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 */
ext2_rec_len_from_disk(__le16 dlen)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
ext2_rec_len_to_disk(unsigned len)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 */
ext2_chunk_size(struct inode * inode)64 static inline unsigned ext2_chunk_size(struct inode *inode)
65 {
66 return inode->i_sb->s_blocksize;
67 }
68
ext2_put_page(struct page * page)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
ext2_last_byte(struct inode * inode,unsigned long page_nr)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
ext2_commit_chunk(struct page * page,loff_t pos,unsigned len)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
ext2_check_page(struct page * page,int quiet)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
ext2_get_page(struct inode * dir,unsigned long n,int quiet)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 */
ext2_match(int len,const char * const name,struct ext2_dir_entry_2 * de)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 */
ext2_next_entry(ext2_dirent * p)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
ext2_validate_entry(char * base,unsigned offset,unsigned mask)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
ext2_set_de_type(ext2_dirent * de,struct inode * inode)255 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
256 {
257 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
258 de->file_type = fs_umode_to_ftype(inode->i_mode);
259 else
260 de->file_type = 0;
261 }
262
263 static int
ext2_readdir(struct file * file,struct dir_context * ctx)264 ext2_readdir(struct file *file, struct dir_context *ctx)
265 {
266 loff_t pos = ctx->pos;
267 struct inode *inode = file_inode(file);
268 struct super_block *sb = inode->i_sb;
269 unsigned int offset = pos & ~PAGE_MASK;
270 unsigned long n = pos >> PAGE_SHIFT;
271 unsigned long npages = dir_pages(inode);
272 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
273 bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
274 bool has_filetype;
275
276 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
277 return 0;
278
279 has_filetype =
280 EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE);
281
282 for ( ; n < npages; n++, offset = 0) {
283 char *kaddr, *limit;
284 ext2_dirent *de;
285 struct page *page = ext2_get_page(inode, n, 0);
286
287 if (IS_ERR(page)) {
288 ext2_error(sb, __func__,
289 "bad page in #%lu",
290 inode->i_ino);
291 ctx->pos += PAGE_SIZE - offset;
292 return PTR_ERR(page);
293 }
294 kaddr = page_address(page);
295 if (unlikely(need_revalidate)) {
296 if (offset) {
297 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
298 ctx->pos = (n<<PAGE_SHIFT) + offset;
299 }
300 file->f_version = inode_query_iversion(inode);
301 need_revalidate = false;
302 }
303 de = (ext2_dirent *)(kaddr+offset);
304 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
305 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
306 if (de->rec_len == 0) {
307 ext2_error(sb, __func__,
308 "zero-length directory entry");
309 ext2_put_page(page);
310 return -EIO;
311 }
312 if (de->inode) {
313 unsigned char d_type = DT_UNKNOWN;
314
315 if (has_filetype)
316 d_type = fs_ftype_to_dtype(de->file_type);
317
318 if (!dir_emit(ctx, de->name, de->name_len,
319 le32_to_cpu(de->inode),
320 d_type)) {
321 ext2_put_page(page);
322 return 0;
323 }
324 }
325 ctx->pos += ext2_rec_len_from_disk(de->rec_len);
326 }
327 ext2_put_page(page);
328 }
329 return 0;
330 }
331
332 /*
333 * ext2_find_entry()
334 *
335 * finds an entry in the specified directory with the wanted name. It
336 * returns the page in which the entry was found (as a parameter - res_page),
337 * and the entry itself. Page is returned mapped and unlocked.
338 * Entry is guaranteed to be valid.
