xref: /linux/fs/f2fs/dir.c (revision a8b70ccf10e38775785d9cb12ead916474549f99)
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 <linux/sched/signal.h>
14 #include "f2fs.h"
15 #include "node.h"
16 #include "acl.h"
17 #include "xattr.h"
18 #include <trace/events/f2fs.h>
19 
20 static unsigned long dir_blocks(struct inode *inode)
21 {
22 	return ((unsigned long long) (i_size_read(inode) + PAGE_SIZE - 1))
23 							>> PAGE_SHIFT;
24 }
25 
26 static unsigned int dir_buckets(unsigned int level, int dir_level)
27 {
28 	if (level + dir_level < MAX_DIR_HASH_DEPTH / 2)
29 		return 1 << (level + dir_level);
30 	else
31 		return MAX_DIR_BUCKETS;
32 }
33 
34 static unsigned int bucket_blocks(unsigned int level)
35 {
36 	if (level < MAX_DIR_HASH_DEPTH / 2)
37 		return 2;
38 	else
39 		return 4;
40 }
41 
42 static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
43 	[F2FS_FT_UNKNOWN]	= DT_UNKNOWN,
44 	[F2FS_FT_REG_FILE]	= DT_REG,
45 	[F2FS_FT_DIR]		= DT_DIR,
46 	[F2FS_FT_CHRDEV]	= DT_CHR,
47 	[F2FS_FT_BLKDEV]	= DT_BLK,
48 	[F2FS_FT_FIFO]		= DT_FIFO,
49 	[F2FS_FT_SOCK]		= DT_SOCK,
50 	[F2FS_FT_SYMLINK]	= DT_LNK,
51 };
52 
53 static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
54 	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,
55 	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,
56 	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,
57 	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,
58 	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,
59 	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,
60 	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
61 };
62 
63 void set_de_type(struct f2fs_dir_entry *de, umode_t mode)
64 {
65 	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
66 }
67 
68 unsigned char get_de_type(struct f2fs_dir_entry *de)
69 {
70 	if (de->file_type < F2FS_FT_MAX)
71 		return f2fs_filetype_table[de->file_type];
72 	return DT_UNKNOWN;
73 }
74 
75 static unsigned long dir_block_index(unsigned int level,
76 				int dir_level, unsigned int idx)
77 {
78 	unsigned long i;
79 	unsigned long bidx = 0;
80 
81 	for (i = 0; i < level; i++)
82 		bidx += dir_buckets(i, dir_level) * bucket_blocks(i);
83 	bidx += idx * bucket_blocks(level);
84 	return bidx;
85 }
86 
87 static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
88 				struct fscrypt_name *fname,
89 				f2fs_hash_t namehash,
90 				int *max_slots,
91 				struct page **res_page)
92 {
93 	struct f2fs_dentry_block *dentry_blk;
94 	struct f2fs_dir_entry *de;
95 	struct f2fs_dentry_ptr d;
96 
97 	dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page);
98 
99 	make_dentry_ptr_block(NULL, &d, dentry_blk);
100 	de = find_target_dentry(fname, namehash, max_slots, &d);
101 	if (de)
102 		*res_page = 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_put_page(*page, 0);
289 	}
290 
291 	return res;
292 }
293 
294 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
295 		struct page *page, struct inode *inode)
296 {
297 	enum page_type type = f2fs_has_inline_dentry(dir) ? NODE : DATA;
298 	lock_page(page);
299 	f2fs_wait_on_page_writeback(page, type, true);
300 	de->ino = cpu_to_le32(inode->i_ino);
301 	set_de_type(de, inode->i_mode);
302 	set_page_dirty(page);
303 
