xref: /linux/fs/f2fs/extent_cache.c (revision d4b996f9ef1fe83d9ce9ad5c1ca0bd8231638ce5)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * f2fs extent cache support
4  *
5  * Copyright (c) 2015 Motorola Mobility
6  * Copyright (c) 2015 Samsung Electronics
7  * Authors: Jaegeuk Kim <jaegeuk@kernel.org>
8  *          Chao Yu <chao2.yu@samsung.com>
9  */
10 
11 #include <linux/fs.h>
12 #include <linux/f2fs_fs.h>
13 
14 #include "f2fs.h"
15 #include "node.h"
16 #include <trace/events/f2fs.h>
17 
18 static struct rb_entry *__lookup_rb_tree_fast(struct rb_entry *cached_re,
19 							unsigned int ofs)
20 {
21 	if (cached_re) {
22 		if (cached_re->ofs <= ofs &&
23 				cached_re->ofs + cached_re->len > ofs) {
24 			return cached_re;
25 		}
26 	}
27 	return NULL;
28 }
29 
30 static struct rb_entry *__lookup_rb_tree_slow(struct rb_root_cached *root,
31 							unsigned int ofs)
32 {
33 	struct rb_node *node = root->rb_root.rb_node;
34 	struct rb_entry *re;
35 
36 	while (node) {
37 		re = rb_entry(node, struct rb_entry, rb_node);
38 
39 		if (ofs < re->ofs)
40 			node = node->rb_left;
41 		else if (ofs >= re->ofs + re->len)
42 			node = node->rb_right;
43 		else
44 			return re;
45 	}
46 	return NULL;
47 }
48 
49 struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
50 				struct rb_entry *cached_re, unsigned int ofs)
51 {
52 	struct rb_entry *re;
53 
54 	re = __lookup_rb_tree_fast(cached_re, ofs);
55 	if (!re)
56 		return __lookup_rb_tree_slow(root, ofs);
57 
58 	return re;
59 }
60 
61 struct rb_node **f2fs_lookup_rb_tree_ext(struct f2fs_sb_info *sbi,
62 					struct rb_root_cached *root,
63 					struct rb_node **parent,
64 					unsigned long long key, bool *leftmost)
65 {
66 	struct rb_node **p = &root->rb_root.rb_node;
67 	struct rb_entry *re;
68 
69 	while (*p) {
70 		*parent = *p;
71 		re = rb_entry(*parent, struct rb_entry, rb_node);
72 
73 		if (key < re->key) {
74 			p = &(*p)->rb_left;
75 		} else {
76 			p = &(*p)->rb_right;
77 			*leftmost = false;
78 		}
79 	}
80 
81 	return p;
82 }
83 
84 struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
85 				struct rb_root_cached *root,
86 				struct rb_node **parent,
87 				unsigned int ofs, bool *leftmost)
88 {
89 	struct rb_node **p = &root->rb_root.rb_node;
90 	struct rb_entry *re;
91 
92 	while (*p) {
93 		*parent = *p;
94 		re = rb_entry(*parent, struct rb_entry, rb_node);
95 
96 		if (ofs < re->ofs) {
97 			p = &(*p)->rb_left;
98 		} else if (ofs >= re->ofs + re->len) {
99 			p = &(*p)->rb_right;
100 			*leftmost = false;
101 		} else {
102 			f2fs_bug_on(sbi, 1);
103 		}
104 	}
105 
106 	return p;
107 }
108 
109 /*
110  * lookup rb entry in position of @ofs in rb-tree,
111  * if hit, return the entry, otherwise, return NULL
112  * @prev_ex: extent before ofs
113  * @next_ex: extent after ofs
114  * @insert_p: insert point for new extent at ofs
115  * in order to simpfy the insertion after.
116  * tree must stay unchanged between lookup and insertion.
