diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
new file mode 100644
index 0000000..216f04d
--- /dev/null
+++ b/fs/f2fs/node.c
@@ -0,0 +1,1763 @@
+/**
+ * fs/f2fs/node.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.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 <linux/mpage.h>
+#include <linux/backing-dev.h>
+#include <linux/blkdev.h>
+#include <linux/pagevec.h>
+#include <linux/swap.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+
+static struct kmem_cache *nat_entry_slab;
+static struct kmem_cache *free_nid_slab;
+
+static void clear_node_page_dirty(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
+	unsigned int long flags;
+
+	if (PageDirty(page)) {
+		spin_lock_irqsave(&mapping->tree_lock, flags);
+		radix_tree_tag_clear(&mapping->page_tree,
+				page_index(page),
+				PAGECACHE_TAG_DIRTY);
+		spin_unlock_irqrestore(&mapping->tree_lock, flags);
+
+		clear_page_dirty_for_io(page);
+		dec_page_count(sbi, F2FS_DIRTY_NODES);
+	}
+	ClearPageUptodate(page);
+}
+
+static struct page *get_current_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	pgoff_t index = current_nat_addr(sbi, nid);
+	return get_meta_page(sbi, index);
+}
+
+static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	struct page *src_page;
+	struct page *dst_page;
+	pgoff_t src_off;
+	pgoff_t dst_off;
+	void *src_addr;
+	void *dst_addr;
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+
+	src_off = current_nat_addr(sbi, nid);
+	dst_off = next_nat_addr(sbi, src_off);
+
+	/* get current nat block page with lock */
+	src_page = get_meta_page(sbi, src_off);
+
+	/* Dirty src_page means that it is already the new target NAT page. */
+	if (PageDirty(src_page))
+		return src_page;
+
+	dst_page = grab_meta_page(sbi, dst_off);
+
+	src_addr = page_address(src_page);
+	dst_addr = page_address(dst_page);
+	memcpy(dst_addr, src_addr, PAGE_CACHE_SIZE);
+	set_page_dirty(dst_page);
+	f2fs_put_page(src_page, 1);
+
+	set_to_next_nat(nm_i, nid);
+
+	return dst_page;
+}
+
+/**
+ * Readahead NAT pages
+ */
+static void ra_nat_pages(struct f2fs_sb_info *sbi, int nid)
+{
+	struct address_space *mapping = sbi->meta_inode->i_mapping;
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct page *page;
+	pgoff_t index;
+	int i;
+
+	for (i = 0; i < FREE_NID_PAGES; i++, nid += NAT_ENTRY_PER_BLOCK) {
+		if (nid >= nm_i->max_nid)
+			nid = 0;
+		index = current_nat_addr(sbi, nid);
+
+		page = grab_cache_page(mapping, index);
+		if (!page)
+			continue;
+		if (f2fs_readpage(sbi, page, index, READ)) {
+			f2fs_put_page(page, 1);
+			continue;
+		}
+		page_cache_release(page);
+	}
+}
+
+static struct nat_entry *__lookup_nat_cache(struct f2fs_nm_info *nm_i, nid_t n)
+{
+	return radix_tree_lookup(&nm_i->nat_root, n);
+}
+
+static unsigned int __gang_lookup_nat_cache(struct f2fs_nm_info *nm_i,
+		nid_t start, unsigned int nr, struct nat_entry **ep)
+{
+	return radix_tree_gang_lookup(&nm_i->nat_root, (void **)ep, start, nr);
+}
+
+static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct nat_entry *e)
+{
+	list_del(&e->list);
+	radix_tree_delete(&nm_i->nat_root, nat_get_nid(e));
+	nm_i->nat_cnt--;
+	kmem_cache_free(nat_entry_slab, e);
+}
+
