fs/f2fs/extent_cache.c - linux-mtk - Git at Google

 /*
  * f2fs extent cache support
  *
  * Copyright (c) 2015 Motorola Mobility
  * Copyright (c) 2015 Samsung Electronics
  * Authors: Jaegeuk Kim <jaegeuk@kernel.org>
  *          Chao Yu <chao2.yu@samsung.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>

 #include "f2fs.h"
 #include "node.h"
 #include <trace/events/f2fs.h>

 static struct rb_entry *__lookup_rb_tree_fast(struct rb_entry *cached_re,
 							unsigned int ofs)
 {
 	if (cached_re) {
 		if (cached_re->ofs <= ofs &&
 				cached_re->ofs + cached_re->len > ofs) {
 			return cached_re;
 		}
 	}
 	return NULL;
 }

 static struct rb_entry *__lookup_rb_tree_slow(struct rb_root *root,
 							unsigned int ofs)
 {
 	struct rb_node *node = root->rb_node;
 	struct rb_entry *re;

 	while (node) {
 		re = rb_entry(node, struct rb_entry, rb_node);

 		if (ofs < re->ofs)
 			node = node->rb_left;
 		else if (ofs >= re->ofs + re->len)
 			node = node->rb_right;
 		else
 			return re;
 	}
 	return NULL;
 }

 struct rb_entry *f2fs_lookup_rb_tree(struct rb_root *root,
 				struct rb_entry *cached_re, unsigned int ofs)
 {
 	struct rb_entry *re;

 	re = __lookup_rb_tree_fast(cached_re, ofs);
 	if (!re)
 		return __lookup_rb_tree_slow(root, ofs);

 	return re;
 }

 struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
 				struct rb_root *root, struct rb_node **parent,
 				unsigned int ofs)
 {
 	struct rb_node **p = &root->rb_node;
 	struct rb_entry *re;

 	while (*p) {
 		*parent = *p;
 		re = rb_entry(*parent, struct rb_entry, rb_node);

 		if (ofs < re->ofs)
 			p = &(*p)->rb_left;
 		else if (ofs >= re->ofs + re->len)
 			p = &(*p)->rb_right;
 		else
 			f2fs_bug_on(sbi, 1);
 	}

 	return p;
 }

 /*
  * lookup rb entry in position of @ofs in rb-tree,
  * if hit, return the entry, otherwise, return NULL
  * @prev_ex: extent before ofs
  * @next_ex: extent after ofs
  * @insert_p: insert point for new extent at ofs
  * in order to simpfy the insertion after.
  * tree must stay unchanged between lookup and insertion.
  */
 struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root *root,
 				struct rb_entry *cached_re,
 				unsigned int ofs,
 				struct rb_entry **prev_entry,
 				struct rb_entry **next_entry,
 				struct rb_node ***insert_p,
 				struct rb_node **insert_parent,
 				bool force)
 {
 	struct rb_node **pnode = &root->rb_node;
 	struct rb_node *parent = NULL, *tmp_node;
 	struct rb_entry *re = cached_re;

 	*insert_p = NULL;
 	*insert_parent = NULL;
 	*prev_entry = NULL;
 	*next_entry = NULL;

 	if (RB_EMPTY_ROOT(root))
 		return NULL;

 	if (re) {
 		if (re->ofs <= ofs && re->ofs + re->len > ofs)
 			goto lookup_neighbors;
 	}

 	while (*pnode) {
 		parent = *pnode;
 		re = rb_entry(*pnode, struct rb_entry, rb_node);

 		if (ofs < re->ofs)
 			pnode = &(*pnode)->rb_left;
 		else if (ofs >= re->ofs + re->len)
 			pnode = &(*pnode)->rb_right;
 		else
 			goto lookup_neighbors;
 	}

 	*insert_p = pnode;
 	*insert_parent = parent;

 	re = rb_entry(parent, struct rb_entry, rb_node);
 	tmp_node = parent;
 	if (parent && ofs > re->ofs)
 		tmp_node = rb_next(parent);
 	*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);

 	tmp_node = parent;
 	if (parent && ofs < re->ofs)
 		tmp_node = rb_prev(parent);
 	*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 	return NULL;

 lookup_neighbors:
 	if (ofs == re->ofs || force) {
 		/* lookup prev node for merging backward later */
 		tmp_node = rb_prev(&re->rb_node);
 		*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 	}
 	if (ofs == re->ofs + re->len - 1 || force) {
 		/* lookup next node for merging frontward later */
 		tmp_node = rb_next(&re->rb_node);
 		*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
 	}
 	return re;
 }

 bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
 						struct rb_root *root)
 {
 #ifdef CONFIG_F2FS_CHECK_FS
 	struct rb_node *cur = rb_first(root), *next;
 	struct rb_entry *cur_re, *next_re;

 	if (!cur)
 		return true;

 	while (cur) {
 		next = rb_next(cur);
 		if (!next)
 			return true;

 		cur_re = rb_entry(cur, struct rb_entry, rb_node);
 		next_re = rb_entry(next, struct rb_entry, rb_node);

 		if (cur_re->ofs + cur_re->len > next_re->ofs) {
 			f2fs_msg(sbi->sb, KERN_INFO, "inconsistent rbtree, "
 				"cur(%u, %u) next(%u, %u)",
 				cur_re->ofs, cur_re->len,
 				next_re->ofs, next_re->len);
 			return false;
 		}

 		cur = next;
 	}
 #endif
 	return true;
 }

 static struct kmem_cache *extent_tree_slab;
 static struct kmem_cache *extent_node_slab;

 static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_info *ei,
 				struct rb_node *parent, struct rb_node **p)
 {
 	struct extent_node *en;

 	en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
 	if (!en)
 		return NULL;

 	en->ei = *ei;
 	INIT_LIST_HEAD(&en->list);
 	en->et = et;

 	rb_link_node(&en->rb_node, parent, p);
 	rb_insert_color(&en->rb_node, &et->root);
 	atomic_inc(&et->node_cnt);
 	atomic_inc(&sbi->total_ext_node);
 	return en;
 }

 static void __detach_extent_node(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_node *en)
 {
 	rb_erase(&en->rb_node, &et->root);
 	atomic_dec(&et->node_cnt);
 	atomic_dec(&sbi->total_ext_node);

 	if (et->cached_en == en)
 		et->cached_en = NULL;
 	kmem_cache_free(extent_node_slab, en);
 }

