xref: /openbmc/linux/fs/f2fs/dir.c (revision a014e037be26b5c9ee6fb4e49e7804141cf3bb89)
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 + dir_level < MAX_DIR_HASH_DEPTH / 2)
27 		return 1 << (level + dir_level);
28 	else
29 		return MAX_DIR_BUCKETS;
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 	const void *dentry_bits = &dentry_blk->dentry_bitmap;
100 	int max_len = 0;
101 
102 	while (bit_pos < NR_DENTRY_IN_BLOCK) {
103 		if (!test_bit_le(bit_pos, dentry_bits)) {
104 			if (bit_pos == 0)
105 				max_len = 1;
106 			else if (!test_bit_le(bit_pos - 1, dentry_bits))
107 				max_len++;
108 			bit_pos++;
109 			continue;
110 		}
111 		de = &dentry_blk->dentry[bit_pos];
112 		if (early_match_name(name, namelen, namehash, de)) {
113 			if (!memcmp(dentry_blk->filename[bit_pos],
114 							name, namelen)) {
115 				*res_page = dentry_page;
116 				goto found;
117 			}
118 		}
119 		if (max_len > *max_slots) {
120 			*max_slots = max_len;
121 			max_len = 0;
122 		}
123 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
124 	}
125 
126 	de = NULL;
127 	kunmap(dentry_page);
128 found:
129 	if (max_len > *max_slots)
130 		*max_slots = max_len;
131 	return de;
132 }
133 
134 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
135 		unsigned int level, const char *name, size_t namelen,
136 			f2fs_hash_t namehash, struct page **res_page)
137 {
138 	int s = GET_DENTRY_SLOTS(namelen);
139 	unsigned int nbucket, nblock;
140 	unsigned int bidx, end_block;
141 	struct page *dentry_page;
142 	struct f2fs_dir_entry *de = NULL;
143 	bool room = false;
144 	int max_slots = 0;
145 
146 	f2fs_bug_on(level > MAX_DIR_HASH_DEPTH);
147 
148 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
149 	nblock = bucket_blocks(level);
150 
151 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
152 					le32_to_cpu(namehash) % nbucket);
153 	end_block = bidx + nblock;
154 
155 	for (; bidx < end_block; bidx++) {
156 		/* no need to allocate new dentry pages to all the indices */
157 		dentry_page = find_data_page(dir, bidx, true);
158 		if (IS_ERR(dentry_page)) {
159 			room = true;
160 			continue;
161 		}
162 
163 		de = find_in_block(dentry_page, name, namelen,
164 					&max_slots, namehash, res_page);
165 		if (de)
166 			break;
167 
168 		if (max_slots >= s)
169 			room = true;
170 		f2fs_put_page(dentry_page, 0);
171 	}
172 
173 	if (!de && room && F2FS_I(dir)->chash != namehash) {
174 		F2FS_I(dir)->chash = namehash;
175 		F2FS_I(dir)->clevel = level;
176 	}
177 
178 	return de;
179 }
180 
181 /*
182  * Find an entry in the specified directory with the wanted name.
183  * It returns the page where the entry was found (as a parameter - res_page),
184  * and the entry itself. Page is returned mapped and unlocked.
185  * Entry is guaranteed to be valid.