+int is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct nat_entry *e;
+	int is_cp = 1;
+
+	read_lock(&nm_i->nat_tree_lock);
+	e = __lookup_nat_cache(nm_i, nid);
+	if (e && !e->checkpointed)
+		is_cp = 0;
+	read_unlock(&nm_i->nat_tree_lock);
+	return is_cp;
+}
+
+static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid)
+{
+	struct nat_entry *new;
+
+	new = kmem_cache_alloc(nat_entry_slab, GFP_ATOMIC);
+	if (!new)
+		return NULL;
+	if (radix_tree_insert(&nm_i->nat_root, nid, new)) {
+		kmem_cache_free(nat_entry_slab, new);
+		return NULL;
+	}
+	memset(new, 0, sizeof(struct nat_entry));
+	nat_set_nid(new, nid);
+	list_add_tail(&new->list, &nm_i->nat_entries);
+	nm_i->nat_cnt++;
+	return new;
+}
+
+static void cache_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid,
+						struct f2fs_nat_entry *ne)
+{
+	struct nat_entry *e;
+retry:
+	write_lock(&nm_i->nat_tree_lock);
+	e = __lookup_nat_cache(nm_i, nid);
+	if (!e) {
+		e = grab_nat_entry(nm_i, nid);
+		if (!e) {
+			write_unlock(&nm_i->nat_tree_lock);
+			goto retry;
+		}
+		nat_set_blkaddr(e, le32_to_cpu(ne->block_addr));
+		nat_set_ino(e, le32_to_cpu(ne->ino));
+		nat_set_version(e, ne->version);
+		e->checkpointed = true;
+	}
+	write_unlock(&nm_i->nat_tree_lock);
+}
+
+static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
+			block_t new_blkaddr)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct nat_entry *e;
+retry:
+	write_lock(&nm_i->nat_tree_lock);
+	e = __lookup_nat_cache(nm_i, ni->nid);
+	if (!e) {
+		e = grab_nat_entry(nm_i, ni->nid);
+		if (!e) {
+			write_unlock(&nm_i->nat_tree_lock);
+			goto retry;
+		}
+		e->ni = *ni;
+		e->checkpointed = true;
+		BUG_ON(ni->blk_addr == NEW_ADDR);
+	} else if (new_blkaddr == NEW_ADDR) {
+		/*
+		 * when nid is reallocated,
+		 * previous nat entry can be remained in nat cache.
+		 * So, reinitialize it with new information.
+		 */
+		e->ni = *ni;
+		BUG_ON(ni->blk_addr != NULL_ADDR);
+	}
+
+	if (new_blkaddr == NEW_ADDR)
+		e->checkpointed = false;
+
+	/* sanity check */
+	BUG_ON(nat_get_blkaddr(e) != ni->blk_addr);
+	BUG_ON(nat_get_blkaddr(e) == NULL_ADDR &&
+			new_blkaddr == NULL_ADDR);
+	BUG_ON(nat_get_blkaddr(e) == NEW_ADDR &&
+			new_blkaddr == NEW_ADDR);
+	BUG_ON(nat_get_blkaddr(e) != NEW_ADDR &&
+			nat_get_blkaddr(e) != NULL_ADDR &&
+			new_blkaddr == NEW_ADDR);
+
+	/* increament version no as node is removed */
+	if (nat_get_blkaddr(e) != NEW_ADDR && new_blkaddr == NULL_ADDR) {
+		unsigned char version = nat_get_version(e);
+		nat_set_version(e, inc_node_version(version));
+	}
+
+	/* change address */
+	nat_set_blkaddr(e, new_blkaddr);
+	__set_nat_cache_dirty(nm_i, e);
+	write_unlock(&nm_i->nat_tree_lock);
+}
+
+static int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+
+	if (nm_i->nat_cnt < 2 * NM_WOUT_THRESHOLD)
+		return 0;
+
+	write_lock(&nm_i->nat_tree_lock);
+	while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
+		struct nat_entry *ne;
+		ne = list_first_entry(&nm_i->nat_entries,
+					struct nat_entry, list);
+		__del_from_nat_cache(nm_i, ne);
+		nr_shrink--;
+	}
+	write_unlock(&nm_i->nat_tree_lock);
+	return nr_shrink;
+}
+
+/**
+ * This function returns always success
+ */
