f2fs-y         := dir.o file.o inode.o namei.o hash.o super.o inline.o
 f2fs-y         += checkpoint.o gc.o data.o node.o segment.o recovery.o
-f2fs-y         += shrinker.o
+f2fs-y         += shrinker.o extent_cache.o
 f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
 f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
 f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
 
 #include "trace.h"
 #include <trace/events/f2fs.h>
 
-static struct kmem_cache *extent_tree_slab;
-static struct kmem_cache *extent_node_slab;
-
 static void f2fs_read_end_io(struct bio *bio, int err)
 {
        struct bio_vec *bvec;
        return err;
 }
 
-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);
-
-       rb_link_node(&en->rb_node, parent, p);
-       rb_insert_color(&en->rb_node, &et->root);
-       et->count++;
-       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);
-       et->count--;
-       atomic_dec(&sbi->total_ext_node);
-
-       if (et->cached_en == en)
-               et->cached_en = NULL;
-}
-
-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;
-
-       down_write(&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);
-               atomic_set(&et->refcount, 0);
-               et->count = 0;
-               sbi->total_ext_tree++;
-       }
-       atomic_inc(&et->refcount);
-       up_write(&sbi->extent_tree_lock);
-
-       /* never died untill evict_inode */
-       F2FS_I(inode)->extent_tree = et;
-
-       return et;
-}
-
-static struct extent_node *__lookup_extent_tree(struct extent_tree *et,
-                                                       unsigned int fofs)
-{
-       struct rb_node *node = et->root.rb_node;
-       struct extent_node *en;
-
-       if (et->cached_en) {
-               struct extent_info *cei = &et->cached_en->ei;
-
-               if (cei->fofs <= fofs && cei->fofs + cei->len > fofs)
-                       return et->cached_en;
-       }
-
-       while (node) {
-               en = rb_entry(node, struct extent_node, rb_node);
-
-               if (fofs < en->ei.fofs)
-                       node = node->rb_left;
-               else if (fofs >= en->ei.fofs + en->ei.len)
-                       node = node->rb_right;
-               else
-                       return en;
-       }
-       return NULL;
-}
-
-static struct extent_node *__try_back_merge(struct f2fs_sb_info *sbi,
-                               struct extent_tree *et, struct extent_node *en)
-{
-       struct extent_node *prev;
-       struct rb_node *node;
-
-       node = rb_prev(&en->rb_node);
-       if (!node)
-               return NULL;
-
-       prev = rb_entry(node, struct extent_node, rb_node);
-       if (__is_back_mergeable(&en->ei, &prev->ei)) {
-               en->ei.fofs = prev->ei.fofs;
-               en->ei.blk = prev->ei.blk;
-               en->ei.len += prev->ei.len;
-               __detach_extent_node(sbi, et, prev);
-               return prev;
-       }
-       return NULL;
-}
-
-static struct extent_node *__try_front_merge(struct f2fs_sb_info *sbi,
-                               struct extent_tree *et, struct extent_node *en)
-{
-       struct extent_node *next;
-       struct rb_node *node;
-
-       node = rb_next(&en->rb_node);
-       if (!node)
-               return NULL;
-
-       next = rb_entry(node, struct extent_node, rb_node);
-       if (__is_front_mergeable(&en->ei, &next->ei)) {
-               en->ei.len += next->ei.len;
-               __detach_extent_node(sbi, et, next);
-               return next;
-       }
-       return NULL;
-}
-
-static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
-                               struct extent_tree *et, struct extent_info *ei,
-                               struct extent_node **den)
-{
-       struct rb_node **p = &et->root.rb_node;
-       struct rb_node *parent = NULL;
-       struct extent_node *en;
-
-       while (*p) {
-               parent = *p;
-               en = rb_entry(parent, struct extent_node, rb_node);
-
-               if (ei->fofs < en->ei.fofs) {
-                       if (__is_front_mergeable(ei, &en->ei)) {
-                               f2fs_bug_on(sbi, !den);
-                               en->ei.fofs = ei->fofs;
-                               en->ei.blk = ei->blk;
-                               en->ei.len += ei->len;