186  */
187 struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
188 			struct qstr *child, struct page **res_page)
189 {
190 	const char *name = child->name;
191 	size_t namelen = child->len;
192 	unsigned long npages = dir_blocks(dir);
193 	struct f2fs_dir_entry *de = NULL;
194 	f2fs_hash_t name_hash;
195 	unsigned int max_depth;
196 	unsigned int level;
197 
198 	if (npages == 0)
199 		return NULL;
200 
201 	*res_page = NULL;
202 
203 	name_hash = f2fs_dentry_hash(name, namelen);
204 	max_depth = F2FS_I(dir)->i_current_depth;
205 
206 	for (level = 0; level < max_depth; level++) {
207 		de = find_in_level(dir, level, name,
208 				namelen, name_hash, res_page);
209 		if (de)
210 			break;
211 	}
212 	if (!de && F2FS_I(dir)->chash != name_hash) {
213 		F2FS_I(dir)->chash = name_hash;
214 		F2FS_I(dir)->clevel = level - 1;
215 	}
216 	return de;
217 }
218 
219 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
220 {
221 	struct page *page;
222 	struct f2fs_dir_entry *de;
223 	struct f2fs_dentry_block *dentry_blk;
224 
225 	page = get_lock_data_page(dir, 0);
226 	if (IS_ERR(page))
227 		return NULL;
228 
229 	dentry_blk = kmap(page);
230 	de = &dentry_blk->dentry[1];
231 	*p = page;
232 	unlock_page(page);
233 	return de;
234 }
235 
236 ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
237 {
238 	ino_t res = 0;
239 	struct f2fs_dir_entry *de;
240 	struct page *page;
241 
242 	de = f2fs_find_entry(dir, qstr, &page);
243 	if (de) {
244 		res = le32_to_cpu(de->ino);
245 		kunmap(page);
246 		f2fs_put_page(page, 0);
247 	}
248 
249 	return res;
250 }
251 
252 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
253 		struct page *page, struct inode *inode)
254 {
255 	lock_page(page);
256 	f2fs_wait_on_page_writeback(page, DATA);
257 	de->ino = cpu_to_le32(inode->i_ino);
258 	set_de_type(de, inode);
259 	kunmap(page);
260 	set_page_dirty(page);
261 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
262 	mark_inode_dirty(dir);
263 
264 	f2fs_put_page(page, 1);
265 }
266 
267 static void init_dent_inode(const struct qstr *name, struct page *ipage)
268 {
269 	struct f2fs_inode *ri;
270 
271 	f2fs_wait_on_page_writeback(ipage, NODE);
272 
273 	/* copy name info. to this inode page */
274 	ri = F2FS_INODE(ipage);
275 	ri->i_namelen = cpu_to_le32(name->len);
276 	memcpy(ri->i_name, name->name, name->len);
277 	set_page_dirty(ipage);
278 }
279 
280 int update_dent_inode(struct inode *inode, const struct qstr *name)
281 {
282 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
283 	struct page *page;
284 
285 	page = get_node_page(sbi, inode->i_ino);
286 	if (IS_ERR(page))
287 		return PTR_ERR(page);
288 
289 	init_dent_inode(name, page);
290 	f2fs_put_page(page, 1);
291 
292 	return 0;
293 }
294 
295 static int make_empty_dir(struct inode *inode,
296 		struct inode *parent, struct page *page)
297 {
298 	struct page *dentry_page;
299 	struct f2fs_dentry_block *dentry_blk;
300 	struct f2fs_dir_entry *de;
301 	void *kaddr;
302 
303 	dentry_page = get_new_data_page(inode, page, 0, true);
304 	if (IS_ERR(dentry_page))
305 		return PTR_ERR(dentry_page);
306 
307 	kaddr = kmap_atomic(dentry_page);
308 	dentry_blk = (struct f2fs_dentry_block *)kaddr;
309 
310 	de = &dentry_blk->dentry[0];
311 	de->name_len = cpu_to_le16(1);
312 	de->hash_code = 0;
313 	de->ino = cpu_to_le32(inode->i_ino);
314 	memcpy(dentry_blk->filename[0], ".", 1);
315 	set_de_type(de, inode);
316 
317 	de = &dentry_blk->dentry[1];
318 	de->hash_code = 0;
319 	de->name_len = cpu_to_le16(2);
320 	de->ino = cpu_to_le32(parent->i_ino);
321 	memcpy(dentry_blk->filename[1], "..", 2);
322 	set_de_type(de, inode);
323 
324 	test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
325 	test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
326 	kunmap_atomic(kaddr);
327 
328 	set_page_dirty(dentry_page);
329 	f2fs_put_page(dentry_page, 1);
330 	return 0;
331 }
332 
333 static struct page *init_inode_metadata(struct inode *inode,
334 		struct inode *dir, const struct qstr *name)
335 {
336 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
337 	struct page *page;
338 	int err;
339 
340 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
341 		page = new_inode_page(inode);
342 		if (IS_ERR(page))
343 			return page;
344 
345 		if (S_ISDIR(inode->i_mode)) {
346 			err = make_empty_dir(inode, dir, page);
347 			if (err)
348 				goto error;
349 		}
350 
351 		err = f2fs_init_acl(inode, dir, page);
352 		if (err)
353 			goto put_error;
354 
355 		err = f2fs_init_security(inode, dir, name, page);
356 		if (err)
357 			goto put_error;
358 	} else {
359 		page = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
360 		if (IS_ERR(page))
361 			return page;
362 
363 		set_cold_node(inode, page);
364 	}
365 
366 	if (name)
367 		init_dent_inode(name, page);
368 
369 	/*
370 	 * This file should be checkpointed during fsync.
