xref: /openbmc/linux/fs/f2fs/dir.c (revision 3843154598a00408f4214a68bd536fdf27b1df10)
1 /*
2  * fs/f2fs/dir.c
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <linux/fs.h>
12 #include <linux/f2fs_fs.h>
13 #include "f2fs.h"
14 #include "node.h"
15 #include "acl.h"
16 #include "xattr.h"
17 
18 static unsigned long dir_blocks(struct inode *inode)
19 {
20 	return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))
21 							>> PAGE_CACHE_SHIFT;
22 }
23 
24 static unsigned int dir_buckets(unsigned int level, int dir_level)
25 {
26 	if (level < MAX_DIR_HASH_DEPTH / 2)
27 		return 1 << (level + dir_level);
28 	else
29 		return 1 << ((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1);
30 }
31 
32 static unsigned int bucket_blocks(unsigned int level)
33 {
34 	if (level < MAX_DIR_HASH_DEPTH / 2)
35 		return 2;
36 	else
37 		return 4;
38 }
39 
40 static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
41 	[F2FS_FT_UNKNOWN]	= DT_UNKNOWN,
42 	[F2FS_FT_REG_FILE]	= DT_REG,
43 	[F2FS_FT_DIR]		= DT_DIR,
44 	[F2FS_FT_CHRDEV]	= DT_CHR,
45 	[F2FS_FT_BLKDEV]	= DT_BLK,
46 	[F2FS_FT_FIFO]		= DT_FIFO,
47 	[F2FS_FT_SOCK]		= DT_SOCK,
48 	[F2FS_FT_SYMLINK]	= DT_LNK,
49 };
50 
51 #define S_SHIFT 12
52 static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
53 	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,
54 	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,
55 	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,
56 	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,
57 	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,
58 	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,
59 	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
60 };
61 
62 static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
63 {
64 	umode_t mode = inode->i_mode;
65 	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
66 }
67 
68 static unsigned long dir_block_index(unsigned int level,
69 				int dir_level, unsigned int idx)
70 {
71 	unsigned long i;
72 	unsigned long bidx = 0;
73 
74 	for (i = 0; i < level; i++)
75 		bidx += dir_buckets(i, dir_level) * bucket_blocks(i);
76 	bidx += idx * bucket_blocks(level);
77 	return bidx;
78 }
79 
80 static bool early_match_name(const char *name, size_t namelen,
81 			f2fs_hash_t namehash, struct f2fs_dir_entry *de)
82 {
83 	if (le16_to_cpu(de->name_len) != namelen)
84 		return false;
85 
86 	if (de->hash_code != namehash)
87 		return false;
88 
89 	return true;
90 }
91 
92 static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
93 			const char *name, size_t namelen, int *max_slots,
94 			f2fs_hash_t namehash, struct page **res_page)
95 {
96 	struct f2fs_dir_entry *de;
97 	unsigned long bit_pos = 0;
98 	struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
99 	int max_len = 0;
100 
101 	while (bit_pos < NR_DENTRY_IN_BLOCK) {
102 		de = &dentry_blk->dentry[bit_pos];
103 		if (!test_bit_le(bit_pos, &dentry_blk->dentry_bitmap)) {
104 			if (bit_pos == 0)
105 				max_len = 1;
106 			else if (!test_bit_le(bit_pos - 1, &dentry_blk->dentry_bitmap))
107 				max_len++;
108 			bit_pos++;
109 			continue;
110 		}
111 		if (early_match_name(name, namelen, namehash, de)) {
112 			if (!memcmp(dentry_blk->filename[bit_pos],
113 							name, namelen)) {
114 				*res_page = dentry_page;
115 				goto found;
116 			}
117 		}
118 		if (max_len > *max_slots) {
119 			*max_slots = max_len;
120 			max_len = 0;
121 		}
122 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
123 	}
124 
125 	de = NULL;
126 	kunmap(dentry_page);
127 found:
128 	if (max_len > *max_slots)
129 		*max_slots = max_len;
130 	return de;
131 }
132 
133 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
134 		unsigned int level, const char *name, size_t namelen,
135 			f2fs_hash_t namehash, struct page **res_page)
136 {
137 	int s = GET_DENTRY_SLOTS(namelen);
138 	unsigned int nbucket, nblock;
139 	unsigned int bidx, end_block;
140 	struct page *dentry_page;
141 	struct f2fs_dir_entry *de = NULL;
142 	bool room = false;
143 	int max_slots = 0;
144 
145 	f2fs_bug_on(level > MAX_DIR_HASH_DEPTH);
146 
147 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
148 	nblock = bucket_blocks(level);
149 
150 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
151 					le32_to_cpu(namehash) % nbucket);
152 	end_block = bidx + nblock;
153 
154 	for (; bidx < end_block; bidx++) {
155 		/* no need to allocate new dentry pages to all the indices */
156 		dentry_page = find_data_page(dir, bidx, true);
157 		if (IS_ERR(dentry_page)) {
158 			room = true;
159 			continue;
160 		}
161 
162 		de = find_in_block(dentry_page, name, namelen,
163 					&max_slots, namehash, res_page);
164 		if (de)
165 			break;
166 
167 		if (max_slots >= s)
168 			room = true;
169 		f2fs_put_page(dentry_page, 0);
170 	}
171 
172 	if (!de && room && F2FS_I(dir)->chash != namehash) {
173 		F2FS_I(dir)->chash = namehash;
174 		F2FS_I(dir)->clevel = level;
175 	}
176 
177 	return de;
178 }
179 
180 /*
181  * Find an entry in the specified directory with the wanted name.
