xref: /openbmc/linux/fs/f2fs/dir.c (revision e6dec923)
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_SIZE - 1))
21 							>> PAGE_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 static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
52 	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,
53 	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,
54 	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,
55 	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,
56 	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,
57 	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,
58 	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
59 };
60 
61 void set_de_type(struct f2fs_dir_entry *de, umode_t mode)
62 {
63 	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
64 }
65 
66 unsigned char get_de_type(struct f2fs_dir_entry *de)
67 {
68 	if (de->file_type < F2FS_FT_MAX)
69 		return f2fs_filetype_table[de->file_type];
70 	return DT_UNKNOWN;
71 }
72 
73 static unsigned long dir_block_index(unsigned int level,
74 				int dir_level, unsigned int idx)
75 {
76 	unsigned long i;
77 	unsigned long bidx = 0;
78 
79 	for (i = 0; i < level; i++)
80 		bidx += dir_buckets(i, dir_level) * bucket_blocks(i);
81 	bidx += idx * bucket_blocks(level);
82 	return bidx;
83 }
84 
85 static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
86 				struct fscrypt_name *fname,
87 				f2fs_hash_t namehash,
88 				int *max_slots,
89 				struct page **res_page)
90 {
91 	struct f2fs_dentry_block *dentry_blk;
92 	struct f2fs_dir_entry *de;
93 	struct f2fs_dentry_ptr d;
94 
95 	dentry_blk = (struct f2fs_dentry_block *)kmap(dentry_page);
96 
97 	make_dentry_ptr_block(NULL, &d, dentry_blk);
98 	de = find_target_dentry(fname, namehash, max_slots, &d);
99 	if (de)
100 		*res_page = dentry_page;
101 	else
102 		kunmap(dentry_page);
103 
104 	return de;
105 }
106 
107 struct f2fs_dir_entry *find_target_dentry(struct fscrypt_name *fname,
108 			f2fs_hash_t namehash, int *max_slots,
109 			struct f2fs_dentry_ptr *d)
110 {
111 	struct f2fs_dir_entry *de;
112 	unsigned long bit_pos = 0;
113 	int max_len = 0;
114 
115 	if (max_slots)
116 		*max_slots = 0;
117 	while (bit_pos < d->max) {
118 		if (!test_bit_le(bit_pos, d->bitmap)) {
119 			bit_pos++;
120 			max_len++;
121 			continue;
122 		}
123 
124 		de = &d->dentry[bit_pos];
125 
126 		if (unlikely(!de->name_len)) {
127 			bit_pos++;
128 			continue;
129 		}
130 
131 		if (de->hash_code == namehash &&
132 		    fscrypt_match_name(fname, d->filename[bit_pos],
133 				       le16_to_cpu(de->name_len)))
134 			goto found;
135 
136 		if (max_slots && max_len > *max_slots)
137 			*max_slots = max_len;
138 		max_len = 0;
139 
140 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
141 	}
142 
143 	de = NULL;
144 found:
145 	if (max_slots && max_len > *max_slots)
146 		*max_slots = max_len;
147 	return de;
148 }
149 
150 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
151 					unsigned int level,
152 					struct fscrypt_name *fname,
153 					struct page **res_page)
154 {
155 	struct qstr name = FSTR_TO_QSTR(&fname->disk_name);
156 	int s = GET_DENTRY_SLOTS(name.len);
157 	unsigned int nbucket, nblock;
158 	unsigned int bidx, end_block;
159 	struct page *dentry_page;
160 	struct f2fs_dir_entry *de = NULL;
161 	bool room = false;
162 	int max_slots;
163 	f2fs_hash_t namehash = f2fs_dentry_hash(&name, fname);
164 
165 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
166 	nblock = bucket_blocks(level);
167 