+void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	struct f2fs_summary_block *sum = curseg->sum_blk;
+	nid_t start_nid = START_NID(nid);
+	struct f2fs_nat_block *nat_blk;
+	struct page *page = NULL;
+	struct f2fs_nat_entry ne;
+	struct nat_entry *e;
+	int i;
+
+	ni->nid = nid;
+
+	/* Check nat cache */
+	read_lock(&nm_i->nat_tree_lock);
+	e = __lookup_nat_cache(nm_i, nid);
+	if (e) {
+		ni->ino = nat_get_ino(e);
+		ni->blk_addr = nat_get_blkaddr(e);
+		ni->version = nat_get_version(e);
+	}
+	read_unlock(&nm_i->nat_tree_lock);
+	if (e)
+		return;
+
+	/* Check current segment summary */
+	mutex_lock(&curseg->curseg_mutex);
+	i = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 0);
+	if (i >= 0) {
+		ne = nat_in_journal(sum, i);
+		node_info_from_raw_nat(ni, &ne);
+	}
+	mutex_unlock(&curseg->curseg_mutex);
+	if (i >= 0)
+		goto cache;
+
+	/* Fill node_info from nat page */
+	page = get_current_nat_page(sbi, start_nid);
+	nat_blk = (struct f2fs_nat_block *)page_address(page);
+	ne = nat_blk->entries[nid - start_nid];
+	node_info_from_raw_nat(ni, &ne);
+	f2fs_put_page(page, 1);
+cache:
+	/* cache nat entry */
+	cache_nat_entry(NM_I(sbi), nid, &ne);
+}
+
+/**
+ * The maximum depth is four.
+ * Offset[0] will have raw inode offset.
+ */
+static int get_node_path(long block, int offset[4], unsigned int noffset[4])
+{
+	const long direct_index = ADDRS_PER_INODE;
+	const long direct_blks = ADDRS_PER_BLOCK;
+	const long dptrs_per_blk = NIDS_PER_BLOCK;
+	const long indirect_blks = ADDRS_PER_BLOCK * NIDS_PER_BLOCK;
+	const long dindirect_blks = indirect_blks * NIDS_PER_BLOCK;
+	int n = 0;
+	int level = 0;
+
+	noffset[0] = 0;
+
+	if (block < direct_index) {
+		offset[n++] = block;
+		level = 0;
+		goto got;
+	}
+	block -= direct_index;
+	if (block < direct_blks) {
+		offset[n++] = NODE_DIR1_BLOCK;
+		noffset[n] = 1;
+		offset[n++] = block;
+		level = 1;
+		goto got;
+	}
+	block -= direct_blks;
+	if (block < direct_blks) {
+		offset[n++] = NODE_DIR2_BLOCK;
+		noffset[n] = 2;
+		offset[n++] = block;
+		level = 1;
+		goto got;
+	}
+	block -= direct_blks;
+	if (block < indirect_blks) {
+		offset[n++] = NODE_IND1_BLOCK;
+		noffset[n] = 3;
+		offset[n++] = block / direct_blks;
+		noffset[n] = 4 + offset[n - 1];
+		offset[n++] = block % direct_blks;
+		level = 2;
+		goto got;
+	}
+	block -= indirect_blks;
+	if (block < indirect_blks) {
+		offset[n++] = NODE_IND2_BLOCK;
+		noffset[n] = 4 + dptrs_per_blk;
+		offset[n++] = block / direct_blks;
+		noffset[n] = 5 + dptrs_per_blk + offset[n - 1];
+		offset[n++] = block % direct_blks;
+		level = 2;
+		goto got;
+	}
+	block -= indirect_blks;
+	if (block < dindirect_blks) {
+		offset[n++] = NODE_DIND_BLOCK;
+		noffset[n] = 5 + (dptrs_per_blk * 2);
+		offset[n++] = block / indirect_blks;
+		noffset[n] = 6 + (dptrs_per_blk * 2) +
+			      offset[n - 1] * (dptrs_per_blk + 1);
+		offset[n++] = (block / direct_blks) % dptrs_per_blk;
+		noffset[n] = 7 + (dptrs_per_blk * 2) +
+			      offset[n - 2] * (dptrs_per_blk + 1) +
+			      offset[n - 1];
+		offset[n++] = block % direct_blks;
+		level = 3;
+		goto got;
+	} else {
+		BUG();
+	}
+got:
+	return level;
+}
+
+/*
+ * Caller should call f2fs_put_dnode(dn).
