xref: /openbmc/linux/fs/f2fs/dir.c (revision 867a0e05) 
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 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 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(size_t namelen, f2fs_hash_t namehash,
81 				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 				struct qstr *name, int *max_slots,
94 				struct page **res_page)
95 {
96 	struct f2fs_dentry_block *dentry_blk;
97 	struct f2fs_dir_entry *de;
98 	struct f2fs_dentry_ptr d;
99 
100 	dentry_blk = (struct f2fs_dentry_block *)kmap(dentry_page);
101 
102 	make_dentry_ptr(&d, (void *)dentry_blk, 1);
103 	de = find_target_dentry(name, max_slots, &d);
104 
105 	if (de)
106 		*res_page = dentry_page;
107 	else
108 		kunmap(dentry_page);
109 
110 	/*
111 	 * For the most part, it should be a bug when name_len is zero.
112 	 * We stop here for figuring out where the bugs has occurred.
113 	 */
114 	f2fs_bug_on(F2FS_P_SB(dentry_page), d.max < 0);
115 	return de;
116 }
117 
118 struct f2fs_dir_entry *find_target_dentry(struct qstr *name, int *max_slots,
119 						struct f2fs_dentry_ptr *d)
120 {
121 	struct f2fs_dir_entry *de;
122 	unsigned long bit_pos = 0;
123 	f2fs_hash_t namehash = f2fs_dentry_hash(name);
124 	int max_len = 0;
125 
126 	if (max_slots)
127 		*max_slots = 0;
128 	while (bit_pos < d->max) {
129 		if (!test_bit_le(bit_pos, d->bitmap)) {
130 			if (bit_pos == 0)
131 				max_len = 1;
132 			else if (!test_bit_le(bit_pos - 1, d->bitmap))
133 				max_len++;
134 			bit_pos++;
135 			continue;
136 		}
137 		de = &d->dentry[bit_pos];
138 		if (early_match_name(name->len, namehash, de) &&
139 			!memcmp(d->filename[bit_pos], name->name, name->len))
140 			goto found;
141 
142 		if (max_slots && *max_slots >= 0 && max_len > *max_slots) {
143 			*max_slots = max_len;
144 			max_len = 0;
145 		}
146 
147 		/* remain bug on condition */
148 		if (unlikely(!de->name_len))
149 			d->max = -1;
150 
151 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
152 	}
153 
154 	de = NULL;
155 found:
156 	if (max_slots && max_len > *max_slots)
157 		*max_slots = max_len;
158 	return de;
159 }
160 
161 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
162 			unsigned int level, struct qstr *name,
163 			f2fs_hash_t namehash, struct page **res_page)
164 {
165 	int s = GET_DENTRY_SLOTS(name->len);
166 	unsigned int nbucket, nblock;
167 	unsigned int bidx, end_block;
168 	struct page *dentry_page;
169 	struct f2fs_dir_entry *de = NULL;
170 	bool room = false;
171 	int max_slots;
172 
173 	f2fs_bug_on(F2FS_I_SB(dir), level > MAX_DIR_HASH_DEPTH);
174 
175 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
176 	nblock = bucket_blocks(level);
177 
178 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
179 					le32_to_cpu(namehash) % nbucket);
180 	end_block = bidx + nblock;
181 
182 	for (; bidx < end_block; bidx++) {
183 		/* no need to allocate new dentry pages to all the indices */
184 		dentry_page = find_data_page(dir, bidx, true);
185 		if (IS_ERR(dentry_page)) {
186 			room = true;
187 			continue;
188 		}
189 
190 		de = find_in_block(dentry_page, name, &max_slots, res_page);
191 		if (de)
192 			break;
193 
194 		if (max_slots >= s)
195 			room = true;
196 		f2fs_put_page(dentry_page, 0);
197 	}
198 
199 	if (!de && room && F2FS_I(dir)->chash != namehash) {
200 		F2FS_I(dir)->chash = namehash;
201 		F2FS_I(dir)->clevel = level;
202 	}
203 
204 	return de;
205 }
206 
207 /*
208  * Find an entry in the specified directory with the wanted name.