 /*
  * Flow to release an extent_node:
  * 1. list_del_init
  * 2. __detach_extent_node
  * 3. kmem_cache_free.
  */
 static void __release_extent_node(struct f2fs_sb_info *sbi,
 			struct extent_tree *et, struct extent_node *en)
 {
 	spin_lock(&sbi->extent_lock);
 	f2fs_bug_on(sbi, list_empty(&en->list));
 	list_del_init(&en->list);
 	spin_unlock(&sbi->extent_lock);

 	__detach_extent_node(sbi, et, en);
 }

 static struct extent_tree *__grab_extent_tree(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et;
 	nid_t ino = inode->i_ino;

 	mutex_lock(&sbi->extent_tree_lock);
 	et = radix_tree_lookup(&sbi->extent_tree_root, ino);
 	if (!et) {
 		et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
 		f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
 		memset(et, 0, sizeof(struct extent_tree));
 		et->ino = ino;
 		et->root = RB_ROOT;
 		et->cached_en = NULL;
 		rwlock_init(&et->lock);
 		INIT_LIST_HEAD(&et->list);
 		atomic_set(&et->node_cnt, 0);
 		atomic_inc(&sbi->total_ext_tree);
 	} else {
 		atomic_dec(&sbi->total_zombie_tree);
 		list_del_init(&et->list);
 	}
 	mutex_unlock(&sbi->extent_tree_lock);

 	/* never died until evict_inode */
 	F2FS_I(inode)->extent_tree = et;

 	return et;
 }

 static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_info *ei)
 {
 	struct rb_node **p = &et->root.rb_node;
 	struct extent_node *en;

 	en = __attach_extent_node(sbi, et, ei, NULL, p);
 	if (!en)
 		return NULL;

 	et->largest = en->ei;
 	et->cached_en = en;
 	return en;
 }

 static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
 					struct extent_tree *et)
 {
 	struct rb_node *node, *next;
 	struct extent_node *en;
 	unsigned int count = atomic_read(&et->node_cnt);

 	node = rb_first(&et->root);
 	while (node) {
 		next = rb_next(node);
 		en = rb_entry(node, struct extent_node, rb_node);
 		__release_extent_node(sbi, et, en);
 		node = next;
 	}

 	return count - atomic_read(&et->node_cnt);
 }

 static void __drop_largest_extent(struct extent_tree *et,
 					pgoff_t fofs, unsigned int len)
 {
 	if (fofs < et->largest.fofs + et->largest.len &&
 			fofs + len > et->largest.fofs) {
 		et->largest.len = 0;
 		et->largest_updated = true;
 	}
 }

 /* return true, if inode page is changed */
 static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et;
 	struct extent_node *en;
 	struct extent_info ei;

 	if (!f2fs_may_extent_tree(inode)) {
 		/* drop largest extent */
 		if (i_ext && i_ext->len) {
 			i_ext->len = 0;
 			return true;
 		}
 		return false;
 	}

 	et = __grab_extent_tree(inode);

 	if (!i_ext || !i_ext->len)
 		return false;

 	get_extent_info(&ei, i_ext);

 	write_lock(&et->lock);
 	if (atomic_read(&et->node_cnt))
 		goto out;

 	en = __init_extent_tree(sbi, et, &ei);
 	if (en) {
 		spin_lock(&sbi->extent_lock);
 		list_add_tail(&en->list, &sbi->extent_list);
 		spin_unlock(&sbi->extent_lock);
 	}
 out:
 	write_unlock(&et->lock);
 	return false;
 }

 bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 {
 	bool ret =  __f2fs_init_extent_tree(inode, i_ext);

 	if (!F2FS_I(inode)->extent_tree)
 		set_inode_flag(inode, FI_NO_EXTENT);

 	return ret;
 }

 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 							struct extent_info *ei)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
 	struct extent_node *en;
 	bool ret = false;

 	f2fs_bug_on(sbi, !et);

 	trace_f2fs_lookup_extent_tree_start(inode, pgofs);

 	read_lock(&et->lock);

 	if (et->largest.fofs <= pgofs &&
 			et->largest.fofs + et->largest.len > pgofs) {
 		*ei = et->largest;
 		ret = true;
 		stat_inc_largest_node_hit(sbi);
 		goto out;
 	}

 	en = (struct extent_node *)f2fs_lookup_rb_tree(&et->root,
 				(struct rb_entry *)et->cached_en, pgofs);
 	if (!en)
 		goto out;

 	if (en == et->cached_en)
 		stat_inc_cached_node_hit(sbi);
 	else
 		stat_inc_rbtree_node_hit(sbi);

 	*ei = en->ei;
 	spin_lock(&sbi->extent_lock);
 	if (!list_empty(&en->list)) {
 		list_move_tail(&en->list, &sbi->extent_list);
 		et->cached_en = en;
 	}
 	spin_unlock(&sbi->extent_lock);
 	ret = true;
 out:
 	stat_inc_total_hit(sbi);
 	read_unlock(&et->lock);

 	trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
 	return ret;
 }

 static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_info *ei,
 				struct extent_node *prev_ex,
 				struct extent_node *next_ex)
 {
 	struct extent_node *en = NULL;

 	if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
 		prev_ex->ei.len += ei->len;
 		ei = &prev_ex->ei;
 		en = prev_ex;
 	}

 	if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
 		next_ex->ei.fofs = ei->fofs;
 		next_ex->ei.blk = ei->blk;
 		next_ex->ei.len += ei->len;
 		if (en)
 			__release_extent_node(sbi, et, prev_ex);

 		en = next_ex;
 	}

 	if (!en)
 		return NULL;