+ */
+int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct page *npage[4];
+	struct page *parent;
+	int offset[4];
+	unsigned int noffset[4];
+	nid_t nids[4];
+	int level, i;
+	int err = 0;
+
+	level = get_node_path(index, offset, noffset);
+
+	nids[0] = dn->inode->i_ino;
+	npage[0] = get_node_page(sbi, nids[0]);
+	if (IS_ERR(npage[0]))
+		return PTR_ERR(npage[0]);
+
+	parent = npage[0];
+	nids[1] = get_nid(parent, offset[0], true);
+	dn->inode_page = npage[0];
+	dn->inode_page_locked = true;
+
+	/* get indirect or direct nodes */
+	for (i = 1; i <= level; i++) {
+		bool done = false;
+
+		if (!nids[i] && !ro) {
+			mutex_lock_op(sbi, NODE_NEW);
+
+			/* alloc new node */
+			if (!alloc_nid(sbi, &(nids[i]))) {
+				mutex_unlock_op(sbi, NODE_NEW);
+				err = -ENOSPC;
+				goto release_pages;
+			}
+
+			dn->nid = nids[i];
+			npage[i] = new_node_page(dn, noffset[i]);
+			if (IS_ERR(npage[i])) {
+				alloc_nid_failed(sbi, nids[i]);
+				mutex_unlock_op(sbi, NODE_NEW);
+				err = PTR_ERR(npage[i]);
+				goto release_pages;
+			}
+
+			set_nid(parent, offset[i - 1], nids[i], i == 1);
+			alloc_nid_done(sbi, nids[i]);
+			mutex_unlock_op(sbi, NODE_NEW);
+			done = true;
+		} else if (ro && i == level && level > 1) {
+			npage[i] = get_node_page_ra(parent, offset[i - 1]);
+			if (IS_ERR(npage[i])) {
+				err = PTR_ERR(npage[i]);
+				goto release_pages;
+			}
+			done = true;
+		}
+		if (i == 1) {
+			dn->inode_page_locked = false;
+			unlock_page(parent);
+		} else {
+			f2fs_put_page(parent, 1);
+		}
+
+		if (!done) {
+			npage[i] = get_node_page(sbi, nids[i]);
+			if (IS_ERR(npage[i])) {
+				err = PTR_ERR(npage[i]);
+				f2fs_put_page(npage[0], 0);
+				goto release_out;
+			}
+		}
+		if (i < level) {
+			parent = npage[i];
+			nids[i + 1] = get_nid(parent, offset[i], false);
+		}
+	}
+	dn->nid = nids[level];
+	dn->ofs_in_node = offset[level];
+	dn->node_page = npage[level];
+	dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
+	return 0;
+
+release_pages:
+	f2fs_put_page(parent, 1);
+	if (i > 1)
+		f2fs_put_page(npage[0], 0);
+release_out:
+	dn->inode_page = NULL;
+	dn->node_page = NULL;
+	return err;
+}
+
+static void truncate_node(struct dnode_of_data *dn)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct node_info ni;
+
+	get_node_info(sbi, dn->nid, &ni);
+	BUG_ON(ni.blk_addr == NULL_ADDR);
+
+	if (ni.blk_addr != NULL_ADDR)
+		invalidate_blocks(sbi, ni.blk_addr);
+
+	/* Deallocate node address */
+	dec_valid_node_count(sbi, dn->inode, 1);
+	set_node_addr(sbi, &ni, NULL_ADDR);
+
+	if (dn->nid == dn->inode->i_ino) {
+		remove_orphan_inode(sbi, dn->nid);
+		dec_valid_inode_count(sbi);
+	} else {
+		sync_inode_page(dn);
+	}
+
+	clear_node_page_dirty(dn->node_page);
+	F2FS_SET_SB_DIRT(sbi);
+
+	f2fs_put_page(dn->node_page, 1);
+	dn->node_page = NULL;
+}
+
+static int truncate_dnode(struct dnode_of_data *dn)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct page *page;
+
+	if (dn->nid == 0)
+		return 1;
+
+	/* get direct node */
+	page = get_node_page(sbi, dn->nid);
+	if (IS_ERR(page) && PTR_ERR(page) == -ENOENT)
+		return 1;