209  * It returns the page where the entry was found (as a parameter - res_page),
210  * and the entry itself. Page is returned mapped and unlocked.
211  * Entry is guaranteed to be valid.
212  */
213 struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
214 			struct qstr *child, struct page **res_page)
215 {
216 	unsigned long npages = dir_blocks(dir);
217 	struct f2fs_dir_entry *de = NULL;
218 	f2fs_hash_t name_hash;
219 	unsigned int max_depth;
220 	unsigned int level;
221 
222 	if (f2fs_has_inline_dentry(dir))
223 		return find_in_inline_dir(dir, child, res_page);
224 
225 	if (npages == 0)
226 		return NULL;
227 
228 	*res_page = NULL;
229 
230 	name_hash = f2fs_dentry_hash(child);
231 	max_depth = F2FS_I(dir)->i_current_depth;
232 
233 	for (level = 0; level < max_depth; level++) {
234 		de = find_in_level(dir, level, child, name_hash, res_page);
235 		if (de)
236 			break;
237 	}
238 	if (!de && F2FS_I(dir)->chash != name_hash) {
239 		F2FS_I(dir)->chash = name_hash;
240 		F2FS_I(dir)->clevel = level - 1;
241 	}
242 	return de;
243 }
244 
245 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
246 {
247 	struct page *page;
248 	struct f2fs_dir_entry *de;
249 	struct f2fs_dentry_block *dentry_blk;
250 
251 	if (f2fs_has_inline_dentry(dir))
252 		return f2fs_parent_inline_dir(dir, p);
253 
254 	page = get_lock_data_page(dir, 0);
255 	if (IS_ERR(page))
256 		return NULL;
257 
258 	dentry_blk = kmap(page);
259 	de = &dentry_blk->dentry[1];
260 	*p = page;
261 	unlock_page(page);
262 	return de;
263 }
264 
265 ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
266 {
267 	ino_t res = 0;
268 	struct f2fs_dir_entry *de;
269 	struct page *page;
270 
271 	de = f2fs_find_entry(dir, qstr, &page);
272 	if (de) {
273 		res = le32_to_cpu(de->ino);
274 		f2fs_dentry_kunmap(dir, page);
275 		f2fs_put_page(page, 0);
276 	}
277 
278 	return res;
279 }
280 
281 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
282 		struct page *page, struct inode *inode)
283 {
284 	enum page_type type = f2fs_has_inline_dentry(dir) ? NODE : DATA;
285 	lock_page(page);
286 	f2fs_wait_on_page_writeback(page, type);
287 	de->ino = cpu_to_le32(inode->i_ino);
288 	set_de_type(de, inode);
289 	if (!f2fs_has_inline_dentry(dir))
290 		kunmap(page);
291 	set_page_dirty(page);
292 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
293 	mark_inode_dirty(dir);
294 
295 	f2fs_put_page(page, 1);
296 }
297 
298 static void init_dent_inode(const struct qstr *name, struct page *ipage)
299 {
300 	struct f2fs_inode *ri;
301 
302 	f2fs_wait_on_page_writeback(ipage, NODE);
303 
304 	/* copy name info. to this inode page */
305 	ri = F2FS_INODE(ipage);
306 	ri->i_namelen = cpu_to_le32(name->len);
307 	memcpy(ri->i_name, name->name, name->len);
308 	set_page_dirty(ipage);
309 }
310 
