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 29typedef 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 */ 36static inline unsigned ext2_rec_len_from_disk(__le16 dlen) 37{ 38 unsigned len = le16_to_cpu(dlen); 39 40#if (PAGE_CACHE_SIZE >= 65536) 41 if (len == EXT2_MAX_REC_LEN) 42 return 1 << 16; 43#endif 44 return len; 45} 46 47static inline __le16 ext2_rec_len_to_disk(unsigned len) 48{ 49#if (PAGE_CACHE_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 */ 62static inline unsigned ext2_chunk_size(struct inode *inode) 63{ 64 return inode->i_sb->s_blocksize; 65} 66 67static inline void ext2_put_page(struct page *page) 68{ 69 kunmap(page); 70 page_cache_release(page); 71} 72 73static inline unsigned long dir_pages(struct inode *inode) 74{ 75 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; 76} 77 78/* 79 * Return the offset into page `page_nr' of the last valid 80 * byte in that page, plus one. 81 */ 82static unsigned 83ext2_last_byte(struct inode *inode, unsigned long page_nr) 84{ 85 unsigned last_byte = inode->i_size; 86 87 last_byte -= page_nr << PAGE_CACHE_SHIFT; 88 if (last_byte > PAGE_CACHE_SIZE) 89 last_byte = PAGE_CACHE_SIZE; 90 return last_byte; 91} 92 93static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) 94{ 95 struct address_space *mapping = page->mapping; 96 struct inode *dir = mapping->host; 97 int err = 0; 98 99 dir->i_version++; 100 block_write_end(NULL, mapping, pos, len, len, page, NULL); 101 102 if (pos+len > dir->i_size) { 103 i_size_write(dir, pos+len); 104 mark_inode_dirty(dir); 105 } 106 107 if (IS_DIRSYNC(dir)) { 108 err = write_one_page(page, 1); 109 if (!err) 110 err = sync_inode_metadata(dir, 1); 111 } else { 112 unlock_page(page); 113 } 114 115 return err; 116} 117 118static void ext2_check_page(struct page *page, int quiet) 119{ 120 struct inode *dir = page->mapping->host; 121 struct super_block *sb = dir->i_sb; 122 unsigned chunk_size = ext2_chunk_size(dir); 123 char *kaddr = page_address(page); 124 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); 125 unsigned offs, rec_len; 126 unsigned limit = PAGE_CACHE_SIZE; 127 ext2_dirent *p; 128 char *error; 129 130 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { 131 limit = dir->i_size & ~PAGE_CACHE_MASK; 132 if (limit & (chunk_size - 1)) 133 goto Ebadsize; 134 if (!limit) 135 goto out; 136 } 137 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { 138 p = (ext2_dirent *)(kaddr + offs); 139 rec_len = ext2_rec_len_from_disk(p->rec_len); 140 141 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1))) 142 goto Eshort; 143 if (unlikely(rec_len & 3)) 144 goto Ealign; 145 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len))) 146 goto Enamelen; 147 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))) 148 goto Espan; 149 if (unlikely(le32_to_cpu(p->inode) > max_inumber)) 150 goto Einumber; 151 } 152 if (offs != limit) 153 goto Eend; 154out: 155 SetPageChecked(page); 156 return; 157 158 /* Too bad, we had an error */ 159 160Ebadsize: 161 if (!quiet) 162 ext2_error(sb, __func__, 163 "size of directory #%lu is not a multiple " 164 "of chunk size", dir->i_ino); 165 goto fail; 166Eshort: 167 error = "rec_len is smaller than minimal"; 168 goto bad_entry; 169Ealign: 170 error = "unaligned directory entry"; 171 goto bad_entry; 172Enamelen: 173 error = "rec_len is too small for name_len"; 174 goto bad_entry; 175Espan: 176 error = "directory entry across blocks"; 177 goto bad_entry; 178Einumber: 179 error = "inode out of bounds"; 180bad_entry: 181 if (!quiet) 182 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - " 183 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", 184 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, 185 (unsigned