 	__try_update_largest_extent(et, en);

 	spin_lock(&sbi->extent_lock);
 	if (!list_empty(&en->list)) {
 		list_move_tail(&en->list, &sbi->extent_list);
 		et->cached_en = en;
 	}
 	spin_unlock(&sbi->extent_lock);
 	return en;
 }

 static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
 				struct extent_tree *et, struct extent_info *ei,
 				struct rb_node **insert_p,
 				struct rb_node *insert_parent)
 {
 	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct extent_node *en = NULL;

 	if (insert_p && insert_parent) {
 		parent = insert_parent;
 		p = insert_p;
 		goto do_insert;
 	}

 	p = f2fs_lookup_rb_tree_for_insert(sbi, &et->root, &parent, ei->fofs);
 do_insert:
 	en = __attach_extent_node(sbi, et, ei, parent, p);
 	if (!en)
 		return NULL;

 	__try_update_largest_extent(et, en);

 	/* update in global extent list */
 	spin_lock(&sbi->extent_lock);
 	list_add_tail(&en->list, &sbi->extent_list);
 	et->cached_en = en;
 	spin_unlock(&sbi->extent_lock);
 	return en;
 }

 static void f2fs_update_extent_tree_range(struct inode *inode,
 				pgoff_t fofs, block_t blkaddr, unsigned int len)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
 	struct extent_node *en = NULL, *en1 = NULL;
 	struct extent_node *prev_en = NULL, *next_en = NULL;
 	struct extent_info ei, dei, prev;
 	struct rb_node **insert_p = NULL, *insert_parent = NULL;
 	unsigned int end = fofs + len;
 	unsigned int pos = (unsigned int)fofs;
 	bool updated = false;

 	if (!et)
 		return;

 	trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len);

 	write_lock(&et->lock);

 	if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
 		write_unlock(&et->lock);
 		return;
 	}

 	prev = et->largest;
 	dei.len = 0;

 	/*
 	 * drop largest extent before lookup, in case it's already
 	 * been shrunk from extent tree
 	 */
 	__drop_largest_extent(et, fofs, len);

 	/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
 	en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
 					(struct rb_entry *)et->cached_en, fofs,
 					(struct rb_entry **)&prev_en,
 					(struct rb_entry **)&next_en,
 					&insert_p, &insert_parent, false);
 	if (!en)
 		en = next_en;

 	/* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */
 	while (en && en->ei.fofs < end) {
 		unsigned int org_end;
 		int parts = 0;	/* # of parts current extent split into */

 		next_en = en1 = NULL;

 		dei = en->ei;
 		org_end = dei.fofs + dei.len;
 		f2fs_bug_on(sbi, pos >= org_end);

 		if (pos > dei.fofs &&	pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
 			en->ei.len = pos - en->ei.fofs;
 			prev_en = en;
 			parts = 1;
 		}

 		if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
 			if (parts) {
 				set_extent_info(&ei, end,
 						end - dei.fofs + dei.blk,
 						org_end - end);
 				en1 = __insert_extent_tree(sbi, et, &ei,
 							NULL, NULL);
 				next_en = en1;
 			} else {
 				en->ei.fofs = end;
 				en->ei.blk += end - dei.fofs;
 				en->ei.len -= end - dei.fofs;
 				next_en = en;
 			}
 			parts++;
 		}

 		if (!next_en) {
 			struct rb_node *node = rb_next(&en->rb_node);

 			next_en = rb_entry_safe(node, struct extent_node,
 						rb_node);
 		}

 		if (parts)
 			__try_update_largest_extent(et, en);
 		else
 			__release_extent_node(sbi, et, en);

 		/*
 		 * if original extent is split into zero or two parts, extent
 		 * tree has been altered by deletion or insertion, therefore
 		 * invalidate pointers regard to tree.
 		 */
 		if (parts != 1) {
 			insert_p = NULL;
 			insert_parent = NULL;
 		}
 		en = next_en;
 	}

 	/* 3. update extent in extent cache */
 	if (blkaddr) {

 		set_extent_info(&ei, fofs, blkaddr, len);
 		if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
 			__insert_extent_tree(sbi, et, &ei,
 						insert_p, insert_parent);

 		/* give up extent_cache, if split and small updates happen */
 		if (dei.len >= 1 &&
 				prev.len < F2FS_MIN_EXTENT_LEN &&
 				et->largest.len < F2FS_MIN_EXTENT_LEN) {
 			et->largest.len = 0;
 			et->largest_updated = true;
 			set_inode_flag(inode, FI_NO_EXTENT);
 		}
 	}

 	if (is_inode_flag_set(inode, FI_NO_EXTENT))
 		__free_extent_tree(sbi, et);

 	if (et->largest_updated) {
 		et->largest_updated = false;
 		updated = true;
 	}

 	write_unlock(&et->lock);

 	if (updated)
 		f2fs_mark_inode_dirty_sync(inode, true);
 }

 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
 {
 	struct extent_tree *et, *next;
 	struct extent_node *en;
 	unsigned int node_cnt = 0, tree_cnt = 0;
 	int remained;

 	if (!test_opt(sbi, EXTENT_CACHE))
 		return 0;

 	if (!atomic_read(&sbi->total_zombie_tree))
 		goto free_node;

 	if (!mutex_trylock(&sbi->extent_tree_lock))
 		goto out;