+	else if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	/* Make dnode_of_data for parameter */
+	dn->node_page = page;
+	dn->ofs_in_node = 0;
+	truncate_data_blocks(dn);
+	truncate_node(dn);
+	return 1;
+}
+
+static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs,
+						int ofs, int depth)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct dnode_of_data rdn = *dn;
+	struct page *page;
+	struct f2fs_node *rn;
+	nid_t child_nid;
+	unsigned int child_nofs;
+	int freed = 0;
+	int i, ret;
+
+	if (dn->nid == 0)
+		return NIDS_PER_BLOCK + 1;
+
+	page = get_node_page(sbi, dn->nid);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	rn = (struct f2fs_node *)page_address(page);
+	if (depth < 3) {
+		for (i = ofs; i < NIDS_PER_BLOCK; i++, freed++) {
+			child_nid = le32_to_cpu(rn->in.nid[i]);
+			if (child_nid == 0)
+				continue;
+			rdn.nid = child_nid;
+			ret = truncate_dnode(&rdn);
+			if (ret < 0)
+				goto out_err;
+			set_nid(page, i, 0, false);
+		}
+	} else {
+		child_nofs = nofs + ofs * (NIDS_PER_BLOCK + 1) + 1;
+		for (i = ofs; i < NIDS_PER_BLOCK; i++) {
+			child_nid = le32_to_cpu(rn->in.nid[i]);
+			if (child_nid == 0) {
+				child_nofs += NIDS_PER_BLOCK + 1;
+				continue;
+			}
+			rdn.nid = child_nid;
+			ret = truncate_nodes(&rdn, child_nofs, 0, depth - 1);
+			if (ret == (NIDS_PER_BLOCK + 1)) {
+				set_nid(page, i, 0, false);
+				child_nofs += ret;
+			} else if (ret < 0 && ret != -ENOENT) {
+				goto out_err;
+			}
+		}
+		freed = child_nofs;
+	}
+
+	if (!ofs) {
+		/* remove current indirect node */
+		dn->node_page = page;
+		truncate_node(dn);
+		freed++;
+	} else {
+		f2fs_put_page(page, 1);
+	}
+	return freed;
+
+out_err:
+	f2fs_put_page(page, 1);
+	return ret;
+}
+
+static int truncate_partial_nodes(struct dnode_of_data *dn,
+			struct f2fs_inode *ri, int *offset, int depth)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct page *pages[2];
+	nid_t nid[3];
+	nid_t child_nid;
+	int err = 0;
+	int i;
+	int idx = depth - 2;
+
+	nid[0] = le32_to_cpu(ri->i_nid[offset[0] - NODE_DIR1_BLOCK]);
+	if (!nid[0])
+		return 0;
+
+	/* get indirect nodes in the path */
+	for (i = 0; i < depth - 1; i++) {
+		/* refernece count'll be increased */
+		pages[i] = get_node_page(sbi, nid[i]);
+		if (IS_ERR(pages[i])) {
+			depth = i + 1;
+			err = PTR_ERR(pages[i]);
+			goto fail;
+		}
+		nid[i + 1] = get_nid(pages[i], offset[i + 1], false);
+	}
+
+	/* free direct nodes linked to a partial indirect node */
+	for (i = offset[depth - 1]; i < NIDS_PER_BLOCK; i++) {
+		child_nid = get_nid(pages[idx], i, false);
+		if (!child_nid)
+			continue;
+		dn->nid = child_nid;
+		err = truncate_dnode(dn);
+		if (err < 0)
+			goto fail;
+		set_nid(pages[idx], i, 0, false);
+	}
+
+	if (offset[depth - 1] == 0) {
+		dn->node_page = pages[idx];
+		dn->nid = nid[idx];
+		truncate_node(dn);
+	} else {
+		f2fs_put_page(pages[idx], 1);
+	}
+	offset[idx]++;
+	offset[depth - 1] = 0;
+fail:
+	for (i = depth - 3; i >= 0; i--)
+		f2fs_put_page(pages[i], 1);
+	return err;
+}
+
+/**
+ * All the block addresses of data and nodes should be nullified.