long) le32_to_cpu(p->inode), 186 rec_len, p->name_len); 187 goto fail; 188Eend: 189 if (!quiet) { 190 p = (ext2_dirent *)(kaddr + offs); 191 ext2_error(sb, "ext2_check_page", 192 "entry in directory #%lu spans the page boundary" 193 "offset=%lu, inode=%lu", 194 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, 195 (unsigned long) le32_to_cpu(p->inode)); 196 } 197fail: 198 SetPageChecked(page); 199 SetPageError(page); 200} 201 202static struct page * ext2_get_page(struct inode *dir, unsigned long n, 203 int quiet) 204{ 205 struct address_space *mapping = dir->i_mapping; 206 struct page *page = read_mapping_page(mapping, n, NULL); 207 if (!IS_ERR(page)) { 208 kmap(page); 209 if (!PageChecked(page)) 210 ext2_check_page(page, quiet); 211 if (PageError(page)) 212 goto fail; 213 } 214 return page; 215 216fail: 217 ext2_put_page(page); 218 return ERR_PTR(-EIO); 219} 220 221/* 222 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. 223 * 224 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. 225 */ 226static inline int ext2_match (int len, const char * const name, 227 struct ext2_dir_entry_2 * de) 228{ 229 if (len != de->name_len) 230 return 0; 231 if (!de->inode) 232 return 0; 233 return !memcmp(name, de->name, len); 234} 235 236/* 237 * p is at least 6 bytes before the end of page 238 */ 239static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) 240{ 241 return (ext2_dirent *)((char *)p + 242 ext2_rec_len_from_disk(p->rec_len)); 243} 244 245static inline unsigned 246ext2_validate_entry(char *base, unsigned offset, unsigned mask) 247{ 248 ext2_dirent *de = (ext2_dirent*)(base + offset); 249 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); 250 while ((char*)p < (char*)de) { 251 if (p->rec_len == 0) 252 break; 253 p = ext2_next_entry(p); 254 } 255 return (char *)p - base; 256} 257 258static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { 259 [EXT2_FT_UNKNOWN] = DT_UNKNOWN, 260 [EXT2_FT_REG_FILE] = DT_REG, 261 [EXT2_FT_DIR] = DT_DIR, 262 [EXT2_FT_CHRDEV] = DT_CHR, 263 [EXT2_FT_BLKDEV] = DT_BLK, 264 [EXT2_FT_FIFO] = DT_FIFO, 265 [EXT2_FT_SOCK] = DT_SOCK, 266 [EXT2_FT_SYMLINK] = DT_LNK, 267}; 268 269#define S_SHIFT 12 270static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { 271 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, 272 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, 273 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, 274 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, 275 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, 276 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, 277 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, 278}; 279 280static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) 281{ 282 umode_t mode = inode->i_mode; 283 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 284 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; 285 else 286 de->file_type = 0; 287} 288 289static int 290ext2_readdir(struct file *file, struct dir_context *ctx) 291{ 292 loff_t pos = ctx->pos; 293 struct inode *inode = file_inode(file); 294 struct super_block *sb = inode->i_sb; 295 unsigned int offset = pos & ~PAGE_CACHE_MASK; 296 unsigned long n = pos >> PAGE_CACHE_SHIFT; 297 unsigned long npages = dir_pages(inode); 298 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); 299 unsigned char *types = NULL; 300 int need_revalidate = file->f_version != inode->i_version; 301 302 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) 303 return 0; 304 305 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) 306 types = ext2_filetype_table; 307 308 for ( ; n < npages; n++, offset = 0) { 309 char *kaddr, *limit; 310 ext2_dirent *de; 311 struct page *page = ext2_get_page(inode, n, 0); 312 313 if (IS_ERR(page)) { 