xref: /openbmc/linux/fs/nilfs2/dir.c (revision 6a87e0f0ce1ae8d70566935215430e718ea776ff)
1  // SPDX-License-Identifier: GPL-2.0+
2  /*
3   * NILFS directory entry operations
4   *
5   * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6   *
7   * Modified for NILFS by Amagai Yoshiji.
8   */
9  /*
10   *  linux/fs/ext2/dir.c
11   *
12   * Copyright (C) 1992, 1993, 1994, 1995
13   * Remy Card (card@masi.ibp.fr)
14   * Laboratoire MASI - Institut Blaise Pascal
15   * Universite Pierre et Marie Curie (Paris VI)
16   *
17   *  from
18   *
19   *  linux/fs/minix/dir.c
20   *
21   *  Copyright (C) 1991, 1992  Linus Torvalds
22   *
23   *  ext2 directory handling functions
24   *
25   *  Big-endian to little-endian byte-swapping/bitmaps by
26   *        David S. Miller (davem@caip.rutgers.edu), 1995
27   *
28   * All code that works with directory layout had been switched to pagecache
29   * and moved here. AV
30   */
31  
32  #include <linux/pagemap.h>
33  #include "nilfs.h"
34  #include "page.h"
35  
36  static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
37  {
38  	unsigned int len = le16_to_cpu(dlen);
39  
40  #if (PAGE_SIZE >= 65536)
41  	if (len == NILFS_MAX_REC_LEN)
42  		return 1 << 16;
43  #endif
44  	return len;
45  }
46  
47  static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
48  {
49  #if (PAGE_SIZE >= 65536)
50  	if (len == (1 << 16))
51  		return cpu_to_le16(NILFS_MAX_REC_LEN);
52  
53  	BUG_ON(len > (1 << 16));
54  #endif
55  	return cpu_to_le16(len);
56  }
57  
58  /*
59   * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
60   * more robust, but we have what we have
61   */
62  static inline unsigned int nilfs_chunk_size(struct inode *inode)
63  {
64  	return inode->i_sb->s_blocksize;
65  }
66  
67  static inline void nilfs_put_page(struct page *page)
68  {
69  	kunmap(page);
70  	put_page(page);
71  }
72  
73  /*
74   * Return the offset into page `page_nr' of the last valid
75   * byte in that page, plus one.
76   */
77  static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
78  {
79  	unsigned int last_byte = inode->i_size;
80  
81  	last_byte -= page_nr << PAGE_SHIFT;
82  	if (last_byte > PAGE_SIZE)
83  		last_byte = PAGE_SIZE;
84  	return last_byte;
85  }
86  
87  static int nilfs_prepare_chunk(struct page *page, unsigned int from,
88  			       unsigned int to)
89  {
90  	loff_t pos = page_offset(page) + from;
91  
92  	return __block_write_begin(page, pos, to - from, nilfs_get_block);
93  }
94  
95  static void nilfs_commit_chunk(struct page *page,
96  			       struct address_space *mapping,
97  			       unsigned int from, unsigned int to)
98  {
99  	struct inode *dir = mapping->host;
100  	loff_t pos = page_offset(page) + from;
101  	unsigned int len = to - from;
102  	unsigned int nr_dirty, copied;
103  	int err;
104  
105  	nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
106  	copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
107  	if (pos + copied > dir->i_size)
108  		i_size_write(dir, pos + copied);
109  	if (IS_DIRSYNC(dir))
110  		nilfs_set_transaction_flag(NILFS_TI_SYNC);
111  	err = nilfs_set_file_dirty(dir, nr_dirty);
112  	WARN_ON(err); /* do not happen */
113  	unlock_page(page);
114  }
115  
116  static bool nilfs_check_page(struct page *page)
117  {
118  	struct inode *dir = page->mapping->host;
119  	struct super_block *sb = dir->i_sb;
120  	unsigned int chunk_size = nilfs_chunk_size(dir);
121  	char *kaddr = page_address(page);
122  	unsigned int offs, rec_len;
123  	unsigned int limit = PAGE_SIZE;
124  	struct nilfs_dir_entry *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 - NILFS_DIR_REC_LEN(1); offs += rec_len) {
135  		p = (struct nilfs_dir_entry *)(kaddr + offs);
136  		rec_len = nilfs_rec_len_from_disk(p->rec_len);
137  
138  		if (rec_len < NILFS_DIR_REC_LEN(1))
139  			goto Eshort;
140  		if (rec_len & 3)
141  			goto Ealign;
142  		if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
143  			goto Enamelen;
144  		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
145  			goto Espan;
146  	}
147  	if (offs != limit)
148  		goto Eend;
149  out:
150  	SetPageChecked(page);
151  	return true;