311 int update_dent_inode(struct inode *inode, const struct qstr *name)
312 {
313 	struct page *page;
314 
315 	page = get_node_page(F2FS_I_SB(inode), inode->i_ino);
316 	if (IS_ERR(page))
317 		return PTR_ERR(page);
318 
319 	init_dent_inode(name, page);
320 	f2fs_put_page(page, 1);
321 
322 	return 0;
323 }
324 
325 void do_make_empty_dir(struct inode *inode, struct inode *parent,
326 					struct f2fs_dentry_ptr *d)
327 {
328 	struct f2fs_dir_entry *de;
329 
330 	de = &d->dentry[0];
331 	de->name_len = cpu_to_le16(1);
332 	de->hash_code = 0;
333 	de->ino = cpu_to_le32(inode->i_ino);
334 	memcpy(d->filename[0], ".", 1);
335 	set_de_type(de, inode);
336 
337 	de = &d->dentry[1];
338 	de->hash_code = 0;
339 	de->name_len = cpu_to_le16(2);
340 	de->ino = cpu_to_le32(parent->i_ino);
341 	memcpy(d->filename[1], "..", 2);
342 	set_de_type(de, inode);
343 
344 	test_and_set_bit_le(0, (void *)d->bitmap);
345 	test_and_set_bit_le(1, (void *)d->bitmap);
346 }
347 
348 static int make_empty_dir(struct inode *inode,
349 		struct inode *parent, struct page *page)
350 {
351 	struct page *dentry_page;
352 	struct f2fs_dentry_block *dentry_blk;
353 	struct f2fs_dentry_ptr d;
354 
355 	if (f2fs_has_inline_dentry(inode))
356 		return make_empty_inline_dir(inode, parent, page);
357 
358 	dentry_page = get_new_data_page(inode, page, 0, true);
359 	if (IS_ERR(dentry_page))
360 		return PTR_ERR(dentry_page);
361 
362 	dentry_blk = kmap_atomic(dentry_page);
363 
364 	make_dentry_ptr(&d, (void *)dentry_blk, 1);
365 	do_make_empty_dir(inode, parent, &d);
366 
367 	kunmap_atomic(dentry_blk);
368 
369 	set_page_dirty(dentry_page);
370 	f2fs_put_page(dentry_page, 1);
371 	return 0;
372 }
373 
374 struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
375 			const struct qstr *name, struct page *dpage)
376 {
377 	struct page *page;
378 	int err;
379 
380 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
381 		page = new_inode_page(inode);
382 		if (IS_ERR(page))
383 			return page;
384 
385 		if (S_ISDIR(inode->i_mode)) {
386 			err = make_empty_dir(inode, dir, page);
387 			if (err)
388 				goto error;
389 		}
390 
391 		err = f2fs_init_acl(inode, dir, page, dpage);
392 		if (err)
393 			goto put_error;
394 
395 		err = f2fs_init_security(inode, dir, name, page);
396 		if (err)
397 			goto put_error;
398 	} else {
399 		page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
400 		if (IS_ERR(page))
401 			return page;
402 
403 		set_cold_node(inode, page);
404 	}
405 
406 	if (name)
407 		init_dent_inode(name, page);
408 
409 	/*
410 	 * This file should be checkpointed during fsync.
411 	 * We lost i_pino from now on.
412 	 */
413 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
414 		file_lost_pino(inode);
415 		/*
416 		 * If link the tmpfile to alias through linkat path,
417 		 * we should remove this inode from orphan list.