-                               *den = __try_back_merge(sbi, et, en);
-                               goto update_out;
-                       }
-                       p = &(*p)->rb_left;
-               } else if (ei->fofs >= en->ei.fofs + en->ei.len) {
-                       if (__is_back_mergeable(ei, &en->ei)) {
-                               f2fs_bug_on(sbi, !den);
-                               en->ei.len += ei->len;
-                               *den = __try_front_merge(sbi, et, en);
-                               goto update_out;
-                       }
-                       p = &(*p)->rb_right;
-               } else {
-                       f2fs_bug_on(sbi, 1);
-               }
-       }
-
-       en = __attach_extent_node(sbi, et, ei, parent, p);
-       if (!en)
-               return NULL;
-update_out:
-       if (en->ei.len > et->largest.len)
-               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, bool free_all)
-{
-       struct rb_node *node, *next;
-       struct extent_node *en;
-       unsigned int count = et->count;
-
-       node = rb_first(&et->root);
-       while (node) {
-               next = rb_next(node);
-               en = rb_entry(node, struct extent_node, rb_node);
-
-               if (free_all) {
-                       spin_lock(&sbi->extent_lock);
-                       if (!list_empty(&en->list))
-                               list_del_init(&en->list);
-                       spin_unlock(&sbi->extent_lock);
-               }
-
-               if (free_all || list_empty(&en->list)) {
-                       __detach_extent_node(sbi, et, en);
-                       kmem_cache_free(extent_node_slab, en);
-               }
-               node = next;
-       }
-
-       return count - et->count;
-}
-
-static void __drop_largest_extent(struct inode *inode, pgoff_t fofs)
-{
-       struct extent_info *largest = &F2FS_I(inode)->extent_tree->largest;
-
-       if (largest->fofs <= fofs && largest->fofs + largest->len > fofs)
-               largest->len = 0;
-}
-
-void 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))
-               return;
-
-       et = __grab_extent_tree(inode);
-
-       if (!i_ext || le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
-               return;
-
-       set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
-               le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
-
-       write_lock(&et->lock);
-       if (et->count)
-               goto out;
-
-       en = __insert_extent_tree(sbi, et, &ei, NULL);
-       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);
-}
-
-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_read_hit(sbi->sb);
-               goto out;
-       }
-
-       en = __lookup_extent_tree(et, pgofs);
-       if (en) {
-               *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;
-               stat_inc_read_hit(sbi->sb);
-       }
-out:
-       stat_inc_total_hit(sbi->sb);
-       read_unlock(&et->lock);
-
-       trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
-       return ret;
-}
-
-/* return true, if on-disk extent should be updated */
-static bool f2fs_update_extent_tree(struct inode *inode, pgoff_t fofs,
-                                                       block_t blkaddr)
-{
-       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, *en2 = NULL, *en3 = NULL;
-       struct extent_node *den = NULL;
-       struct extent_info ei, dei, prev;
-       unsigned int endofs;
-
-       if (!et)
-               return false;
-
-       trace_f2fs_update_extent_tree(inode, fofs, blkaddr);
-
-       write_lock(&et->lock);
-
-       if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) {
-               write_unlock(&et->lock);
-               return false;
-       }
-
-       prev = et->largest;
-       dei.len = 0;
-
-       /* we do not guarantee that the largest extent is cached all the time */
-       __drop_largest_extent(inode, fofs);
-
-       /* 1. lookup and remove existing extent info in cache */
-       en = __lookup_extent_tree(et, fofs);
-       if (!en)
-               goto update_extent;
-
-       dei = en->ei;
-       __detach_extent_node(sbi, et, en);
-
-       /* 2. if extent can be split more, split and insert the left part */
-       if (dei.len > F2FS_MIN_EXTENT_LEN) {
-               /*  insert left part of split extent into cache */