168 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
169 					le32_to_cpu(namehash) % nbucket);
170 	end_block = bidx + nblock;
171 
172 	for (; bidx < end_block; bidx++) {
173 		/* no need to allocate new dentry pages to all the indices */
174 		dentry_page = find_data_page(dir, bidx);
175 		if (IS_ERR(dentry_page)) {
176 			if (PTR_ERR(dentry_page) == -ENOENT) {
177 				room = true;
178 				continue;
179 			} else {
180 				*res_page = dentry_page;
181 				break;
182 			}
183 		}
184 
185 		de = find_in_block(dentry_page, fname, namehash, &max_slots,
186 								res_page);
187 		if (de)
188 			break;
189 
190 		if (max_slots >= s)
191 			room = true;
192 		f2fs_put_page(dentry_page, 0);
193 	}
194 
195 	if (!de && room && F2FS_I(dir)->chash != namehash) {
196 		F2FS_I(dir)->chash = namehash;
197 		F2FS_I(dir)->clevel = level;
198 	}
199 
200 	return de;
201 }
202 
203 struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
204 			struct fscrypt_name *fname, struct page **res_page)
205 {
206 	unsigned long npages = dir_blocks(dir);
207 	struct f2fs_dir_entry *de = NULL;
208 	unsigned int max_depth;
209 	unsigned int level;
210 
211 	if (f2fs_has_inline_dentry(dir)) {
212 		*res_page = NULL;
213 		de = find_in_inline_dir(dir, fname, res_page);
214 		goto out;
215 	}
216 
217 	if (npages == 0) {
218 		*res_page = NULL;
219 		goto out;
220 	}
221 
222 	max_depth = F2FS_I(dir)->i_current_depth;
223 	if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
224 		f2fs_msg(F2FS_I_SB(dir)->sb, KERN_WARNING,
225 				"Corrupted max_depth of %lu: %u",
226 				dir->i_ino, max_depth);
227 		max_depth = MAX_DIR_HASH_DEPTH;
228 		f2fs_i_depth_write(dir, max_depth);
229 	}
230 
231 	for (level = 0; level < max_depth; level++) {
232 		*res_page = NULL;
233 		de = find_in_level(dir, level, fname, res_page);
234 		if (de || IS_ERR(*res_page))
235 			break;
236 	}
237 out:
238 	/* This is to increase the speed of f2fs_create */
239 	if (!de)
240 		F2FS_I(dir)->task = current;
241 	return de;
242 }
243 
244 /*
245  * Find an entry in the specified directory with the wanted name.
246  * It returns the page where the entry was found (as a parameter - res_page),
247  * and the entry itself. Page is returned mapped and unlocked.
248  * Entry is guaranteed to be valid.
249  */
250 struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
251 			const struct qstr *child, struct page **res_page)
252 {
253 	struct f2fs_dir_entry *de = NULL;
254 	struct fscrypt_name fname;
255 	int err;
256 
257 	err = fscrypt_setup_filename(dir, child, 1, &fname);
258 	if (err) {
259 		if (err == -ENOENT)
260 			*res_page = NULL;
261 		else
262 			*res_page = ERR_PTR(err);
263 		return NULL;
264 	}
265 
266 	de = __f2fs_find_entry(dir, &fname, res_page);
267 
268 	fscrypt_free_filename(&fname);
269 	return de;
270 }
271 
272 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
273 {
274 	struct qstr dotdot = QSTR_INIT("..", 2);
275 
276 	return f2fs_find_entry(dir, &dotdot, p);
277 }
278 
279 ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,
280 							struct page **page)
281 {
282 	ino_t res = 0;
283 	struct f2fs_dir_entry *de;
284 
285 	de = f2fs_find_entry(dir, qstr, page);
286 	if (de) {
287 		res = le32_to_cpu(de->ino);
288 		f2fs_dentry_kunmap(dir, *page);
289 		f2fs_put_page(*page, 0);
290 	}
291 
292 	return res;
293 }
294 
295 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
296 		struct page *page, struct inode *inode)
297 {
298 	enum page_type type = f2fs_has_inline_dentry(dir) ? NODE : DATA;