418 		 */
419 		if (inode->i_nlink == 0)
420 			remove_orphan_inode(F2FS_I_SB(dir), inode->i_ino);
421 		inc_nlink(inode);
422 	}
423 	return page;
424 
425 put_error:
426 	f2fs_put_page(page, 1);
427 error:
428 	/* once the failed inode becomes a bad inode, i_mode is S_IFREG */
429 	truncate_inode_pages(&inode->i_data, 0);
430 	truncate_blocks(inode, 0, false);
431 	remove_dirty_dir_inode(inode);
432 	remove_inode_page(inode);
433 	return ERR_PTR(err);
434 }
435 
436 void update_parent_metadata(struct inode *dir, struct inode *inode,
437 						unsigned int current_depth)
438 {
439 	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
440 		if (S_ISDIR(inode->i_mode)) {
441 			inc_nlink(dir);
442 			set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
443 		}
444 		clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
445 	}
446 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
447 	mark_inode_dirty(dir);
448 
449 	if (F2FS_I(dir)->i_current_depth != current_depth) {
450 		F2FS_I(dir)->i_current_depth = current_depth;
451 		set_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
452 	}
453 
454 	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
455 		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
456 }
457 
458 int room_for_filename(const void *bitmap, int slots, int max_slots)
459 {
460 	int bit_start = 0;
461 	int zero_start, zero_end;
462 next:
463 	zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
464 	if (zero_start >= max_slots)
465 		return max_slots;
466 
467 	zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
468 	if (zero_end - zero_start >= slots)
469 		return zero_start;
470 
471 	bit_start = zero_end + 1;
472 
473 	if (zero_end + 1 >= max_slots)
474 		return max_slots;
475 	goto next;
476 }
477 
478 /*
479  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
480  * f2fs_unlock_op().
481  */
482 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
483 						struct inode *inode)
484 {
485 	unsigned int bit_pos;
486 	unsigned int level;
487 	unsigned int current_depth;
488 	unsigned long bidx, block;
489 	f2fs_hash_t dentry_hash;
490 	struct f2fs_dir_entry *de;
491 	unsigned int nbucket, nblock;
492 	size_t namelen = name->len;
493 	struct page *dentry_page = NULL;
494 	struct f2fs_dentry_block *dentry_blk = NULL;
495 	int slots = GET_DENTRY_SLOTS(namelen);
496 	struct page *page;
497 	int err = 0;
498 	int i;
499 
500 	if (f2fs_has_inline_dentry(dir)) {
501 		err = f2fs_add_inline_entry(dir, name, inode);
502 		if (!err || err != -EAGAIN)
503 			return err;
504 		else
505 			err = 0;
506 	}
507 
508 	dentry_hash = f2fs_dentry_hash(name);
509 	level = 0;
510 	current_depth = F2FS_I(dir)->i_current_depth;
511 	if (F2FS_I(dir)->chash == dentry_hash) {
512 		level = F2FS_I(dir)->clevel;
513 		F2FS_I(dir)->chash = 0;
514 	}
515 
516 start:
517 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
518 		return -ENOSPC;
519 
520 	/* Increase the depth, if required */
521 	if (level == current_depth)
522 		++current_depth;
523 
524 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
525 	nblock = bucket_blocks(level);
526 
527 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
528 				(le32_to_cpu(dentry_hash) % nbucket));
529 
530 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
531 		dentry_page = get_new_data_page(dir, NULL, block, true);
532 		if (IS_ERR(dentry_page))
533 			return PTR_ERR(dentry_page);
534 
535 		dentry_blk = kmap(dentry_page);
536 		bit_pos = room_for_filename(&dentry_blk->dentry_bitmap,
537 						slots, NR_DENTRY_IN_BLOCK);
538 		if (bit_pos < NR_DENTRY_IN_BLOCK)
539 			goto add_dentry;
540 
541 		kunmap(dentry_page);