339 */
ext2_find_entry(struct inode * dir,const struct qstr * child,struct page ** res_page)340 struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
341 const struct qstr *child, struct page **res_page)
342 {
343 const char *name = child->name;
344 int namelen = child->len;
345 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
346 unsigned long start, n;
347 unsigned long npages = dir_pages(dir);
348 struct page *page = NULL;
349 struct ext2_inode_info *ei = EXT2_I(dir);
350 ext2_dirent * de;
351
352 if (npages == 0)
353 goto out;
354
355 /* OFFSET_CACHE */
356 *res_page = NULL;
357
358 start = ei->i_dir_start_lookup;
359 if (start >= npages)
360 start = 0;
361 n = start;
362 do {
363 char *kaddr;
364 page = ext2_get_page(dir, n, 0);
365 if (IS_ERR(page))
366 return ERR_CAST(page);
367
368 kaddr = page_address(page);
369 de = (ext2_dirent *) kaddr;
370 kaddr += ext2_last_byte(dir, n) - reclen;
371 while ((char *) de <= kaddr) {
372 if (de->rec_len == 0) {
373 ext2_error(dir->i_sb, __func__,
374 "zero-length directory entry");
375 ext2_put_page(page);
376 goto out;
377 }
378 if (ext2_match(namelen, name, de))
379 goto found;
380 de = ext2_next_entry(de);
381 }
382 ext2_put_page(page);
383
384 if (++n >= npages)
385 n = 0;
386 /* next page is past the blocks we've got */
387 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
388 ext2_error(dir->i_sb, __func__,
389 "dir %lu size %lld exceeds block count %llu",
390 dir->i_ino, dir->i_size,
391 (unsigned long long)dir->i_blocks);
392 goto out;
393 }
394 } while (n != start);
395 out:
396 return ERR_PTR(-ENOENT);
397
398 found:
399 *res_page = page;
400 ei->i_dir_start_lookup = n;
401 return de;
402 }
403
ext2_dotdot(struct inode * dir,struct page ** p)404 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
405 {
406 struct page *page = ext2_get_page(dir, 0, 0);
407 ext2_dirent *de = NULL;
408
409 if (!IS_ERR(page)) {
410 de = ext2_next_entry((ext2_dirent *) page_address(page));
411 *p = page;
412 }
413 return de;
414 }
415
ext2_inode_by_name(struct inode * dir,const struct qstr * child,ino_t * ino)416 int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino)
417 {
418 struct ext2_dir_entry_2 *de;
419 struct page *page;
420
421 de = ext2_find_entry(dir, child, &page);
422 if (IS_ERR(de))
423 return PTR_ERR(de);
424
425 *ino = le32_to_cpu(de->inode);
426 ext2_put_page(page);
427 return 0;
428 }
429
ext2_prepare_chunk(struct page * page,loff_t pos,unsigned len)430 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
431 {
432 return __block_write_begin(page, pos, len, ext2_get_block);
433 }
434
435 /* Releases the page */
ext2_set_link(struct inode * dir,struct ext2_dir_entry_2 * de,struct page * page,struct inode * inode,int update_times)436 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
437 struct page *page, struct inode *inode, int update_times)
438 {
439 loff_t pos = page_offset(page) +
440 (char *) de - (char *) page_address(page);
441 unsigned len = ext2_rec_len_from_disk(de->rec_len);
442 int err;
443
444 lock_page(page);
445 err = ext2_prepare_chunk(page, pos, len);
446 BUG_ON(err);
447 de->inode = cpu_to_le32(inode->i_ino);
448 ext2_set_de_type(de, inode);
449 err = ext2_commit_chunk(page, pos, len);
450 ext2_put_page(page);
451 if (update_times)
452 dir->i_mtime = dir->i_ctime = current_time(dir);
453 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
454 mark_inode_dirty(dir);
455 }
456
457 /*
458 * Parent is locked.
459 */
ext2_add_link(struct dentry * dentry,struct inode * inode)460 int ext2_add_link (struct dentry *dentry, struct inode *inode)
461 {
462 struct inode *dir = d_inode(dentry->d_parent);
463 const char *name = dentry->d_name.name;
464 int namelen = dentry->d_name.len;
465 unsigned chunk_size = ext2_chunk_size(dir);
466 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
467 unsigned short rec_len, name_len;
468 struct page *page = NULL;
469 ext2_dirent * de;
470 unsigned long npages = dir_pages(dir);
471 unsigned long n;
472 char *kaddr;
473 loff_t pos;
474 int err;
475
476 /*
477 * We take care of directory expansion in the same loop.