152  
153  	/* Too bad, we had an error */
154  
155  Ebadsize:
156  	nilfs_error(sb,
157  		    "size of directory #%lu is not a multiple of chunk size",
158  		    dir->i_ino);
159  	goto fail;
160  Eshort:
161  	error = "rec_len is smaller than minimal";
162  	goto bad_entry;
163  Ealign:
164  	error = "unaligned directory entry";
165  	goto bad_entry;
166  Enamelen:
167  	error = "rec_len is too small for name_len";
168  	goto bad_entry;
169  Espan:
170  	error = "directory entry across blocks";
171  bad_entry:
172  	nilfs_error(sb,
173  		    "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
174  		    dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
175  		    (unsigned long)le64_to_cpu(p->inode),
176  		    rec_len, p->name_len);
177  	goto fail;
178  Eend:
179  	p = (struct nilfs_dir_entry *)(kaddr + offs);
180  	nilfs_error(sb,
181  		    "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
182  		    dir->i_ino, (page->index << PAGE_SHIFT) + offs,
183  		    (unsigned long)le64_to_cpu(p->inode));
184  fail:
185  	SetPageError(page);
186  	return false;
187  }
188  
189  static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
190  {
191  	struct address_space *mapping = dir->i_mapping;
192  	struct page *page = read_mapping_page(mapping, n, NULL);
193  
194  	if (!IS_ERR(page)) {
195  		kmap(page);
196  		if (unlikely(!PageChecked(page))) {
197  			if (!nilfs_check_page(page))
198  				goto fail;
199  		}
200  	}
201  	return page;
202  
203  fail:
204  	nilfs_put_page(page);
205  	return ERR_PTR(-EIO);
206  }
207  
208  /*
209   * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
210   *
211   * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
212   */
213  static int
214  nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
215  {
216  	if (len != de->name_len)
217  		return 0;
218  	if (!de->inode)
219  		return 0;
220  	return !memcmp(name, de->name, len);
221  }
222  
223  /*
224   * p is at least 6 bytes before the end of page
225   */
226  static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
227  {
228  	return (struct nilfs_dir_entry *)((char *)p +
229  					  nilfs_rec_len_from_disk(p->rec_len));
230  }
231  
232  static unsigned char
233  nilfs_filetype_table[NILFS_FT_MAX] = {
234  	[NILFS_FT_UNKNOWN]	= DT_UNKNOWN,
235  	[NILFS_FT_REG_FILE]	= DT_REG,
236  	[NILFS_FT_DIR]		= DT_DIR,
237  	[NILFS_FT_CHRDEV]	= DT_CHR,
238  	[NILFS_FT_BLKDEV]	= DT_BLK,
239  	[NILFS_FT_FIFO]		= DT_FIFO,
240  	[NILFS_FT_SOCK]		= DT_SOCK,
241  	[NILFS_FT_SYMLINK]	= DT_LNK,
242  };
243  
244  #define S_SHIFT 12
245  static unsigned char
246  nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
247  	[S_IFREG >> S_SHIFT]	= NILFS_FT_REG_FILE,
248  	[S_IFDIR >> S_SHIFT]	= NILFS_FT_DIR,
249  	[S_IFCHR >> S_SHIFT]	= NILFS_FT_CHRDEV,
250  	[S_IFBLK >> S_SHIFT]	= NILFS_FT_BLKDEV,
251  	[S_IFIFO >> S_SHIFT]	= NILFS_FT_FIFO,
252  	[S_IFSOCK >> S_SHIFT]	= NILFS_FT_SOCK,
253  	[S_IFLNK >> S_SHIFT]	= NILFS_FT_SYMLINK,
254  };
255  
256  static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
257  {
258  	umode_t mode = inode->i_mode;
259  
260  	de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
261  }
262  
263  static int nilfs_readdir(struct file *file, struct dir_context *ctx)
264  {
265  	loff_t pos = ctx->pos;
266  	struct inode *inode = file_inode(file);
267  	struct super_block *sb = inode->i_sb;
268  	unsigned int offset = pos & ~PAGE_MASK;
269  	unsigned long n = pos >> PAGE_SHIFT;
270  	unsigned long npages = dir_pages(inode);
271  
272  	if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
273  		return 0;
274  
275  	for ( ; n < npages; n++, offset = 0) {
276  		char *kaddr, *limit;
277  		struct nilfs_dir_entry *de;
278  		struct page *page = nilfs_get_page(inode, n);
279  
280  		if (IS_ERR(page)) {
281  			nilfs_error(sb, "bad page in #%lu", inode->i_ino);
282  			ctx->pos += PAGE_SIZE - offset;
283  			return -EIO;
284  		}
285  		kaddr = page_address(page);
286  		de = (struct nilfs_dir_entry *)(kaddr + offset);
287  		limit = kaddr + nilfs_last_byte(inode, n) -
288  			NILFS_DIR_REC_LEN(1);
289  		for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