542 		f2fs_put_page(dentry_page, 1);
543 	}
544 
545 	/* Move to next level to find the empty slot for new dentry */
546 	++level;
547 	goto start;
548 add_dentry:
549 	f2fs_wait_on_page_writeback(dentry_page, DATA);
550 
551 	down_write(&F2FS_I(inode)->i_sem);
552 	page = init_inode_metadata(inode, dir, name, NULL);
553 	if (IS_ERR(page)) {
554 		err = PTR_ERR(page);
555 		goto fail;
556 	}
557 	de = &dentry_blk->dentry[bit_pos];
558 	de->hash_code = dentry_hash;
559 	de->name_len = cpu_to_le16(namelen);
560 	memcpy(dentry_blk->filename[bit_pos], name->name, name->len);
561 	de->ino = cpu_to_le32(inode->i_ino);
562 	set_de_type(de, inode);
563 	for (i = 0; i < slots; i++)
564 		test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
565 	set_page_dirty(dentry_page);
566 
567 	/* we don't need to mark_inode_dirty now */
568 	F2FS_I(inode)->i_pino = dir->i_ino;
569 	update_inode(inode, page);
570 	f2fs_put_page(page, 1);
571 
572 	update_parent_metadata(dir, inode, current_depth);
573 fail:
574 	up_write(&F2FS_I(inode)->i_sem);
575 
576 	if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
577 		update_inode_page(dir);
578 		clear_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
579 	}
580 	kunmap(dentry_page);
581 	f2fs_put_page(dentry_page, 1);
582 	return err;
583 }
584 
585 int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
586 {
587 	struct page *page;
588 	int err = 0;
589 
590 	down_write(&F2FS_I(inode)->i_sem);
591 	page = init_inode_metadata(inode, dir, NULL, NULL);
592 	if (IS_ERR(page)) {
593 		err = PTR_ERR(page);
594 		goto fail;
595 	}
596 	/* we don't need to mark_inode_dirty now */
597 	update_inode(inode, page);
598 	f2fs_put_page(page, 1);
599 
600 	clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
601 fail:
602 	up_write(&F2FS_I(inode)->i_sem);
603 	return err;
604 }
605 
606 void f2fs_drop_nlink(struct inode *dir, struct inode *inode, struct page *page)
607 {
608 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
609 
610 	down_write(&F2FS_I(inode)->i_sem);
611 
612 	if (S_ISDIR(inode->i_mode)) {
613 		drop_nlink(dir);
614 		if (page)
615 			update_inode(dir, page);
616 		else
617 			update_inode_page(dir);
618 	}
619 	inode->i_ctime = CURRENT_TIME;
620 
621 	drop_nlink(inode);
622 	if (S_ISDIR(inode->i_mode)) {
623 		drop_nlink(inode);
624 		i_size_write(inode, 0);
625 	}
626 	up_write(&F2FS_I(inode)->i_sem);
627 	update_inode_page(inode);
628 
629 	if (inode->i_nlink == 0)
630 		add_orphan_inode(sbi, inode->i_ino);
631 	else
632 		release_orphan_inode(sbi);
633 }
634 
635 /*
636  * It only removes the dentry from the dentry page, corresponding name
637  * entry in name page does not need to be touched during deletion.
638  */
639 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
640 					struct inode *dir, struct inode *inode)
641 {
642 	struct	f2fs_dentry_block *dentry_blk;
643 	unsigned int bit_pos;
644 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
645 	int i;
646 
647 	if (f2fs_has_inline_dentry(dir))
648 		return f2fs_delete_inline_entry(dentry, page, dir, inode);
649 
650 	lock_page(page);
651 	f2fs_wait_on_page_writeback(page, DATA);
652 
653 	dentry_blk = page_address(page);
654 	bit_pos = dentry - dentry_blk->dentry;
655 	for (i = 0; i < slots; i++)
656 		clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
657 
658 	/* Let's check and deallocate this dentry page */
659 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
660 			NR_DENTRY_IN_BLOCK,
661 			0);
662 	kunmap(page); /* kunmap - pair of f2fs_find_entry */
663 	set_page_dirty(page);
664 
665 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
666 
667 	if (inode)