182  * It returns the page where the entry was found (as a parameter - res_page),
183  * and the entry itself. Page is returned mapped and unlocked.
184  * Entry is guaranteed to be valid.
185  */
186 struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
187 			struct qstr *child, struct page **res_page)
188 {
189 	const char *name = child->name;
190 	size_t namelen = child->len;
191 	unsigned long npages = dir_blocks(dir);
192 	struct f2fs_dir_entry *de = NULL;
193 	f2fs_hash_t name_hash;
194 	unsigned int max_depth;
195 	unsigned int level;
196 
197 	if (npages == 0)
198 		return NULL;
199 
200 	*res_page = NULL;
201 
202 	name_hash = f2fs_dentry_hash(name, namelen);
203 	max_depth = F2FS_I(dir)->i_current_depth;
204 
205 	for (level = 0; level < max_depth; level++) {
206 		de = find_in_level(dir, level, name,
207 				namelen, name_hash, res_page);
208 		if (de)
209 			break;
210 	}
211 	if (!de && F2FS_I(dir)->chash != name_hash) {
212 		F2FS_I(dir)->chash = name_hash;
213 		F2FS_I(dir)->clevel = level - 1;
214 	}
215 	return de;
216 }
217 
218 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
219 {
220 	struct page *page;
221 	struct f2fs_dir_entry *de;
222 	struct f2fs_dentry_block *dentry_blk;
223 
224 	page = get_lock_data_page(dir, 0);
225 	if (IS_ERR(page))
226 		return NULL;
227 
228 	dentry_blk = kmap(page);
229 	de = &dentry_blk->dentry[1];
230 	*p = page;
231 	unlock_page(page);
232 	return de;
233 }
234 
235 ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
236 {
237 	ino_t res = 0;
238 	struct f2fs_dir_entry *de;
239 	struct page *page;
240 
241 	de = f2fs_find_entry(dir, qstr, &page);
242 	if (de) {
243 		res = le32_to_cpu(de->ino);
244 		kunmap(page);
245 		f2fs_put_page(page, 0);
246 	}
247 
248 	return res;
249 }
250 
251 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
252 		struct page *page, struct inode *inode)
253 {
254 	lock_page(page);
255 	wait_on_page_writeback(page);
256 	de->ino = cpu_to_le32(inode->i_ino);
257 	set_de_type(de, inode);
258 	kunmap(page);
259 	set_page_dirty(page);
260 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
261 	mark_inode_dirty(dir);
262 
263 	f2fs_put_page(page, 1);
264 }
265 
266 static void init_dent_inode(const struct qstr *name, struct page *ipage)
267 {
268 	struct f2fs_inode *ri;
269 
270 	/* copy name info. to this inode page */
271 	ri = F2FS_INODE(ipage);
272 	ri->i_namelen = cpu_to_le32(name->len);
273 	memcpy(ri->i_name, name->name, name->len);
274 	set_page_dirty(ipage);
275 }
276 
277 int update_dent_inode(struct inode *inode, const struct qstr *name)
278 {
279 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
280 	struct page *page;
281 
282 	page = get_node_page(sbi, inode->i_ino);
283 	if (IS_ERR(page))
284 		return PTR_ERR(page);
285 
286 	init_dent_inode(name, page);
287 	f2fs_put_page(page, 1);
288 
289 	return 0;
290 }
291 
292 static int make_empty_dir(struct inode *inode,
293 		struct inode *parent, struct page *page)
294 {
295 	struct page *dentry_page;
296 	struct f2fs_dentry_block *dentry_blk;
297 	struct f2fs_dir_entry *de;
298 	void *kaddr;
299 
300 	dentry_page = get_new_data_page(inode, page, 0, true);
301 	if (IS_ERR(dentry_page))
302 		return PTR_ERR(dentry_page);
303 
304 	kaddr = kmap_atomic(dentry_page);
305 	dentry_blk = (struct f2fs_dentry_block *)kaddr;
306 
307 	de = &dentry_blk->dentry[0];
308 	de->name_len = cpu_to_le16(1);
309 	de->hash_code = 0;
310 	de->ino = cpu_to_le32(inode->i_ino);
311 	memcpy(dentry_blk->filename[0], ".", 1);