304 	dir->i_mtime = dir->i_ctime = current_time(dir);
305 	f2fs_mark_inode_dirty_sync(dir, false);
306 	f2fs_put_page(page, 1);
307 }
308 
309 static void init_dent_inode(const struct qstr *name, struct page *ipage)
310 {
311 	struct f2fs_inode *ri;
312 
313 	f2fs_wait_on_page_writeback(ipage, NODE, true);
314 
315 	/* copy name info. to this inode page */
316 	ri = F2FS_INODE(ipage);
317 	ri->i_namelen = cpu_to_le32(name->len);
318 	memcpy(ri->i_name, name->name, name->len);
319 	set_page_dirty(ipage);
320 }
321 
322 void do_make_empty_dir(struct inode *inode, struct inode *parent,
323 					struct f2fs_dentry_ptr *d)
324 {
325 	struct qstr dot = QSTR_INIT(".", 1);
326 	struct qstr dotdot = QSTR_INIT("..", 2);
327 
328 	/* update dirent of "." */
329 	f2fs_update_dentry(inode->i_ino, inode->i_mode, d, &dot, 0, 0);
330 
331 	/* update dirent of ".." */
332 	f2fs_update_dentry(parent->i_ino, parent->i_mode, d, &dotdot, 0, 1);
333 }
334 
335 static int make_empty_dir(struct inode *inode,
336 		struct inode *parent, struct page *page)
337 {
338 	struct page *dentry_page;
339 	struct f2fs_dentry_block *dentry_blk;
340 	struct f2fs_dentry_ptr d;
341 
342 	if (f2fs_has_inline_dentry(inode))
343 		return make_empty_inline_dir(inode, parent, page);
344 
345 	dentry_page = get_new_data_page(inode, page, 0, true);
346 	if (IS_ERR(dentry_page))
347 		return PTR_ERR(dentry_page);
348 
349 	dentry_blk = page_address(dentry_page);
350 
351 	make_dentry_ptr_block(NULL, &d, dentry_blk);
352 	do_make_empty_dir(inode, parent, &d);
353 
354 	set_page_dirty(dentry_page);
355 	f2fs_put_page(dentry_page, 1);
356 	return 0;
357 }
358 
359 struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
360 			const struct qstr *new_name, const struct qstr *orig_name,
361 			struct page *dpage)
362 {
363 	struct page *page;
364 	int dummy_encrypt = DUMMY_ENCRYPTION_ENABLED(F2FS_I_SB(dir));
365 	int err;
366 
367 	if (is_inode_flag_set(inode, FI_NEW_INODE)) {
368 		page = new_inode_page(inode);
369 		if (IS_ERR(page))
370 			return page;
371 
372 		if (S_ISDIR(inode->i_mode)) {
373 			/* in order to handle error case */
374 			get_page(page);
375 			err = make_empty_dir(inode, dir, page);
376 			if (err) {
377 				lock_page(page);
378 				goto put_error;
379 			}
380 			put_page(page);
381 		}
382 
383 		err = f2fs_init_acl(inode, dir, page, dpage);
384 		if (err)
385 			goto put_error;
386 
387 		err = f2fs_init_security(inode, dir, orig_name, page);
388 		if (err)
389 			goto put_error;
390 
391 		if ((f2fs_encrypted_inode(dir) || dummy_encrypt) &&
392 					f2fs_may_encrypt(inode)) {
393 			err = fscrypt_inherit_context(dir, inode, page, false);
394 			if (err)
395 				goto put_error;
396 		}
397 	} else {
398 		page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
399 		if (IS_ERR(page))
400 			return page;
401 	}
402 
403 	if (new_name) {
404 		init_dent_inode(new_name, page);
405 		if (f2fs_encrypted_inode(dir))
406 			file_set_enc_name(inode);
407 	}
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(inode, FI_INC_LINK)) {
414 		if (!S_ISDIR(inode->i_mode))
415 			file_lost_pino(inode);
416 		/*
417 		 * If link the tmpfile to alias through linkat path,
418 		 * we should remove this inode from orphan list.