117  */
118 struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
119 				struct rb_entry *cached_re,
120 				unsigned int ofs,
121 				struct rb_entry **prev_entry,
122 				struct rb_entry **next_entry,
123 				struct rb_node ***insert_p,
124 				struct rb_node **insert_parent,
125 				bool force, bool *leftmost)
126 {
127 	struct rb_node **pnode = &root->rb_root.rb_node;
128 	struct rb_node *parent = NULL, *tmp_node;
129 	struct rb_entry *re = cached_re;
130 
131 	*insert_p = NULL;
132 	*insert_parent = NULL;
133 	*prev_entry = NULL;
134 	*next_entry = NULL;
135 
136 	if (RB_EMPTY_ROOT(&root->rb_root))
137 		return NULL;
138 
139 	if (re) {
140 		if (re->ofs <= ofs && re->ofs + re->len > ofs)
141 			goto lookup_neighbors;
142 	}
143 
144 	if (leftmost)
145 		*leftmost = true;
146 
147 	while (*pnode) {
148 		parent = *pnode;
149 		re = rb_entry(*pnode, struct rb_entry, rb_node);
150 
151 		if (ofs < re->ofs) {
152 			pnode = &(*pnode)->rb_left;
153 		} else if (ofs >= re->ofs + re->len) {
154 			pnode = &(*pnode)->rb_right;
155 			if (leftmost)
156 				*leftmost = false;
157 		} else {
158 			goto lookup_neighbors;
159 		}
160 	}
161 
162 	*insert_p = pnode;
163 	*insert_parent = parent;
164 
165 	re = rb_entry(parent, struct rb_entry, rb_node);
166 	tmp_node = parent;
167 	if (parent && ofs > re->ofs)
168 		tmp_node = rb_next(parent);
169 	*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
170 
171 	tmp_node = parent;
172 	if (parent && ofs < re->ofs)
173 		tmp_node = rb_prev(parent);
174 	*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
175 	return NULL;
176 
177 lookup_neighbors:
178 	if (ofs == re->ofs || force) {
179 		/* lookup prev node for merging backward later */
180 		tmp_node = rb_prev(&re->rb_node);
181 		*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
182 	}
183 	if (ofs == re->ofs + re->len - 1 || force) {
184 		/* lookup next node for merging frontward later */
185 		tmp_node = rb_next(&re->rb_node);
186 		*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
187 	}
188 	return re;
189 }
190 
191 bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
192 				struct rb_root_cached *root, bool check_key)
193 {
194 #ifdef CONFIG_F2FS_CHECK_FS
195 	struct rb_node *cur = rb_first_cached(root), *next;
196 	struct rb_entry *cur_re, *next_re;
197 
198 	if (!cur)
199 		return true;
200 
201 	while (cur) {
202 		next = rb_next(cur);
203 		if (!next)
204 			return true;
205 
206 		cur_re = rb_entry(cur, struct rb_entry, rb_node);
207 		next_re = rb_entry(next, struct rb_entry, rb_node);
208 
209 		if (check_key) {
210 			if (cur_re->key > next_re->key) {
211 				f2fs_info(sbi, "inconsistent rbtree, "
212 					"cur(%llu) next(%llu)",
213 					cur_re->key, next_re->key);
214 				return false;
215 			}
216 			goto next;
217 		}
218 
219 		if (cur_re->ofs + cur_re->len > next_re->ofs) {
220 			f2fs_info(sbi, "inconsistent rbtree, cur(%u, %u) next(%u, %u)",
221 				  cur_re->ofs, cur_re->len,
222 				  next_re->ofs, next_re->len);
223 			return false;
224 		}
225 next:
226 		cur = next;
227 	}
228 #endif
229 	return true;
230 }
231 
232 static struct kmem_cache *extent_tree_slab;
233 static struct kmem_cache *extent_node_slab;
234 
235 static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
236 				struct extent_tree *et, struct extent_info *ei,
237 				struct rb_node *parent, struct rb_node **p,
238 				bool leftmost)
239 {
240 	struct extent_node *en;
241 
242 	en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
243 	if (!en)
244 		return NULL;
245 
246 	en->ei = *ei;
247 	INIT_LIST_HEAD(&en->list);
248 	en->et = et;
249 
250 	rb_link_node(&en->rb_node, parent, p);
251 	rb_insert_color_cached(&en->rb_node, &et->root, leftmost);
252 	atomic_inc(&et->node_cnt);
253 	atomic_inc(&sbi->total_ext_node);
254 	return en;
255 }
256 
257 static void __detach_extent_node(struct f2fs_sb_info *sbi,
258 				struct extent_tree *et, struct extent_node *en)
259 {
260 	rb_erase_cached(&en->rb_node, &et->root);
261 	atomic_dec(&et->node_cnt);
262 	atomic_dec(&sbi->total_ext_node);
263 
264 	if (et->cached_en == en)
265 		et->cached_en = NULL;
266 	kmem_cache_free(extent_node_slab, en);
267 }
268 
269 /*
270  * Flow to release an extent_node:
271  * 1. list_del_init
272  * 2. __detach_extent_node
273  * 3. kmem_cache_free.