299 	lock_page(page);
300 	f2fs_wait_on_page_writeback(page, type, true);
301 	de->ino = cpu_to_le32(inode->i_ino);
302 	set_de_type(de, inode->i_mode);
303 	f2fs_dentry_kunmap(dir, page);
304 	set_page_dirty(page);
305 
306 	dir->i_mtime = dir->i_ctime = current_time(dir);
307 	f2fs_mark_inode_dirty_sync(dir, false);
308 	f2fs_put_page(page, 1);
309 }
310 
311 static void init_dent_inode(const struct qstr *name, struct page *ipage)
312 {
313 	struct f2fs_inode *ri;
314 
315 	f2fs_wait_on_page_writeback(ipage, NODE, true);
316 
317 	/* copy name info. to this inode page */
318 	ri = F2FS_INODE(ipage);
319 	ri->i_namelen = cpu_to_le32(name->len);
320 	memcpy(ri->i_name, name->name, name->len);
321 	set_page_dirty(ipage);
322 }
323 
324 void do_make_empty_dir(struct inode *inode, struct inode *parent,
325 					struct f2fs_dentry_ptr *d)
326 {
327 	struct qstr dot = QSTR_INIT(".", 1);
328 	struct qstr dotdot = QSTR_INIT("..", 2);
329 
330 	/* update dirent of "." */
331 	f2fs_update_dentry(inode->i_ino, inode->i_mode, d, &dot, 0, 0);
332 
333 	/* update dirent of ".." */
334 	f2fs_update_dentry(parent->i_ino, parent->i_mode, d, &dotdot, 0, 1);
335 }
336 
337 static int make_empty_dir(struct inode *inode,
338 		struct inode *parent, struct page *page)
339 {
340 	struct page *dentry_page;
341 	struct f2fs_dentry_block *dentry_blk;
342 	struct f2fs_dentry_ptr d;
343 
344 	if (f2fs_has_inline_dentry(inode))
345 		return make_empty_inline_dir(inode, parent, page);
346 
347 	dentry_page = get_new_data_page(inode, page, 0, true);
348 	if (IS_ERR(dentry_page))
349 		return PTR_ERR(dentry_page);
350 
351 	dentry_blk = kmap_atomic(dentry_page);
352 
353 	make_dentry_ptr_block(NULL, &d, dentry_blk);
354 	do_make_empty_dir(inode, parent, &d);
355 
356 	kunmap_atomic(dentry_blk);
357 
358 	set_page_dirty(dentry_page);
359 	f2fs_put_page(dentry_page, 1);
360 	return 0;
361 }
362 
363 struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
364 			const struct qstr *new_name, const struct qstr *orig_name,
365 			struct page *dpage)
366 {
367 	struct page *page;
368 	int err;
369 
370 	if (is_inode_flag_set(inode, FI_NEW_INODE)) {
371 		page = new_inode_page(inode);
372 		if (IS_ERR(page))
373 			return page;
374 
375 		if (S_ISDIR(inode->i_mode)) {
376 			/* in order to handle error case */
377 			get_page(page);
378 			err = make_empty_dir(inode, dir, page);
379 			if (err) {
380 				lock_page(page);
381 				goto put_error;
382 			}
383 			put_page(page);
384 		}
385 
386 		err = f2fs_init_acl(inode, dir, page, dpage);
387 		if (err)
388 			goto put_error;
389 
390 		err = f2fs_init_security(inode, dir, orig_name, page);
391 		if (err)
392 			goto put_error;
393 
394 		if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode)) {
395 			err = fscrypt_inherit_context(dir, inode, page, false);
396 			if (err)
397 				goto put_error;
398 		}
399 	} else {
400 		page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
401 		if (IS_ERR(page))
402 			return page;
403 
404 		set_cold_node(inode, page);
405 	}
406 
407 	if (new_name) {
408 		init_dent_inode(new_name, page);
409 		if (f2fs_encrypted_inode(dir))
410 			file_set_enc_name(inode);
411 	}
412 
413 	/*
414 	 * This file should be checkpointed during fsync.
415 	 * We lost i_pino from now on.
416 	 */
417 	if (is_inode_flag_set(inode, FI_INC_LINK)) {
418 		if (!S_ISDIR(inode->i_mode))
419 			file_lost_pino(inode);
420 		/*
421 		 * If link the tmpfile to alias through linkat path,
422 		 * we should remove this inode from orphan list.