+ */
+int truncate_inode_blocks(struct inode *inode, pgoff_t from)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	int err = 0, cont = 1;
+	int level, offset[4], noffset[4];
+	unsigned int nofs;
+	struct f2fs_node *rn;
+	struct dnode_of_data dn;
+	struct page *page;
+
+	level = get_node_path(from, offset, noffset);
+
+	page = get_node_page(sbi, inode->i_ino);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	set_new_dnode(&dn, inode, page, NULL, 0);
+	unlock_page(page);
+
+	rn = page_address(page);
+	switch (level) {
+	case 0:
+	case 1:
+		nofs = noffset[1];
+		break;
+	case 2:
+		nofs = noffset[1];
+		if (!offset[level - 1])
+			goto skip_partial;
+		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
+		if (err < 0 && err != -ENOENT)
+			goto fail;
+		nofs += 1 + NIDS_PER_BLOCK;
+		break;
+	case 3:
+		nofs = 5 + 2 * NIDS_PER_BLOCK;
+		if (!offset[level - 1])
+			goto skip_partial;
+		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
+		if (err < 0 && err != -ENOENT)
+			goto fail;
+		break;
+	default:
+		BUG();
+	}
+
+skip_partial:
+	while (cont) {
+		dn.nid = le32_to_cpu(rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]);
+		switch (offset[0]) {
+		case NODE_DIR1_BLOCK:
+		case NODE_DIR2_BLOCK:
+			err = truncate_dnode(&dn);
+			break;
+
+		case NODE_IND1_BLOCK:
+		case NODE_IND2_BLOCK:
+			err = truncate_nodes(&dn, nofs, offset[1], 2);
+			break;
+
+		case NODE_DIND_BLOCK:
+			err = truncate_nodes(&dn, nofs, offset[1], 3);
+			cont = 0;
+			break;
+
+		default:
+			BUG();
+		}
+		if (err < 0 && err != -ENOENT)
+			goto fail;
+		if (offset[1] == 0 &&
+				rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]) {
+			lock_page(page);
+			wait_on_page_writeback(page);
+			rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
+			set_page_dirty(page);
+			unlock_page(page);
+		}
+		offset[1] = 0;
+		offset[0]++;
+		nofs += err;
+	}
+fail:
+	f2fs_put_page(page, 0);
+	return err > 0 ? 0 : err;
+}
+
+int remove_inode_page(struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct page *page;
+	nid_t ino = inode->i_ino;
+	struct dnode_of_data dn;
+
+	mutex_lock_op(sbi, NODE_TRUNC);
+	page = get_node_page(sbi, ino);
+	if (IS_ERR(page)) {
+		mutex_unlock_op(sbi, NODE_TRUNC);
+		return PTR_ERR(page);
+	}
+
+	if (F2FS_I(inode)->i_xattr_nid) {
+		nid_t nid = F2FS_I(inode)->i_xattr_nid;
+		struct page *npage = get_node_page(sbi, nid);
+
+		if (IS_ERR(npage)) {
+			mutex_unlock_op(sbi, NODE_TRUNC);
+			return PTR_ERR(npage);
+		}
+
+		F2FS_I(inode)->i_xattr_nid = 0;
+		set_new_dnode(&dn, inode, page, npage, nid);
+		dn.inode_page_locked = 1;
+		truncate_node(&dn);
+	}
+	if (inode->i_blocks == 1) {
+		/* inernally call f2fs_put_page() */
+		set_new_dnode(&dn, inode, page, page, ino);
+		truncate_node(&dn);
+	} else if (inode->i_blocks == 0) {
+		struct node_info ni;
+		get_node_info(sbi, inode->i_ino, &ni);
+
+		/* called after f2fs_new_inode() is failed */
