xref: /openbmc/linux/fs/f2fs/dir.c (revision 80483c3a)
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 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(NULL, &d, (void *)dentry_blk, 1);
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 	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
115 	struct fscrypt_str *name = &fname->disk_name;
116 
117 	if (max_slots)
118 		*max_slots = 0;
119 	while (bit_pos < d->max) {
120 		if (!test_bit_le(bit_pos, d->bitmap)) {
121 			bit_pos++;
122 			max_len++;
123 			continue;
124 		}
125 
126 		de = &d->dentry[bit_pos];
127 
128 		if (unlikely(!de->name_len)) {
129 			bit_pos++;
130 			continue;
131 		}
132 
133 		/* encrypted case */
134 		de_name.name = d->filename[bit_pos];
135 		de_name.len = le16_to_cpu(de->name_len);
136 
137 		/* show encrypted name */
138 		if (fname->hash) {
139 			if (de->hash_code == fname->hash)
140 				goto found;
141 		} else if (de_name.len == name->len &&
142 			de->hash_code == namehash &&
143 			!memcmp(de_name.name, name->name, name->len))
144 			goto found;
145 
146 		if (max_slots && max_len > *max_slots)
147 			*max_slots = max_len;
148 		max_len = 0;
149 
150 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
151 	}
152 
153 	de = NULL;
154 found:
155 	if (max_slots && max_len > *max_slots)
156 		*max_slots = max_len;
157 	return de;
158 }
159 
160 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
161 					unsigned int level,
162 					struct fscrypt_name *fname,
163 					struct page **res_page)
164 {
165 	struct qstr name = FSTR_TO_QSTR(&fname->disk_name);
166 	int s = GET_DENTRY_SLOTS(name.len);
167 	unsigned int nbucket, nblock;
168 	unsigned int bidx, end_block;
169 	struct page *dentry_page;
170 	struct f2fs_dir_entry *de = NULL;
171 	bool room = false;
172 	int max_slots;
173 	f2fs_hash_t namehash;
174 
175 	namehash = f2fs_dentry_hash(&name);
176 
177 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
178 	nblock = bucket_blocks(level);
179 
180 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
181 					le32_to_cpu(namehash) % nbucket);
182 	end_block = bidx + nblock;
183 
184 	for (; bidx < end_block; bidx++) {
185 		/* no need to allocate new dentry pages to all the indices */
186 		dentry_page = find_data_page(dir, bidx);
187 		if (IS_ERR(dentry_page)) {
188 			if (PTR_ERR(dentry_page) == -ENOENT) {
189 				room = true;
190 				continue;
191 			} else {
192 				*res_page = dentry_page;
193 				break;
194 			}
195 		}
196 
197 		de = find_in_block(dentry_page, fname, namehash, &max_slots,
198 								res_page);
199 		if (de)
200 			break;
201 
202 		if (max_slots >= s)
203 			room = true;
204 		f2fs_put_page(dentry_page, 0);
205 	}
206 
207 	if (!de && room && F2FS_I(dir)->chash != namehash) {
208 		F2FS_I(dir)->chash = namehash;
209 		F2FS_I(dir)->clevel = level;
210 	}
211 
212 	return de;
213 }
214 
215 /*
216  * Find an entry in the specified directory with the wanted name.
217  * It returns the page where the entry was found (as a parameter - res_page),
218  * and the entry itself. Page is returned mapped and unlocked.
219  * Entry is guaranteed to be valid.