419 		 */
420 		if (inode->i_nlink == 0)
421 			remove_orphan_inode(F2FS_I_SB(dir), inode->i_ino);
422 		f2fs_i_links_write(inode, true);
423 	}
424 	return page;
425 
426 put_error:
427 	clear_nlink(inode);
428 	update_inode(inode, page);
429 	f2fs_put_page(page, 1);
430 	return ERR_PTR(err);
431 }
432 
433 void update_parent_metadata(struct inode *dir, struct inode *inode,
434 						unsigned int current_depth)
435 {
436 	if (inode && is_inode_flag_set(inode, FI_NEW_INODE)) {
437 		if (S_ISDIR(inode->i_mode))
438 			f2fs_i_links_write(dir, true);
439 		clear_inode_flag(inode, FI_NEW_INODE);
440 	}
441 	dir->i_mtime = dir->i_ctime = current_time(dir);
442 	f2fs_mark_inode_dirty_sync(dir, false);
443 
444 	if (F2FS_I(dir)->i_current_depth != current_depth)
445 		f2fs_i_depth_write(dir, current_depth);
446 
447 	if (inode && is_inode_flag_set(inode, FI_INC_LINK))
448 		clear_inode_flag(inode, FI_INC_LINK);
449 }
450 
451 int room_for_filename(const void *bitmap, int slots, int max_slots)
452 {
453 	int bit_start = 0;
454 	int zero_start, zero_end;
455 next:
456 	zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
457 	if (zero_start >= max_slots)
458 		return max_slots;
459 
460 	zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
461 	if (zero_end - zero_start >= slots)
462 		return zero_start;
463 
464 	bit_start = zero_end + 1;
465 
466 	if (zero_end + 1 >= max_slots)
467 		return max_slots;
468 	goto next;
469 }
470 
471 void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
472 				const struct qstr *name, f2fs_hash_t name_hash,
473 				unsigned int bit_pos)
474 {
475 	struct f2fs_dir_entry *de;
476 	int slots = GET_DENTRY_SLOTS(name->len);
477 	int i;
478 
479 	de = &d->dentry[bit_pos];
480 	de->hash_code = name_hash;
481 	de->name_len = cpu_to_le16(name->len);
482 	memcpy(d->filename[bit_pos], name->name, name->len);
483 	de->ino = cpu_to_le32(ino);
484 	set_de_type(de, mode);
485 	for (i = 0; i < slots; i++) {
486 		__set_bit_le(bit_pos + i, (void *)d->bitmap);
487 		/* avoid wrong garbage data for readdir */
488 		if (i)
489 			(de + i)->name_len = 0;
490 	}
491 }
492 
493 int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
494 				const struct qstr *orig_name,
495 				struct inode *inode, nid_t ino, umode_t mode)
496 {
497 	unsigned int bit_pos;
498 	unsigned int level;
499 	unsigned int current_depth;
500 	unsigned long bidx, block;
501 	f2fs_hash_t dentry_hash;
502 	unsigned int nbucket, nblock;
503 	struct page *dentry_page = NULL;
504 	struct f2fs_dentry_block *dentry_blk = NULL;
505 	struct f2fs_dentry_ptr d;
506 	struct page *page = NULL;
507 	int slots, err = 0;
508 
509 	level = 0;
510 	slots = GET_DENTRY_SLOTS(new_name->len);
511 	dentry_hash = f2fs_dentry_hash(new_name, NULL);
512 
513 	current_depth = F2FS_I(dir)->i_current_depth;
514 	if (F2FS_I(dir)->chash == dentry_hash) {
515 		level = F2FS_I(dir)->clevel;
516 		F2FS_I(dir)->chash = 0;
517 	}
518 
519 start:
520 #ifdef CONFIG_F2FS_FAULT_INJECTION
521 	if (time_to_inject(F2FS_I_SB(dir), FAULT_DIR_DEPTH)) {
522 		f2fs_show_injection_info(FAULT_DIR_DEPTH);
523 		return -ENOSPC;
524 	}
525 #endif
526 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
527 		return -ENOSPC;
528 
529 	/* Increase the depth, if required */
530 	if (level == current_depth)
531 		++current_depth;
532 
533 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
534 	nblock = bucket_blocks(level);
535 
536 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
537 				(le32_to_cpu(dentry_hash) % nbucket));
538 
539 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
540 		dentry_page = get_new_data_page(dir, NULL, block, true);
541 		if (IS_ERR(dentry_page))
542 			return PTR_ERR(dentry_page);
543 
544 		dentry_blk = page_address(dentry_page);
545 		bit_pos = room_for_filename(&dentry_blk->dentry_bitmap,
546 						slots, NR_DENTRY_IN_BLOCK);
547 		if (bit_pos < NR_DENTRY_IN_BLOCK)
548 			goto add_dentry;
549 
550 		f2fs_put_page(dentry_page, 1);