423 		 */
424 		if (inode->i_nlink == 0)
425 			remove_orphan_inode(F2FS_I_SB(dir), inode->i_ino);
426 		f2fs_i_links_write(inode, true);
427 	}
428 	return page;
429 
430 put_error:
431 	clear_nlink(inode);
432 	update_inode(inode, page);
433 	f2fs_put_page(page, 1);
434 	return ERR_PTR(err);
435 }
436 
437 void update_parent_metadata(struct inode *dir, struct inode *inode,
438 						unsigned int current_depth)
439 {
440 	if (inode && is_inode_flag_set(inode, FI_NEW_INODE)) {
441 		if (S_ISDIR(inode->i_mode))
442 			f2fs_i_links_write(dir, true);
443 		clear_inode_flag(inode, FI_NEW_INODE);
444 	}
445 	dir->i_mtime = dir->i_ctime = current_time(dir);
446 	f2fs_mark_inode_dirty_sync(dir, false);
447 
448 	if (F2FS_I(dir)->i_current_depth != current_depth)
449 		f2fs_i_depth_write(dir, current_depth);
450 
451 	if (inode && is_inode_flag_set(inode, FI_INC_LINK))
452 		clear_inode_flag(inode, FI_INC_LINK);
453 }
454 
455 int room_for_filename(const void *bitmap, int slots, int max_slots)
456 {
457 	int bit_start = 0;
458 	int zero_start, zero_end;
459 next:
460 	zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
461 	if (zero_start >= max_slots)
462 		return max_slots;
463 
464 	zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
465 	if (zero_end - zero_start >= slots)
466 		return zero_start;
467 
468 	bit_start = zero_end + 1;
469 
470 	if (zero_end + 1 >= max_slots)
471 		return max_slots;
472 	goto next;
473 }
474 
475 void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
476 				const struct qstr *name, f2fs_hash_t name_hash,
477 				unsigned int bit_pos)
478 {
479 	struct f2fs_dir_entry *de;
480 	int slots = GET_DENTRY_SLOTS(name->len);
481 	int i;
482 
483 	de = &d->dentry[bit_pos];
484 	de->hash_code = name_hash;
485 	de->name_len = cpu_to_le16(name->len);
486 	memcpy(d->filename[bit_pos], name->name, name->len);
487 	de->ino = cpu_to_le32(ino);
488 	set_de_type(de, mode);
489 	for (i = 0; i < slots; i++) {
490 		__set_bit_le(bit_pos + i, (void *)d->bitmap);
491 		/* avoid wrong garbage data for readdir */
492 		if (i)
493 			(de + i)->name_len = 0;
494 	}
495 }
496 
497 int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
498 				const struct qstr *orig_name,
499 				struct inode *inode, nid_t ino, umode_t mode)
500 {
501 	unsigned int bit_pos;
502 	unsigned int level;
503 	unsigned int current_depth;
504 	unsigned long bidx, block;
505 	f2fs_hash_t dentry_hash;
506 	unsigned int nbucket, nblock;
507 	struct page *dentry_page = NULL;
508 	struct f2fs_dentry_block *dentry_blk = NULL;
509 	struct f2fs_dentry_ptr d;
510 	struct page *page = NULL;
511 	int slots, err = 0;
512 
513 	level = 0;
514 	slots = GET_DENTRY_SLOTS(new_name->len);
515 	dentry_hash = f2fs_dentry_hash(new_name, NULL);
516 
517 	current_depth = F2FS_I(dir)->i_current_depth;
518 	if (F2FS_I(dir)->chash == dentry_hash) {
519 		level = F2FS_I(dir)->clevel;
520 		F2FS_I(dir)->chash = 0;
521 	}
522 
523 start:
524 #ifdef CONFIG_F2FS_FAULT_INJECTION
525 	if (time_to_inject(F2FS_I_SB(dir), FAULT_DIR_DEPTH)) {
526 		f2fs_show_injection_info(FAULT_DIR_DEPTH);
527 		return -ENOSPC;
528 	}
529 #endif