220  */
221 struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
222 			const struct qstr *child, struct page **res_page)
223 {
224 	unsigned long npages = dir_blocks(dir);
225 	struct f2fs_dir_entry *de = NULL;
226 	unsigned int max_depth;
227 	unsigned int level;
228 	struct fscrypt_name fname;
229 	int err;
230 
231 	err = fscrypt_setup_filename(dir, child, 1, &fname);
232 	if (err) {
233 		*res_page = ERR_PTR(err);
234 		return NULL;
235 	}
236 
237 	if (f2fs_has_inline_dentry(dir)) {
238 		*res_page = NULL;
239 		de = find_in_inline_dir(dir, &fname, res_page);
240 		goto out;
241 	}
242 
243 	if (npages == 0) {
244 		*res_page = NULL;
245 		goto out;
246 	}
247 
248 	max_depth = F2FS_I(dir)->i_current_depth;
249 	if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
250 		f2fs_msg(F2FS_I_SB(dir)->sb, KERN_WARNING,
251 				"Corrupted max_depth of %lu: %u",
252 				dir->i_ino, max_depth);
253 		max_depth = MAX_DIR_HASH_DEPTH;
254 		f2fs_i_depth_write(dir, max_depth);
255 	}
256 
257 	for (level = 0; level < max_depth; level++) {
258 		*res_page = NULL;
259 		de = find_in_level(dir, level, &fname, res_page);
260 		if (de || IS_ERR(*res_page))
261 			break;
262 	}
263 out:
264 	fscrypt_free_filename(&fname);
265 	return de;
266 }
267 
268 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
269 {
270 	struct qstr dotdot = QSTR_INIT("..", 2);
271 
272 	return f2fs_find_entry(dir, &dotdot, p);
273 }
274 
275 ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,
276 							struct page **page)
277 {
278 	ino_t res = 0;
279 	struct f2fs_dir_entry *de;
280 
281 	de = f2fs_find_entry(dir, qstr, page);
282 	if (de) {
283 		res = le32_to_cpu(de->ino);
284 		f2fs_dentry_kunmap(dir, *page);
285 		f2fs_put_page(*page, 0);
286 	}
287 
288 	return res;
289 }
290 
291 void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
292 		struct page *page, struct inode *inode)
293 {
294 	enum page_type type = f2fs_has_inline_dentry(dir) ? NODE : DATA;
295 	lock_page(page);
296 	f2fs_wait_on_page_writeback(page, type, true);
297 	de->ino = cpu_to_le32(inode->i_ino);
298 	set_de_type(de, inode->i_mode);
299 	f2fs_dentry_kunmap(dir, page);
300 	set_page_dirty(page);
301 
302 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
303 	f2fs_mark_inode_dirty_sync(dir);
304 	f2fs_put_page(page, 1);
305 }
306 
307 static void init_dent_inode(const struct qstr *name, struct page *ipage)
308 {
309 	struct f2fs_inode *ri;
310 
311 	f2fs_wait_on_page_writeback(ipage, NODE, true);
312 
313 	/* copy name info. to this inode page */
314 	ri = F2FS_INODE(ipage);
315 	ri->i_namelen = cpu_to_le32(name->len);
316 	memcpy(ri->i_name, name->name, name->len);
317 	set_page_dirty(ipage);
318 }
319 