290  			if (de->rec_len == 0) {
291  				nilfs_error(sb, "zero-length directory entry");
292  				nilfs_put_page(page);
293  				return -EIO;
294  			}
295  			if (de->inode) {
296  				unsigned char t;
297  
298  				if (de->file_type < NILFS_FT_MAX)
299  					t = nilfs_filetype_table[de->file_type];
300  				else
301  					t = DT_UNKNOWN;
302  
303  				if (!dir_emit(ctx, de->name, de->name_len,
304  						le64_to_cpu(de->inode), t)) {
305  					nilfs_put_page(page);
306  					return 0;
307  				}
308  			}
309  			ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
310  		}
311  		nilfs_put_page(page);
312  	}
313  	return 0;
314  }
315  
316  /*
317   *	nilfs_find_entry()
318   *
319   * finds an entry in the specified directory with the wanted name. It
320   * returns the page in which the entry was found, and the entry itself
321   * (as a parameter - res_dir). Page is returned mapped and unlocked.
322   * Entry is guaranteed to be valid.
323   */
324  struct nilfs_dir_entry *
325  nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
326  		 struct page **res_page)
327  {
328  	const unsigned char *name = qstr->name;
329  	int namelen = qstr->len;
330  	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
331  	unsigned long start, n;
332  	unsigned long npages = dir_pages(dir);
333  	struct page *page = NULL;
334  	struct nilfs_inode_info *ei = NILFS_I(dir);
335  	struct nilfs_dir_entry *de;
336  
337  	if (npages == 0)
338  		goto out;
339  
340  	/* OFFSET_CACHE */
341  	*res_page = NULL;
342  
343  	start = ei->i_dir_start_lookup;
344  	if (start >= npages)
345  		start = 0;
346  	n = start;
347  	do {
348  		char *kaddr;
349  
350  		page = nilfs_get_page(dir, n);
351  		if (!IS_ERR(page)) {
352  			kaddr = page_address(page);
353  			de = (struct nilfs_dir_entry *)kaddr;
354  			kaddr += nilfs_last_byte(dir, n) - reclen;
355  			while ((char *) de <= kaddr) {
356  				if (de->rec_len == 0) {
357  					nilfs_error(dir->i_sb,
358  						"zero-length directory entry");
359  					nilfs_put_page(page);
360  					goto out;
361  				}
362  				if (nilfs_match(namelen, name, de))
363  					goto found;
364  				de = nilfs_next_entry(de);
365  			}
366  			nilfs_put_page(page);
367  		}
368  		if (++n >= npages)
369  			n = 0;
370  		/* next page is past the blocks we've got */
371  		if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
372  			nilfs_error(dir->i_sb,
373  			       "dir %lu size %lld exceeds block count %llu",
374  			       dir->i_ino, dir->i_size,
375  			       (unsigned long long)dir->i_blocks);
376  			goto out;
377  		}
378  	} while (n != start);
379  out:
380  	return NULL;
381  
382  found:
383  	*res_page = page;
384  	ei->i_dir_start_lookup = n;
385  	return de;
386  }
387  
388  struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
389  {
390  	struct page *page = nilfs_get_page(dir, 0);
391  	struct nilfs_dir_entry *de = NULL;
392  
393  	if (!IS_ERR(page)) {
394  		de = nilfs_next_entry(
395  			(struct nilfs_dir_entry *)page_address(page));
396  		*p = page;
397  	}
398  	return de;
399  }
400  
401  ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
402  {
403  	ino_t res = 0;
404  	struct nilfs_dir_entry *de;
405  	struct page *page;
406  
407  	de = nilfs_find_entry(dir, qstr, &page);
408  	if (de) {
409  		res = le64_to_cpu(de->inode);
410  		kunmap(page);
411  		put_page(page);
412  	}
413  	return res;
414  }
415  
416  /* Releases the page */
417  void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
418  		    struct page *page, struct inode *inode)
419  {
420  	unsigned int from = (char *)de - (char *)page_address(page);
421  	unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
422  	struct address_space *mapping = page->mapping;
423  	int err;
424  
425  	lock_page(page);
426  	err = nilfs_prepare_chunk(page, from, to);
427  	BUG_ON(err);
428  	de->inode = cpu_to_le64(inode->i_ino);
429  	nilfs_set_de_type(de, inode);
430  	nilfs_commit_chunk(page, mapping, from, to);
431  	nilfs_put_page(page);
432  	dir->i_mtime = dir->i_ctime = current_time(dir);
433  }
434  
435  /*
436   *	Parent is locked.