 	/* 1. remove unreferenced extent tree */
 	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
 		if (atomic_read(&et->node_cnt)) {
 			write_lock(&et->lock);
 			node_cnt += __free_extent_tree(sbi, et);
 			write_unlock(&et->lock);
 		}
 		f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
 		list_del_init(&et->list);
 		radix_tree_delete(&sbi->extent_tree_root, et->ino);
 		kmem_cache_free(extent_tree_slab, et);
 		atomic_dec(&sbi->total_ext_tree);
 		atomic_dec(&sbi->total_zombie_tree);
 		tree_cnt++;

 		if (node_cnt + tree_cnt >= nr_shrink)
 			goto unlock_out;
 		cond_resched();
 	}
 	mutex_unlock(&sbi->extent_tree_lock);

 free_node:
 	/* 2. remove LRU extent entries */
 	if (!mutex_trylock(&sbi->extent_tree_lock))
 		goto out;

 	remained = nr_shrink - (node_cnt + tree_cnt);

 	spin_lock(&sbi->extent_lock);
 	for (; remained > 0; remained--) {
 		if (list_empty(&sbi->extent_list))
 			break;
 		en = list_first_entry(&sbi->extent_list,
 					struct extent_node, list);
 		et = en->et;
 		if (!write_trylock(&et->lock)) {
 			/* refresh this extent node's position in extent list */
 			list_move_tail(&en->list, &sbi->extent_list);
 			continue;
 		}

 		list_del_init(&en->list);
 		spin_unlock(&sbi->extent_lock);

 		__detach_extent_node(sbi, et, en);

 		write_unlock(&et->lock);
 		node_cnt++;
 		spin_lock(&sbi->extent_lock);
 	}
 	spin_unlock(&sbi->extent_lock);

 unlock_out:
 	mutex_unlock(&sbi->extent_tree_lock);
 out:
 	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);

 	return node_cnt + tree_cnt;
 }

 unsigned int f2fs_destroy_extent_node(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
 	unsigned int node_cnt = 0;

 	if (!et || !atomic_read(&et->node_cnt))
 		return 0;

 	write_lock(&et->lock);
 	node_cnt = __free_extent_tree(sbi, et);
 	write_unlock(&et->lock);

 	return node_cnt;
 }

 void f2fs_drop_extent_tree(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
 	bool updated = false;

 	if (!f2fs_may_extent_tree(inode))
 		return;

 	set_inode_flag(inode, FI_NO_EXTENT);

 	write_lock(&et->lock);
 	__free_extent_tree(sbi, et);
 	if (et->largest.len) {
 		et->largest.len = 0;
 		updated = true;
 	}
 	write_unlock(&et->lock);
 	if (updated)
 		f2fs_mark_inode_dirty_sync(inode, true);
 }

 void f2fs_destroy_extent_tree(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et = F2FS_I(inode)->extent_tree;
 	unsigned int node_cnt = 0;

 	if (!et)
 		return;

 	if (inode->i_nlink && !is_bad_inode(inode) &&
 					atomic_read(&et->node_cnt)) {
 		mutex_lock(&sbi->extent_tree_lock);
 		list_add_tail(&et->list, &sbi->zombie_list);
 		atomic_inc(&sbi->total_zombie_tree);
 		mutex_unlock(&sbi->extent_tree_lock);
 		return;
 	}

 	/* free all extent info belong to this extent tree */
 	node_cnt = f2fs_destroy_extent_node(inode);

 	/* delete extent tree entry in radix tree */
 	mutex_lock(&sbi->extent_tree_lock);
 	f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
 	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
 	kmem_cache_free(extent_tree_slab, et);
 	atomic_dec(&sbi->total_ext_tree);
 	mutex_unlock(&sbi->extent_tree_lock);

 	F2FS_I(inode)->extent_tree = NULL;

 	trace_f2fs_destroy_extent_tree(inode, node_cnt);
 }

 bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
 					struct extent_info *ei)
 {
 	if (!f2fs_may_extent_tree(inode))
 		return false;

 	return f2fs_lookup_extent_tree(inode, pgofs, ei);
 }

 void f2fs_update_extent_cache(struct dnode_of_data *dn)
 {
 	pgoff_t fofs;
 	block_t blkaddr;

 	if (!f2fs_may_extent_tree(dn->inode))
 		return;

 	if (dn->data_blkaddr == NEW_ADDR)
 		blkaddr = NULL_ADDR;
 	else
 		blkaddr = dn->data_blkaddr;

 	fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
 								dn->ofs_in_node;
 	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1);
 }

 void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
 				pgoff_t fofs, block_t blkaddr, unsigned int len)

 {
 	if (!f2fs_may_extent_tree(dn->inode))
 		return;

 	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len);
 }

 void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
 {
 	INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
 	mutex_init(&sbi->extent_tree_lock);
 	INIT_LIST_HEAD(&sbi->extent_list);
 	spin_lock_init(&sbi->extent_lock);
 	atomic_set(&sbi->total_ext_tree, 0);
 	INIT_LIST_HEAD(&sbi->zombie_list);
 	atomic_set(&sbi->total_zombie_tree, 0);
 	atomic_set(&sbi->total_ext_node, 0);
 }

 int __init f2fs_create_extent_cache(void)
 {
 	extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
 			sizeof(struct extent_tree));
 	if (!extent_tree_slab)
 		return -ENOMEM;
 	extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
 			sizeof(struct extent_node));
 	if (!extent_node_slab) {
 		kmem_cache_destroy(extent_tree_slab);
 		return -ENOMEM;
 	}
 	return 0;
 }

 void f2fs_destroy_extent_cache(void)
 {
 	kmem_cache_destroy(extent_node_slab);
 	kmem_cache_destroy(extent_tree_slab);
 }
	/*
	* f2fs extent cache support
	*
	* Copyright (c) 2015 Motorola Mobility
	* Copyright (c) 2015 Samsung Electronics
	* Authors: Jaegeuk Kim <jaegeuk@kernel.org>
	* Chao Yu <chao2.yu@samsung.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/fs.h>
	#include <linux/f2fs_fs.h>