274  */
275 static void __release_extent_node(struct f2fs_sb_info *sbi,
276 			struct extent_tree *et, struct extent_node *en)
277 {
278 	spin_lock(&sbi->extent_lock);
279 	f2fs_bug_on(sbi, list_empty(&en->list));
280 	list_del_init(&en->list);
281 	spin_unlock(&sbi->extent_lock);
282 
283 	__detach_extent_node(sbi, et, en);
284 }
285 
286 static struct extent_tree *__grab_extent_tree(struct inode *inode)
287 {
288 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
289 	struct extent_tree *et;
290 	nid_t ino = inode->i_ino;
291 
292 	mutex_lock(&sbi->extent_tree_lock);
293 	et = radix_tree_lookup(&sbi->extent_tree_root, ino);
294 	if (!et) {
295 		et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
296 		f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
297 		memset(et, 0, sizeof(struct extent_tree));
298 		et->ino = ino;
299 		et->root = RB_ROOT_CACHED;
300 		et->cached_en = NULL;
301 		rwlock_init(&et->lock);
302 		INIT_LIST_HEAD(&et->list);
303 		atomic_set(&et->node_cnt, 0);
304 		atomic_inc(&sbi->total_ext_tree);
305 	} else {
306 		atomic_dec(&sbi->total_zombie_tree);
307 		list_del_init(&et->list);
308 	}
309 	mutex_unlock(&sbi->extent_tree_lock);
310 
311 	/* never died until evict_inode */
312 	F2FS_I(inode)->extent_tree = et;
313 
314 	return et;
315 }
316 
317 static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi,
318 				struct extent_tree *et, struct extent_info *ei)
319 {
320 	struct rb_node **p = &et->root.rb_root.rb_node;
321 	struct extent_node *en;
322 
323 	en = __attach_extent_node(sbi, et, ei, NULL, p, true);
324 	if (!en)
325 		return NULL;
326 
327 	et->largest = en->ei;
328 	et->cached_en = en;
329 	return en;
330 }
331 
332 static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
333 					struct extent_tree *et)
334 {
335 	struct rb_node *node, *next;
336 	struct extent_node *en;
337 	unsigned int count = atomic_read(&et->node_cnt);
338 
339 	node = rb_first_cached(&et->root);
340 	while (node) {
341 		next = rb_next(node);
342 		en = rb_entry(node, struct extent_node, rb_node);
343 		__release_extent_node(sbi, et, en);
344 		node = next;
345 	}
346 
347 	return count - atomic_read(&et->node_cnt);
348 }
349 
350 static void __drop_largest_extent(struct extent_tree *et,
351 					pgoff_t fofs, unsigned int len)
352 {
353 	if (fofs < et->largest.fofs + et->largest.len &&
354 			fofs + len > et->largest.fofs) {
355 		et->largest.len = 0;
356 		et->largest_updated = true;
357 	}
358 }
359 
360 /* return true, if inode page is changed */
361 static void __f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
362 {
363 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
364 	struct f2fs_extent *i_ext = ipage ? &F2FS_INODE(ipage)->i_ext : NULL;
365 	struct extent_tree *et;
366 	struct extent_node *en;
367 	struct extent_info ei;
368 
369 	if (!f2fs_may_extent_tree(inode)) {
370 		/* drop largest extent */
371 		if (i_ext && i_ext->len) {
372 			f2fs_wait_on_page_writeback(ipage, NODE, true, true);
373 			i_ext->len = 0;
374 			set_page_dirty(ipage);
375 			return;
376 		}
377 		return;
378 	}
379 
380 	et = __grab_extent_tree(inode);
381 
382 	if (!i_ext || !i_ext->len)
383 		return;
384 
385 	get_extent_info(&ei, i_ext);
386 
387 	write_lock(&et->lock);