530 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
531 		return -ENOSPC;
532 
533 	/* Increase the depth, if required */
534 	if (level == current_depth)
535 		++current_depth;
536 
537 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
538 	nblock = bucket_blocks(level);
539 
540 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
541 				(le32_to_cpu(dentry_hash) % nbucket));
542 
543 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
544 		dentry_page = get_new_data_page(dir, NULL, block, true);
545 		if (IS_ERR(dentry_page))
546 			return PTR_ERR(dentry_page);
547 
548 		dentry_blk = kmap(dentry_page);
549 		bit_pos = room_for_filename(&dentry_blk->dentry_bitmap,
550 						slots, NR_DENTRY_IN_BLOCK);
551 		if (bit_pos < NR_DENTRY_IN_BLOCK)
552 			goto add_dentry;
553 
554 		kunmap(dentry_page);
555 		f2fs_put_page(dentry_page, 1);
556 	}
557 
558 	/* Move to next level to find the empty slot for new dentry */
559 	++level;
560 	goto start;
561 add_dentry:
562 	f2fs_wait_on_page_writeback(dentry_page, DATA, true);
563 
564 	if (inode) {
565 		down_write(&F2FS_I(inode)->i_sem);
566 		page = init_inode_metadata(inode, dir, new_name,
567 						orig_name, NULL);
568 		if (IS_ERR(page)) {
569 			err = PTR_ERR(page);
570 			goto fail;
571 		}
572 	}
573 
574 	make_dentry_ptr_block(NULL, &d, dentry_blk);
575 	f2fs_update_dentry(ino, mode, &d, new_name, dentry_hash, bit_pos);
576 
577 	set_page_dirty(dentry_page);
578 
579 	if (inode) {
580 		f2fs_i_pino_write(inode, dir->i_ino);
581 		f2fs_put_page(page, 1);
582 	}
583 
584 	update_parent_metadata(dir, inode, current_depth);
585 fail:
586 	if (inode)
587 		up_write(&F2FS_I(inode)->i_sem);
588 
589 	kunmap(dentry_page);
590 	f2fs_put_page(dentry_page, 1);
591 
592 	return err;
593 }
594 
595 int __f2fs_do_add_link(struct inode *dir, struct fscrypt_name *fname,
596 				struct inode *inode, nid_t ino, umode_t mode)
597 {
598 	struct qstr new_name;
599 	int err = -EAGAIN;
600 
601 	new_name.name = fname_name(fname);
602 	new_name.len = fname_len(fname);
603 
604 	if (f2fs_has_inline_dentry(dir))
605 		err = f2fs_add_inline_entry(dir, &new_name, fname->usr_fname,
606 							inode, ino, mode);
607 	if (err == -EAGAIN)
608 		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
609 							inode, ino, mode);
610 
611 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
612 	return err;
613 }
614 
615 /*
616  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
617  * f2fs_unlock_op().
618  */
619 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
620 				struct inode *inode, nid_t ino, umode_t mode)
621 {
622 	struct fscrypt_name fname;
623 	struct page *page = NULL;
624 	struct f2fs_dir_entry *de = NULL;
625 	int err;
626 
627 	err = fscrypt_setup_filename(dir, name, 0, &fname);
628 	if (err)
629 		return err;
630 
631 	/*
632 	 * An immature stakable filesystem shows a race condition between lookup
633 	 * and create. If we have same task when doing lookup and create, it's
634 	 * definitely fine as expected by VFS normally. Otherwise, let's just
635 	 * verify on-disk dentry one more time, which guarantees filesystem
636 	 * consistency more.