312 	set_de_type(de, inode);
313 
314 	de = &dentry_blk->dentry[1];
315 	de->hash_code = 0;
316 	de->name_len = cpu_to_le16(2);
317 	de->ino = cpu_to_le32(parent->i_ino);
318 	memcpy(dentry_blk->filename[1], "..", 2);
319 	set_de_type(de, inode);
320 
321 	test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
322 	test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
323 	kunmap_atomic(kaddr);
324 
325 	set_page_dirty(dentry_page);
326 	f2fs_put_page(dentry_page, 1);
327 	return 0;
328 }
329 
330 static struct page *init_inode_metadata(struct inode *inode,
331 		struct inode *dir, const struct qstr *name)
332 {
333 	struct page *page;
334 	int err;
335 
336 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
337 		page = new_inode_page(inode, name);
338 		if (IS_ERR(page))
339 			return page;
340 
341 		if (S_ISDIR(inode->i_mode)) {
342 			err = make_empty_dir(inode, dir, page);
343 			if (err)
344 				goto error;
345 		}
346 
347 		err = f2fs_init_acl(inode, dir, page);
348 		if (err)
349 			goto put_error;
350 
351 		err = f2fs_init_security(inode, dir, name, page);
352 		if (err)
353 			goto put_error;
354 
355 		wait_on_page_writeback(page);
356 	} else {
357 		page = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
358 		if (IS_ERR(page))
359 			return page;
360 
361 		wait_on_page_writeback(page);
362 		set_cold_node(inode, page);
363 	}
364 
365 	init_dent_inode(name, page);
366 
367 	/*
368 	 * This file should be checkpointed during fsync.
369 	 * We lost i_pino from now on.
370 	 */
371 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
372 		file_lost_pino(inode);
373 		inc_nlink(inode);
374 	}
375 	return page;
376 
377 put_error:
378 	f2fs_put_page(page, 1);
379 	/* once the failed inode becomes a bad inode, i_mode is S_IFREG */
380 	truncate_inode_pages(&inode->i_data, 0);
381 	truncate_blocks(inode, 0);
382 	remove_dirty_dir_inode(inode);
383 error:
384 	remove_inode_page(inode);
385 	return ERR_PTR(err);
386 }
387 
388 static void update_parent_metadata(struct inode *dir, struct inode *inode,
389 						unsigned int current_depth)
390 {
391 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
392 		if (S_ISDIR(inode->i_mode)) {
393 			inc_nlink(dir);
394 			set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
395 		}
396 		clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
397 	}
398 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
399 	mark_inode_dirty(dir);
400 
401 	if (F2FS_I(dir)->i_current_depth != current_depth) {
402 		F2FS_I(dir)->i_current_depth = current_depth;
403 		set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
404 	}
405 
406 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
407 		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
408 }
409 
410 static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
411 {
412 	int bit_start = 0;
413 	int zero_start, zero_end;
414 next:
415 	zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
416 						NR_DENTRY_IN_BLOCK,
417 						bit_start);
418 	if (zero_start >= NR_DENTRY_IN_BLOCK)
419 		return NR_DENTRY_IN_BLOCK;
420 
421 	zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
422 						NR_DENTRY_IN_BLOCK,
423 						zero_start);
424 	if (zero_end - zero_start >= slots)
425 		return zero_start;
426 
427 	bit_start = zero_end + 1;
428 
429 	if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
430 		return NR_DENTRY_IN_BLOCK;
431 	goto next;
432 }
433 
434 /*
435  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
436  * f2fs_unlock_op().