388 	if (atomic_read(&et->node_cnt))
389 		goto out;
390 
391 	en = __init_extent_tree(sbi, et, &ei);
392 	if (en) {
393 		spin_lock(&sbi->extent_lock);
394 		list_add_tail(&en->list, &sbi->extent_list);
395 		spin_unlock(&sbi->extent_lock);
396 	}
397 out:
398 	write_unlock(&et->lock);
399 }
400 
401 void f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
402 {
403 	__f2fs_init_extent_tree(inode, ipage);
404 
405 	if (!F2FS_I(inode)->extent_tree)
406 		set_inode_flag(inode, FI_NO_EXTENT);
407 }
408 
409 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
410 							struct extent_info *ei)
411 {
412 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
413 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
414 	struct extent_node *en;
415 	bool ret = false;
416 
417 	f2fs_bug_on(sbi, !et);
418 
419 	trace_f2fs_lookup_extent_tree_start(inode, pgofs);
420 
421 	read_lock(&et->lock);
422 
423 	if (et->largest.fofs <= pgofs &&
424 			et->largest.fofs + et->largest.len > pgofs) {
425 		*ei = et->largest;
426 		ret = true;
427 		stat_inc_largest_node_hit(sbi);
428 		goto out;
429 	}
430 
431 	en = (struct extent_node *)f2fs_lookup_rb_tree(&et->root,
432 				(struct rb_entry *)et->cached_en, pgofs);
433 	if (!en)
434 		goto out;
435 
436 	if (en == et->cached_en)
437 		stat_inc_cached_node_hit(sbi);
438 	else
439 		stat_inc_rbtree_node_hit(sbi);
440 
441 	*ei = en->ei;
442 	spin_lock(&sbi->extent_lock);
443 	if (!list_empty(&en->list)) {
444 		list_move_tail(&en->list, &sbi->extent_list);
445 		et->cached_en = en;
446 	}
447 	spin_unlock(&sbi->extent_lock);
448 	ret = true;
449 out:
450 	stat_inc_total_hit(sbi);
451 	read_unlock(&et->lock);
452 
453 	trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
454 	return ret;
455 }
456 
457 static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
458 				struct extent_tree *et, struct extent_info *ei,
459 				struct extent_node *prev_ex,
460 				struct extent_node *next_ex)
461 {
462 	struct extent_node *en = NULL;
463 
464 	if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
465 		prev_ex->ei.len += ei->len;
466 		ei = &prev_ex->ei;
467 		en = prev_ex;
468 	}
469 
470 	if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
471 		next_ex->ei.fofs = ei->fofs;
472 		next_ex->ei.blk = ei->blk;
473 		next_ex->ei.len += ei->len;
474 		if (en)
475 			__release_extent_node(sbi, et, prev_ex);
476 
477 		en = next_ex;
478 	}
479 
480 	if (!en)
481 		return NULL;
482 
483 	__try_update_largest_extent(et, en);
484 
485 	spin_lock(&sbi->extent_lock);
486 	if (!list_empty(&en->list)) {
487 		list_move_tail(&en->list, &sbi->extent_list);
488 		et->cached_en = en;
489 	}
490 	spin_unlock(&sbi->extent_lock);
491 	return en;
492 }
493 
494 static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
495 				struct extent_tree *et, struct extent_info *ei,
496 				struct rb_node **insert_p,
497 				struct rb_node *insert_parent,
498 				bool leftmost)
499 {
500 	struct rb_node **p;
501 	struct rb_node *parent = NULL;
502 	struct extent_node *en = NULL;
503 
504 	if (insert_p && insert_parent) {
505 		parent = insert_parent;
506 		p = insert_p;
507 		goto do_insert;
508 	}
509 
510 	leftmost = true;
511 
512 	p = f2fs_lookup_rb_tree_for_insert(sbi, &et->root, &parent,