371 	 * We lost i_pino from now on.
372 	 */
373 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
374 		file_lost_pino(inode);
375 		/*
376 		 * If link the tmpfile to alias through linkat path,
377 		 * we should remove this inode from orphan list.
378 		 */
379 		if (inode->i_nlink == 0)
380 			remove_orphan_inode(sbi, inode->i_ino);
381 		inc_nlink(inode);
382 	}
383 	return page;
384 
385 put_error:
386 	f2fs_put_page(page, 1);
387 error:
388 	/* once the failed inode becomes a bad inode, i_mode is S_IFREG */
389 	truncate_inode_pages(&inode->i_data, 0);
390 	truncate_blocks(inode, 0);
391 	remove_dirty_dir_inode(inode);
392 	remove_inode_page(inode);
393 	return ERR_PTR(err);
394 }
395 
396 static void update_parent_metadata(struct inode *dir, struct inode *inode,
397 						unsigned int current_depth)
398 {
399 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
400 		if (S_ISDIR(inode->i_mode)) {
401 			inc_nlink(dir);
402 			set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
403 		}
404 		clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
405 	}
406 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
407 	mark_inode_dirty(dir);
408 
409 	if (F2FS_I(dir)->i_current_depth != current_depth) {
410 		F2FS_I(dir)->i_current_depth = current_depth;
411 		set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
412 	}
413 
414 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
415 		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
416 }
417 
418 static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
419 {
420 	int bit_start = 0;
421 	int zero_start, zero_end;
422 next:
423 	zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
424 						NR_DENTRY_IN_BLOCK,
425 						bit_start);
426 	if (zero_start >= NR_DENTRY_IN_BLOCK)
427 		return NR_DENTRY_IN_BLOCK;
428 
429 	zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
430 						NR_DENTRY_IN_BLOCK,
431 						zero_start);
432 	if (zero_end - zero_start >= slots)
433 		return zero_start;
434 
435 	bit_start = zero_end + 1;
436 
437 	if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
438 		return NR_DENTRY_IN_BLOCK;
439 	goto next;
440 }
441 
442 /*
443  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
444  * f2fs_unlock_op().
445  */
446 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
447 						struct inode *inode)
448 {
449 	unsigned int bit_pos;
450 	unsigned int level;
451 	unsigned int current_depth;
452 	unsigned long bidx, block;
453 	f2fs_hash_t dentry_hash;
454 	struct f2fs_dir_entry *de;
455 	unsigned int nbucket, nblock;
456 	size_t namelen = name->len;
457 	struct page *dentry_page = NULL;
458 	struct f2fs_dentry_block *dentry_blk = NULL;
459 	int slots = GET_DENTRY_SLOTS(namelen);
460 	struct page *page;
461 	int err = 0;
462 	int i;
463 
464 	dentry_hash = f2fs_dentry_hash(name->name, name->len);
465 	level = 0;
466 	current_depth = F2FS_I(dir)->i_current_depth;
467 	if (F2FS_I(dir)->chash == dentry_hash) {
468 		level = F2FS_I(dir)->clevel;
469 		F2FS_I(dir)->chash = 0;
470 	}
471 
472 start:
473 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
474 		return -ENOSPC;
475 
476 	/* Increase the depth, if required */
477 	if (level == current_depth)
478 		++current_depth;
479 
480 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
481 	nblock = bucket_blocks(level);
482 
483 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
484 				(le32_to_cpu(dentry_hash) % nbucket));
485 
486 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
487 		dentry_page = get_new_data_page(dir, NULL, block, true);