	#include "f2fs.h"
	#include "node.h"
	#include <trace/events/f2fs.h>

	static struct rb_entry __lookup_rb_tree_fast(struct rb_entry cached_re,
	unsigned int ofs)
	{
	if (cached_re) {
	if (cached_re->ofs <= ofs &&
	cached_re->ofs + cached_re->len > ofs) {
	return cached_re;
	}
	}
	return NULL;
	}

	static struct rb_entry __lookup_rb_tree_slow(struct rb_root root,
	unsigned int ofs)
	{
	struct rb_node *node = root->rb_node;
	struct rb_entry *re;

	while (node) {
	re = rb_entry(node, struct rb_entry, rb_node);

	if (ofs < re->ofs)
	node = node->rb_left;
	else if (ofs >= re->ofs + re->len)
	node = node->rb_right;
	else
	return re;
	}
	return NULL;
	}

	struct rb_entry f2fs_lookup_rb_tree(struct rb_root root,
	struct rb_entry *cached_re, unsigned int ofs)
	{
	struct rb_entry *re;

	re = __lookup_rb_tree_fast(cached_re, ofs);
	if (!re)
	return __lookup_rb_tree_slow(root, ofs);

	return re;
	}

	struct rb_node *f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info sbi,
	struct rb_root root, struct rb_node *parent,
	unsigned int ofs)
	{
	struct rb_node **p = &root->rb_node;
	struct rb_entry *re;

	while (*p) {
	parent = p;
	re = rb_entry(*parent, struct rb_entry, rb_node);

	if (ofs < re->ofs)
	p = &(*p)->rb_left;
	else if (ofs >= re->ofs + re->len)
	p = &(*p)->rb_right;
	else
	f2fs_bug_on(sbi, 1);
	}

	return p;
	}

	/*
	* lookup rb entry in position of @ofs in rb-tree,
	* if hit, return the entry, otherwise, return NULL
	* @prev_ex: extent before ofs
	* @next_ex: extent after ofs
	* @insert_p: insert point for new extent at ofs
	* in order to simpfy the insertion after.
	* tree must stay unchanged between lookup and insertion.
	*/
	struct rb_entry f2fs_lookup_rb_tree_ret(struct rb_root root,
	struct rb_entry *cached_re,
	unsigned int ofs,
	struct rb_entry **prev_entry,
	struct rb_entry **next_entry,
	struct rb_node ***insert_p,
	struct rb_node **insert_parent,
	bool force)
	{
	struct rb_node **pnode = &root->rb_node;
	struct rb_node parent = NULL, tmp_node;
	struct rb_entry *re = cached_re;

	*insert_p = NULL;
	*insert_parent = NULL;
	*prev_entry = NULL;
	*next_entry = NULL;

	if (RB_EMPTY_ROOT(root))
	return NULL;

	if (re) {
	if (re->ofs <= ofs && re->ofs + re->len > ofs)
	goto lookup_neighbors;
	}

	while (*pnode) {
	parent = *pnode;
	re = rb_entry(*pnode, struct rb_entry, rb_node);

	if (ofs < re->ofs)
	pnode = &(*pnode)->rb_left;
	else if (ofs >= re->ofs + re->len)
	pnode = &(*pnode)->rb_right;
	else
	goto lookup_neighbors;
	}

	*insert_p = pnode;
	*insert_parent = parent;

	re = rb_entry(parent, struct rb_entry, rb_node);
	tmp_node = parent;
	if (parent && ofs > re->ofs)
	tmp_node = rb_next(parent);
	*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);

	tmp_node = parent;
	if (parent && ofs < re->ofs)
	tmp_node = rb_prev(parent);
	*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	return NULL;

	lookup_neighbors:
	if (ofs == re->ofs \|\| force) {
	/* lookup prev node for merging backward later */
	tmp_node = rb_prev(&re->rb_node);
	*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	}
	if (ofs == re->ofs + re->len - 1 \|\| force) {
	/* lookup next node for merging frontward later */
	tmp_node = rb_next(&re->rb_node);
	*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	}
	return re;
	}

	bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
	struct rb_root *root)
	{
	#ifdef CONFIG_F2FS_CHECK_FS
	struct rb_node cur = rb_first(root), next;
	struct rb_entry cur_re, next_re;

	if (!cur)
	return true;

	while (cur) {
	next = rb_next(cur);
	if (!next)
	return true;

	cur_re = rb_entry(cur, struct rb_entry, rb_node);
	next_re = rb_entry(next, struct rb_entry, rb_node);

	if (cur_re->ofs + cur_re->len > next_re->ofs) {
	f2fs_msg(sbi->sb, KERN_INFO, "inconsistent rbtree, "
	"cur(%u, %u) next(%u, %u)",
	cur_re->ofs, cur_re->len,
	next_re->ofs, next_re->len);
	return false;
	}

	cur = next;
	}
	#endif
	return true;
	}

	static struct kmem_cache *extent_tree_slab;
	static struct kmem_cache *extent_node_slab;

	static struct extent_node __attach_extent_node(struct f2fs_sb_info sbi,
	struct extent_tree et, struct extent_info ei,
	struct rb_node parent, struct rb_node *p)
	{
	struct extent_node *en;

	en = kmem_cache_alloc(extent_node_slab, GFP_ATOMIC);
	if (!en)
	return NULL;

	en->ei = *ei;
	INIT_LIST_HEAD(&en->list);
	en->et = et;

	rb_link_node(&en->rb_node, parent, p);
	rb_insert_color(&en->rb_node, &et->root);
	atomic_inc(&et->node_cnt);
	atomic_inc(&sbi->total_ext_node);
	return en;
	}

	static void __detach_extent_node(struct f2fs_sb_info *sbi,
	struct extent_tree et, struct extent_node en)
	{
	rb_erase(&en->rb_node, &et->root);
	atomic_dec(&et->node_cnt);
	atomic_dec(&sbi->total_ext_node);

	if (et->cached_en == en)
	et->cached_en = NULL;
	kmem_cache_free(extent_node_slab, en);
	}