-               if (fofs - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
-                       set_extent_info(&ei, dei.fofs, dei.blk,
-                                                       fofs - dei.fofs);
-                       en1 = __insert_extent_tree(sbi, et, &ei, NULL);
-               }
-
-               /* insert right part of split extent into cache */
-               endofs = dei.fofs + dei.len - 1;
-               if (endofs - fofs >= F2FS_MIN_EXTENT_LEN) {
-                       set_extent_info(&ei, fofs + 1,
-                               fofs - dei.fofs + dei.blk + 1, endofs - fofs);
-                       en2 = __insert_extent_tree(sbi, et, &ei, NULL);
-               }
-       }
-
-update_extent:
-       /* 3. update extent in extent cache */
-       if (blkaddr) {
-               set_extent_info(&ei, fofs, blkaddr, 1);
-               en3 = __insert_extent_tree(sbi, et, &ei, &den);
-
-               /* 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;
-                       set_inode_flag(F2FS_I(inode), FI_NO_EXTENT);
-               }
-       }
-
-       /* 4. update in global extent list */
-       spin_lock(&sbi->extent_lock);
-       if (en && !list_empty(&en->list))
-               list_del(&en->list);
-       /*
-        * en1 and en2 split from en, they will become more and more smaller
-        * fragments after splitting several times. So if the length is smaller
-        * than F2FS_MIN_EXTENT_LEN, we will not add them into extent tree.
-        */
-       if (en1)
-               list_add_tail(&en1->list, &sbi->extent_list);
-       if (en2)
-               list_add_tail(&en2->list, &sbi->extent_list);
-       if (en3) {
-               if (list_empty(&en3->list))
-                       list_add_tail(&en3->list, &sbi->extent_list);
-               else
-                       list_move_tail(&en3->list, &sbi->extent_list);
-       }
-       if (den && !list_empty(&den->list))
-               list_del(&den->list);
-       spin_unlock(&sbi->extent_lock);
-
-       /* 5. release extent node */
-       if (en)
-               kmem_cache_free(extent_node_slab, en);
-       if (den)
-               kmem_cache_free(extent_node_slab, den);
-
-       if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))
-               __free_extent_tree(sbi, et, true);
-
-       write_unlock(&et->lock);
-
-       return !__is_extent_same(&prev, &et->largest);
-}
-
-unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
-{
-       struct extent_tree *treevec[EXT_TREE_VEC_SIZE];
-       struct extent_node *en, *tmp;
-       unsigned long ino = F2FS_ROOT_INO(sbi);
-       struct radix_tree_root *root = &sbi->extent_tree_root;
-       unsigned int found;
-       unsigned int node_cnt = 0, tree_cnt = 0;
-       int remained;
-
-       if (!test_opt(sbi, EXTENT_CACHE))
-               return 0;
-
-       if (!down_write_trylock(&sbi->extent_tree_lock))
-               goto out;
-
-       /* 1. remove unreferenced extent tree */
-       while ((found = radix_tree_gang_lookup(root,
-                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
-               unsigned i;
-
-               ino = treevec[found - 1]->ino + 1;
-               for (i = 0; i < found; i++) {
-                       struct extent_tree *et = treevec[i];
-
-                       if (!atomic_read(&et->refcount)) {
-                               write_lock(&et->lock);
-                               node_cnt += __free_extent_tree(sbi, et, true);
-                               write_unlock(&et->lock);
-
-                               radix_tree_delete(root, et->ino);
-                               kmem_cache_free(extent_tree_slab, et);
-                               sbi->total_ext_tree--;
-                               tree_cnt++;
-
-                               if (node_cnt + tree_cnt >= nr_shrink)
-                                       goto unlock_out;
-                       }
-               }
-       }
-       up_write(&sbi->extent_tree_lock);
-
-       /* 2. remove LRU extent entries */
-       if (!down_write_trylock(&sbi->extent_tree_lock))
-               goto out;
-
-       remained = nr_shrink - (node_cnt + tree_cnt);
-
-       spin_lock(&sbi->extent_lock);
-       list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) {
-               if (!remained--)