437   */
438  int nilfs_add_link(struct dentry *dentry, struct inode *inode)
439  {
440  	struct inode *dir = d_inode(dentry->d_parent);
441  	const unsigned char *name = dentry->d_name.name;
442  	int namelen = dentry->d_name.len;
443  	unsigned int chunk_size = nilfs_chunk_size(dir);
444  	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
445  	unsigned short rec_len, name_len;
446  	struct page *page = NULL;
447  	struct nilfs_dir_entry *de;
448  	unsigned long npages = dir_pages(dir);
449  	unsigned long n;
450  	char *kaddr;
451  	unsigned int from, to;
452  	int err;
453  
454  	/*
455  	 * We take care of directory expansion in the same loop.
456  	 * This code plays outside i_size, so it locks the page
457  	 * to protect that region.
458  	 */
459  	for (n = 0; n <= npages; n++) {
460  		char *dir_end;
461  
462  		page = nilfs_get_page(dir, n);
463  		err = PTR_ERR(page);
464  		if (IS_ERR(page))
465  			goto out;
466  		lock_page(page);
467  		kaddr = page_address(page);
468  		dir_end = kaddr + nilfs_last_byte(dir, n);
469  		de = (struct nilfs_dir_entry *)kaddr;
470  		kaddr += PAGE_SIZE - reclen;
471  		while ((char *)de <= kaddr) {
472  			if ((char *)de == dir_end) {
473  				/* We hit i_size */
474  				name_len = 0;
475  				rec_len = chunk_size;
476  				de->rec_len = nilfs_rec_len_to_disk(chunk_size);
477  				de->inode = 0;
478  				goto got_it;
479  			}
480  			if (de->rec_len == 0) {
481  				nilfs_error(dir->i_sb,
482  					    "zero-length directory entry");
483  				err = -EIO;
484  				goto out_unlock;
485  			}
486  			err = -EEXIST;
487  			if (nilfs_match(namelen, name, de))
488  				goto out_unlock;
489  			name_len = NILFS_DIR_REC_LEN(de->name_len);
490  			rec_len = nilfs_rec_len_from_disk(de->rec_len);
491  			if (!de->inode && rec_len >= reclen)
492  				goto got_it;
493  			if (rec_len >= name_len + reclen)
494  				goto got_it;
495  			de = (struct nilfs_dir_entry *)((char *)de + rec_len);
496  		}
497  		unlock_page(page);
498  		nilfs_put_page(page);
499  	}
500  	BUG();
501  	return -EINVAL;
502  
503  got_it:
504  	from = (char *)de - (char *)page_address(page);
505  	to = from + rec_len;
506  	err = nilfs_prepare_chunk(page, from, to);
507  	if (err)
508  		goto out_unlock;
509  	if (de->inode) {
510  		struct nilfs_dir_entry *de1;
511  
512  		de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
513  		de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
514  		de->rec_len = nilfs_rec_len_to_disk(name_len);
515  		de = de1;
516  	}
517  	de->name_len = namelen;
518  	memcpy(de->name, name, namelen);
519  	de->inode = cpu_to_le64(inode->i_ino);
520  	nilfs_set_de_type(de, inode);
521  	nilfs_commit_chunk(page, page->mapping, from, to);
522  	dir->i_mtime = dir->i_ctime = current_time(dir);
523  	nilfs_mark_inode_dirty(dir);
524  	/* OFFSET_CACHE */
525  out_put:
526  	nilfs_put_page(page);
527  out:
528  	return err;
529  out_unlock:
530  	unlock_page(page);
531  	goto out_put;
532  }
533  
534  /*
535   * nilfs_delete_entry deletes a directory entry by merging it with the
536   * previous entry. Page is up-to-date. Releases the page.