	/*
	* Flow to release an extent_node:
	* 1. list_del_init
	* 2. __detach_extent_node
	* 3. kmem_cache_free.
	*/
	static void __release_extent_node(struct f2fs_sb_info *sbi,
	struct extent_tree et, struct extent_node en)
	{
	spin_lock(&sbi->extent_lock);
	f2fs_bug_on(sbi, list_empty(&en->list));
	list_del_init(&en->list);
	spin_unlock(&sbi->extent_lock);

	__detach_extent_node(sbi, et, en);
	}

	static struct extent_tree __grab_extent_tree(struct inode inode)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et;
	nid_t ino = inode->i_ino;

	mutex_lock(&sbi->extent_tree_lock);
	et = radix_tree_lookup(&sbi->extent_tree_root, ino);
	if (!et) {
	et = f2fs_kmem_cache_alloc(extent_tree_slab, GFP_NOFS);
	f2fs_radix_tree_insert(&sbi->extent_tree_root, ino, et);
	memset(et, 0, sizeof(struct extent_tree));
	et->ino = ino;
	et->root = RB_ROOT;
	et->cached_en = NULL;
	rwlock_init(&et->lock);
	INIT_LIST_HEAD(&et->list);
	atomic_set(&et->node_cnt, 0);
	atomic_inc(&sbi->total_ext_tree);
	} else {
	atomic_dec(&sbi->total_zombie_tree);
	list_del_init(&et->list);
	}
	mutex_unlock(&sbi->extent_tree_lock);

	/* never died until evict_inode */
	F2FS_I(inode)->extent_tree = et;

	return et;
	}

	static struct extent_node __init_extent_tree(struct f2fs_sb_info sbi,
	struct extent_tree et, struct extent_info ei)
	{
	struct rb_node **p = &et->root.rb_node;
	struct extent_node *en;

	en = __attach_extent_node(sbi, et, ei, NULL, p);
	if (!en)
	return NULL;

	et->largest = en->ei;
	et->cached_en = en;
	return en;
	}

	static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
	struct extent_tree *et)
	{
	struct rb_node node, next;
	struct extent_node *en;
	unsigned int count = atomic_read(&et->node_cnt);

	node = rb_first(&et->root);
	while (node) {
	next = rb_next(node);
	en = rb_entry(node, struct extent_node, rb_node);
	__release_extent_node(sbi, et, en);
	node = next;
	}

	return count - atomic_read(&et->node_cnt);
	}

	static void __drop_largest_extent(struct extent_tree *et,
	pgoff_t fofs, unsigned int len)
	{
	if (fofs < et->largest.fofs + et->largest.len &&
	fofs + len > et->largest.fofs) {
	et->largest.len = 0;
	et->largest_updated = true;
	}
	}

	/* return true, if inode page is changed */
	static bool __f2fs_init_extent_tree(struct inode inode, struct f2fs_extent i_ext)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et;
	struct extent_node *en;
	struct extent_info ei;

	if (!f2fs_may_extent_tree(inode)) {
	/* drop largest extent */
	if (i_ext && i_ext->len) {
	i_ext->len = 0;
	return true;
	}
	return false;
	}

	et = __grab_extent_tree(inode);

	if (!i_ext \|\| !i_ext->len)
	return false;

	get_extent_info(&ei, i_ext);

	write_lock(&et->lock);
	if (atomic_read(&et->node_cnt))
	goto out;

	en = __init_extent_tree(sbi, et, &ei);
	if (en) {
	spin_lock(&sbi->extent_lock);
	list_add_tail(&en->list, &sbi->extent_list);
	spin_unlock(&sbi->extent_lock);
	}
	out:
	write_unlock(&et->lock);
	return false;
	}

	bool f2fs_init_extent_tree(struct inode inode, struct f2fs_extent i_ext)
	{
	bool ret = __f2fs_init_extent_tree(inode, i_ext);

	if (!F2FS_I(inode)->extent_tree)
	set_inode_flag(inode, FI_NO_EXTENT);

	return ret;
	}

	static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
	struct extent_info *ei)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et = F2FS_I(inode)->extent_tree;
	struct extent_node *en;
	bool ret = false;

	f2fs_bug_on(sbi, !et);

	trace_f2fs_lookup_extent_tree_start(inode, pgofs);

	read_lock(&et->lock);

	if (et->largest.fofs <= pgofs &&
	et->largest.fofs + et->largest.len > pgofs) {
	*ei = et->largest;
	ret = true;
	stat_inc_largest_node_hit(sbi);
	goto out;
	}

	en = (struct extent_node *)f2fs_lookup_rb_tree(&et->root,
	(struct rb_entry *)et->cached_en, pgofs);
	if (!en)
	goto out;

	if (en == et->cached_en)
	stat_inc_cached_node_hit(sbi);
	else
	stat_inc_rbtree_node_hit(sbi);

	*ei = en->ei;
	spin_lock(&sbi->extent_lock);
	if (!list_empty(&en->list)) {
	list_move_tail(&en->list, &sbi->extent_list);
	et->cached_en = en;
	}
	spin_unlock(&sbi->extent_lock);
	ret = true;
	out:
	stat_inc_total_hit(sbi);
	read_unlock(&et->lock);

	trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
	return ret;
	}

	static struct extent_node __try_merge_extent_node(struct f2fs_sb_info sbi,
	struct extent_tree et, struct extent_info ei,
	struct extent_node *prev_ex,
	struct extent_node *next_ex)
	{
	struct extent_node *en = NULL;

	if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
	prev_ex->ei.len += ei->len;
	ei = &prev_ex->ei;
	en = prev_ex;
	}

	if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) {
	next_ex->ei.fofs = ei->fofs;
	next_ex->ei.blk = ei->blk;
	next_ex->ei.len += ei->len;
	if (en)
	__release_extent_node(sbi, et, prev_ex);

	en = next_ex;
	}

	if (!en)
	return NULL;

