xref: /openbmc/linux/fs/ext2/dir.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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/pagemap.h>
26 #include <linux/smp_lock.h>
27 
28 typedef struct ext2_dir_entry_2 ext2_dirent;
29 
30 /*
31  * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
32  * more robust, but we have what we have
33  */
34 static inline unsigned ext2_chunk_size(struct inode *inode)
35 {
36 	return inode->i_sb->s_blocksize;
37 }
38 
39 static inline void ext2_put_page(struct page *page)
40 {
41 	kunmap(page);
42 	page_cache_release(page);
43 }
44 
45 static inline unsigned long dir_pages(struct inode *inode)
46 {
47 	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
48 }
49 
50 /*
51  * Return the offset into page `page_nr' of the last valid
52  * byte in that page, plus one.
53  */
54 static unsigned
55 ext2_last_byte(struct inode *inode, unsigned long page_nr)
56 {
57 	unsigned last_byte = inode->i_size;
58 
59 	last_byte -= page_nr << PAGE_CACHE_SHIFT;
60 	if (last_byte > PAGE_CACHE_SIZE)
61 		last_byte = PAGE_CACHE_SIZE;
62 	return last_byte;
63 }
64 
65 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
66 {
67 	struct inode *dir = page->mapping->host;
68 	int err = 0;
69 	dir->i_version++;
70 	page->mapping->a_ops->commit_write(NULL, page, from, to);
71 	if (IS_DIRSYNC(dir))
72 		err = write_one_page(page, 1);
73 	else
74 		unlock_page(page);
75 	return err;
76 }
77 
78 static void ext2_check_page(struct page *page)
79 {
80 	struct inode *dir = page->mapping->host;
81 	struct super_block *sb = dir->i_sb;
82 	unsigned chunk_size = ext2_chunk_size(dir);
83 	char *kaddr = page_address(page);
84 	u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
85 	unsigned offs, rec_len;
86 	unsigned limit = PAGE_CACHE_SIZE;
87 	ext2_dirent *p;
88 	char *error;
89 
90 	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
91 		limit = dir->i_size & ~PAGE_CACHE_MASK;
92 		if (limit & (chunk_size - 1))
93 			goto Ebadsize;
94 		if (!limit)
95 			goto out;
96 	}
97 	for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
98 		p = (ext2_dirent *)(kaddr + offs);
99 		rec_len = le16_to_cpu(p->rec_len);
100 
101 		if (rec_len < EXT2_DIR_REC_LEN(1))
102 			goto Eshort;
103 		if (rec_len & 3)
104 			goto Ealign;
105 		if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
106 			goto Enamelen;
107 		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
108 			goto Espan;
109 		if (le32_to_cpu(p->inode) > max_inumber)
110 			goto Einumber;
111 	}
112 	if (offs != limit)
113 		goto Eend;
114 out:
115 	SetPageChecked(page);
116 	return;
117 
118 	/* Too bad, we had an error */
119 
120 Ebadsize:
121 	ext2_error(sb, "ext2_check_page",
122 		"size of directory #%lu is not a multiple of chunk size",
123 		dir->i_ino
124 	);
125 	goto fail;
126 Eshort:
127 	error = "rec_len is smaller than minimal";
128 	goto bad_entry;
129 Ealign:
130 	error = "unaligned directory entry";
131 	goto bad_entry;
132 Enamelen:
133 	error = "rec_len is too small for name_len";
134 	goto bad_entry;
135 Espan:
136 	error = "directory entry across blocks";
137 	goto bad_entry;
138 Einumber:
139 	error = "inode out of bounds";
140 bad_entry:
141 	ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "
142 		"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
143 		dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
144 		(unsigned long) le32_to_cpu(p->inode),
145 		rec_len, p->name_len);
146 	goto fail;
147 Eend:
148 	p = (ext2_dirent *)(kaddr + offs);
149 	ext2_error (sb, "ext2_check_page",
150 		"entry in directory #%lu spans the page boundary"
151 		"offset=%lu, inode=%lu",
152 		dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
153 		(unsigned long) le32_to_cpu(p->inode));
154 fail:
155 	SetPageChecked(page);
156 	SetPageError(page);
157 }
158 
159 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