513 						ei->fofs, &leftmost);
514 do_insert:
515 	en = __attach_extent_node(sbi, et, ei, parent, p, leftmost);
516 	if (!en)
517 		return NULL;
518 
519 	__try_update_largest_extent(et, en);
520 
521 	/* update in global extent list */
522 	spin_lock(&sbi->extent_lock);
523 	list_add_tail(&en->list, &sbi->extent_list);
524 	et->cached_en = en;
525 	spin_unlock(&sbi->extent_lock);
526 	return en;
527 }
528 
529 static void f2fs_update_extent_tree_range(struct inode *inode,
530 				pgoff_t fofs, block_t blkaddr, unsigned int len)
531 {
532 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
533 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
534 	struct extent_node *en = NULL, *en1 = NULL;
535 	struct extent_node *prev_en = NULL, *next_en = NULL;
536 	struct extent_info ei, dei, prev;
537 	struct rb_node **insert_p = NULL, *insert_parent = NULL;
538 	unsigned int end = fofs + len;
539 	unsigned int pos = (unsigned int)fofs;
540 	bool updated = false;
541 	bool leftmost = false;
542 
543 	if (!et)
544 		return;
545 
546 	trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len);
547 
548 	write_lock(&et->lock);
549 
550 	if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
551 		write_unlock(&et->lock);
552 		return;
553 	}
554 
555 	prev = et->largest;
556 	dei.len = 0;
557 
558 	/*
559 	 * drop largest extent before lookup, in case it's already
560 	 * been shrunk from extent tree
561 	 */
562 	__drop_largest_extent(et, fofs, len);
563 
564 	/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
565 	en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
566 					(struct rb_entry *)et->cached_en, fofs,
567 					(struct rb_entry **)&prev_en,
568 					(struct rb_entry **)&next_en,
569 					&insert_p, &insert_parent, false,
570 					&leftmost);
571 	if (!en)
572 		en = next_en;
573 
574 	/* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */
575 	while (en && en->ei.fofs < end) {
576 		unsigned int org_end;
577 		int parts = 0;	/* # of parts current extent split into */
578 
579 		next_en = en1 = NULL;
580 
581 		dei = en->ei;
582 		org_end = dei.fofs + dei.len;
583 		f2fs_bug_on(sbi, pos >= org_end);
584 
585 		if (pos > dei.fofs &&	pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
586 			en->ei.len = pos - en->ei.fofs;
587 			prev_en = en;
588 			parts = 1;
589 		}
590 
591 		if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
592 			if (parts) {
593 				set_extent_info(&ei, end,
594 						end - dei.fofs + dei.blk,
595 						org_end - end);
596 				en1 = __insert_extent_tree(sbi, et, &ei,
597 							NULL, NULL, true);
598 				next_en = en1;
599 			} else {
600 				en->ei.fofs = end;
601 				en->ei.blk += end - dei.fofs;
602 				en->ei.len -= end - dei.fofs;
603 				next_en = en;
604 			}
605 			parts++;
606 		}
607 
608 		if (!next_en) {
609 			struct rb_node *node = rb_next(&en->rb_node);
610 
611 			next_en = rb_entry_safe(node, struct extent_node,
612 						rb_node);
613 		}
614 
615 		if (parts)
616 			__try_update_largest_extent(et, en);
617 		else
618 			__release_extent_node(sbi, et, en);
619 
620 		/*
621 		 * if original extent is split into zero or two parts, extent
622 		 * tree has been altered by deletion or insertion, therefore
623 		 * invalidate pointers regard to tree.