437  */
438 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
439 						struct inode *inode)
440 {
441 	unsigned int bit_pos;
442 	unsigned int level;
443 	unsigned int current_depth;
444 	unsigned long bidx, block;
445 	f2fs_hash_t dentry_hash;
446 	struct f2fs_dir_entry *de;
447 	unsigned int nbucket, nblock;
448 	size_t namelen = name->len;
449 	struct page *dentry_page = NULL;
450 	struct f2fs_dentry_block *dentry_blk = NULL;
451 	int slots = GET_DENTRY_SLOTS(namelen);
452 	struct page *page;
453 	int err = 0;
454 	int i;
455 
456 	dentry_hash = f2fs_dentry_hash(name->name, name->len);
457 	level = 0;
458 	current_depth = F2FS_I(dir)->i_current_depth;
459 	if (F2FS_I(dir)->chash == dentry_hash) {
460 		level = F2FS_I(dir)->clevel;
461 		F2FS_I(dir)->chash = 0;
462 	}
463 
464 start:
465 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
466 		return -ENOSPC;
467 
468 	/* Increase the depth, if required */
469 	if (level == current_depth)
470 		++current_depth;
471 
472 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
473 	nblock = bucket_blocks(level);
474 
475 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
476 				(le32_to_cpu(dentry_hash) % nbucket));
477 
478 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
479 		dentry_page = get_new_data_page(dir, NULL, block, true);
480 		if (IS_ERR(dentry_page))
481 			return PTR_ERR(dentry_page);
482 
483 		dentry_blk = kmap(dentry_page);
484 		bit_pos = room_for_filename(dentry_blk, slots);
485 		if (bit_pos < NR_DENTRY_IN_BLOCK)
486 			goto add_dentry;
487 
488 		kunmap(dentry_page);
489 		f2fs_put_page(dentry_page, 1);
490 	}
491 
492 	/* Move to next level to find the empty slot for new dentry */
493 	++level;
494 	goto start;
495 add_dentry:
496 	wait_on_page_writeback(dentry_page);
497 
498 	page = init_inode_metadata(inode, dir, name);
499 	if (IS_ERR(page)) {
500 		err = PTR_ERR(page);
501 		goto fail;
502 	}
503 	de = &dentry_blk->dentry[bit_pos];
504 	de->hash_code = dentry_hash;
505 	de->name_len = cpu_to_le16(namelen);
506 	memcpy(dentry_blk->filename[bit_pos], name->name, name->len);
507 	de->ino = cpu_to_le32(inode->i_ino);
508 	set_de_type(de, inode);
509 	for (i = 0; i < slots; i++)
510 		test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
511 	set_page_dirty(dentry_page);
512 
513 	/* we don't need to mark_inode_dirty now */
514 	F2FS_I(inode)->i_pino = dir->i_ino;
515 	update_inode(inode, page);
516 	f2fs_put_page(page, 1);
517 
518 	update_parent_metadata(dir, inode, current_depth);
519 fail:
520 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
521 		update_inode_page(dir);
522 		clear_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
523 	}
524 	kunmap(dentry_page);
525 	f2fs_put_page(dentry_page, 1);
526 	return err;
527 }
528 
529 /*
530  * It only removes the dentry from the dentry page,corresponding name
531  * entry in name page does not need to be touched during deletion.