160 {
161 	struct address_space *mapping = dir->i_mapping;
162 	struct page *page = read_cache_page(mapping, n,
163 				(filler_t*)mapping->a_ops->readpage, NULL);
164 	if (!IS_ERR(page)) {
165 		wait_on_page_locked(page);
166 		kmap(page);
167 		if (!PageUptodate(page))
168 			goto fail;
169 		if (!PageChecked(page))
170 			ext2_check_page(page);
171 		if (PageError(page))
172 			goto fail;
173 	}
174 	return page;
175 
176 fail:
177 	ext2_put_page(page);
178 	return ERR_PTR(-EIO);
179 }
180 
181 /*
182  * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
183  *
184  * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
185  */
186 static inline int ext2_match (int len, const char * const name,
187 					struct ext2_dir_entry_2 * de)
188 {
189 	if (len != de->name_len)
190 		return 0;
191 	if (!de->inode)
192 		return 0;
193 	return !memcmp(name, de->name, len);
194 }
195 
196 /*
197  * p is at least 6 bytes before the end of page
198  */
199 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
200 {
201 	return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
202 }
203 
204 static inline unsigned
205 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
206 {
207 	ext2_dirent *de = (ext2_dirent*)(base + offset);
208 	ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
209 	while ((char*)p < (char*)de) {
210 		if (p->rec_len == 0)
211 			break;
212 		p = ext2_next_entry(p);
213 	}
214 	return (char *)p - base;
215 }
216 
217 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
218 	[EXT2_FT_UNKNOWN]	= DT_UNKNOWN,
219 	[EXT2_FT_REG_FILE]	= DT_REG,
220 	[EXT2_FT_DIR]		= DT_DIR,
221 	[EXT2_FT_CHRDEV]	= DT_CHR,
222 	[EXT2_FT_BLKDEV]	= DT_BLK,
223 	[EXT2_FT_FIFO]		= DT_FIFO,
224 	[EXT2_FT_SOCK]		= DT_SOCK,
225 	[EXT2_FT_SYMLINK]	= DT_LNK,
226 };
227 
228 #define S_SHIFT 12
229 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
230 	[S_IFREG >> S_SHIFT]	= EXT2_FT_REG_FILE,
231 	[S_IFDIR >> S_SHIFT]	= EXT2_FT_DIR,
232 	[S_IFCHR >> S_SHIFT]	= EXT2_FT_CHRDEV,
233 	[S_IFBLK >> S_SHIFT]	= EXT2_FT_BLKDEV,
234 	[S_IFIFO >> S_SHIFT]	= EXT2_FT_FIFO,
235 	[S_IFSOCK >> S_SHIFT]	= EXT2_FT_SOCK,
236 	[S_IFLNK >> S_SHIFT]	= EXT2_FT_SYMLINK,
237 };
238 
239 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
240 {
241 	mode_t mode = inode->i_mode;
242 	if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
243 		de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
244 	else
245 		de->file_type = 0;
246 }
247 
248 static int
249 ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
250 {
251 	loff_t pos = filp->f_pos;
252 	struct inode *inode = filp->f_dentry->d_inode;
253 	struct super_block *sb = inode->i_sb;
254 	unsigned int offset = pos & ~PAGE_CACHE_MASK;
255 	unsigned long n = pos >> PAGE_CACHE_SHIFT;
256 	unsigned long npages = dir_pages(inode);
257 	unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
258 	unsigned char *types = NULL;
259 	int need_revalidate = (filp->f_version != inode->i_version);
260 	int ret;
261 
262 	if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
263 		goto success;
264 
265 	if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
266 		types = ext2_filetype_table;
267 
268 	for ( ; n < npages; n++, offset = 0) {
269 		char *kaddr, *limit;
270 		ext2_dirent *de;
271 		struct page *page = ext2_get_page(inode, n);
272 
273 		if (IS_ERR(page)) {
274 			ext2_error(sb, __FUNCTION__,
275 				   "bad page in #%lu",
276 				   inode->i_ino);
277 			filp->f_pos += PAGE_CACHE_SIZE - offset;
278 			ret = -EIO;
279 			goto done;
280 		}
281 		kaddr = page_address(page);
282 		if (need_revalidate) {
283 			offset = ext2_validate_entry(kaddr, offset, chunk_mask);
284 			need_revalidate = 0;
285 		}
286 		de = (ext2_dirent *)(kaddr+offset);
287 		limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
288 		for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