478 * This code plays outside i_size, so it locks the page
479 * to protect that region.
480 */
481 for (n = 0; n <= npages; n++) {
482 char *dir_end;
483
484 page = ext2_get_page(dir, n, 0);
485 err = PTR_ERR(page);
486 if (IS_ERR(page))
487 goto out;
488 lock_page(page);
489 kaddr = page_address(page);
490 dir_end = kaddr + ext2_last_byte(dir, n);
491 de = (ext2_dirent *)kaddr;
492 kaddr += PAGE_SIZE - reclen;
493 while ((char *)de <= kaddr) {
494 if ((char *)de == dir_end) {
495 /* We hit i_size */
496 name_len = 0;
497 rec_len = chunk_size;
498 de->rec_len = ext2_rec_len_to_disk(chunk_size);
499 de->inode = 0;
500 goto got_it;
501 }
502 if (de->rec_len == 0) {
503 ext2_error(dir->i_sb, __func__,
504 "zero-length directory entry");
505 err = -EIO;
506 goto out_unlock;
507 }
508 err = -EEXIST;
509 if (ext2_match (namelen, name, de))
510 goto out_unlock;
511 name_len = EXT2_DIR_REC_LEN(de->name_len);
512 rec_len = ext2_rec_len_from_disk(de->rec_len);
513 if (!de->inode && rec_len >= reclen)
514 goto got_it;
515 if (rec_len >= name_len + reclen)
516 goto got_it;
517 de = (ext2_dirent *) ((char *) de + rec_len);
518 }
519 unlock_page(page);
520 ext2_put_page(page);
521 }
522 BUG();
523 return -EINVAL;
524
525 got_it:
526 pos = page_offset(page) +
527 (char*)de - (char*)page_address(page);
528 err = ext2_prepare_chunk(page, pos, rec_len);
529 if (err)
530 goto out_unlock;
531 if (de->inode) {
532 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
533 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
534 de->rec_len = ext2_rec_len_to_disk(name_len);
535 de = de1;
536 }
537 de->name_len = namelen;
538 memcpy(de->name, name, namelen);
539 de->inode = cpu_to_le32(inode->i_ino);
540 ext2_set_de_type (de, inode);
541 err = ext2_commit_chunk(page, pos, rec_len);
542 dir->i_mtime = dir->i_ctime = current_time(dir);
543 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
544 mark_inode_dirty(dir);
545 /* OFFSET_CACHE */
546 out_put:
547 ext2_put_page(page);
548 out:
549 return err;
550 out_unlock:
551 unlock_page(page);
552 goto out_put;
553 }
554
555 /*
556 * ext2_delete_entry deletes a directory entry by merging it with the
557 * previous entry. Page is up-to-date. Releases the page.
558 */
ext2_delete_entry(struct ext2_dir_entry_2 * dir,struct page * page)559 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
560 {
561 struct inode *inode = page->mapping->host;
562 char *kaddr = page_address(page);
563 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
564 unsigned to = ((char *)dir - kaddr) +
565 ext2_rec_len_from_disk(dir->rec_len);
566 loff_t pos;
567 ext2_dirent * pde = NULL;
568 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
569 int err;
570
571 while ((char*)de < (char*)dir) {
572 if (de->rec_len == 0) {
573 ext2_error(inode->i_sb, __func__,
574 "zero-length directory entry");
575 err = -EIO;
576 goto out;
577 }
578 pde = de;
579 de = ext2_next_entry(de);
580 }
581 if (pde)
582 from = (char*)pde - (char*)page_address(page);
583 pos = page_offset(page) + from;
584 lock_page(page);
585 err = ext2_prepare_chunk(page, pos, to - from);
586 BUG_ON(err);
587 if (pde)
588 pde->rec_len = ext2_rec_len_to_disk(to - from);
589 dir->inode = 0;
590 err = ext2_commit_chunk(page, pos, to - from);
591 inode->i_ctime = inode->i_mtime = current_time(inode);
592 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
593 mark_inode_dirty(inode);
594 out:
595 ext2_put_page(page);
596 return err;
597 }
598
599 /*
600 * Set the first fragment of directory.