320 int update_dent_inode(struct inode *inode, struct inode *to,
321 					const struct qstr *name)
322 {
323 	struct page *page;
324 
325 	if (file_enc_name(to))
326 		return 0;
327 
328 	page = get_node_page(F2FS_I_SB(inode), inode->i_ino);
329 	if (IS_ERR(page))
330 		return PTR_ERR(page);
331 
332 	init_dent_inode(name, page);
333 	f2fs_put_page(page, 1);
334 
335 	return 0;
336 }
337 
338 void do_make_empty_dir(struct inode *inode, struct inode *parent,
339 					struct f2fs_dentry_ptr *d)
340 {
341 	struct qstr dot = QSTR_INIT(".", 1);
342 	struct qstr dotdot = QSTR_INIT("..", 2);
343 
344 	/* update dirent of "." */
345 	f2fs_update_dentry(inode->i_ino, inode->i_mode, d, &dot, 0, 0);
346 
347 	/* update dirent of ".." */
348 	f2fs_update_dentry(parent->i_ino, parent->i_mode, d, &dotdot, 0, 1);
349 }
350 
351 static int make_empty_dir(struct inode *inode,
352 		struct inode *parent, struct page *page)
353 {
354 	struct page *dentry_page;
355 	struct f2fs_dentry_block *dentry_blk;
356 	struct f2fs_dentry_ptr d;
357 
358 	if (f2fs_has_inline_dentry(inode))
359 		return make_empty_inline_dir(inode, parent, page);
360 
361 	dentry_page = get_new_data_page(inode, page, 0, true);
362 	if (IS_ERR(dentry_page))
363 		return PTR_ERR(dentry_page);
364 
365 	dentry_blk = kmap_atomic(dentry_page);
366 
367 	make_dentry_ptr(NULL, &d, (void *)dentry_blk, 1);
368 	do_make_empty_dir(inode, parent, &d);
369 
370 	kunmap_atomic(dentry_blk);
371 
372 	set_page_dirty(dentry_page);
373 	f2fs_put_page(dentry_page, 1);
374 	return 0;
375 }
376 
377 struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
378 			const struct qstr *name, struct page *dpage)
379 {
380 	struct page *page;
381 	int err;
382 
383 	if (is_inode_flag_set(inode, FI_NEW_INODE)) {
384 		page = new_inode_page(inode);
385 		if (IS_ERR(page))
386 			return page;
387 
388 		if (S_ISDIR(inode->i_mode)) {
389 			/* in order to handle error case */
390 			get_page(page);
391 			err = make_empty_dir(inode, dir, page);
392 			if (err) {
393 				lock_page(page);
394 				goto put_error;
395 			}
396 			put_page(page);
397 		}
398 
399 		err = f2fs_init_acl(inode, dir, page, dpage);
400 		if (err)
401 			goto put_error;
402 
403 		err = f2fs_init_security(inode, dir, name, page);
404 		if (err)
405 			goto put_error;
406 
407 		if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode)) {
408 			err = fscrypt_inherit_context(dir, inode, page, false);
409 			if (err)
410 				goto put_error;
411 		}
412 	} else {
413 		page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
414 		if (IS_ERR(page))
415 			return page;
416 
417 		set_cold_node(inode, page);
418 	}
419 
420 	if (name)
421 		init_dent_inode(name, page);
422 
423 	/*
424 	 * This file should be checkpointed during fsync.