551 	}
552 
553 	/* Move to next level to find the empty slot for new dentry */
554 	++level;
555 	goto start;
556 add_dentry:
557 	f2fs_wait_on_page_writeback(dentry_page, DATA, true);
558 
559 	if (inode) {
560 		down_write(&F2FS_I(inode)->i_sem);
561 		page = init_inode_metadata(inode, dir, new_name,
562 						orig_name, NULL);
563 		if (IS_ERR(page)) {
564 			err = PTR_ERR(page);
565 			goto fail;
566 		}
567 	}
568 
569 	make_dentry_ptr_block(NULL, &d, dentry_blk);
570 	f2fs_update_dentry(ino, mode, &d, new_name, dentry_hash, bit_pos);
571 
572 	set_page_dirty(dentry_page);
573 
574 	if (inode) {
575 		f2fs_i_pino_write(inode, dir->i_ino);
576 		f2fs_put_page(page, 1);
577 	}
578 
579 	update_parent_metadata(dir, inode, current_depth);
580 fail:
581 	if (inode)
582 		up_write(&F2FS_I(inode)->i_sem);
583 
584 	f2fs_put_page(dentry_page, 1);
585 
586 	return err;
587 }
588 
589 int __f2fs_do_add_link(struct inode *dir, struct fscrypt_name *fname,
590 				struct inode *inode, nid_t ino, umode_t mode)
591 {
592 	struct qstr new_name;
593 	int err = -EAGAIN;
594 
595 	new_name.name = fname_name(fname);
596 	new_name.len = fname_len(fname);
597 
598 	if (f2fs_has_inline_dentry(dir))
599 		err = f2fs_add_inline_entry(dir, &new_name, fname->usr_fname,
600 							inode, ino, mode);
601 	if (err == -EAGAIN)
602 		err = f2fs_add_regular_entry(dir, &new_name, fname->usr_fname,
603 							inode, ino, mode);
604 
605 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
606 	return err;
607 }
608 
609 /*
610  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
611  * f2fs_unlock_op().
612  */
613 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
614 				struct inode *inode, nid_t ino, umode_t mode)
615 {
616 	struct fscrypt_name fname;
617 	struct page *page = NULL;
618 	struct f2fs_dir_entry *de = NULL;
619 	int err;
620 
621 	err = fscrypt_setup_filename(dir, name, 0, &fname);
622 	if (err)
623 		return err;
624 
625 	/*
626 	 * An immature stakable filesystem shows a race condition between lookup
627 	 * and create. If we have same task when doing lookup and create, it's
628 	 * definitely fine as expected by VFS normally. Otherwise, let's just
629 	 * verify on-disk dentry one more time, which guarantees filesystem
630 	 * consistency more.
631 	 */
632 	if (current != F2FS_I(dir)->task) {
633 		de = __f2fs_find_entry(dir, &fname, &page);
634 		F2FS_I(dir)->task = NULL;
635 	}
636 	if (de) {
637 		f2fs_put_page(page, 0);
638 		err = -EEXIST;
639 	} else if (IS_ERR(page)) {
640 		err = PTR_ERR(page);
641 	} else {
642 		err = __f2fs_do_add_link(dir, &fname, inode, ino, mode);
643 	}
644 	fscrypt_free_filename(&fname);
645 	return err;
646 }
647 
648 int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
649 {
650 	struct page *page;
651 	int err = 0;
652 
653 	down_write(&F2FS_I(inode)->i_sem);
654 	page = init_inode_metadata(inode, dir, NULL, NULL, NULL);
655 	if (IS_ERR(page)) {
656 		err = PTR_ERR(page);
657 		goto fail;
658 	}
659 	f2fs_put_page(page, 1);
660 
661 	clear_inode_flag(inode, FI_NEW_INODE);
662 fail:
663 	up_write(&F2FS_I(inode)->i_sem);
664 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
665 	return err;
666 }
667 
668 void f2fs_drop_nlink(struct inode *dir, struct inode *inode)
669 {
670 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
671 
672 	down_write(&F2FS_I(inode)->i_sem);
673 
674 	if (S_ISDIR(inode->i_mode))
675 		f2fs_i_links_write(dir, false);
676 	inode->i_ctime = current_time(inode);
677 
678 	f2fs_i_links_write(inode, false);
679 	if (S_ISDIR(inode->i_mode)) {
680 		f2fs_i_links_write(inode, false);
681 		f2fs_i_size_write(inode, 0);
682 	}
683 	up_write(&F2FS_I(inode)->i_sem);
684 
685 	if (inode->i_nlink == 0)
686 		add_orphan_inode(inode);
687 	else
688 		release_orphan_inode(sbi);
689 }
690 
691 /*
692  * It only removes the dentry from the dentry page, corresponding name
693  * entry in name page does not need to be touched during deletion.