601 */
ext2_make_empty(struct inode * inode,struct inode * parent)602 int ext2_make_empty(struct inode *inode, struct inode *parent)
603 {
604 struct page *page = grab_cache_page(inode->i_mapping, 0);
605 unsigned chunk_size = ext2_chunk_size(inode);
606 struct ext2_dir_entry_2 * de;
607 int err;
608 void *kaddr;
609
610 if (!page)
611 return -ENOMEM;
612
613 err = ext2_prepare_chunk(page, 0, chunk_size);
614 if (err) {
615 unlock_page(page);
616 goto fail;
617 }
618 kaddr = kmap_atomic(page);
619 memset(kaddr, 0, chunk_size);
620 de = (struct ext2_dir_entry_2 *)kaddr;
621 de->name_len = 1;
622 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
623 memcpy (de->name, ".\0\0", 4);
624 de->inode = cpu_to_le32(inode->i_ino);
625 ext2_set_de_type (de, inode);
626
627 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
628 de->name_len = 2;
629 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
630 de->inode = cpu_to_le32(parent->i_ino);
631 memcpy (de->name, "..\0", 4);
632 ext2_set_de_type (de, inode);
633 kunmap_atomic(kaddr);
634 err = ext2_commit_chunk(page, 0, chunk_size);
635 fail:
636 put_page(page);
637 return err;
638 }
639
640 /*
641 * routine to check that the specified directory is empty (for rmdir)
642 */
ext2_empty_dir(struct inode * inode)643 int ext2_empty_dir (struct inode * inode)
644 {
645 struct page *page = NULL;
646 unsigned long i, npages = dir_pages(inode);
647 int dir_has_error = 0;
648
649 for (i = 0; i < npages; i++) {
650 char *kaddr;
651 ext2_dirent * de;
652 page = ext2_get_page(inode, i, dir_has_error);
653
654 if (IS_ERR(page)) {
655 dir_has_error = 1;
656 continue;
657 }
658
659 kaddr = page_address(page);
660 de = (ext2_dirent *)kaddr;
661 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
662
663 while ((char *)de <= kaddr) {
664 if (de->rec_len == 0) {
665 ext2_error(inode->i_sb, __func__,
666 "zero-length directory entry");
667 printk("kaddr=%p, de=%p\n", kaddr, de);
668 goto not_empty;
669 }
670 if (de->inode != 0) {
671 /* check for . and .. */
672 if (de->name[0] != '.')
673 goto not_empty;
674 if (de->name_len > 2)
675 goto not_empty;
676 if (de->name_len < 2) {
677 if (de->inode !=
678 cpu_to_le32(inode->i_ino))
679 goto not_empty;
680 } else if (de->name[1] != '.')
681 goto not_empty;
682 }
683 de = ext2_next_entry(de);
684 }
685 ext2_put_page(page);
686 }
687 return 1;
688
689 not_empty:
690 ext2_put_page(page);
691 return 0;
692 }
693
694 const struct file_operations ext2_dir_operations = {
695 .llseek = generic_file_llseek,
696 .read = generic_read_dir,
697 .iterate_shared = ext2_readdir,
698 .unlocked_ioctl = ext2_ioctl,
699 #ifdef CONFIG_COMPAT
700 .compat_ioctl = ext2_compat_ioctl,
701 #endif
702 .fsync = ext2_fsync,
703 };
704