537   */
538  int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
539  {
540  	struct address_space *mapping = page->mapping;
541  	struct inode *inode = mapping->host;
542  	char *kaddr = page_address(page);
543  	unsigned int from, to;
544  	struct nilfs_dir_entry *de, *pde = NULL;
545  	int err;
546  
547  	from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
548  	to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
549  	de = (struct nilfs_dir_entry *)(kaddr + from);
550  
551  	while ((char *)de < (char *)dir) {
552  		if (de->rec_len == 0) {
553  			nilfs_error(inode->i_sb,
554  				    "zero-length directory entry");
555  			err = -EIO;
556  			goto out;
557  		}
558  		pde = de;
559  		de = nilfs_next_entry(de);
560  	}
561  	if (pde)
562  		from = (char *)pde - (char *)page_address(page);
563  	lock_page(page);
564  	err = nilfs_prepare_chunk(page, from, to);
565  	BUG_ON(err);
566  	if (pde)
567  		pde->rec_len = nilfs_rec_len_to_disk(to - from);
568  	dir->inode = 0;
569  	nilfs_commit_chunk(page, mapping, from, to);
570  	inode->i_ctime = inode->i_mtime = current_time(inode);
571  out:
572  	nilfs_put_page(page);
573  	return err;
574  }
575  
576  /*
577   * Set the first fragment of directory.
578   */
579  int nilfs_make_empty(struct inode *inode, struct inode *parent)
580  {
581  	struct address_space *mapping = inode->i_mapping;
582  	struct page *page = grab_cache_page(mapping, 0);
583  	unsigned int chunk_size = nilfs_chunk_size(inode);
584  	struct nilfs_dir_entry *de;
585  	int err;
586  	void *kaddr;
587  
588  	if (!page)
589  		return -ENOMEM;
590  
591  	err = nilfs_prepare_chunk(page, 0, chunk_size);
592  	if (unlikely(err)) {
593  		unlock_page(page);
594  		goto fail;
595  	}
596  	kaddr = kmap_atomic(page);
597  	memset(kaddr, 0, chunk_size);
598  	de = (struct nilfs_dir_entry *)kaddr;
599  	de->name_len = 1;
600  	de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
601  	memcpy(de->name, ".\0\0", 4);
602  	de->inode = cpu_to_le64(inode->i_ino);
603  	nilfs_set_de_type(de, inode);
604  
605  	de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
606  	de->name_len = 2;
607  	de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
608  	de->inode = cpu_to_le64(parent->i_ino);
609  	memcpy(de->name, "..\0", 4);
610  	nilfs_set_de_type(de, inode);
611  	kunmap_atomic(kaddr);
612  	nilfs_commit_chunk(page, mapping, 0, chunk_size);
613  fail:
614  	put_page(page);
615  	return err;
616  }
617  
618  /*
619   * routine to check that the specified directory is empty (for rmdir)
620   */
621  int nilfs_empty_dir(struct inode *inode)
622  {
623  	struct page *page = NULL;
624  	unsigned long i, npages = dir_pages(inode);
625  
626  	for (i = 0; i < npages; i++) {
627  		char *kaddr;
628  		struct nilfs_dir_entry *de;
629  
630  		page = nilfs_get_page(inode, i);
631  		if (IS_ERR(page))
632  			continue;
633  
634  		kaddr = page_address(page);
635  		de = (struct nilfs_dir_entry *)kaddr;
636  		kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
637  
638  		while ((char *)de <= kaddr) {
639  			if (de->rec_len == 0) {
640  				nilfs_error(inode->i_sb,
641  					    "zero-length directory entry (kaddr=%p, de=%p)",
642  					    kaddr, de);
643  				goto not_empty;
644  			}
645  			if (de->inode != 0) {
646  				/* check for . and .. */
647  				if (de->name[0] != '.')
648  					goto not_empty;
649  				if (de->name_len > 2)
650  					goto not_empty;
651  				if (de->name_len < 2) {
652  					if (de->inode !=
653  					    cpu_to_le64(inode->i_ino))
654  						goto not_empty;
655  				} else if (de->name[1] != '.')
656  					goto not_empty;
657  			}
658  			de = nilfs_next_entry(de);
659  		}
660  		nilfs_put_page(page);
661  	}
662  	return 1;
663  
664  not_empty:
665  	nilfs_put_page(page);
666  	return 0;
667  }
668  
669  const struct file_operations nilfs_dir_operations = {
670  	.llseek		= generic_file_llseek,
671  	.read		= generic_read_dir,
672  	.iterate_shared	= nilfs_readdir,
673  	.unlocked_ioctl	= nilfs_ioctl,
674  #ifdef CONFIG_COMPAT
675  	.compat_ioctl	= nilfs_compat_ioctl,
676  #endif	/* CONFIG_COMPAT */
677  	.fsync		= nilfs_sync_file,
678  
679  };
680