694  */
695 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
696 					struct inode *dir, struct inode *inode)
697 {
698 	struct	f2fs_dentry_block *dentry_blk;
699 	unsigned int bit_pos;
700 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
701 	struct address_space *mapping = page_mapping(page);
702 	unsigned long flags;
703 	int i;
704 
705 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
706 
707 	if (F2FS_OPTION(F2FS_I_SB(dir)).fsync_mode == FSYNC_MODE_STRICT)
708 		add_ino_entry(F2FS_I_SB(dir), dir->i_ino, TRANS_DIR_INO);
709 
710 	if (f2fs_has_inline_dentry(dir))
711 		return f2fs_delete_inline_entry(dentry, page, dir, inode);
712 
713 	lock_page(page);
714 	f2fs_wait_on_page_writeback(page, DATA, true);
715 
716 	dentry_blk = page_address(page);
717 	bit_pos = dentry - dentry_blk->dentry;
718 	for (i = 0; i < slots; i++)
719 		__clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
720 
721 	/* Let's check and deallocate this dentry page */
722 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
723 			NR_DENTRY_IN_BLOCK,
724 			0);
725 	set_page_dirty(page);
726 
727 	dir->i_ctime = dir->i_mtime = current_time(dir);
728 	f2fs_mark_inode_dirty_sync(dir, false);
729 
730 	if (inode)
731 		f2fs_drop_nlink(dir, inode);
732 
733 	if (bit_pos == NR_DENTRY_IN_BLOCK &&
734 			!truncate_hole(dir, page->index, page->index + 1)) {
735 		xa_lock_irqsave(&mapping->i_pages, flags);
736 		radix_tree_tag_clear(&mapping->i_pages, page_index(page),
737 				     PAGECACHE_TAG_DIRTY);
738 		xa_unlock_irqrestore(&mapping->i_pages, flags);
739 
740 		clear_page_dirty_for_io(page);
741 		ClearPagePrivate(page);
742 		ClearPageUptodate(page);
743 		inode_dec_dirty_pages(dir);
744 		remove_dirty_inode(dir);
745 	}
746 	f2fs_put_page(page, 1);
747 }
748 
749 bool f2fs_empty_dir(struct inode *dir)
750 {
751 	unsigned long bidx;
752 	struct page *dentry_page;
753 	unsigned int bit_pos;
754 	struct f2fs_dentry_block *dentry_blk;
755 	unsigned long nblock = dir_blocks(dir);
756 
757 	if (f2fs_has_inline_dentry(dir))
758 		return f2fs_empty_inline_dir(dir);
759 
760 	for (bidx = 0; bidx < nblock; bidx++) {
761 		dentry_page = get_lock_data_page(dir, bidx, false);
762 		if (IS_ERR(dentry_page)) {
763 			if (PTR_ERR(dentry_page) == -ENOENT)
764 				continue;
765 			else
766 				return false;
767 		}
768 
769 		dentry_blk = page_address(dentry_page);
770 		if (bidx == 0)
771 			bit_pos = 2;
772 		else
773 			bit_pos = 0;
774 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
775 						NR_DENTRY_IN_BLOCK,
776 						bit_pos);
777 
778 		f2fs_put_page(dentry_page, 1);
779 
780 		if (bit_pos < NR_DENTRY_IN_BLOCK)
781 			return false;
782 	}
783 	return true;
784 }
785 
786 int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
787 			unsigned int start_pos, struct fscrypt_str *fstr)
788 {
789 	unsigned char d_type = DT_UNKNOWN;
790 	unsigned int bit_pos;
791 	struct f2fs_dir_entry *de = NULL;
792 	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
793 	struct f2fs_sb_info *sbi = F2FS_I_SB(d->inode);
794 
795 	bit_pos = ((unsigned long)ctx->pos % d->max);
796 
797 	while (bit_pos < d->max) {
798 		bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
799 		if (bit_pos >= d->max)
800 			break;
801 
802 		de = &d->dentry[bit_pos];
803 		if (de->name_len == 0) {
804 			bit_pos++;
805 			ctx->pos = start_pos + bit_pos;
806 			continue;
807 		}