637 	 */
638 	if (current != F2FS_I(dir)->task) {
639 		de = __f2fs_find_entry(dir, &fname, &page);
640 		F2FS_I(dir)->task = NULL;
641 	}
642 	if (de) {
643 		f2fs_dentry_kunmap(dir, page);
644 		f2fs_put_page(page, 0);
645 		err = -EEXIST;
646 	} else if (IS_ERR(page)) {
647 		err = PTR_ERR(page);
648 	} else {
649 		err = __f2fs_do_add_link(dir, &fname, inode, ino, mode);
650 	}
651 	fscrypt_free_filename(&fname);
652 	return err;
653 }
654 
655 int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
656 {
657 	struct page *page;
658 	int err = 0;
659 
660 	down_write(&F2FS_I(inode)->i_sem);
661 	page = init_inode_metadata(inode, dir, NULL, NULL, NULL);
662 	if (IS_ERR(page)) {
663 		err = PTR_ERR(page);
664 		goto fail;
665 	}
666 	f2fs_put_page(page, 1);
667 
668 	clear_inode_flag(inode, FI_NEW_INODE);
669 fail:
670 	up_write(&F2FS_I(inode)->i_sem);
671 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
672 	return err;
673 }
674 
675 void f2fs_drop_nlink(struct inode *dir, struct inode *inode)
676 {
677 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
678 
679 	down_write(&F2FS_I(inode)->i_sem);
680 
681 	if (S_ISDIR(inode->i_mode))
682 		f2fs_i_links_write(dir, false);
683 	inode->i_ctime = current_time(inode);
684 
685 	f2fs_i_links_write(inode, false);
686 	if (S_ISDIR(inode->i_mode)) {
687 		f2fs_i_links_write(inode, false);
688 		f2fs_i_size_write(inode, 0);
689 	}
690 	up_write(&F2FS_I(inode)->i_sem);
691 
692 	if (inode->i_nlink == 0)
693 		add_orphan_inode(inode);
694 	else
695 		release_orphan_inode(sbi);
696 }
697 
698 /*
699  * It only removes the dentry from the dentry page, corresponding name
700  * entry in name page does not need to be touched during deletion.
701  */
702 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
703 					struct inode *dir, struct inode *inode)
704 {
705 	struct	f2fs_dentry_block *dentry_blk;
706 	unsigned int bit_pos;
707 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
708 	int i;
709 
710 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
711 
712 	if (f2fs_has_inline_dentry(dir))
713 		return f2fs_delete_inline_entry(dentry, page, dir, inode);
714 
715 	lock_page(page);
716 	f2fs_wait_on_page_writeback(page, DATA, true);
717 
718 	dentry_blk = page_address(page);
719 	bit_pos = dentry - dentry_blk->dentry;
720 	for (i = 0; i < slots; i++)
721 		__clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
722 
723 	/* Let's check and deallocate this dentry page */
724 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
725 			NR_DENTRY_IN_BLOCK,
726 			0);
727 	kunmap(page); /* kunmap - pair of f2fs_find_entry */
728 	set_page_dirty(page);
729 
730 	dir->i_ctime = dir->i_mtime = current_time(dir);
731 	f2fs_mark_inode_dirty_sync(dir, false);
732 
733 	if (inode)
734 		f2fs_drop_nlink(dir, inode);
735 
736 	if (bit_pos == NR_DENTRY_IN_BLOCK &&
737 			!truncate_hole(dir, page->index, page->index + 1)) {
738 		clear_page_dirty_for_io(page);
739 		ClearPagePrivate(page);
740 		ClearPageUptodate(page);
741 		inode_dec_dirty_pages(dir);
742 		remove_dirty_inode(dir);
743 	}
744 	f2fs_put_page(page, 1);
745 }
746 
747 bool f2fs_empty_dir(struct inode *dir)
748 {
749 	unsigned long bidx;
750 	struct page *dentry_page;
751 	unsigned int bit_pos;
752 	struct f2fs_dentry_block *dentry_blk;
753 	unsigned long nblock = dir_blocks(dir);
754 
755 	if (f2fs_has_inline_dentry(dir))
756 		return f2fs_empty_inline_dir(dir);
757 
758 	for (bidx = 0; bidx < nblock; bidx++) {
759 		dentry_page = get_lock_data_page(dir, bidx, false);
760 		if (IS_ERR(dentry_page)) {
761 			if (PTR_ERR(dentry_page) == -ENOENT)
762 				continue;
763 			else
764 				return false;
765 		}
766 
767 		dentry_blk = kmap_atomic(dentry_page);
768 		if (bidx == 0)
769 			bit_pos = 2;
770 		else
771 			bit_pos = 0;
772 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
773 						NR_DENTRY_IN_BLOCK,
774 						bit_pos);