-                       break;
-               list_del_init(&en->list);
-       }
-       spin_unlock(&sbi->extent_lock);
-
-       while ((found = radix_tree_gang_lookup(root,
-                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
-               unsigned i;
-
-               ino = treevec[found - 1]->ino + 1;
-               for (i = 0; i < found; i++) {
-                       struct extent_tree *et = treevec[i];
-
-                       write_lock(&et->lock);
-                       node_cnt += __free_extent_tree(sbi, et, false);
-                       write_unlock(&et->lock);
-
-                       if (node_cnt + tree_cnt >= nr_shrink)
-                               break;
-               }
-       }
-unlock_out:
-       up_write(&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)
-               return 0;
-
-       write_lock(&et->lock);
-       node_cnt = __free_extent_tree(sbi, et, true);
-       write_unlock(&et->lock);
-
-       return node_cnt;
-}
-
-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) && et->count) {
-               atomic_dec(&et->refcount);
-               return;
-       }
-
-       /* free all extent info belong to this extent tree */
-       node_cnt = f2fs_destroy_extent_node(inode);
-
-       /* delete extent tree entry in radix tree */
-       down_write(&sbi->extent_tree_lock);
-       atomic_dec(&et->refcount);
-       f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count);
-       radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
-       kmem_cache_free(extent_tree_slab, et);
-       sbi->total_ext_tree--;
-       up_write(&sbi->extent_tree_lock);
-
-       F2FS_I(inode)->extent_tree = NULL;
-
-       trace_f2fs_destroy_extent_tree(inode, node_cnt);
-       return;
-}
-
-static 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)
-{
-       struct f2fs_inode_info *fi = F2FS_I(dn->inode);
-       pgoff_t fofs;
-
-       if (!f2fs_may_extent_tree(dn->inode))
-               return;
-
-       f2fs_bug_on(F2FS_I_SB(dn->inode), dn->data_blkaddr == NEW_ADDR);
-
-       fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
-                                                       dn->ofs_in_node;
-
-       if (f2fs_update_extent_tree(dn->inode, fofs, dn->data_blkaddr))
-               sync_inode_page(dn);
-}
-
 struct page *get_read_data_page(struct inode *inode, pgoff_t index, int rw)
 {
        struct address_space *mapping = inode->i_mapping;
                i_size_write(dn->inode, ((fofs + 1) << PAGE_CACHE_SHIFT));
 
        /* direct IO doesn't use extent cache to maximize the performance */
-       __drop_largest_extent(dn->inode, fofs);
+       f2fs_drop_largest_extent(dn->inode, fofs);
 
        return 0;
 }
        return generic_block_bmap(mapping, block, get_data_block);
 }
 
-void init_extent_cache_info(struct f2fs_sb_info *sbi)
-{
-       INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
-       init_rwsem(&sbi->extent_tree_lock);
-       INIT_LIST_HEAD(&sbi->extent_list);
-       spin_lock_init(&sbi->extent_lock);
-       sbi->total_ext_tree = 0;
-       atomic_set(&sbi->total_ext_node, 0);
-}
-
-int __init 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 destroy_extent_cache(void)
-{
-       kmem_cache_destroy(extent_node_slab);
-       kmem_cache_destroy(extent_tree_slab);
-}
-
 const struct address_space_operations f2fs_dblock_aops = {
        .readpage       = f2fs_read_data_page,
        .readpages      = f2fs_read_data_pages,
 
--- /dev/null
+/*
+ * 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 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);
+
+       rb_link_node(&en->rb_node, parent, p);
+       rb_insert_color(&en->rb_node, &et->root);
+       et->count++;
+       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);
+       et->count--;
+       atomic_dec(&sbi->total_ext_node);
+
+       if (et->cached_en == en)
+               et->cached_en = NULL;
+}
+
+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;
+
+       down_write(&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);
+               atomic_set(&et->refcount, 0);
+               et->count = 0;
+               sbi->total_ext_tree++;
+       }
+       atomic_inc(&et->refcount);
+       up_write(&sbi->extent_tree_lock);
+
+       /* never died until evict_inode */