425 	 * We lost i_pino from now on.
426 	 */
427 	if (is_inode_flag_set(inode, FI_INC_LINK)) {
428 		file_lost_pino(inode);
429 		/*
430 		 * If link the tmpfile to alias through linkat path,
431 		 * we should remove this inode from orphan list.
432 		 */
433 		if (inode->i_nlink == 0)
434 			remove_orphan_inode(F2FS_I_SB(dir), inode->i_ino);
435 		f2fs_i_links_write(inode, true);
436 	}
437 	return page;
438 
439 put_error:
440 	clear_nlink(inode);
441 	update_inode(inode, page);
442 	f2fs_put_page(page, 1);
443 	return ERR_PTR(err);
444 }
445 
446 void update_parent_metadata(struct inode *dir, struct inode *inode,
447 						unsigned int current_depth)
448 {
449 	if (inode && is_inode_flag_set(inode, FI_NEW_INODE)) {
450 		if (S_ISDIR(inode->i_mode))
451 			f2fs_i_links_write(dir, true);
452 		clear_inode_flag(inode, FI_NEW_INODE);
453 	}
454 	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
455 	f2fs_mark_inode_dirty_sync(dir);
456 
457 	if (F2FS_I(dir)->i_current_depth != current_depth)
458 		f2fs_i_depth_write(dir, current_depth);
459 
460 	if (inode && is_inode_flag_set(inode, FI_INC_LINK))
461 		clear_inode_flag(inode, FI_INC_LINK);
462 }
463 
464 int room_for_filename(const void *bitmap, int slots, int max_slots)
465 {
466 	int bit_start = 0;
467 	int zero_start, zero_end;
468 next:
469 	zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
470 	if (zero_start >= max_slots)
471 		return max_slots;
472 
473 	zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
474 	if (zero_end - zero_start >= slots)
475 		return zero_start;
476 
477 	bit_start = zero_end + 1;
478 
479 	if (zero_end + 1 >= max_slots)
480 		return max_slots;
481 	goto next;
482 }
483 
484 void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
485 				const struct qstr *name, f2fs_hash_t name_hash,
486 				unsigned int bit_pos)
487 {
488 	struct f2fs_dir_entry *de;
489 	int slots = GET_DENTRY_SLOTS(name->len);
490 	int i;
491 
492 	de = &d->dentry[bit_pos];
493 	de->hash_code = name_hash;
494 	de->name_len = cpu_to_le16(name->len);
495 	memcpy(d->filename[bit_pos], name->name, name->len);
496 	de->ino = cpu_to_le32(ino);
497 	set_de_type(de, mode);
498 	for (i = 0; i < slots; i++) {
499 		test_and_set_bit_le(bit_pos + i, (void *)d->bitmap);
500 		/* avoid wrong garbage data for readdir */
501 		if (i)
502 			(de + i)->name_len = 0;
503 	}
504 }
505 
506 int f2fs_add_regular_entry(struct inode *dir, const struct qstr *new_name,
507 				struct inode *inode, nid_t ino, umode_t mode)
508 {
509 	unsigned int bit_pos;
510 	unsigned int level;
511 	unsigned int current_depth;
512 	unsigned long bidx, block;
513 	f2fs_hash_t dentry_hash;
514 	unsigned int nbucket, nblock;
515 	struct page *dentry_page = NULL;
516 	struct f2fs_dentry_block *dentry_blk = NULL;
517 	struct f2fs_dentry_ptr d;
518 	struct page *page = NULL;
519 	int slots, err = 0;
520 
521 	level = 0;
522 	slots = GET_DENTRY_SLOTS(new_name->len);
523 	dentry_hash = f2fs_dentry_hash(new_name);
524 
525 	current_depth = F2FS_I(dir)->i_current_depth;
526 	if (F2FS_I(dir)->chash == dentry_hash) {
527 		level = F2FS_I(dir)->clevel;
528 		F2FS_I(dir)->chash = 0;
529 	}
530 
531 start:
532 #ifdef CONFIG_F2FS_FAULT_INJECTION
533 	if (time_to_inject(FAULT_DIR_DEPTH))
534 		return -ENOSPC;
535 #endif
536 	if (unlikely(current_depth == MAX_DIR_HASH_DEPTH))
537 		return -ENOSPC;
538 
539 	/* Increase the depth, if required */
540 	if (level == current_depth)
541 		++current_depth;
542 
543 	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
544 	nblock = bucket_blocks(level);
545 
546 	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
547 				(le32_to_cpu(dentry_hash) % nbucket));
548 
549 	for (block = bidx; block <= (bidx + nblock - 1); block++) {
550 		dentry_page = get_new_data_page(dir, NULL, block, true);
551 		if (IS_ERR(dentry_page))
552 			return PTR_ERR(dentry_page);
553 
554 		dentry_blk = kmap(dentry_page);
555 		bit_pos = room_for_filename(&dentry_blk->dentry_bitmap,
556 						slots, NR_DENTRY_IN_BLOCK);
557 		if (bit_pos < NR_DENTRY_IN_BLOCK)
558 			goto add_dentry;
559 
560 		kunmap(dentry_page);
561 		f2fs_put_page(dentry_page, 1);
562 	}
563 
564 	/* Move to next level to find the empty slot for new dentry */
565 	++level;
566 	goto start;
567 add_dentry:
568 	f2fs_wait_on_page_writeback(dentry_page, DATA, true);
569 
570 	if (inode) {
571 		down_write(&F2FS_I(inode)->i_sem);
572 		page = init_inode_metadata(inode, dir, new_name, NULL);
573 		if (IS_ERR(page)) {
574 			err = PTR_ERR(page);
575 			goto fail;
576 		}
577 		if (f2fs_encrypted_inode(dir))
578 			file_set_enc_name(inode);
579 	}
580 
581 	make_dentry_ptr(NULL, &d, (void *)dentry_blk, 1);
582 	f2fs_update_dentry(ino, mode, &d, new_name, dentry_hash, bit_pos);
583 
584 	set_page_dirty(dentry_page);
585 
586 	if (inode) {
587 		f2fs_i_pino_write(inode, dir->i_ino);
588 		f2fs_put_page(page, 1);
589 	}
590 
591 	update_parent_metadata(dir, inode, current_depth);
592 fail:
593 	if (inode)
594 		up_write(&F2FS_I(inode)->i_sem);
595 
596 	kunmap(dentry_page);
597 	f2fs_put_page(dentry_page, 1);
598 
599 	return err;
600 }
601 
602 /*
603  * Caller should grab and release a rwsem by calling f2fs_lock_op() and
604  * f2fs_unlock_op().