314 ext2_error(sb, __func__, 315 "bad page in #%lu", 316 inode->i_ino); 317 ctx->pos += PAGE_CACHE_SIZE - offset; 318 return PTR_ERR(page); 319 } 320 kaddr = page_address(page); 321 if (unlikely(need_revalidate)) { 322 if (offset) { 323 offset = ext2_validate_entry(kaddr, offset, chunk_mask); 324 ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset; 325 } 326 file->f_version = inode->i_version; 327 need_revalidate = 0; 328 } 329 de = (ext2_dirent *)(kaddr+offset); 330 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); 331 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { 332 if (de->rec_len == 0) { 333 ext2_error(sb, __func__, 334 "zero-length directory entry"); 335 ext2_put_page(page); 336 return -EIO; 337 } 338 if (de->inode) { 339 unsigned char d_type = DT_UNKNOWN; 340 341 if (types && de->file_type < EXT2_FT_MAX) 342 d_type = types[de->file_type]; 343 344 if (!dir_emit(ctx, de->name, de->name_len, 345 le32_to_cpu(de->inode), 346 d_type)) { 347 ext2_put_page(page); 348 return 0; 349 } 350 } 351 ctx->pos += ext2_rec_len_from_disk(de->rec_len); 352 } 353 ext2_put_page(page); 354 } 355 return 0; 356} 357 358/* 359 * ext2_find_entry() 360 * 361 * finds an entry in the specified directory with the wanted name. It 362 * returns the page in which the entry was found (as a parameter - res_page), 363 * and the entry itself. Page is returned mapped and unlocked. 364 * Entry is guaranteed to be valid. 365 */ 366struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir, 367 struct qstr *child, struct page ** res_page) 368{ 369 const char *name = child->name; 370 int namelen = child->len; 371 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 372 unsigned long start, n; 373 unsigned long npages = dir_pages(dir); 374 struct page *page = NULL; 375 struct ext2_inode_info *ei = EXT2_I(dir); 376 ext2_dirent * de; 377 int dir_has_error = 0; 378 379 if (npages == 0) 380 goto out; 381 382 /* OFFSET_CACHE */ 383 *res_page = NULL; 384 385 start = ei->i_dir_start_lookup; 386 if (start >= npages) 387 start = 0; 388 n = start; 389 do { 390 char *kaddr; 391 page = ext2_get_page(dir, n, dir_has_error); 392 if (!IS_ERR(page)) { 393 kaddr = page_address(page); 394 de = (ext2_dirent *) kaddr; 395 kaddr += ext2_last_byte(dir, n) - reclen; 396 while ((char *) de <= kaddr) { 397 if (de->rec_len == 0) { 398 ext2_error(dir->i_sb, __func__, 399 "zero-length directory entry"); 400 ext2_put_page(page); 401 goto out; 402 } 403 if (ext2_match (namelen, name, de)) 404 goto found; 405 de = ext2_next_entry(de); 406 } 407 ext2_put_page(page); 408 } else 409 dir_has_error = 1; 410 411 if (++n >= npages) 412 n = 0; 413 /* next page is past the blocks we've got */ 414 if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { 415 ext2_error(dir->i_sb, __func__, 416 "dir %lu size %lld exceeds block count %llu", 417 dir->i_ino, dir->i_size, 418 (unsigned long long)dir->i_blocks); 419 goto out; 420 } 421 } while (n != start); 422out: 423 return NULL; 424 425found: 426 *res_page = page; 427 ei->i_dir_start_lookup = n; 428 return de; 429} 430 431struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) 432{ 433 struct page *page = ext2_get_page(dir, 0, 0); 434 ext2_dirent *de = NULL; 435 436 if (!IS_ERR(page)) { 437 de = ext2_next_entry((ext2_dirent *) page_address(page)); 438 *p = page; 439 } 440 return de; 441} 442 443ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child) 444{ 445 ino_t res = 0; 446 struct ext2_dir_entry_2 *de; 447 struct page *page; 448 449 de = ext2_find_entry (dir, child, &page); 450 if (de) { 451 res = le32_to_cpu(de->inode); 452 ext2_put_page(page); 453 } 454 return res; 455} 456 457static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len) 458{ 459 return __block_write_begin(page, pos, len, ext2_get_block); 460} 461 462/* Releases the page */ 463void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, 464 struct page *page, struct inode *inode, int update_times) 465{ 466 loff_t pos = page_offset(page) + 467 (char *) de - (char *) page_address(page); 468 unsigned len = ext2_rec_len_from_disk(de->rec_len); 469 int err; 470 471 lock_page(page); 472 err = ext2_prepare_chunk(page, pos, len); 473 BUG_ON(err); 474 de->inode = cpu_to_le32(inode->i_ino); 475 ext2_set_de_type(de, inode); 476 err = ext2_commit_chunk(page, pos, len); 477 ext2_put_page(page); 478 if (update_times) 479 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 480 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 481 mark_inode_dirty(dir); 482} 483 484/* 485 * Parent is locked. 486 */ 487int ext2_add_link (struct dentry *dentry, struct inode *inode) 488{ 489 struct inode *dir = dentry->d_parent->d_inode; 490 const char *name = dentry->d_name.name; 491 int namelen = dentry->d_name.len; 492 unsigned chunk_size = ext2_chunk_size(dir); 493 unsigned reclen = EXT2_DIR_REC_LEN(namelen); 494 unsigned short rec_len, name_len; 495 struct page *page = NULL; 496 ext2_dirent * de; 497 unsigned long npages = dir_pages(dir); 498 unsigned long n; 499 char *kaddr; 500 loff_t pos; 501 int err; 502 503 /* 504 * We take care of directory expansion in the same loop. 505 * This code plays outside i_size, so it locks the page 506 * to protect that region. 507 */ 508 for (n = 0; n <= npages; n++) { 509 char *dir_end; 510 511 page = ext2_get_page(dir, n, 0); 512 err = PTR_ERR(page); 513 if (IS_ERR(page)) 514 goto out; 515 lock_page(page); 516 kaddr = page_address(page); 517 dir_end = kaddr + ext2_last_byte(dir, n); 518 de = (ext2_dirent *)kaddr; 519 kaddr += PAGE_CACHE_SIZE - reclen; 520 while ((char *)de <= kaddr) { 521 if ((char *)de == dir_end) { 522 /* We hit i_size */ 523 name_len = 0; 524 rec_len = chunk_size; 525 de->rec_len = ext2_rec_len_to_disk(chunk_size); 526 de->inode = 0; 527 goto got_it; 528 } 529 if (de->rec_len == 0) { 530 ext2_error(dir->i_sb, __func__, 531 "zero-length directory entry"); 532 err = -EIO; 533 goto out_unlock; 534 } 535 err = -EEXIST; 536 if (ext2_match (namelen, name, de)) 537 goto out_unlock; 538 name_len = EXT2_DIR_REC_LEN(de->name_len); 539 rec_len = ext2_rec_len_from_disk(de->rec_len); 540 if (!de->inode && rec_len >= reclen) 541 goto got_it; 542 if (rec_len >= name_len + reclen) 543 goto got_it; 544 de = (ext2_dirent *) ((char *) de + rec_len); 545 } 546 unlock_page(page); 547 ext2_put_page(page); 548 } 549 BUG(); 550 return -EINVAL; 551 552got_it: 553 pos = page_offset(page) + 554 (char*)de - (char*)page_address(page); 555 err = ext2_prepare_chunk(page, pos, rec_len); 556 if (err) 557 goto out_unlock; 558 if (de->inode) { 559 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); 560 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); 561 de->rec_len = ext2_rec_len_to_disk(name_len); 562 de = de1; 563 } 564 de->name_len = namelen; 565 memcpy(de->name, name, namelen); 566 de->inode = cpu_to_le32(inode->i_ino); 567 ext2_set_de_type (de, inode); 568 err = ext2_commit_chunk(page, pos, rec_len); 569 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; 570 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; 571 mark_inode_dirty(dir); 572 /* OFFSET_CACHE */ 573out_put: 574 ext2_put_page(page); 575out: 576 return err; 577out_unlock: 578 unlock_page(page); 579 goto out_put; 580} 581 582/* 583 * ext2_delete_entry deletes a directory entry by merging it with the 584 * previous entry. Page is up-to-date. Releases the page. 585 */ 586int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) 587{ 588 struct inode *inode = page->mapping->host; 589 