+       F2FS_I(inode)->extent_tree = et;
+
+       return et;
+}
+
+static struct extent_node *__lookup_extent_tree(struct extent_tree *et,
+                                                       unsigned int fofs)
+{
+       struct rb_node *node = et->root.rb_node;
+       struct extent_node *en;
+
+       if (et->cached_en) {
+               struct extent_info *cei = &et->cached_en->ei;
+
+               if (cei->fofs <= fofs && cei->fofs + cei->len > fofs)
+                       return et->cached_en;
+       }
+
+       while (node) {
+               en = rb_entry(node, struct extent_node, rb_node);
+
+               if (fofs < en->ei.fofs)
+                       node = node->rb_left;
+               else if (fofs >= en->ei.fofs + en->ei.len)
+                       node = node->rb_right;
+               else
+                       return en;
+       }
+       return NULL;
+}
+
+static struct extent_node *__try_back_merge(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_node *en)
+{
+       struct extent_node *prev;
+       struct rb_node *node;
+
+       node = rb_prev(&en->rb_node);
+       if (!node)
+               return NULL;
+
+       prev = rb_entry(node, struct extent_node, rb_node);
+       if (__is_back_mergeable(&en->ei, &prev->ei)) {
+               en->ei.fofs = prev->ei.fofs;
+               en->ei.blk = prev->ei.blk;
+               en->ei.len += prev->ei.len;
+               __detach_extent_node(sbi, et, prev);
+               return prev;
+       }
+       return NULL;
+}
+
+static struct extent_node *__try_front_merge(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_node *en)
+{
+       struct extent_node *next;
+       struct rb_node *node;
+
+       node = rb_next(&en->rb_node);
+       if (!node)
+               return NULL;
+
+       next = rb_entry(node, struct extent_node, rb_node);
+       if (__is_front_mergeable(&en->ei, &next->ei)) {
+               en->ei.len += next->ei.len;
+               __detach_extent_node(sbi, et, next);
+               return next;
+       }
+       return NULL;
+}
+
+static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
+                               struct extent_tree *et, struct extent_info *ei,
+                               struct extent_node **den)
+{
+       struct rb_node **p = &et->root.rb_node;
+       struct rb_node *parent = NULL;
+       struct extent_node *en;
+
+       while (*p) {
+               parent = *p;
+               en = rb_entry(parent, struct extent_node, rb_node);
+
+               if (ei->fofs < en->ei.fofs) {
+                       if (__is_front_mergeable(ei, &en->ei)) {
+                               f2fs_bug_on(sbi, !den);
+                               en->ei.fofs = ei->fofs;
+                               en->ei.blk = ei->blk;
+                               en->ei.len += ei->len;
+                               *den = __try_back_merge(sbi, et, en);
+                               goto update_out;
+                       }
+                       p = &(*p)->rb_left;
+               } else if (ei->fofs >= en->ei.fofs + en->ei.len) {
+                       if (__is_back_mergeable(ei, &en->ei)) {
+                               f2fs_bug_on(sbi, !den);
+                               en->ei.len += ei->len;
+                               *den = __try_front_merge(sbi, et, en);
+                               goto update_out;
+                       }
+                       p = &(*p)->rb_right;
+               } else {
+                       f2fs_bug_on(sbi, 1);
+               }
+       }
+
+       en = __attach_extent_node(sbi, et, ei, parent, p);
+       if (!en)
+               return NULL;
+update_out:
+       if (en->ei.len > et->largest.len)
+               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, bool free_all)
+{
+       struct rb_node *node, *next;
+       struct extent_node *en;
+       unsigned int count = et->count;
+
+       node = rb_first(&et->root);
+       while (node) {
+               next = rb_next(node);
+               en = rb_entry(node, struct extent_node, rb_node);
+
+               if (free_all) {
+                       spin_lock(&sbi->extent_lock);
+                       if (!list_empty(&en->list))
+                               list_del_init(&en->list);
+                       spin_unlock(&sbi->extent_lock);
+               }
+