605  */
606 int __f2fs_add_link(struct inode *dir, const struct qstr *name,
607 				struct inode *inode, nid_t ino, umode_t mode)
608 {
609 	struct fscrypt_name fname;
610 	struct qstr new_name;
611 	int err;
612 
613 	err = fscrypt_setup_filename(dir, name, 0, &fname);
614 	if (err)
615 		return err;
616 
617 	new_name.name = fname_name(&fname);
618 	new_name.len = fname_len(&fname);
619 
620 	err = -EAGAIN;
621 	if (f2fs_has_inline_dentry(dir))
622 		err = f2fs_add_inline_entry(dir, &new_name, inode, ino, mode);
623 	if (err == -EAGAIN)
624 		err = f2fs_add_regular_entry(dir, &new_name, inode, ino, mode);
625 
626 	fscrypt_free_filename(&fname);
627 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
628 	return err;
629 }
630 
631 int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
632 {
633 	struct page *page;
634 	int err = 0;
635 
636 	down_write(&F2FS_I(inode)->i_sem);
637 	page = init_inode_metadata(inode, dir, NULL, NULL);
638 	if (IS_ERR(page)) {
639 		err = PTR_ERR(page);
640 		goto fail;
641 	}
642 	f2fs_put_page(page, 1);
643 
644 	clear_inode_flag(inode, FI_NEW_INODE);
645 fail:
646 	up_write(&F2FS_I(inode)->i_sem);
647 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
648 	return err;
649 }
650 
651 void f2fs_drop_nlink(struct inode *dir, struct inode *inode)
652 {
653 	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
654 
655 	down_write(&F2FS_I(inode)->i_sem);
656 
657 	if (S_ISDIR(inode->i_mode))
658 		f2fs_i_links_write(dir, false);
659 	inode->i_ctime = CURRENT_TIME;
660 
661 	f2fs_i_links_write(inode, false);
662 	if (S_ISDIR(inode->i_mode)) {
663 		f2fs_i_links_write(inode, false);
664 		f2fs_i_size_write(inode, 0);
665 	}
666 	up_write(&F2FS_I(inode)->i_sem);
667 
668 	if (inode->i_nlink == 0)
669 		add_orphan_inode(inode);
670 	else
671 		release_orphan_inode(sbi);
672 }
673 
674 /*
675  * It only removes the dentry from the dentry page, corresponding name
676  * entry in name page does not need to be touched during deletion.
677  */
678 void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
679 					struct inode *dir, struct inode *inode)
680 {
681 	struct	f2fs_dentry_block *dentry_blk;
682 	unsigned int bit_pos;
683 	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
684 	int i;
685 
686 	f2fs_update_time(F2FS_I_SB(dir), REQ_TIME);
687 
688 	if (f2fs_has_inline_dentry(dir))
689 		return f2fs_delete_inline_entry(dentry, page, dir, inode);
690 
691 	lock_page(page);
692 	f2fs_wait_on_page_writeback(page, DATA, true);
693 
694 	dentry_blk = page_address(page);
695 	bit_pos = dentry - dentry_blk->dentry;
696 	for (i = 0; i < slots; i++)
697 		clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
698 
699 	/* Let's check and deallocate this dentry page */
700 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
701 			NR_DENTRY_IN_BLOCK,
702 			0);
703 	kunmap(page); /* kunmap - pair of f2fs_find_entry */
704 	set_page_dirty(page);
705 
706 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
707 	f2fs_mark_inode_dirty_sync(dir);
708 
709 	if (inode)
710 		f2fs_drop_nlink(dir, inode);
711 
712 	if (bit_pos == NR_DENTRY_IN_BLOCK &&
713 			!truncate_hole(dir, page->index, page->index + 1)) {
714 		clear_page_dirty_for_io(page);
715 		ClearPagePrivate(page);
716 		ClearPageUptodate(page);
717 		inode_dec_dirty_pages(dir);
718 	}
719 	f2fs_put_page(page, 1);
720 }
721 
722 bool f2fs_empty_dir(struct inode *dir)
723 {
724 	unsigned long bidx;
725 	struct page *dentry_page;
726 	unsigned int bit_pos;
727 	struct f2fs_dentry_block *dentry_blk;
728 	unsigned long nblock = dir_blocks(dir);
729 
730 	if (f2fs_has_inline_dentry(dir))
731 		return f2fs_empty_inline_dir(dir);
732 
733 	for (bidx = 0; bidx < nblock; bidx++) {
734 		dentry_page = get_lock_data_page(dir, bidx, false);
735 		if (IS_ERR(dentry_page)) {
736 			if (PTR_ERR(dentry_page) == -ENOENT)
737 				continue;
738 			else
739 				return false;
740 		}
741 
742 		dentry_blk = kmap_atomic(dentry_page);
743 		if (bidx == 0)
744 			bit_pos = 2;
745 		else
746 			bit_pos = 0;
747 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
748 						NR_DENTRY_IN_BLOCK,