668 		f2fs_drop_nlink(dir, inode, NULL);
669 
670 	if (bit_pos == NR_DENTRY_IN_BLOCK) {
671 		truncate_hole(dir, page->index, page->index + 1);
672 		clear_page_dirty_for_io(page);
673 		ClearPageUptodate(page);
674 		inode_dec_dirty_pages(dir);
675 	}
676 	f2fs_put_page(page, 1);
677 }
678 
679 bool f2fs_empty_dir(struct inode *dir)
680 {
681 	unsigned long bidx;
682 	struct page *dentry_page;
683 	unsigned int bit_pos;
684 	struct f2fs_dentry_block *dentry_blk;
685 	unsigned long nblock = dir_blocks(dir);
686 
687 	if (f2fs_has_inline_dentry(dir))
688 		return f2fs_empty_inline_dir(dir);
689 
690 	for (bidx = 0; bidx < nblock; bidx++) {
691 		dentry_page = get_lock_data_page(dir, bidx);
692 		if (IS_ERR(dentry_page)) {
693 			if (PTR_ERR(dentry_page) == -ENOENT)
694 				continue;
695 			else
696 				return false;
697 		}
698 
699 		dentry_blk = kmap_atomic(dentry_page);
700 		if (bidx == 0)
701 			bit_pos = 2;
702 		else
703 			bit_pos = 0;
704 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
705 						NR_DENTRY_IN_BLOCK,
706 						bit_pos);
707 		kunmap_atomic(dentry_blk);
708 
709 		f2fs_put_page(dentry_page, 1);
710 
711 		if (bit_pos < NR_DENTRY_IN_BLOCK)
712 			return false;
713 	}
714 	return true;
715 }
716 
717 bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
718 						unsigned int start_pos)
719 {
720 	unsigned char d_type = DT_UNKNOWN;
721 	unsigned int bit_pos;
722 	struct f2fs_dir_entry *de = NULL;
723 
724 	bit_pos = ((unsigned long)ctx->pos % d->max);
725 
726 	while (bit_pos < d->max) {
727 		bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
728 		if (bit_pos >= d->max)
729 			break;
730 
731 		de = &d->dentry[bit_pos];
732 		if (de->file_type < F2FS_FT_MAX)
733 			d_type = f2fs_filetype_table[de->file_type];
734 		else
735 			d_type = DT_UNKNOWN;
736 		if (!dir_emit(ctx, d->filename[bit_pos],
737 					le16_to_cpu(de->name_len),
738 					le32_to_cpu(de->ino), d_type))
739 			return true;
740 
741 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
742 		ctx->pos = start_pos + bit_pos;
743 	}
744 	return false;
745 }
746 
747 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
748 {
749 	struct inode *inode = file_inode(file);
750 	unsigned long npages = dir_blocks(inode);
751 	struct f2fs_dentry_block *dentry_blk = NULL;
752 	struct page *dentry_page = NULL;
753 	struct file_ra_state *ra = &file->f_ra;
754 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
755 	struct f2fs_dentry_ptr d;
756 
757 	if (f2fs_has_inline_dentry(inode))
758 		return f2fs_read_inline_dir(file, ctx);
759 
760 	/* readahead for multi pages of dir */
761 	if (npages - n > 1 && !ra_has_index(ra, n))
762 		page_cache_sync_readahead(inode->i_mapping, ra, file, n,
763 				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
764 
765 	for (; n < npages; n++) {
766 		dentry_page = get_lock_data_page(inode, n);
767 		if (IS_ERR(dentry_page))
768 			continue;
769 
770 		dentry_blk = kmap(dentry_page);
771 
772 		make_dentry_ptr(&d, (void *)dentry_blk, 1);
773 
774 		if (f2fs_fill_dentries(ctx, &d, n * NR_DENTRY_IN_BLOCK))
775 			goto stop;
776 
777 		ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
778 		kunmap(dentry_page);
779 		f2fs_put_page(dentry_page, 1);
780 		dentry_page = NULL;
781 	}
782 stop:
783 	if (dentry_page && !IS_ERR(dentry_page)) {
784 		kunmap(dentry_page);
785 		f2fs_put_page(dentry_page, 1);
786 	}
787 
788 	return 0;
789 }
790 
791 const struct file_operations f2fs_dir_operations = {
792 	.llseek		= generic_file_llseek,
793 	.read		= generic_read_dir,
794 	.iterate	= f2fs_readdir,
795 	.fsync		= f2fs_sync_file,
796 	.unlocked_ioctl	= f2fs_ioctl,
797 };
798