289 			if (de->rec_len == 0) {
290 				ext2_error(sb, __FUNCTION__,
291 					"zero-length directory entry");
292 				ret = -EIO;
293 				ext2_put_page(page);
294 				goto done;
295 			}
296 			if (de->inode) {
297 				int over;
298 				unsigned char d_type = DT_UNKNOWN;
299 
300 				if (types && de->file_type < EXT2_FT_MAX)
301 					d_type = types[de->file_type];
302 
303 				offset = (char *)de - kaddr;
304 				over = filldir(dirent, de->name, de->name_len,
305 						(n<<PAGE_CACHE_SHIFT) | offset,
306 						le32_to_cpu(de->inode), d_type);
307 				if (over) {
308 					ext2_put_page(page);
309 					goto success;
310 				}
311 			}
312 			filp->f_pos += le16_to_cpu(de->rec_len);
313 		}
314 		ext2_put_page(page);
315 	}
316 
317 success:
318 	ret = 0;
319 done:
320 	filp->f_version = inode->i_version;
321 	return ret;
322 }
323 
324 /*
325  *	ext2_find_entry()
326  *
327  * finds an entry in the specified directory with the wanted name. It
328  * returns the page in which the entry was found, and the entry itself
329  * (as a parameter - res_dir). Page is returned mapped and unlocked.
330  * Entry is guaranteed to be valid.
331  */
332 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
333 			struct dentry *dentry, struct page ** res_page)
334 {
335 	const char *name = dentry->d_name.name;
336 	int namelen = dentry->d_name.len;
337 	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
338 	unsigned long start, n;
339 	unsigned long npages = dir_pages(dir);
340 	struct page *page = NULL;
341 	struct ext2_inode_info *ei = EXT2_I(dir);
342 	ext2_dirent * de;
343 
344 	if (npages == 0)
345 		goto out;
346 
347 	/* OFFSET_CACHE */
348 	*res_page = NULL;
349 
350 	start = ei->i_dir_start_lookup;
351 	if (start >= npages)
352 		start = 0;
353 	n = start;
354 	do {
355 		char *kaddr;
356 		page = ext2_get_page(dir, n);
357 		if (!IS_ERR(page)) {
358 			kaddr = page_address(page);
359 			de = (ext2_dirent *) kaddr;
360 			kaddr += ext2_last_byte(dir, n) - reclen;
361 			while ((char *) de <= kaddr) {
362 				if (de->rec_len == 0) {
363 					ext2_error(dir->i_sb, __FUNCTION__,
364 						"zero-length directory entry");
365 					ext2_put_page(page);
366 					goto out;
367 				}
368 				if (ext2_match (namelen, name, de))
369 					goto found;
370 				de = ext2_next_entry(de);
371 			}
372 			ext2_put_page(page);
373 		}
374 		if (++n >= npages)
375 			n = 0;
376 	} while (n != start);
377 out:
378 	return NULL;
379 
380 found:
381 	*res_page = page;
382 	ei->i_dir_start_lookup = n;
383 	return de;
384 }
385 
386 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
387 {
388 	struct page *page = ext2_get_page(dir, 0);
389 	ext2_dirent *de = NULL;
390 
391 	if (!IS_ERR(page)) {
392 		de = ext2_next_entry((ext2_dirent *) page_address(page));
393 		*p = page;
394 	}
395 	return de;
396 }
397 
398 ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry)
399 {
400 	ino_t res = 0;
401 	struct ext2_dir_entry_2 * de;
402 	struct page *page;
403 
404 	de = ext2_find_entry (dir, dentry, &page);
405 	if (de) {
406 		res = le32_to_cpu(de->inode);
407 		kunmap(page);
408 		page_cache_release(page);
409 	}
410 	return res;
411 }
412 
413 /* Releases the page */
414 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
415 			struct page *page, struct inode *inode)
416 {
417 	unsigned from = (char *) de - (char *) page_address(page);
418 	unsigned to = from + le16_to_cpu(de->rec_len);
419 	int err;
420 
421 	lock_page(page);
422 	err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
423 	if (err)
424 		BUG();
425 	de->inode = cpu_to_le32(inode->i_ino);
426 	ext2_set_de_type (de, inode);
427 	err = ext2_commit_chunk(page, from, to);
428 	ext2_put_page(page);
429 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
430 	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
431 	mark_inode_dirty(dir);
432 }
433 
434 /*
435  *	Parent is locked.