749 						bit_pos);
750 		kunmap_atomic(dentry_blk);
751 
752 		f2fs_put_page(dentry_page, 1);
753 
754 		if (bit_pos < NR_DENTRY_IN_BLOCK)
755 			return false;
756 	}
757 	return true;
758 }
759 
760 bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
761 			unsigned int start_pos, struct fscrypt_str *fstr)
762 {
763 	unsigned char d_type = DT_UNKNOWN;
764 	unsigned int bit_pos;
765 	struct f2fs_dir_entry *de = NULL;
766 	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
767 
768 	bit_pos = ((unsigned long)ctx->pos % d->max);
769 
770 	while (bit_pos < d->max) {
771 		bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
772 		if (bit_pos >= d->max)
773 			break;
774 
775 		de = &d->dentry[bit_pos];
776 		if (de->name_len == 0) {
777 			bit_pos++;
778 			ctx->pos = start_pos + bit_pos;
779 			continue;
780 		}
781 
782 		d_type = get_de_type(de);
783 
784 		de_name.name = d->filename[bit_pos];
785 		de_name.len = le16_to_cpu(de->name_len);
786 
787 		if (f2fs_encrypted_inode(d->inode)) {
788 			int save_len = fstr->len;
789 			int ret;
790 
791 			de_name.name = f2fs_kmalloc(de_name.len, GFP_NOFS);
792 			if (!de_name.name)
793 				return false;
794 
795 			memcpy(de_name.name, d->filename[bit_pos], de_name.len);
796 
797 			ret = fscrypt_fname_disk_to_usr(d->inode,
798 						(u32)de->hash_code, 0,
799 						&de_name, fstr);
800 			kfree(de_name.name);
801 			if (ret < 0)
802 				return true;
803 
804 			de_name = *fstr;
805 			fstr->len = save_len;
806 		}
807 
808 		if (!dir_emit(ctx, de_name.name, de_name.len,
809 					le32_to_cpu(de->ino), d_type))
810 			return true;
811 
812 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
813 		ctx->pos = start_pos + bit_pos;
814 	}
815 	return false;
816 }
817 
818 static int f2fs_readdir(struct file *file, struct dir_context *ctx)
819 {
820 	struct inode *inode = file_inode(file);
821 	unsigned long npages = dir_blocks(inode);
822 	struct f2fs_dentry_block *dentry_blk = NULL;
823 	struct page *dentry_page = NULL;
824 	struct file_ra_state *ra = &file->f_ra;
825 	unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
826 	struct f2fs_dentry_ptr d;
827 	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
828 	int err = 0;
829 
830 	if (f2fs_encrypted_inode(inode)) {
831 		err = fscrypt_get_encryption_info(inode);
832 		if (err && err != -ENOKEY)
833 			return err;
834 
835 		err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr);
836 		if (err < 0)
837 			return err;
838 	}
839 
840 	if (f2fs_has_inline_dentry(inode)) {
841 		err = f2fs_read_inline_dir(file, ctx, &fstr);
842 		goto out;
843 	}
844 
845 	/* readahead for multi pages of dir */
846 	if (npages - n > 1 && !ra_has_index(ra, n))
847 		page_cache_sync_readahead(inode->i_mapping, ra, file, n,
848 				min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
849 
850 	for (; n < npages; n++) {
851 		dentry_page = get_lock_data_page(inode, n, false);
852 		if (IS_ERR(dentry_page)) {
853 			err = PTR_ERR(dentry_page);
854 			if (err == -ENOENT)
855 				continue;
856 			else
857 				goto out;
858 		}
859 
860 		dentry_blk = kmap(dentry_page);
861 
862 		make_dentry_ptr(inode, &d, (void *)dentry_blk, 1);
863 
864 		if (f2fs_fill_dentries(ctx, &d, n * NR_DENTRY_IN_BLOCK, &fstr)) {
865 			kunmap(dentry_page);
866 			f2fs_put_page(dentry_page, 1);
867 			break;
868 		}
869 
870 		ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
871 		kunmap(dentry_page);
872 		f2fs_put_page(dentry_page, 1);
873 	}
874 	err = 0;
875 out:
876 	fscrypt_fname_free_buffer(&fstr);
877 	return err;
878 }
879 
880 static int f2fs_dir_open(struct inode *inode, struct file *filp)
881 {
882 	if (f2fs_encrypted_inode(inode))
883 		return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
884 	return 0;
885 }
886 
887 const struct file_operations f2fs_dir_operations = {
888 	.llseek		= generic_file_llseek,
889 	.read		= generic_read_dir,
890 	.iterate_shared	= f2fs_readdir,
891 	.fsync		= f2fs_sync_file,
892 	.open		= f2fs_dir_open,
893 	.unlocked_ioctl	= f2fs_ioctl,
894 #ifdef CONFIG_COMPAT
895 	.compat_ioctl   = f2fs_compat_ioctl,
896 #endif
897 };
898