488 		if (IS_ERR(dentry_page))
489 			return PTR_ERR(dentry_page);
490 
491 		dentry_blk = kmap(dentry_page);
492 		bit_pos = room_for_filename(dentry_blk, slots);
493 		if (bit_pos < NR_DENTRY_IN_BLOCK)
494 			goto add_dentry;
495 
496 		kunmap(dentry_page);
497 		f2fs_put_page(dentry_page, 1);
498 	}
499 
500 	/* Move to next level to find the empty slot for new dentry */
501 	++level;
502 	goto start;
503 add_dentry:
504 	f2fs_wait_on_page_writeback(dentry_page, DATA);
505 
506 	down_write(&F2FS_I(inode)->i_sem);
507 	page = init_inode_metadata(inode, dir, name);
508 	if (IS_ERR(page)) {
509 		err = PTR_ERR(page);
510 		goto fail;
511 	}
512 	de = &dentry_blk->dentry[bit_pos];
513 	de->hash_code = dentry_hash;
514 	de->name_len = cpu_to_le16(namelen);
515 	memcpy(dentry_blk->filename[bit_pos], name->name, name->len);
516 	de->ino = cpu_to_le32(inode->i_ino);
517 	set_de_type(de, inode);
518 	for (i = 0; i < slots; i++)
519 		test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
520 	set_page_dirty(dentry_page);
521 
522 	/* we don't need to mark_inode_dirty now */
523 	F2FS_I(inode)->i_pino = dir->i_ino;
524 	update_inode(inode, page);
525 	f2fs_put_page(page, 1);
526 
527 	update_parent_metadata(dir, inode, current_depth);
528 fail:
529 	up_write(&F2FS_I(inode)->i_sem);
530 
531 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
532 		update_inode_page(dir);
533 		clear_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
534 	}
535 	kunmap(dentry_page);
536 	f2fs_put_page(dentry_page, 1);
537 	return err;
538 }
539 
540 int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
541 {
542 	struct page *page;
543 	int err = 0;
544 
545 	down_write(&F2FS_I(inode)->i_sem);
546 	page = init_inode_metadata(inode, dir, NULL);
547 	if (IS_ERR(page)) {
548 		err = PTR_ERR(page);
549 		goto fail;
550 	}
551 	/* we don't need to mark_inode_dirty now */
552 	update_inode(inode, page);
553 	f2fs_put_page(page, 1);
554 
555 	clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
556 fail:
557 	up_write(&F2FS_I(inode)->i_sem);
558 	return err;
559 }
560 
561 /*
562  * It only removes the dentry from the dentry page,corresponding name
563  * entry in name page does not need to be touched during deletion.
564  */
565 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
566 						struct inode *inode)
567 {
568 	struct	f2fs_dentry_block *dentry_blk;
569 	unsigned int bit_pos;
570 	struct address_space *mapping = page->mapping;
571 	struct inode *dir = mapping->host;
572 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
573 	void *kaddr = page_address(page);
574 	int i;
575 
576 	lock_page(page);
577 	f2fs_wait_on_page_writeback(page, DATA);
578 
579 	dentry_blk = (struct f2fs_dentry_block *)kaddr;
580 	bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
581 	for (i = 0; i < slots; i++)
582 		test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
583 
584 	/* Let's check and deallocate this dentry page */
585 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
586 			NR_DENTRY_IN_BLOCK,
587 			0);
588 	kunmap(page); /* kunmap - pair of f2fs_find_entry */
589 	set_page_dirty(page);
590 
591 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
592 
593 	if (inode) {
594 		struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
595 
596 		down_write(&F2FS_I(inode)->i_sem);
597 
598 		if (S_ISDIR(inode->i_mode)) {
599 			drop_nlink(dir);
600 			update_inode_page(dir);
601 		}
602 		inode->i_ctime = CURRENT_TIME;
603 		drop_nlink(inode);
604 		if (S_ISDIR(inode->i_mode)) {
605 			drop_nlink(inode);
606 			i_size_write(inode, 0);
