xref: /linux/fs/ext2/dir.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 
261 	if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
262 		return 0;
263 
264 	if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
265 		types = ext2_filetype_table;
266 
267 	for ( ; n < npages; n++, offset = 0) {
268 		char *kaddr, *limit;
269 		ext2_dirent *de;
270 		struct page *page = ext2_get_page(inode, n);
271 
272 		if (IS_ERR(page)) {
273 			ext2_error(sb, __FUNCTION__,
274 				   "bad page in #%lu",
275 				   inode->i_ino);
276 			filp->f_pos += PAGE_CACHE_SIZE - offset;
277 			return -EIO;
278 		}
279 		kaddr = page_address(page);
280 		if (unlikely(need_revalidate)) {
281 			if (offset) {
282 				offset = ext2_validate_entry(kaddr, offset, chunk_mask);
283 				filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
284 			}
285 			filp->f_version = inode->i_version;
286 			need_revalidate = 0;
287 		}
288 		de = (ext2_dirent *)(kaddr+offset);
289 		limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
290 		for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
291 			if (de->rec_len == 0) {
292 				ext2_error(sb, __FUNCTION__,
293 					"zero-length directory entry");
294 				ext2_put_page(page);
295 				return -EIO;
296 			}
297 			if (de->inode) {
298 				int over;
299 				unsigned char d_type = DT_UNKNOWN;
300 
301 				if (types && de->file_type < EXT2_FT_MAX)
302 					d_type = types[de->file_type];
303 
304 				offset = (char *)de - kaddr;
305 				over = filldir(dirent, de->name, de->name_len,
306 						(n<<PAGE_CACHE_SHIFT) | offset,
307 						le32_to_cpu(de->inode), d_type);
308 				if (over) {
309 					ext2_put_page(page);
310 					return 0;
311 				}
312 			}
313 			filp->f_pos += le16_to_cpu(de->rec_len);
314 		}
315 		ext2_put_page(page);
316 	}
317 	return 0;
318 }
319 
320 /*
321  *	ext2_find_entry()
322  *
323  * finds an entry in the specified directory with the wanted name. It
324  * returns the page in which the entry was found, and the entry itself
325  * (as a parameter - res_dir). Page is returned mapped and unlocked.
326  * Entry is guaranteed to be valid.
327  */
328 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
329 			struct dentry *dentry, struct page ** res_page)
330 {
331 	const char *name = dentry->d_name.name;
332 	int namelen = dentry->d_name.len;
333 	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
334 	unsigned long start, n;
335 	unsigned long npages = dir_pages(dir);
336 	struct page *page = NULL;
337 	struct ext2_inode_info *ei = EXT2_I(dir);
338 	ext2_dirent * de;
339 
340 	if (npages == 0)
341 		goto out;
342 
343 	/* OFFSET_CACHE */
344 	*res_page = NULL;
345 
346 	start = ei->i_dir_start_lookup;
347 	if (start >= npages)
348 		start = 0;
349 	n = start;
350 	do {
351 		char *kaddr;
352 		page = ext2_get_page(dir, n);
353 		if (!IS_ERR(page)) {
354 			kaddr = page_address(page);
355 			de = (ext2_dirent *) kaddr;
356 			kaddr += ext2_last_byte(dir, n) - reclen;
357 			while ((char *) de <= kaddr) {
358 				if (de->rec_len == 0) {
359 					ext2_error(dir->i_sb, __FUNCTION__,
360 						"zero-length directory entry");
361 					ext2_put_page(page);
362 					goto out;
363 				}
364 				if (ext2_match (namelen, name, de))
365 					goto found;
366 				de = ext2_next_entry(de);
367 			}
368 			ext2_put_page(page);
369 		}
370 		if (++n >= npages)
371 			n = 0;
372 	} while (n != start);
373 out:
374 	return NULL;
375 
376 found:
377 	*res_page = page;
378 	ei->i_dir_start_lookup = n;
379 	return de;
380 }
381 
382 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
383 {
384 	struct page *page = ext2_get_page(dir, 0);
385 	ext2_dirent *de = NULL;
386 
387 	if (!IS_ERR(page)) {
388 		de = ext2_next_entry((ext2_dirent *) page_address(page));
389 		*p = page;
390 	}
391 	return de;
392 }
393 
394 ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry)
395 {
396 	ino_t res = 0;
397 	struct ext2_dir_entry_2 * de;
398 	struct page *page;
399 
400 	de = ext2_find_entry (dir, dentry, &page);
401 	if (de) {
402 		res = le32_to_cpu(de->inode);
403 		kunmap(page);
404 		page_cache_release(page);
405 	}
406 	return res;
407 }
408 
409 /* Releases the page */
410 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
411 			struct page *page, struct inode *inode)
412 {
413 	unsigned from = (char *) de - (char *) page_address(page);
414 	unsigned to = from + le16_to_cpu(de->rec_len);
415 	int err;
416 
417 	lock_page(page);
418 	err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
419 	BUG_ON(err);
420 	de->inode = cpu_to_le32(inode->i_ino);
421 	ext2_set_de_type (de, inode);
422 	err = ext2_commit_chunk(page, from, to);
423 	ext2_put_page(page);
424 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
425 	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
426 	mark_inode_dirty(dir);
427 }
428 
429 /*
430  *	Parent is locked.