+               if (free_all || list_empty(&en->list)) {
+                       __detach_extent_node(sbi, et, en);
+                       kmem_cache_free(extent_node_slab, en);
+               }
+               node = next;
+       }
+
+       return count - et->count;
+}
+
+void f2fs_drop_largest_extent(struct inode *inode, pgoff_t fofs)
+{
+       struct extent_info *largest = &F2FS_I(inode)->extent_tree->largest;
+
+       if (largest->fofs <= fofs && largest->fofs + largest->len > fofs)
+               largest->len = 0;
+}
+
+void 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))
+               return;
+
+       et = __grab_extent_tree(inode);
+
+       if (!i_ext || le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
+               return;
+
+       set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
+               le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
+
+       write_lock(&et->lock);
+       if (et->count)
+               goto out;
+
+       en = __insert_extent_tree(sbi, et, &ei, NULL);
+       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);
+}
+
+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_read_hit(sbi->sb);
+               goto out;
+       }
+
+       en = __lookup_extent_tree(et, pgofs);
+       if (en) {
+               *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;
+               stat_inc_read_hit(sbi->sb);
+       }
+out:
+       stat_inc_total_hit(sbi->sb);
+       read_unlock(&et->lock);
+
+       trace_f2fs_lookup_extent_tree_end(inode, pgofs, ei);
+       return ret;
+}
+
+/* return true, if on-disk extent should be updated */
+static bool f2fs_update_extent_tree(struct inode *inode, pgoff_t fofs,
+                                                       block_t blkaddr)
+{
+       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, *en2 = NULL, *en3 = NULL;
+       struct extent_node *den = NULL;
+       struct extent_info ei, dei, prev;
+       unsigned int endofs;
+
+       if (!et)
+               return false;
+
+       trace_f2fs_update_extent_tree(inode, fofs, blkaddr);
+
+       write_lock(&et->lock);
+
+       if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT)) {
+               write_unlock(&et->lock);
+               return false;
+       }
+
+       prev = et->largest;
+       dei.len = 0;
+
+       /* we do not guarantee that the largest extent is cached all the time */
+       f2fs_drop_largest_extent(inode, fofs);
+
+       /* 1. lookup and remove existing extent info in cache */
+       en = __lookup_extent_tree(et, fofs);
+       if (!en)
+               goto update_extent;
+
+       dei = en->ei;
+       __detach_extent_node(sbi, et, en);
+
+       /* 2. if extent can be split more, split and insert the left part */
+       if (dei.len > F2FS_MIN_EXTENT_LEN) {
+               /*  insert left part of split extent into cache */
+               if (fofs - dei.fofs >= F2FS_MIN_EXTENT_LEN) {
+                       set_extent_info(&ei, dei.fofs, dei.blk,
+                                                       fofs - dei.fofs);
+                       en1 = __insert_extent_tree(sbi, et, &ei, NULL);
+               }
+
+               /* insert right part of split extent into cache */
+               endofs = dei.fofs + dei.len - 1;
+               if (endofs - fofs >= F2FS_MIN_EXTENT_LEN) {
+                       set_extent_info(&ei, fofs + 1,
+                               fofs - dei.fofs + dei.blk + 1, endofs - fofs);
+                       en2 = __insert_extent_tree(sbi, et, &ei, NULL);
+               }
+       }
+
+update_extent:
+       /* 3. update extent in extent cache */
+       if (blkaddr) {
+               set_extent_info(&ei, fofs, blkaddr, 1);
+               en3 = __insert_extent_tree(sbi, et, &ei, &den);
+
+               /* 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;
+                       set_inode_flag(F2FS_I(inode), FI_NO_EXTENT);
+               }
+       }
+
+       /* 4. update in global extent list */
+       spin_lock(&sbi->extent_lock);
+       if (en && !list_empty(&en->list))
+               list_del(&en->list);
+       /*
+        * en1 and en2 split from en, they will become more and more smaller
+        * fragments after splitting several times. So if the length is smaller
+        * than F2FS_MIN_EXTENT_LEN, we will not add them into extent tree.