436  */
437 int ext2_add_link (struct dentry *dentry, struct inode *inode)
438 {
439 	struct inode *dir = dentry->d_parent->d_inode;
440 	const char *name = dentry->d_name.name;
441 	int namelen = dentry->d_name.len;
442 	unsigned chunk_size = ext2_chunk_size(dir);
443 	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
444 	unsigned short rec_len, name_len;
445 	struct page *page = NULL;
446 	ext2_dirent * de;
447 	unsigned long npages = dir_pages(dir);
448 	unsigned long n;
449 	char *kaddr;
450 	unsigned from, to;
451 	int err;
452 
453 	/*
454 	 * We take care of directory expansion in the same loop.
455 	 * This code plays outside i_size, so it locks the page
456 	 * to protect that region.
457 	 */
458 	for (n = 0; n <= npages; n++) {
459 		char *dir_end;
460 
461 		page = ext2_get_page(dir, n);
462 		err = PTR_ERR(page);
463 		if (IS_ERR(page))
464 			goto out;
465 		lock_page(page);
466 		kaddr = page_address(page);
467 		dir_end = kaddr + ext2_last_byte(dir, n);
468 		de = (ext2_dirent *)kaddr;
469 		kaddr += PAGE_CACHE_SIZE - reclen;
470 		while ((char *)de <= kaddr) {
471 			if ((char *)de == dir_end) {
472 				/* We hit i_size */
473 				name_len = 0;
474 				rec_len = chunk_size;
475 				de->rec_len = cpu_to_le16(chunk_size);
476 				de->inode = 0;
477 				goto got_it;
478 			}
479 			if (de->rec_len == 0) {
480 				ext2_error(dir->i_sb, __FUNCTION__,
481 					"zero-length directory entry");
482 				err = -EIO;
483 				goto out_unlock;
484 			}
485 			err = -EEXIST;
486 			if (ext2_match (namelen, name, de))
487 				goto out_unlock;
488 			name_len = EXT2_DIR_REC_LEN(de->name_len);
489 			rec_len = le16_to_cpu(de->rec_len);
490 			if (!de->inode && rec_len >= reclen)
491 				goto got_it;
492 			if (rec_len >= name_len + reclen)
493 				goto got_it;
494 			de = (ext2_dirent *) ((char *) de + rec_len);
495 		}
496 		unlock_page(page);
497 		ext2_put_page(page);
498 	}
499 	BUG();
500 	return -EINVAL;
501 
502 got_it:
503 	from = (char*)de - (char*)page_address(page);
504 	to = from + rec_len;
505 	err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
506 	if (err)
507 		goto out_unlock;
508 	if (de->inode) {
509 		ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
510 		de1->rec_len = cpu_to_le16(rec_len - name_len);
511 		de->rec_len = cpu_to_le16(name_len);
512 		de = de1;
513 	}
514 	de->name_len = namelen;
515 	memcpy (de->name, name, namelen);
516 	de->inode = cpu_to_le32(inode->i_ino);
517 	ext2_set_de_type (de, inode);
518 	err = ext2_commit_chunk(page, from, to);
519 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
520 	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
521 	mark_inode_dirty(dir);
522 	/* OFFSET_CACHE */
523 out_put:
524 	ext2_put_page(page);
525 out:
526 	return err;
527 out_unlock:
528 	unlock_page(page);
529 	goto out_put;
530 }
531 
532 /*
533  * ext2_delete_entry deletes a directory entry by merging it with the
534  * previous entry. Page is up-to-date. Releases the page.