+		BUG_ON(ni.blk_addr != NULL_ADDR);
+		f2fs_put_page(page, 1);
+	} else {
+		BUG();
+	}
+	mutex_unlock_op(sbi, NODE_TRUNC);
+	return 0;
+}
+
+int new_inode_page(struct inode *inode, struct dentry *dentry)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct page *page;
+	struct dnode_of_data dn;
+
+	/* allocate inode page for new inode */
+	set_new_dnode(&dn, inode, NULL, NULL, inode->i_ino);
+	mutex_lock_op(sbi, NODE_NEW);
+	page = new_node_page(&dn, 0);
+	init_dent_inode(dentry, page);
+	mutex_unlock_op(sbi, NODE_NEW);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	f2fs_put_page(page, 1);
+	return 0;
+}
+
+struct page *new_node_page(struct dnode_of_data *dn, unsigned int ofs)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+	struct node_info old_ni, new_ni;
+	struct page *page;
+	int err;
+
+	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
+		return ERR_PTR(-EPERM);
+
+	page = grab_cache_page(mapping, dn->nid);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	get_node_info(sbi, dn->nid, &old_ni);
+
+	SetPageUptodate(page);
+	fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, true);
+
+	/* Reinitialize old_ni with new node page */
+	BUG_ON(old_ni.blk_addr != NULL_ADDR);
+	new_ni = old_ni;
+	new_ni.ino = dn->inode->i_ino;
+
+	if (!inc_valid_node_count(sbi, dn->inode, 1)) {
+		err = -ENOSPC;
+		goto fail;
+	}
+	set_node_addr(sbi, &new_ni, NEW_ADDR);
+
+	dn->node_page = page;
+	sync_inode_page(dn);
+	set_page_dirty(page);
+	set_cold_node(dn->inode, page);
+	if (ofs == 0)
+		inc_valid_inode_count(sbi);
+
+	return page;
+
+fail:
+	f2fs_put_page(page, 1);
+	return ERR_PTR(err);
+}
+
+static int read_node_page(struct page *page, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
+	struct node_info ni;
+
+	get_node_info(sbi, page->index, &ni);
+
+	if (ni.blk_addr == NULL_ADDR)
+		return -ENOENT;
+	return f2fs_readpage(sbi, page, ni.blk_addr, type);
+}
+
+/**
+ * Readahead a node page
+ */
+void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+	struct page *apage;
+
+	apage = find_get_page(mapping, nid);
+	if (apage && PageUptodate(apage))
+		goto release_out;
+	f2fs_put_page(apage, 0);
+
+	apage = grab_cache_page(mapping, nid);
+	if (!apage)
+		return;
+
+	if (read_node_page(apage, READA))
+		goto unlock_out;
+
+	page_cache_release(apage);
+	return;
+
+unlock_out:
+	unlock_page(apage);
+release_out:
+	page_cache_release(apage);
+}
+
+struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
+{
+	int err;
+	struct page *page;
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+
+	page = grab_cache_page(mapping, nid);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	err = read_node_page(page, READ_SYNC);
+	if (err) {
+		f2fs_put_page(page, 1);
+		return ERR_PTR(err);
+	}
+
+	BUG_ON(nid != nid_of_node(page));
+	mark_page_accessed(page);
+	return page;
+}
+
+/**
+ * Return a locked page for the desired node page.
+ * And, readahead MAX_RA_NODE number of node pages.