char *kaddr = page_address(page); 590 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); 591 unsigned to = ((char *)dir - kaddr) + 592 ext2_rec_len_from_disk(dir->rec_len); 593 loff_t pos; 594 ext2_dirent * pde = NULL; 595 ext2_dirent * de = (ext2_dirent *) (kaddr + from); 596 int err; 597 598 while ((char*)de < (char*)dir) { 599 if (de->rec_len == 0) { 600 ext2_error(inode->i_sb, __func__, 601 "zero-length directory entry"); 602 err = -EIO; 603 goto out; 604 } 605 pde = de; 606 de = ext2_next_entry(de); 607 } 608 if (pde) 609 from = (char*)pde - (char*)page_address(page); 610 pos = page_offset(page) + from; 611 lock_page(page); 612 err = ext2_prepare_chunk(page, pos, to - from); 613 BUG_ON(err); 614 if (pde) 615 pde->rec_len = ext2_rec_len_to_disk(to - from); 616 dir->inode = 0; 617 err = ext2_commit_chunk(page, pos, to - from); 618 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 619 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; 620 mark_inode_dirty(inode); 621out: 622 ext2_put_page(page); 623 return err; 624} 625 626/* 627 * Set the first fragment of directory. 628 */ 629int ext2_make_empty(struct inode *inode, struct inode *parent) 630{ 631 struct page *page = grab_cache_page(inode->i_mapping, 0); 632 unsigned chunk_size = ext2_chunk_size(inode); 633 struct ext2_dir_entry_2 * de; 634 int err; 635 void *kaddr; 636 637 if (!page) 638 return -ENOMEM; 639 640 err = ext2_prepare_chunk(page, 0, chunk_size); 641 if (err) { 642 unlock_page(page); 643 goto fail; 644 } 645 kaddr = kmap_atomic(page); 646 memset(kaddr, 0, chunk_size); 647 de = (struct ext2_dir_entry_2 *)kaddr; 648 de->name_len = 1; 649 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1)); 650 memcpy (de->name, ".\0\0", 4); 651 de->inode = cpu_to_le32(inode->i_ino); 652 ext2_set_de_type (de, inode); 653 654 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); 655 de->name_len = 2; 656 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1)); 657 de->inode = cpu_to_le32(parent->i_ino); 658 memcpy (de->name, "..\0", 4); 659 ext2_set_de_type (de, inode); 660 kunmap_atomic(kaddr); 661 err = ext2_commit_chunk(page, 0, chunk_size); 662fail: 663 page_cache_release(page); 664 return err; 665} 666 667/* 668 * routine to check that the specified directory is empty (for rmdir) 669 */ 670int ext2_empty_dir (struct inode * inode) 671{ 672 struct page *page = NULL; 673 unsigned long i, npages = dir_pages(inode); 674 int dir_has_error = 0; 675 676 for (i = 0; i < npages; i++) { 677 char *kaddr; 678 ext2_dirent * de; 679 page = ext2_get_page(inode, i, dir_has_error); 680 681 if (IS_ERR(page)) { 682 dir_has_error = 1; 683 continue; 684 } 685 686 kaddr = page_address(page); 687 de = (ext2_dirent *)kaddr; 688 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); 689 690 while ((char *)de <= kaddr) { 691 if (de->rec_len == 0) { 692 ext2_error(inode->i_sb, __func__, 693 "zero-length directory entry"); 694 printk("kaddr=%p, de=%p\n", kaddr, de); 695 goto not_empty; 696 } 697 if (de->inode != 0) { 698 /* check for . and .. */ 699 if (de->name[0] != '.') 700 goto not_empty; 701 if (de->name_len > 2) 702 goto not_empty; 703 if (de->name_len < 2) { 704 if (de->inode != 705 cpu_to_le32(inode->i_ino)) 706 goto not_empty; 707 } else if (de->name[1] != '.') 708 goto not_empty; 709 } 710 de = ext2_next_entry(de); 711 } 712 ext2_put_page(page); 713 } 714 return 1; 715 716not_empty: 717 ext2_put_page(page); 718 return 0; 719} 720 721const struct file_operations ext2_dir_operations = { 722 .llseek = generic_file_llseek, 723 .read = generic_read_dir, 724 .iterate = ext2_readdir, 725 .unlocked_ioctl = ext2_ioctl, 726#ifdef CONFIG_COMPAT 727 .compat_ioctl = ext2_compat_ioctl, 728#endif 729 .fsync = ext2_fsync, 730}; 731