535  */
536 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
537 {
538 	struct address_space *mapping = page->mapping;
539 	struct inode *inode = mapping->host;
540 	char *kaddr = page_address(page);
541 	unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
542 	unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
543 	ext2_dirent * pde = NULL;
544 	ext2_dirent * de = (ext2_dirent *) (kaddr + from);
545 	int err;
546 
547 	while ((char*)de < (char*)dir) {
548 		if (de->rec_len == 0) {
549 			ext2_error(inode->i_sb, __FUNCTION__,
550 				"zero-length directory entry");
551 			err = -EIO;
552 			goto out;
553 		}
554 		pde = de;
555 		de = ext2_next_entry(de);
556 	}
557 	if (pde)
558 		from = (char*)pde - (char*)page_address(page);
559 	lock_page(page);
560 	err = mapping->a_ops->prepare_write(NULL, page, from, to);
561 	if (err)
562 		BUG();
563 	if (pde)
564 		pde->rec_len = cpu_to_le16(to-from);
565 	dir->inode = 0;
566 	err = ext2_commit_chunk(page, from, to);
567 	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
568 	EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
569 	mark_inode_dirty(inode);
570 out:
571 	ext2_put_page(page);
572 	return err;
573 }
574 
575 /*
576  * Set the first fragment of directory.
577  */
578 int ext2_make_empty(struct inode *inode, struct inode *parent)
579 {
580 	struct address_space *mapping = inode->i_mapping;
581 	struct page *page = grab_cache_page(mapping, 0);
582 	unsigned chunk_size = ext2_chunk_size(inode);
583 	struct ext2_dir_entry_2 * de;
584 	int err;
585 	void *kaddr;
586 
587 	if (!page)
588 		return -ENOMEM;
589 	err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
590 	if (err) {
591 		unlock_page(page);
592 		goto fail;
593 	}
594 	kaddr = kmap_atomic(page, KM_USER0);
595        memset(kaddr, 0, chunk_size);
596 	de = (struct ext2_dir_entry_2 *)kaddr;
597 	de->name_len = 1;
598 	de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
599 	memcpy (de->name, ".\0\0", 4);
600 	de->inode = cpu_to_le32(inode->i_ino);
601 	ext2_set_de_type (de, inode);
602 
603 	de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
604 	de->name_len = 2;
605 	de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
606 	de->inode = cpu_to_le32(parent->i_ino);
607 	memcpy (de->name, "..\0", 4);
608 	ext2_set_de_type (de, inode);
609 	kunmap_atomic(kaddr, KM_USER0);
610 	err = ext2_commit_chunk(page, 0, chunk_size);
611 fail:
612 	page_cache_release(page);
613 	return err;
614 }
615 
616 /*
617  * routine to check that the specified directory is empty (for rmdir)
618  */
619 int ext2_empty_dir (struct inode * inode)
620 {
621 	struct page *page = NULL;
622 	unsigned long i, npages = dir_pages(inode);
623 
624 	for (i = 0; i < npages; i++) {
625 		char *kaddr;
626 		ext2_dirent * de;
627 		page = ext2_get_page(inode, i);
628 
629 		if (IS_ERR(page))
630 			continue;
631 
632 		kaddr = page_address(page);
633 		de = (ext2_dirent *)kaddr;
634 		kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
635 
636 		while ((char *)de <= kaddr) {
637 			if (de->rec_len == 0) {
638 				ext2_error(inode->i_sb, __FUNCTION__,
639 					"zero-length directory entry");
640 				printk("kaddr=%p, de=%p\n", kaddr, de);
641 				goto not_empty;
642 			}
643 			if (de->inode != 0) {
644 				/* check for . and .. */
645 				if (de->name[0] != '.')
646 					goto not_empty;
647 				if (de->name_len > 2)
648 					goto not_empty;
649 				if (de->name_len < 2) {
650 					if (de->inode !=
651 					    cpu_to_le32(inode->i_ino))
652 						goto not_empty;
653 				} else if (de->name[1] != '.')
654 					goto not_empty;
655 			}
656 			de = ext2_next_entry(de);
657 		}
658 		ext2_put_page(page);
659 	}
660 	return 1;
661 
662 not_empty:
663 	ext2_put_page(page);
664 	return 0;
665 }
666 
667 struct file_operations ext2_dir_operations = {
668 	.llseek		= generic_file_llseek,
669 	.read		= generic_read_dir,
670 	.readdir	= ext2_readdir,
671 	.ioctl		= ext2_ioctl,
672 	.fsync		= ext2_sync_file,
673 };
674