, struct dir_context *ctx) 288 { 289 loff_t pos = ctx->pos; 290 struct inode *inode = file_inode(file); 291 struct super_block *sb = inode->i_sb; 292 unsigned int offset = pos & ~PAGE_MASK; 293 unsigned long n = pos >> PAGE_SHIFT; 294 unsigned long npages = dir_pages(inode); 295 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); 296 unsigned char *types = NULL; 297 bool need_revalidate = !inode_eq_iversion(inode, file->f_version); 298 299 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) 300 return 0; 301 302 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 303 types = ext2_filetype_table; 304 305 for ( ; n < npages; n++, offset = 0) { 306 char *kaddr, *limit; 307 ext2_dirent *de; 308 struct page *page = ext2_get_page(inode, n, 0); 309 310 if (IS_ERR(page)) { 311 ext2_error(sb, __func__, 312 "bad page in #%lu", 313 inode->i_ino); 314 ctx->pos += PAGE_SIZE - offset; 315 return PTR_ERR(page); 316 } 317 kaddr = page_address(page); 318 if (unlikely(need_revalidate)) { 319 if (offset) { 320 offset = ext2_validate_entry(kaddr, offset, chunk_mask); 321 ctx->pos = (n<<PAGE_SHIFT) + offset; 322 } 323 file->f_version = inode_query_iversion(inode); 324 need_revalidate = false; 325 } 326 de = (ext2_dirent *)(kaddr+offset); 327 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); 328 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { 329 if (de->rec_len == 0) { 330 ext2_error(sb, __func__, 331 "zero-length directory entry"); 332 ext2_put_page(page); 333 return -EIO; 334 } 335 if (de->inode) { 336 unsigned char d_type = DT_UNKNOWN; 337 338 if (types && de->file_type < EXT2_FT_MAX) 339 d_type = types[de->file_type]; 340 341 if (!dir_emit(ctx, de->name, de->name_len, 342 le32_to_cpu(de->inode), 343 d_type)) { 344 ext2_put_page(page); 345 return 0; 346 } 347 } 348 ctx->pos += ext2_rec_len_from_disk(de->rec_len); 349 } 350 ext2_put_page(page); 351 } 352 return 0; 353 } 354 355 /* 356 * ext2_find_entry() 357 * 358 * finds an entry in the specified directory with the wanted name. It 359 * returns the page in which the entry was found (as a parameter - res_page), 360 * and the entry itself. Page is returned mapped and unlocked. 361 * Entry is guaranteed to be valid. 362 */ 363 struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir, 364 const struct qstr *child, struct page **res_page) 365 { 366 const char *name = child->name; 367 int namelen = child->len; 368 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 369 unsigned long start, n; 370 unsigned long npages = dir_pages(dir); 371 struct page *page = NULL; 372 struct ext2_inode_info *ei = EXT2_I(dir); 373 ext2_dirent * de; 374 int dir_has_error = 0; 375 376 if (npages == 0) 377 goto out; 378 379 /* OFFSET_CACHE */ 380 *res_page = NULL; 381 382 start = ei->i_dir_start_lookup; 383 if (start >= npages) 384 start = 0; 385 n = start; 386 do { 387 char *kaddr; 388 page = ext2_get_page(dir, n, dir_has_error); 389 if (!IS_ERR(page)) { 390 kaddr = page_address(page); 391 de = (ext2_dirent *) kaddr; 392 kaddr += ext2_last_byte(dir, n) - reclen; 393 while ((char *) de <= kaddr) { 394 if (de->rec_len == 0) { 395 ext2_error(dir->i_sb, __func__, 396 "zero-length directory entry"); 397 ext2_put_page(page); 398 goto out; 399 } 400 if (ext2_match (namelen, name, de)) 401 goto found; 402 de = ext2_next_entry(de); 403 } 404 ext2_put_page(page); 405 } else 406 dir_has_error = 1; 407 408 if (++n >= npages) 409 n = 0; 410 /* next page is past the blocks we've got */ 411 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) { 412 ext2_error(dir->i_sb, __func__, 413 "dir %lu size %lld exceeds block count %llu", 414 dir->i_ino, dir->i_size, 415 (unsigned long long)dir->i_blocks); 416 goto out; 417 } 418 } while (n != start); 419 out: 420 return NULL; 421 422 found: 423 *res_page = page; 424 ei->i_dir_start_lookup = n; 425 return de; 426 } 427 428 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) 429 { 430 struct page *page = ext2_get_page(dir, 0, 0); 431 ext2_dirent *de = NULL; 432 433 if (!IS_ERR(page)) { 434 de = ext2_next_entry((ext2_dirent *) page_address(page)); 435 *p = page; 436 } 437 return de; 438 } 439 440 ino_t ext2_inode_by_name(struct inode *dir, const struct qstr *child) 441 { 442 ino_t res = 0; 443 struct ext2_dir_entry_2 *de; 444 struct page *page; 445 446 de = ext2_find_entry (dir, child, &page); 447 if (de) { 448 res = le32_to_cpu(de->inode); 449 ext2_put_page(page); 450 } 451 return res; 452 } 453 454 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len) 455 { 456 return __block_write_begin(page, pos, len, ext2_get_block); 457 } 458 459 /* Releases the page */ 460 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, 461 struct page *page, struct inode *inode, int update_times) 462 { 463 loff_t pos = page_offset(page) + 464 (char *) de - (char *) page_address(page); 465 unsigned len = ext2_rec_len_from_disk(de->rec_len); 466 int err; 467 468 lock_page(page); 469 err = ext2_prepare_chunk(page, pos, len); 470 BUG_ON(err); 471 de->inode = cpu_to_le32(inode->i_ino); 472 ext2_set_de_type(de, inode); 473 err = ext2_commit_chunk(page, pos, len); 474 ext2_put_page(page); 475 if (update_times) 476 dir->i_mtime = dir->i_ctime = current_time(dir); 477 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 478 mark_inode_dirty(dir); 479 } 480 481 /* 482 * Parent is locked. 483 */ 484 int ext2_add_link (struct dentry *dentry, struct inode *inode) 485 { 486 struct inode *dir = d_inode(dentry->d_parent); 487 const char *name = dentry->d_name.name; 488 int namelen = dentry->d_name.len; 489 unsigned chunk_size = ext2_chunk_size(dir); 490 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 491 unsigned short rec_len, name_len; 492 struct page *page = NULL; 493 ext2_dirent * de; 494 unsigned long npages = dir_pages(dir); 495 unsigned long n; 496 char *kaddr; 497 loff_t pos; 498 int err; 499 500 /* 501 * We take care of directory expansion in the same loop. 502 * This code plays outside i_size, so it locks the page 503 * to protect that region. 504 */ 505 for (n = 0; n <= npages; n++) { 506 char *dir_end; 507 508 page = ext2_get_page(dir, n, 0); 509 err = PTR_ERR(page); 510 if (IS_ERR(page)) 511 goto out; 512 lock_page(page); 513 kaddr = page_address(page); 514 dir_end = kaddr + ext2_last_byte(dir, n); 515 de = (ext2_dirent *)kaddr; 516 kaddr += PAGE_SIZE - reclen; 517 while ((char *)de <= kaddr) { 518 if ((char *)de == dir_end) { 519 /* We hit i_size */ 520 name_len = 0; 521 rec_len = chunk_size; 522 de->rec_len = ext2_rec_len_to_disk(chunk_size); 523 de->inode = 0; 524 goto got_it; 525 } 526 if (de->rec_len == 0) { 527 ext2_error(dir->i_sb, __func__, 528 "zero-length directory entry"); 529 err = -EIO; 530 goto out_unlock; 531 } 532 err = -EEXIST; 533 if (ext2_match (namelen, name, de)) 534 goto out_unlock; 535 name_len = EXT2_DIR_REC_LEN(de->name_len); 536 rec_len = ext2_rec_len_from_disk(de->rec_len); 537 if (!de->inode && rec_len >= reclen) 538 goto got_it; 539 if (rec_len >= name_len + reclen) 540 goto got_it; 541 de = (ext2_dirent *) ((char *) de + rec_len); 542 } 543 unlock_page(page); 544 ext2_put_page(page); 545 } 546 BUG(); 547 return -EINVAL; 548 549 got_it: 550 pos = page_offset(page) + 551 (char*)de - (char*)page_address(page); 552 err = ext2_prepare_chunk(page, pos, rec_len); 553 if (err) 554 goto out_unlock; 555 if (de->inode) { 556 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); 557 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); 558 de->rec_len = ext2_rec_len_to_disk(name_len); 559 de = de1; 560 } 561 de->name_len = namelen; 562 memcpy(de->name, name, namelen); 563 de->inode = cpu_to_le32(inode->i_ino); 564 ext2_set_de_type (de, inode); 565 err = ext2_commit_chunk(page, pos, rec_len); 566 dir->i_mtime = dir->i_ctime = current_time(dir); 567 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 568 mark_inode_dirty(dir); 569 /* OFFSET_CACHE */ 570 out_put: 571 ext2_put_page(page); 572 out: 573 return err; 574 out_unlock: 575 unlock_page(page); 576 goto out_put; 577 } 578 579 /* 580 * ext2_delete_entry deletes a directory entry by merging it with the 581 * previous entry. Page is up-to-date. Releases the page. 582 */ 583 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) 584 { 585 struct inode *inode = page->mapping->host; 586 char *kaddr = page_address(page); 587 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); 588 unsigned to = ((char *)dir - kaddr) + 589 ext2_rec_len_from_disk(dir->rec_len); 590 loff_t pos; 591 ext2_dirent * pde = NULL; 592 ext2_dirent * de = (ext2_dirent *) (kaddr + from); 593 int err; 594 595 while ((char*)de < (char*)dir) { 596 if (de->rec_len == 0) { 597 ext2_error(inode->i_sb, __func__, 598 "zero-length directory entry"); 599 err = -EIO; 600 goto out; 601 } 602 pde = de; 603 de = ext2_next_entry(de); 604 } 605 if (pde) 606 from = (char*)pde - (char*)page_address(page); 607 pos = page_offset(page) + from; 608 lock_page(page); 609 err = ext2_prepare_chunk(page, pos, to - from); 610 BUG_ON(err); 611 if (pde) 612 pde->rec_len = ext2_rec_len_to_disk(to - from); 613 dir->inode = 0; 614 err = ext2_commit_chunk(page, pos, to - from); 615 inode->i_ctime = inode->i_mtime = current_time(inode); 616 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; 617 mark_inode_dirty(inode); 618 out: 619 ext2_put_page(page); 620 return err; 621 } 622 623 /* 624 * Set the first fragment of directory. 625 */ 626 int ext2_make_empty(struct inode *inode, struct inode *parent) 627 { 628 struct page *page = grab_cache_page(inode->i_mapping, 0); 629 unsigned chunk_size = ext2_chunk_size(inode); 630 struct ext2_dir_entry_2 * de; 631 int err; 632 void *kaddr; 633 634 if (!page) 635 return -ENOMEM; 636 637 err = ext2_prepare_chunk(page, 0, chunk_size); 638 if (err) { 639 unlock_page(page); 640 goto fail; 641 } 642 kaddr = kmap_atomic(page); 643 memset(kaddr, 0, chunk_size); 644 de = (struct ext2_dir_entry_2 *)kaddr; 645 de->name_len = 1; 646 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1)); 647 memcpy (de->name, ".\0\0", 4); 648 de->inode = cpu_to_le32(inode->i_ino); 649 ext2_set_de_type (de, inode); 650 651 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); 652 de->name_len = 2; 653 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1)); 654 de->inode = cpu_to_le32(parent->i_ino); 655 memcpy (de->name, "..\0", 4); 656 ext2_set_de_type (de, inode); 657 kunmap_atomic(kaddr); 658 err = ext2_commit_chunk(page, 0, chunk_size); 659 fail: 660 put_page(page); 661 return err; 662 } 663 664 /* 665 * routine to check that the specified directory is empty (for rmdir) 666 */ 667 int ext2_empty_dir (struct inode * inode) 668 { 669 struct page *page = NULL; 670 unsigned long i, npages = dir_pages(inode); 671 int dir_has_error = 0; 672 673 for (i = 0; i < npages; i++) { 674 char *kaddr; 675 ext2_dirent * de; 676 page = ext2_get_page(inode, i, dir_has_error); 677 678 if (IS_ERR(page)) { 679 dir_has_error = 1; 680 continue; 681 } 682 683 kaddr = page_address(page); 684 de = (ext2_dirent *)kaddr; 685 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); 686 687 while ((char *)de <= kaddr) { 688 if (de->rec_len == 0) { 689 ext2_error(inode->i_sb, __func__, 690 "zero-length directory entry"); 691 printk("kaddr=%p, de=%p\n", kaddr, de); 692 goto not_empty; 693 } 694 if (de->inode != 0) { 695 /* check for . and .. */ 696 if (de->name[0] != '.') 697 goto not_empty; 698 if (de->name_len > 2) 699 goto not_empty; 700 if (de->name_len < 2) { 701 if (de->inode != 702 cpu_to_le32(inode->i_ino)) 703 goto not_empty; 704 } else if (de->name[1] != '.') 705 goto not_empty; 706 } 707 de = ext2_next_entry(de); 708 } 709 ext2_put_page(page); 710 } 711 return 1; 712 713 not_empty: 714 ext2_put_page(page); 715 return 0; 716 } 717 718 const struct file_operations ext2_dir_operations = { 719 .llseek = generic_file_llseek, 720 .read = generic_read_dir, 721 .iterate_shared = ext2_readdir, 722 .unlocked_ioctl = ext2_ioctl, 723 #ifdef CONFIG_COMPAT 724 .compat_ioctl = ext2_compat_ioctl, 725 #endif 726 .fsync = ext2_fsync, 727 }; 728