	__try_update_largest_extent(et, en);

	spin_lock(&sbi->extent_lock);
	if (!list_empty(&en->list)) {
	list_move_tail(&en->list, &sbi->extent_list);
	et->cached_en = en;
	}
	spin_unlock(&sbi->extent_lock);
	return en;
	}

	static struct extent_node __insert_extent_tree(struct f2fs_sb_info sbi,
	struct extent_tree et, struct extent_info ei,
	struct rb_node **insert_p,
	struct rb_node *insert_parent)
	{
	struct rb_node **p;
	struct rb_node *parent = NULL;
	struct extent_node *en = NULL;

	if (insert_p && insert_parent) {
	parent = insert_parent;
	p = insert_p;
	goto do_insert;
	}

	p = f2fs_lookup_rb_tree_for_insert(sbi, &et->root, &parent, ei->fofs);
	do_insert:
	en = __attach_extent_node(sbi, et, ei, parent, p);
	if (!en)
	return NULL;

	__try_update_largest_extent(et, en);

	/* update in global extent list */
	spin_lock(&sbi->extent_lock);
	list_add_tail(&en->list, &sbi->extent_list);
	et->cached_en = en;
	spin_unlock(&sbi->extent_lock);
	return en;
	}

	static void f2fs_update_extent_tree_range(struct inode *inode,
	pgoff_t fofs, block_t blkaddr, unsigned int len)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et = F2FS_I(inode)->extent_tree;
	struct extent_node en = NULL, en1 = NULL;
	struct extent_node prev_en = NULL, next_en = NULL;
	struct extent_info ei, dei, prev;
	struct rb_node *insert_p = NULL, insert_parent = NULL;
	unsigned int end = fofs + len;
	unsigned int pos = (unsigned int)fofs;
	bool updated = false;

	if (!et)
	return;

	trace_f2fs_update_extent_tree_range(inode, fofs, blkaddr, len);

	write_lock(&et->lock);

	if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
	write_unlock(&et->lock);
	return;
	}

	prev = et->largest;
	dei.len = 0;

	/*
	* drop largest extent before lookup, in case it's already
	* been shrunk from extent tree
	*/
	__drop_largest_extent(et, fofs, len);

	/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
	en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
	(struct rb_entry *)et->cached_en, fofs,
	(struct rb_entry **)&prev_en,
	(struct rb_entry **)&next_en,
	&insert_p, &insert_parent, false);
	if (!en)
	en = next_en;

	/* 2. invlidate all extent nodes in range [fofs, fofs + len - 1] */
	while (en && en->ei.fofs < end) {
	unsigned int org_end;
	int parts = 0; /* # of parts current extent split into */

	next_en = en1 = NULL;

	dei = en->ei;
	org_end = dei.fofs + dei.len;
	f2fs_bug_on(sbi, pos >= org_end);

	if (pos > dei.fofs && pos - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
	en->ei.len = pos - en->ei.fofs;
	prev_en = en;
	parts = 1;
	}

	if (end < org_end && org_end - end >= F2FS_MIN_EXTENT_LEN) {
	if (parts) {
	set_extent_info(&ei, end,
	end - dei.fofs + dei.blk,
	org_end - end);
	en1 = __insert_extent_tree(sbi, et, &ei,
	NULL, NULL);
	next_en = en1;
	} else {
	en->ei.fofs = end;
	en->ei.blk += end - dei.fofs;
	en->ei.len -= end - dei.fofs;
	next_en = en;
	}
	parts++;
	}

	if (!next_en) {
	struct rb_node *node = rb_next(&en->rb_node);

	next_en = rb_entry_safe(node, struct extent_node,
	rb_node);
	}

	if (parts)
	__try_update_largest_extent(et, en);
	else
	__release_extent_node(sbi, et, en);

	/*
	* if original extent is split into zero or two parts, extent
	* tree has been altered by deletion or insertion, therefore
	* invalidate pointers regard to tree.
	*/
	if (parts != 1) {
	insert_p = NULL;
	insert_parent = NULL;
	}
	en = next_en;
	}

	/* 3. update extent in extent cache */
	if (blkaddr) {

	set_extent_info(&ei, fofs, blkaddr, len);
	if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
	__insert_extent_tree(sbi, et, &ei,
	insert_p, insert_parent);

	/* give up extent_cache, if split and small updates happen */
	if (dei.len >= 1 &&
	prev.len < F2FS_MIN_EXTENT_LEN &&
	et->largest.len < F2FS_MIN_EXTENT_LEN) {
	et->largest.len = 0;
	et->largest_updated = true;
	set_inode_flag(inode, FI_NO_EXTENT);
	}
	}

	if (is_inode_flag_set(inode, FI_NO_EXTENT))
	__free_extent_tree(sbi, et);

	if (et->largest_updated) {
	et->largest_updated = false;
	updated = true;
	}

	write_unlock(&et->lock);

	if (updated)
	f2fs_mark_inode_dirty_sync(inode, true);
	}

	unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
	{
	struct extent_tree et, next;
	struct extent_node *en;
	unsigned int node_cnt = 0, tree_cnt = 0;
	int remained;

	if (!test_opt(sbi, EXTENT_CACHE))
	return 0;

	if (!atomic_read(&sbi->total_zombie_tree))
	goto free_node;

	if (!mutex_trylock(&sbi->extent_tree_lock))
	goto out;