624 		 */
625 		if (parts != 1) {
626 			insert_p = NULL;
627 			insert_parent = NULL;
628 		}
629 		en = next_en;
630 	}
631 
632 	/* 3. update extent in extent cache */
633 	if (blkaddr) {
634 
635 		set_extent_info(&ei, fofs, blkaddr, len);
636 		if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
637 			__insert_extent_tree(sbi, et, &ei,
638 					insert_p, insert_parent, leftmost);
639 
640 		/* give up extent_cache, if split and small updates happen */
641 		if (dei.len >= 1 &&
642 				prev.len < F2FS_MIN_EXTENT_LEN &&
643 				et->largest.len < F2FS_MIN_EXTENT_LEN) {
644 			et->largest.len = 0;
645 			et->largest_updated = true;
646 			set_inode_flag(inode, FI_NO_EXTENT);
647 		}
648 	}
649 
650 	if (is_inode_flag_set(inode, FI_NO_EXTENT))
651 		__free_extent_tree(sbi, et);
652 
653 	if (et->largest_updated) {
654 		et->largest_updated = false;
655 		updated = true;
656 	}
657 
658 	write_unlock(&et->lock);
659 
660 	if (updated)
661 		f2fs_mark_inode_dirty_sync(inode, true);
662 }
663 
664 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
665 {
666 	struct extent_tree *et, *next;
667 	struct extent_node *en;
668 	unsigned int node_cnt = 0, tree_cnt = 0;
669 	int remained;
670 
671 	if (!test_opt(sbi, EXTENT_CACHE))
672 		return 0;
673 
674 	if (!atomic_read(&sbi->total_zombie_tree))
675 		goto free_node;
676 
677 	if (!mutex_trylock(&sbi->extent_tree_lock))
678 		goto out;
679 
680 	/* 1. remove unreferenced extent tree */
681 	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
682 		if (atomic_read(&et->node_cnt)) {
683 			write_lock(&et->lock);
684 			node_cnt += __free_extent_tree(sbi, et);
685 			write_unlock(&et->lock);
686 		}
687 		f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
688 		list_del_init(&et->list);
689 		radix_tree_delete(&sbi->extent_tree_root, et->ino);
690 		kmem_cache_free(extent_tree_slab, et);
691 		atomic_dec(&sbi->total_ext_tree);
692 		atomic_dec(&sbi->total_zombie_tree);
693 		tree_cnt++;
694 
695 		if (node_cnt + tree_cnt >= nr_shrink)
696 			goto unlock_out;
697 		cond_resched();
698 	}
699 	mutex_unlock(&sbi->extent_tree_lock);
700 
701 free_node:
702 	/* 2. remove LRU extent entries */
703 	if (!mutex_trylock(&sbi->extent_tree_lock))
704 		goto out;
705 
706 	remained = nr_shrink - (node_cnt + tree_cnt);
707 
708 	spin_lock(&sbi->extent_lock);
709 	for (; remained > 0; remained--) {
710 		if (list_empty(&sbi->extent_list))
711 			break;
712 		en = list_first_entry(&sbi->extent_list,
713 					struct extent_node, list);
714 		et = en->et;
715 		if (!write_trylock(&et->lock)) {
716 			/* refresh this extent node's position in extent list */
717 			list_move_tail(&en->list, &sbi->extent_list);
718 			continue;
719 		}
720 
721 		list_del_init(&en->list);
722 		spin_unlock(&sbi->extent_lock);
723 
724 		__detach_extent_node(sbi, et, en);
725 
726 		write_unlock(&et->lock);
727 		node_cnt++;
728 		spin_lock(&sbi->extent_lock);
729 	}
730 	spin_unlock(&sbi->extent_lock);
731 
732 unlock_out:
733 	mutex_unlock(&sbi->extent_tree_lock);
734 out:
735 	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);
736 
737 	return node_cnt + tree_cnt;
738 }
739 
740 unsigned int f2fs_destroy_extent_node(struct inode *inode)
741 {
742 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
743 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
744 	unsigned int node_cnt = 0;
745 
746 	if (!et || !atomic_read(&et->node_cnt))
747 		return 0;
748 
749 	write_lock(&et->lock);
750 	node_cnt = __free_extent_tree(sbi, et);
751 	write_unlock(&et->lock);
752 
753 	return node_cnt;
754 }
755 