532  */
533 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
534 						struct inode *inode)
535 {
536 	struct	f2fs_dentry_block *dentry_blk;
537 	unsigned int bit_pos;
538 	struct address_space *mapping = page->mapping;
539 	struct inode *dir = mapping->host;
540 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
541 	void *kaddr = page_address(page);
542 	int i;
543 
544 	lock_page(page);
545 	wait_on_page_writeback(page);
546 
547 	dentry_blk = (struct f2fs_dentry_block *)kaddr;
548 	bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
549 	for (i = 0; i < slots; i++)
550 		test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
551 
552 	/* Let's check and deallocate this dentry page */
553 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
554 			NR_DENTRY_IN_BLOCK,
555 			0);
556 	kunmap(page); /* kunmap - pair of f2fs_find_entry */
557 	set_page_dirty(page);
558 
559 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
560 
561 	if (inode) {
562 		struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
563 
564 		if (S_ISDIR(inode->i_mode)) {
565 			drop_nlink(dir);
566 			update_inode_page(dir);
567 		}
568 		inode->i_ctime = CURRENT_TIME;
569 		drop_nlink(inode);
570 		if (S_ISDIR(inode->i_mode)) {
571 			drop_nlink(inode);
572 			i_size_write(inode, 0);
573 		}
574 		update_inode_page(inode);
575 
576 		if (inode->i_nlink == 0)
577 			add_orphan_inode(sbi, inode->i_ino);
578 		else
579 			release_orphan_inode(sbi);
580 	}
581 
582 	if (bit_pos == NR_DENTRY_IN_BLOCK) {
583 		truncate_hole(dir, page->index, page->index + 1);
584 		clear_page_dirty_for_io(page);
585 		ClearPageUptodate(page);
586 		inode_dec_dirty_dents(dir);
587 	}
588 	f2fs_put_page(page, 1);
589 }
590 
591 bool f2fs_empty_dir(struct inode *dir)
592 {
593 	unsigned long bidx;
594 	struct page *dentry_page;
595 	unsigned int bit_pos;
596 	struct	f2fs_dentry_block *dentry_blk;
597 	unsigned long nblock = dir_blocks(dir);
598 
599 	for (bidx = 0; bidx < nblock; bidx++) {
600 		void *kaddr;
601 		dentry_page = get_lock_data_page(dir, bidx);
602 		if (IS_ERR(dentry_page)) {
603 			if (PTR_ERR(dentry_page) == -ENOENT)
604 				continue;
605 			else
606 				return false;
607 		}
608 
609 		kaddr = kmap_atomic(dentry_page);
610 		dentry_blk = (struct f2fs_dentry_block *)kaddr;
611 		if (bidx == 0)
612 			bit_pos = 2;
613 		else
614 			bit_pos = 0;
615 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
616 						NR_DENTRY_IN_BLOCK,
617 						bit_pos);
618 		kunmap_atomic(kaddr);
619 
620 		f2fs_put_page(dentry_page, 1);
621 
622 		if (bit_pos < NR_DENTRY_IN_BLOCK)
623 			return false;
624 	}
625 	return true;
626 }
627 
628 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
629 {
630 	struct inode *inode = file_inode(file);
631 	unsigned long npages = dir_blocks(inode);
632 	unsigned int bit_pos = 0;
633 	struct f2fs_dentry_block *dentry_blk = NULL;
634 	struct f2fs_dir_entry *de = NULL;
635 	struct page *dentry_page = NULL;
636 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
637 	unsigned char d_type = DT_UNKNOWN;
638 
639 	bit_pos = ((unsigned long)ctx->pos % NR_DENTRY_IN_BLOCK);
640 
641 	for (; n < npages; n++) {
642 		dentry_page = get_lock_data_page(inode, n);
643 		if (IS_ERR(dentry_page))
644 			continue;
645 
646 		dentry_blk = kmap(dentry_page);
647 		while (bit_pos < NR_DENTRY_IN_BLOCK) {
648 			bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
649 							NR_DENTRY_IN_BLOCK,
650 							bit_pos);
651 			if (bit_pos >= NR_DENTRY_IN_BLOCK)
652 				break;
653 
654 			de = &dentry_blk->dentry[bit_pos];
655 			if (de->file_type < F2FS_FT_MAX)
656 				d_type = f2fs_filetype_table[de->file_type];
657 			else
658 				d_type = DT_UNKNOWN;
659 			if (!dir_emit(ctx,
660 					dentry_blk->filename[bit_pos],
661 					le16_to_cpu(de->name_len),
662 					le32_to_cpu(de->ino), d_type))
663 				goto stop;
664 
665 			bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
666 			ctx->pos = n * NR_DENTRY_IN_BLOCK + bit_pos;
667 		}
668 		bit_pos = 0;
669 		ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
670 		kunmap(dentry_page);
671 		f2fs_put_page(dentry_page, 1);
672 		dentry_page = NULL;
673 	}
674 stop:
675 	if (dentry_page && !IS_ERR(dentry_page)) {
676 		kunmap(dentry_page);
677 		f2fs_put_page(dentry_page, 1);
678 	}
679 
680 	return 0;
681 }
682 
683 const struct file_operations f2fs_dir_operations = {
684 	.llseek		= generic_file_llseek,
685 	.read		= generic_read_dir,
686 	.iterate	= f2fs_readdir,
687 	.fsync		= f2fs_sync_file,
688 	.unlocked_ioctl	= f2fs_ioctl,
689 };
690