	/* 1. remove unreferenced extent tree */
	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {
	if (atomic_read(&et->node_cnt)) {
	write_lock(&et->lock);
	node_cnt += __free_extent_tree(sbi, et);
	write_unlock(&et->lock);
	}
	f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
	list_del_init(&et->list);
	radix_tree_delete(&sbi->extent_tree_root, et->ino);
	kmem_cache_free(extent_tree_slab, et);
	atomic_dec(&sbi->total_ext_tree);
	atomic_dec(&sbi->total_zombie_tree);
	tree_cnt++;

	if (node_cnt + tree_cnt >= nr_shrink)
	goto unlock_out;
	cond_resched();
	}
	mutex_unlock(&sbi->extent_tree_lock);

	free_node:
	/* 2. remove LRU extent entries */
	if (!mutex_trylock(&sbi->extent_tree_lock))
	goto out;

	remained = nr_shrink - (node_cnt + tree_cnt);

	spin_lock(&sbi->extent_lock);
	for (; remained > 0; remained--) {
	if (list_empty(&sbi->extent_list))
	break;
	en = list_first_entry(&sbi->extent_list,
	struct extent_node, list);
	et = en->et;
	if (!write_trylock(&et->lock)) {
	/* refresh this extent node's position in extent list */
	list_move_tail(&en->list, &sbi->extent_list);
	continue;
	}

	list_del_init(&en->list);
	spin_unlock(&sbi->extent_lock);

	__detach_extent_node(sbi, et, en);

	write_unlock(&et->lock);
	node_cnt++;
	spin_lock(&sbi->extent_lock);
	}
	spin_unlock(&sbi->extent_lock);

	unlock_out:
	mutex_unlock(&sbi->extent_tree_lock);
	out:
	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);

	return node_cnt + tree_cnt;
	}

	unsigned int f2fs_destroy_extent_node(struct inode *inode)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et = F2FS_I(inode)->extent_tree;
	unsigned int node_cnt = 0;

	if (!et \|\| !atomic_read(&et->node_cnt))
	return 0;

	write_lock(&et->lock);
	node_cnt = __free_extent_tree(sbi, et);
	write_unlock(&et->lock);

	return node_cnt;
	}

	void f2fs_drop_extent_tree(struct inode *inode)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et = F2FS_I(inode)->extent_tree;
	bool updated = false;

	if (!f2fs_may_extent_tree(inode))
	return;

	set_inode_flag(inode, FI_NO_EXTENT);

	write_lock(&et->lock);
	__free_extent_tree(sbi, et);
	if (et->largest.len) {
	et->largest.len = 0;
	updated = true;
	}
	write_unlock(&et->lock);
	if (updated)
	f2fs_mark_inode_dirty_sync(inode, true);
	}

	void f2fs_destroy_extent_tree(struct inode *inode)
	{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct extent_tree *et = F2FS_I(inode)->extent_tree;
	unsigned int node_cnt = 0;

	if (!et)
	return;

	if (inode->i_nlink && !is_bad_inode(inode) &&
	atomic_read(&et->node_cnt)) {
	mutex_lock(&sbi->extent_tree_lock);
	list_add_tail(&et->list, &sbi->zombie_list);
	atomic_inc(&sbi->total_zombie_tree);
	mutex_unlock(&sbi->extent_tree_lock);
	return;
	}

	/* free all extent info belong to this extent tree */
	node_cnt = f2fs_destroy_extent_node(inode);

	/* delete extent tree entry in radix tree */
	mutex_lock(&sbi->extent_tree_lock);
	f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
	kmem_cache_free(extent_tree_slab, et);
	atomic_dec(&sbi->total_ext_tree);
	mutex_unlock(&sbi->extent_tree_lock);

	F2FS_I(inode)->extent_tree = NULL;

	trace_f2fs_destroy_extent_tree(inode, node_cnt);
	}

	bool f2fs_lookup_extent_cache(struct inode *inode, pgoff_t pgofs,
	struct extent_info *ei)
	{
	if (!f2fs_may_extent_tree(inode))
	return false;

	return f2fs_lookup_extent_tree(inode, pgofs, ei);
	}

	void f2fs_update_extent_cache(struct dnode_of_data *dn)
	{
	pgoff_t fofs;
	block_t blkaddr;

	if (!f2fs_may_extent_tree(dn->inode))
	return;

	if (dn->data_blkaddr == NEW_ADDR)
	blkaddr = NULL_ADDR;
	else
	blkaddr = dn->data_blkaddr;

	fofs = f2fs_start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
	dn->ofs_in_node;
	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, 1);
	}

	void f2fs_update_extent_cache_range(struct dnode_of_data *dn,
	pgoff_t fofs, block_t blkaddr, unsigned int len)

	{
	if (!f2fs_may_extent_tree(dn->inode))
	return;

	f2fs_update_extent_tree_range(dn->inode, fofs, blkaddr, len);
	}

	void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
	{
	INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
	mutex_init(&sbi->extent_tree_lock);
	INIT_LIST_HEAD(&sbi->extent_list);
	spin_lock_init(&sbi->extent_lock);
	atomic_set(&sbi->total_ext_tree, 0);
	INIT_LIST_HEAD(&sbi->zombie_list);
	atomic_set(&sbi->total_zombie_tree, 0);
	atomic_set(&sbi->total_ext_node, 0);
	}

	int __init f2fs_create_extent_cache(void)
	{
	extent_tree_slab = f2fs_kmem_cache_create("f2fs_extent_tree",
	sizeof(struct extent_tree));
	if (!extent_tree_slab)
	return -ENOMEM;
	extent_node_slab = f2fs_kmem_cache_create("f2fs_extent_node",
	sizeof(struct extent_node));
	if (!extent_node_slab) {
	kmem_cache_destroy(extent_tree_slab);
	return -ENOMEM;
	}
	return 0;
	}

	void f2fs_destroy_extent_cache(void)
	{
	kmem_cache_destroy(extent_node_slab);
	kmem_cache_destroy(extent_tree_slab);
	}