808 
809 		d_type = get_de_type(de);
810 
811 		de_name.name = d->filename[bit_pos];
812 		de_name.len = le16_to_cpu(de->name_len);
813 
814 		if (f2fs_encrypted_inode(d->inode)) {
815 			int save_len = fstr->len;
816 			int err;
817 
818 			err = fscrypt_fname_disk_to_usr(d->inode,
819 						(u32)de->hash_code, 0,
820 						&de_name, fstr);
821 			if (err)
822 				return err;
823 
824 			de_name = *fstr;
825 			fstr->len = save_len;
826 		}
827 
828 		if (!dir_emit(ctx, de_name.name, de_name.len,
829 					le32_to_cpu(de->ino), d_type))
830 			return 1;
831 
832 		if (sbi->readdir_ra == 1)
833 			ra_node_page(sbi, le32_to_cpu(de->ino));
834 
835 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
836 		ctx->pos = start_pos + bit_pos;
837 	}
838 	return 0;
839 }
840 
841 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
842 {
843 	struct inode *inode = file_inode(file);
844 	unsigned long npages = dir_blocks(inode);
845 	struct f2fs_dentry_block *dentry_blk = NULL;
846 	struct page *dentry_page = NULL;
847 	struct file_ra_state *ra = &file->f_ra;
848 	loff_t start_pos = ctx->pos;
849 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
850 	struct f2fs_dentry_ptr d;
851 	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
852 	int err = 0;
853 
854 	if (f2fs_encrypted_inode(inode)) {
855 		err = fscrypt_get_encryption_info(inode);
856 		if (err && err != -ENOKEY)
857 			goto out;
858 
859 		err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr);
860 		if (err < 0)
861 			goto out;
862 	}
863 
864 	if (f2fs_has_inline_dentry(inode)) {
865 		err = f2fs_read_inline_dir(file, ctx, &fstr);
866 		goto out_free;
867 	}
868 
869 	for (; n < npages; n++, ctx->pos = n * NR_DENTRY_IN_BLOCK) {
870 
871 		/* allow readdir() to be interrupted */
872 		if (fatal_signal_pending(current)) {
873 			err = -ERESTARTSYS;
874 			goto out_free;
875 		}
876 		cond_resched();
877 
878 		/* readahead for multi pages of dir */
879 		if (npages - n > 1 && !ra_has_index(ra, n))
880 			page_cache_sync_readahead(inode->i_mapping, ra, file, n,
881 				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
882 
883 		dentry_page = get_lock_data_page(inode, n, false);
884 		if (IS_ERR(dentry_page)) {
885 			err = PTR_ERR(dentry_page);
886 			if (err == -ENOENT) {
887 				err = 0;
888 				continue;
889 			} else {
890 				goto out_free;
891 			}
892 		}
893 
894 		dentry_blk = page_address(dentry_page);
895 
896 		make_dentry_ptr_block(inode, &d, dentry_blk);
897 
898 		err = f2fs_fill_dentries(ctx, &d,
899 				n * NR_DENTRY_IN_BLOCK, &fstr);
900 		if (err) {
901 			f2fs_put_page(dentry_page, 1);
902 			break;
903 		}
904 
905 		f2fs_put_page(dentry_page, 1);
906 	}
907 out_free:
908 	fscrypt_fname_free_buffer(&fstr);
909 out:
910 	trace_f2fs_readdir(inode, start_pos, ctx->pos, err);
911 	return err < 0 ? err : 0;
912 }
913 
914 static int f2fs_dir_open(struct inode *inode, struct file *filp)
915 {
916 	if (f2fs_encrypted_inode(inode))
917 		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
918 	return 0;
919 }
920 
921 const struct file_operations f2fs_dir_operations = {
922 	.llseek		= generic_file_llseek,
923 	.read		= generic_read_dir,
924 	.iterate_shared	= f2fs_readdir,
925 	.fsync		= f2fs_sync_file,
926 	.open		= f2fs_dir_open,
927 	.unlocked_ioctl	= f2fs_ioctl,
928 #ifdef CONFIG_COMPAT
929 	.compat_ioctl   = f2fs_compat_ioctl,
930 #endif
931 };
932