431  */
432 int ext2_add_link (struct dentry *dentry, struct inode *inode)
433 {
434 	struct inode *dir = dentry->d_parent->d_inode;
435 	const char *name = dentry->d_name.name;
436 	int namelen = dentry->d_name.len;
437 	unsigned chunk_size = ext2_chunk_size(dir);
438 	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
439 	unsigned short rec_len, name_len;
440 	struct page *page = NULL;
441 	ext2_dirent * de;
442 	unsigned long npages = dir_pages(dir);
443 	unsigned long n;
444 	char *kaddr;
445 	unsigned from, to;
446 	int err;
447 
448 	/*
449 	 * We take care of directory expansion in the same loop.
450 	 * This code plays outside i_size, so it locks the page
451 	 * to protect that region.
452 	 */
453 	for (n = 0; n <= npages; n++) {
454 		char *dir_end;
455 
456 		page = ext2_get_page(dir, n);
457 		err = PTR_ERR(page);
458 		if (IS_ERR(page))
459 			goto out;
460 		lock_page(page);
461 		kaddr = page_address(page);
462 		dir_end = kaddr + ext2_last_byte(dir, n);
463 		de = (ext2_dirent *)kaddr;
464 		kaddr += PAGE_CACHE_SIZE - reclen;
465 		while ((char *)de <= kaddr) {
466 			if ((char *)de == dir_end) {
467 				/* We hit i_size */
468 				name_len = 0;
469 				rec_len = chunk_size;
470 				de->rec_len = cpu_to_le16(chunk_size);
471 				de->inode = 0;
472 				goto got_it;
473 			}
474 			if (de->rec_len == 0) {
475 				ext2_error(dir->i_sb, __FUNCTION__,
476 					"zero-length directory entry");
477 				err = -EIO;
478 				goto out_unlock;
479 			}
480 			err = -EEXIST;
481 			if (ext2_match (namelen, name, de))
482 				goto out_unlock;
483 			name_len = EXT2_DIR_REC_LEN(de->name_len);
484 			rec_len = le16_to_cpu(de->rec_len);
485 			if (!de->inode && rec_len >= reclen)
486 				goto got_it;
487 			if (rec_len >= name_len + reclen)
488 				goto got_it;
489 			de = (ext2_dirent *) ((char *) de + rec_len);
490 		}
491 		unlock_page(page);
492 		ext2_put_page(page);
493 	}
494 	BUG();
495 	return -EINVAL;
496 
497 got_it:
498 	from = (char*)de - (char*)page_address(page);
499 	to = from + rec_len;
500 	err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
501 	if (err)
502 		goto out_unlock;
503 	if (de->inode) {
504 		ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
505 		de1->rec_len = cpu_to_le16(rec_len - name_len);
506 		de->rec_len = cpu_to_le16(name_len);
507 		de = de1;
508 	}
509 	de->name_len = namelen;
510 	memcpy (de->name, name, namelen);
511 	de->inode = cpu_to_le32(inode->i_ino);
512 	ext2_set_de_type (de, inode);
513 	err = ext2_commit_chunk(page, from, to);
514 	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
515 	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
516 	mark_inode_dirty(dir);
517 	/* OFFSET_CACHE */
518 out_put:
519 	ext2_put_page(page);
520 out:
521 	return err;
522 out_unlock:
523 	unlock_page(page);
524 	goto out_put;
525 }
526 
527 /*
528  * ext2_delete_entry deletes a directory entry by merging it with the
529  * previous entry. Page is up-to-date. Releases the page.