+        */
+       if (en1)
+               list_add_tail(&en1->list, &sbi->extent_list);
+       if (en2)
+               list_add_tail(&en2->list, &sbi->extent_list);
+       if (en3) {
+               if (list_empty(&en3->list))
+                       list_add_tail(&en3->list, &sbi->extent_list);
+               else
+                       list_move_tail(&en3->list, &sbi->extent_list);
+       }
+       if (den && !list_empty(&den->list))
+               list_del(&den->list);
+       spin_unlock(&sbi->extent_lock);
+
+       /* 5. release extent node */
+       if (en)
+               kmem_cache_free(extent_node_slab, en);
+       if (den)
+               kmem_cache_free(extent_node_slab, den);
+
+       if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))
+               __free_extent_tree(sbi, et, true);
+
+       write_unlock(&et->lock);
+
+       return !__is_extent_same(&prev, &et->largest);
+}
+
+unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
+{
+       struct extent_tree *treevec[EXT_TREE_VEC_SIZE];
+       struct extent_node *en, *tmp;
+       unsigned long ino = F2FS_ROOT_INO(sbi);
+       struct radix_tree_root *root = &sbi->extent_tree_root;
+       unsigned int found;
+       unsigned int node_cnt = 0, tree_cnt = 0;
+       int remained;
+
+       if (!test_opt(sbi, EXTENT_CACHE))
+               return 0;
+
+       if (!down_write_trylock(&sbi->extent_tree_lock))
+               goto out;
+
+       /* 1. remove unreferenced extent tree */
+       while ((found = radix_tree_gang_lookup(root,
+                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
+               unsigned i;
+
+               ino = treevec[found - 1]->ino + 1;
+               for (i = 0; i < found; i++) {
+                       struct extent_tree *et = treevec[i];
+
+                       if (!atomic_read(&et->refcount)) {
+                               write_lock(&et->lock);
+                               node_cnt += __free_extent_tree(sbi, et, true);
+                               write_unlock(&et->lock);
+
+                               radix_tree_delete(root, et->ino);
+                               kmem_cache_free(extent_tree_slab, et);
+                               sbi->total_ext_tree--;
+                               tree_cnt++;
+
+                               if (node_cnt + tree_cnt >= nr_shrink)
+                                       goto unlock_out;
+                       }
+               }
+       }
+       up_write(&sbi->extent_tree_lock);
+
+       /* 2. remove LRU extent entries */
+       if (!down_write_trylock(&sbi->extent_tree_lock))
+               goto out;
+
+       remained = nr_shrink - (node_cnt + tree_cnt);
+
+       spin_lock(&sbi->extent_lock);
+       list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) {
+               if (!remained--)
+                       break;
+               list_del_init(&en->list);
+       }
+       spin_unlock(&sbi->extent_lock);
+
+       while ((found = radix_tree_gang_lookup(root,
+                               (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
+               unsigned i;
+
+               ino = treevec[found - 1]->ino + 1;
+               for (i = 0; i < found; i++) {
+                       struct extent_tree *et = treevec[i];
+
+                       write_lock(&et->lock);
+                       node_cnt += __free_extent_tree(sbi, et, false);
+                       write_unlock(&et->lock);
+
+                       if (node_cnt + tree_cnt >= nr_shrink)
+                               break;
+               }
+       }
+unlock_out:
+       up_write(&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)
+               return 0;
+
+       write_lock(&et->lock);
+       node_cnt = __free_extent_tree(sbi, et, true);
+       write_unlock(&et->lock);
+
+       return node_cnt;
+}
+
+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) && et->count) {
+               atomic_dec(&et->refcount);
+               return;
+       }
+
+       /* free all extent info belong to this extent tree */
+       node_cnt = f2fs_destroy_extent_node(inode);
+
+       /* delete extent tree entry in radix tree */
+       down_write(&sbi->extent_tree_lock);
+       atomic_dec(&et->refcount);
+       f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count);
+       radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);
+       kmem_cache_free(extent_tree_slab, et);
+       sbi->total_ext_tree--;
+       up_write(&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)
+{
+       struct f2fs_inode_info *fi = F2FS_I(dn->inode);
+       pgoff_t fofs;
+
+       if (!f2fs_may_extent_tree(dn->inode))
+               return;
+
+       f2fs_bug_on(F2FS_I_SB(dn->inode), dn->data_blkaddr == NEW_ADDR);
+
+       fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
+                                                       dn->ofs_in_node;
+
+       if (f2fs_update_extent_tree(dn->inode, fofs, dn->data_blkaddr))
+               sync_inode_page(dn);
+}
+
+void init_extent_cache_info(struct f2fs_sb_info *sbi)
+{
+       INIT_RADIX_TREE(&sbi->extent_tree_root, GFP_NOIO);
+       init_rwsem(&sbi->extent_tree_lock);
+       INIT_LIST_HEAD(&sbi->extent_list);
+       spin_lock_init(&sbi->extent_lock);
+       sbi->total_ext_tree = 0;
+       atomic_set(&sbi->total_ext_node, 0);
+}
+
+int __init 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 destroy_extent_cache(void)
+{
+       kmem_cache_destroy(extent_node_slab);
+       kmem_cache_destroy(extent_tree_slab);
+}
 
 void set_data_blkaddr(struct dnode_of_data *);
 int reserve_new_block(struct dnode_of_data *);
 int f2fs_reserve_block(struct dnode_of_data *, pgoff_t);
-unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
-void f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
-unsigned int f2fs_destroy_extent_node(struct inode *);
-void f2fs_destroy_extent_tree(struct inode *);
-void f2fs_update_extent_cache(struct dnode_of_data *);
 struct page *get_read_data_page(struct inode *, pgoff_t, int);
 struct page *find_data_page(struct inode *, pgoff_t);
 struct page *get_lock_data_page(struct inode *, pgoff_t);
 struct page *get_new_data_page(struct inode *, struct page *, pgoff_t, bool);
 int do_write_data_page(struct f2fs_io_info *);
 int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *, u64, u64);
-void init_extent_cache_info(struct f2fs_sb_info *);
-int __init create_extent_cache(void);
-void destroy_extent_cache(void);
 void f2fs_invalidate_page(struct page *, unsigned int, unsigned int);
 int f2fs_release_page(struct page *, gfp_t);
 
 void f2fs_join_shrinker(struct f2fs_sb_info *);
 void f2fs_leave_shrinker(struct f2fs_sb_info *);
 
+/*
+ * extent_cache.c
+ */
+unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
+void f2fs_drop_largest_extent(struct inode *, pgoff_t);
+void f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
+unsigned int f2fs_destroy_extent_node(struct inode *);
+void f2fs_destroy_extent_tree(struct inode *);
+bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);
+void f2fs_update_extent_cache(struct dnode_of_data *);
+void init_extent_cache_info(struct f2fs_sb_info *);
+int __init create_extent_cache(void);
+void destroy_extent_cache(void);
+
 /*
  * crypto support
  */