756 void f2fs_drop_extent_tree(struct inode *inode)
757 {
758 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
759 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
760 	bool updated = false;
761 
762 	if (!f2fs_may_extent_tree(inode))
763 		return;
764 
765 	set_inode_flag(inode, FI_NO_EXTENT);
766 
767 	write_lock(&et->lock);
768 	__free_extent_tree(sbi, et);
769 	if (et->largest.len) {
770 		et->largest.len = 0;
771 		updated = true;
772 	}
773 	write_unlock(&et->lock);
774 	if (updated)
775 		f2fs_mark_inode_dirty_sync(inode, true);
776 }
777 
778 void f2fs_destroy_extent_tree(struct inode *inode)
779 {
780 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
781 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
782 	unsigned int node_cnt = 0;
783 
784 	if (!et)
785 		return;
786 
787 	if (inode->i_nlink && !is_bad_inode(inode) &&
788 					atomic_read(&et->node_cnt)) {
789 		mutex_lock(&sbi->extent_tree_lock);
790 		list_add_tail(&et->list, &sbi->zombie_list);
791 		atomic_inc(&sbi->total_zombie_tree);
792 		mutex_unlock(&sbi->extent_tree_lock);
793 		return;
794 	}
795 
796 	/* free all extent info belong to this extent tree */
797 	node_cnt = f2fs_destroy_extent_node(inode);
798 
799 	/* delete extent tree entry in radix tree */
800 	mutex_lock(&sbi->extent_tree_lock);
801 	f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
802 	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
803 	kmem_cache_free(extent_tree_slab, et);
804 	atomic_dec(&sbi->total_ext_tree);
805 	mutex_unlock(&sbi->extent_tree_lock);
806 
807 	F2FS_I(inode)->extent_tree = NULL;
808 
809 	trace_f2fs_destroy_extent_tree(inode, node_cnt);
810 }
811 
812 bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
813 					struct extent_info *ei)
814 {
815 	if (!f2fs_may_extent_tree(inode))
816 		return false;
817 
818 	return f2fs_lookup_extent_tree(inode, pgofs, ei);
819 }
820 
821 void f2fs_update_extent_cache(struct dnode_of_data *dn)
822 {
823 	pgoff_t fofs;
824 	block_t blkaddr;
825 
826 	if (!f2fs_may_extent_tree(dn->inode))
827 		return;
828 
829 	if (dn->data_blkaddr == NEW_ADDR)
830 		blkaddr = NULL_ADDR;
831 	else
832 		blkaddr = dn->data_blkaddr;
833 
834 	fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
835 								dn->ofs_in_node;
836 	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1);
837 }
838 
839 void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
840 				pgoff_t fofs, block_t blkaddr, unsigned int len)
841 
842 {
843 	if (!f2fs_may_extent_tree(dn->inode))
844 		return;
845 
846 	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len);
847 }
848 
849 void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
850 {
851 	INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
852 	mutex_init(&sbi->extent_tree_lock);
853 	INIT_LIST_HEAD(&sbi->extent_list);
854 	spin_lock_init(&sbi->extent_lock);
855 	atomic_set(&sbi->total_ext_tree, 0);
856 	INIT_LIST_HEAD(&sbi->zombie_list);
857 	atomic_set(&sbi->total_zombie_tree, 0);
858 	atomic_set(&sbi->total_ext_node, 0);
859 }
860 
861 int __init f2fs_create_extent_cache(void)
862 {
863 	extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
864 			sizeof(struct extent_tree));
865 	if (!extent_tree_slab)
866 		return -ENOMEM;
867 	extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
868 			sizeof(struct extent_node));
869 	if (!extent_node_slab) {
870 		kmem_cache_destroy(extent_tree_slab);
871 		return -ENOMEM;
872 	}
873 	return 0;
874 }
875 
876 void f2fs_destroy_extent_cache(void)
877 {
878 	kmem_cache_destroy(extent_node_slab);
879 	kmem_cache_destroy(extent_tree_slab);
880 }
881