530  */
531 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
532 {
533 	struct address_space *mapping = page->mapping;
534 	struct inode *inode = mapping->host;
535 	char *kaddr = page_address(page);
536 	unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
537 	unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
538 	ext2_dirent * pde = NULL;
539 	ext2_dirent * de = (ext2_dirent *) (kaddr + from);
540 	int err;
541 
542 	while ((char*)de < (char*)dir) {
543 		if (de->rec_len == 0) {
544 			ext2_error(inode->i_sb, __FUNCTION__,
545 				"zero-length directory entry");
546 			err = -EIO;
547 			goto out;
548 		}
549 		pde = de;
550 		de = ext2_next_entry(de);
551 	}
552 	if (pde)
553 		from = (char*)pde - (char*)page_address(page);
554 	lock_page(page);
555 	err = mapping->a_ops->prepare_write(NULL, page, from, to);
556 	BUG_ON(err);
557 	if (pde)
558 		pde->rec_len = cpu_to_le16(to-from);
559 	dir->inode = 0;
560 	err = ext2_commit_chunk(page, from, to);
561 	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
562 	EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
563 	mark_inode_dirty(inode);
564 out:
565 	ext2_put_page(page);
566 	return err;
567 }
568 
569 /*
570  * Set the first fragment of directory.
571  */
572 int ext2_make_empty(struct inode *inode, struct inode *parent)
573 {
574 	struct address_space *mapping = inode->i_mapping;
575 	struct page *page = grab_cache_page(mapping, 0);
576 	unsigned chunk_size = ext2_chunk_size(inode);
577 	struct ext2_dir_entry_2 * de;
578 	int err;
579 	void *kaddr;
580 
581 	if (!page)
582 		return -ENOMEM;
583 	err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
584 	if (err) {
585 		unlock_page(page);
586 		goto fail;
587 	}
588 	kaddr = kmap_atomic(page, KM_USER0);
589 	memset(kaddr, 0, chunk_size);
590 	de = (struct ext2_dir_entry_2 *)kaddr;
591 	de->name_len = 1;
592 	de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
593 	memcpy (de->name, ".\0\0", 4);
594 	de->inode = cpu_to_le32(inode->i_ino);
595 	ext2_set_de_type (de, inode);
596 
597 	de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
598 	de->name_len = 2;
599 	de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
600 	de->inode = cpu_to_le32(parent->i_ino);
601 	memcpy (de->name, "..\0", 4);
602 	ext2_set_de_type (de, inode);
603 	kunmap_atomic(kaddr, KM_USER0);
604 	err = ext2_commit_chunk(page, 0, chunk_size);
605 fail:
606 	page_cache_release(page);
607 	return err;
608 }
609 
610 /*
611  * routine to check that the specified directory is empty (for rmdir)
612  */
613 int ext2_empty_dir (struct inode * inode)
614 {
615 	struct page *page = NULL;
616 	unsigned long i, npages = dir_pages(inode);
617 
618 	for (i = 0; i < npages; i++) {
619 		char *kaddr;
620 		ext2_dirent * de;
621 		page = ext2_get_page(inode, i);
622 
623 		if (IS_ERR(page))
624 			continue;
625 
626 		kaddr = page_address(page);
627 		de = (ext2_dirent *)kaddr;
628 		kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
629 
630 		while ((char *)de <= kaddr) {
631 			if (de->rec_len == 0) {
632 				ext2_error(inode->i_sb, __FUNCTION__,
633 					"zero-length directory entry");
634 				printk("kaddr=%p, de=%p\n", kaddr, de);
635 				goto not_empty;
636 			}
637 			if (de->inode != 0) {
638 				/* check for . and .. */
639 				if (de->name[0] != '.')
640 					goto not_empty;
641 				if (de->name_len > 2)
642 					goto not_empty;
643 				if (de->name_len < 2) {
644 					if (de->inode !=
645 					    cpu_to_le32(inode->i_ino))
646 						goto not_empty;
647 				} else if (de->name[1] != '.')
648 					goto not_empty;
649 			}
650 			de = ext2_next_entry(de);
651 		}
652 		ext2_put_page(page);
653 	}
654 	return 1;
655 
656 not_empty:
657 	ext2_put_page(page);
658 	return 0;
659 }
660 
661 const struct file_operations ext2_dir_operations = {
662 	.llseek		= generic_file_llseek,
663 	.read		= generic_read_dir,
664 	.readdir	= ext2_readdir,
665 	.ioctl		= ext2_ioctl,
666 	.fsync		= ext2_sync_file,
667 };
668