607 		}
608 		up_write(&F2FS_I(inode)->i_sem);
609 		update_inode_page(inode);
610 
611 		if (inode->i_nlink == 0)
612 			add_orphan_inode(sbi, inode->i_ino);
613 		else
614 			release_orphan_inode(sbi);
615 	}
616 
617 	if (bit_pos == NR_DENTRY_IN_BLOCK) {
618 		truncate_hole(dir, page->index, page->index + 1);
619 		clear_page_dirty_for_io(page);
620 		ClearPageUptodate(page);
621 		inode_dec_dirty_dents(dir);
622 	}
623 	f2fs_put_page(page, 1);
624 }
625 
626 bool f2fs_empty_dir(struct inode *dir)
627 {
628 	unsigned long bidx;
629 	struct page *dentry_page;
630 	unsigned int bit_pos;
631 	struct	f2fs_dentry_block *dentry_blk;
632 	unsigned long nblock = dir_blocks(dir);
633 
634 	for (bidx = 0; bidx < nblock; bidx++) {
635 		void *kaddr;
636 		dentry_page = get_lock_data_page(dir, bidx);
637 		if (IS_ERR(dentry_page)) {
638 			if (PTR_ERR(dentry_page) == -ENOENT)
639 				continue;
640 			else
641 				return false;
642 		}
643 
644 		kaddr = kmap_atomic(dentry_page);
645 		dentry_blk = (struct f2fs_dentry_block *)kaddr;
646 		if (bidx == 0)
647 			bit_pos = 2;
648 		else
649 			bit_pos = 0;
650 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
651 						NR_DENTRY_IN_BLOCK,
652 						bit_pos);
653 		kunmap_atomic(kaddr);
654 
655 		f2fs_put_page(dentry_page, 1);
656 
657 		if (bit_pos < NR_DENTRY_IN_BLOCK)
658 			return false;
659 	}
660 	return true;
661 }
662 
663 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
664 {
665 	struct inode *inode = file_inode(file);
666 	unsigned long npages = dir_blocks(inode);
667 	unsigned int bit_pos = 0;
668 	struct f2fs_dentry_block *dentry_blk = NULL;
669 	struct f2fs_dir_entry *de = NULL;
670 	struct page *dentry_page = NULL;
671 	struct file_ra_state *ra = &file->f_ra;
672 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
673 	unsigned char d_type = DT_UNKNOWN;
674 
675 	bit_pos = ((unsigned long)ctx->pos % NR_DENTRY_IN_BLOCK);
676 
677 	/* readahead for multi pages of dir */
678 	if (npages - n > 1 && !ra_has_index(ra, n))
679 		page_cache_sync_readahead(inode->i_mapping, ra, file, n,
680 				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
681 
682 	for (; n < npages; n++) {
683 		dentry_page = get_lock_data_page(inode, n);
684 		if (IS_ERR(dentry_page))
685 			continue;
686 
687 		dentry_blk = kmap(dentry_page);
688 		while (bit_pos < NR_DENTRY_IN_BLOCK) {
689 			bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
690 							NR_DENTRY_IN_BLOCK,
691 							bit_pos);
692 			if (bit_pos >= NR_DENTRY_IN_BLOCK)
693 				break;
694 
695 			de = &dentry_blk->dentry[bit_pos];
696 			if (de->file_type < F2FS_FT_MAX)
697 				d_type = f2fs_filetype_table[de->file_type];
698 			else
699 				d_type = DT_UNKNOWN;
700 			if (!dir_emit(ctx,
701 					dentry_blk->filename[bit_pos],
702 					le16_to_cpu(de->name_len),
703 					le32_to_cpu(de->ino), d_type))
704 				goto stop;
705 
706 			bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
707 			ctx->pos = n * NR_DENTRY_IN_BLOCK + bit_pos;
708 		}
709 		bit_pos = 0;
710 		ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
711 		kunmap(dentry_page);
712 		f2fs_put_page(dentry_page, 1);
713 		dentry_page = NULL;
714 	}
715 stop:
716 	if (dentry_page && !IS_ERR(dentry_page)) {
717 		kunmap(dentry_page);
718 		f2fs_put_page(dentry_page, 1);
719 	}
720 
721 	return 0;
722 }
723 
724 const struct file_operations f2fs_dir_operations = {
725 	.llseek		= generic_file_llseek,
726 	.read		= generic_read_dir,
727 	.iterate	= f2fs_readdir,
728 	.fsync		= f2fs_sync_file,
729 	.unlocked_ioctl	= f2fs_ioctl,
730 };
731