775 		kunmap_atomic(dentry_blk);
776 
777 		f2fs_put_page(dentry_page, 1);
778 
779 		if (bit_pos < NR_DENTRY_IN_BLOCK)
780 			return false;
781 	}
782 	return true;
783 }
784 
785 int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
786 			unsigned int start_pos, struct fscrypt_str *fstr)
787 {
788 	unsigned char d_type = DT_UNKNOWN;
789 	unsigned int bit_pos;
790 	struct f2fs_dir_entry *de = NULL;
791 	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
792 
793 	bit_pos = ((unsigned long)ctx->pos % d->max);
794 
795 	while (bit_pos < d->max) {
796 		bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
797 		if (bit_pos >= d->max)
798 			break;
799 
800 		de = &d->dentry[bit_pos];
801 		if (de->name_len == 0) {
802 			bit_pos++;
803 			ctx->pos = start_pos + bit_pos;
804 			continue;
805 		}
806 
807 		d_type = get_de_type(de);
808 
809 		de_name.name = d->filename[bit_pos];
810 		de_name.len = le16_to_cpu(de->name_len);
811 
812 		if (f2fs_encrypted_inode(d->inode)) {
813 			int save_len = fstr->len;
814 			int err;
815 
816 			err = fscrypt_fname_disk_to_usr(d->inode,
817 						(u32)de->hash_code, 0,
818 						&de_name, fstr);
819 			if (err)
820 				return err;
821 
822 			de_name = *fstr;
823 			fstr->len = save_len;
824 		}
825 
826 		if (!dir_emit(ctx, de_name.name, de_name.len,
827 					le32_to_cpu(de->ino), d_type))
828 			return 1;
829 
830 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
831 		ctx->pos = start_pos + bit_pos;
832 	}
833 	return 0;
834 }
835 
836 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
837 {
838 	struct inode *inode = file_inode(file);
839 	unsigned long npages = dir_blocks(inode);
840 	struct f2fs_dentry_block *dentry_blk = NULL;
841 	struct page *dentry_page = NULL;
842 	struct file_ra_state *ra = &file->f_ra;
843 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
844 	struct f2fs_dentry_ptr d;
845 	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
846 	int err = 0;
847 
848 	if (f2fs_encrypted_inode(inode)) {
849 		err = fscrypt_get_encryption_info(inode);
850 		if (err && err != -ENOKEY)
851 			return err;
852 
853 		err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr);
854 		if (err < 0)
855 			return err;
856 	}
857 
858 	if (f2fs_has_inline_dentry(inode)) {
859 		err = f2fs_read_inline_dir(file, ctx, &fstr);
860 		goto out;
861 	}
862 
863 	/* readahead for multi pages of dir */
864 	if (npages - n > 1 && !ra_has_index(ra, n))
865 		page_cache_sync_readahead(inode->i_mapping, ra, file, n,
866 				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
867 
868 	for (; n < npages; n++) {
869 		dentry_page = get_lock_data_page(inode, n, false);
870 		if (IS_ERR(dentry_page)) {
871 			err = PTR_ERR(dentry_page);
872 			if (err == -ENOENT) {
873 				err = 0;
874 				continue;
875 			} else {
876 				goto out;
877 			}
878 		}
879 
880 		dentry_blk = kmap(dentry_page);
881 
882 		make_dentry_ptr_block(inode, &d, dentry_blk);
883 
884 		err = f2fs_fill_dentries(ctx, &d,
885 				n * NR_DENTRY_IN_BLOCK, &fstr);
886 		if (err) {
887 			kunmap(dentry_page);
888 			f2fs_put_page(dentry_page, 1);
889 			break;
890 		}
891 
892 		ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
893 		kunmap(dentry_page);
894 		f2fs_put_page(dentry_page, 1);
895 	}
896 out:
897 	fscrypt_fname_free_buffer(&fstr);
898 	return err < 0 ? err : 0;
899 }
900 
901 static int f2fs_dir_open(struct inode *inode, struct file *filp)
902 {
903 	if (f2fs_encrypted_inode(inode))
904 		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
905 	return 0;
906 }
907 
908 const struct file_operations f2fs_dir_operations = {
909 	.llseek		= generic_file_llseek,
910 	.read		= generic_read_dir,
911 	.iterate_shared	= f2fs_readdir,
912 	.fsync		= f2fs_sync_file,
913 	.open		= f2fs_dir_open,
914 	.unlocked_ioctl	= f2fs_ioctl,
915 #ifdef CONFIG_COMPAT
916 	.compat_ioctl   = f2fs_compat_ioctl,
917 #endif
918 };
919