+ */
+struct page *get_node_page_ra(struct page *parent, int start)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(parent->mapping->host->i_sb);
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+	int i, end;
+	int err = 0;
+	nid_t nid;
+	struct page *page;
+
+	/* First, try getting the desired direct node. */
+	nid = get_nid(parent, start, false);
+	if (!nid)
+		return ERR_PTR(-ENOENT);
+
+	page = find_get_page(mapping, nid);
+	if (page && PageUptodate(page))
+		goto page_hit;
+	f2fs_put_page(page, 0);
+
+repeat:
+	page = grab_cache_page(mapping, nid);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	err = read_node_page(page, READA);
+	if (err) {
+		f2fs_put_page(page, 1);
+		return ERR_PTR(err);
+	}
+
+	/* Then, try readahead for siblings of the desired node */
+	end = start + MAX_RA_NODE;
+	end = min(end, NIDS_PER_BLOCK);
+	for (i = start + 1; i < end; i++) {
+		nid = get_nid(parent, i, false);
+		if (!nid)
+			continue;
+		ra_node_page(sbi, nid);
+	}
+
+page_hit:
+	lock_page(page);
+	if (PageError(page)) {
+		f2fs_put_page(page, 1);
+		return ERR_PTR(-EIO);
+	}
+
+	/* Has the page been truncated? */
+	if (page->mapping != mapping) {
+		f2fs_put_page(page, 1);
+		goto repeat;
+	}
+	return page;
+}
+
+void sync_inode_page(struct dnode_of_data *dn)
+{
+	if (IS_INODE(dn->node_page) || dn->inode_page == dn->node_page) {
+		update_inode(dn->inode, dn->node_page);
+	} else if (dn->inode_page) {
+		if (!dn->inode_page_locked)
+			lock_page(dn->inode_page);
+		update_inode(dn->inode, dn->inode_page);
+		if (!dn->inode_page_locked)
+			unlock_page(dn->inode_page);
+	} else {
+		f2fs_write_inode(dn->inode, NULL);
+	}
+}
+
+int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
+					struct writeback_control *wbc)
+{
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+	pgoff_t index, end;
+	struct pagevec pvec;
+	int step = ino ? 2 : 0;
+	int nwritten = 0, wrote = 0;
+
+	pagevec_init(&pvec, 0);
+
+next_step:
+	index = 0;
+	end = LONG_MAX;
+
+	while (index <= end) {
+		int i, nr_pages;
+		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+				PAGECACHE_TAG_DIRTY,
+				min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
+		if (nr_pages == 0)
+			break;
+
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			/*
+			 * flushing sequence with step:
+			 * 0. indirect nodes
+			 * 1. dentry dnodes
+			 * 2. file dnodes
+			 */
+			if (step == 0 && IS_DNODE(page))
+				continue;
+			if (step == 1 && (!IS_DNODE(page) ||
+						is_cold_node(page)))
+				continue;
+			if (step == 2 && (!IS_DNODE(page) ||
+						!is_cold_node(page)))
+				continue;
+
+			/*
+			 * If an fsync mode,
+			 * we should not skip writing node pages.
+			 */
+			if (ino && ino_of_node(page) == ino)
+				lock_page(page);
+			else if (!trylock_page(page))
+				continue;
+
+			if (unlikely(page->mapping != mapping)) {
+continue_unlock:
+				unlock_page(page);
+				continue;
+			}
+			if (ino && ino_of_node(page) != ino)
+				goto continue_unlock;
+
+			if (!PageDirty(page)) {
+				/* someone wrote it for us */
+				goto continue_unlock;
+			}
+
+			if (!clear_page_dirty_for_io(page))
+				goto continue_unlock;
+
+			/* called by fsync() */
+			if (ino && IS_DNODE(page)) {
+				int mark = !is_checkpointed_node(sbi, ino);
+				set_fsync_mark(page, 1);
+				if (IS_INODE(page))
+					set_dentry_mark(page, mark);
+				nwritten++;
+			} else {
+				set_fsync_mark(page, 0);
+				set_dentry_mark(page, 0);
+			}
+			mapping->a_ops->writepage(page, wbc);
+			wrote++;
+
+			if (--wbc->nr_to_write == 0)
+				break;
+		}
+		pagevec_release(&pvec);
+		cond_resched();
+
+		if (wbc->nr_to_write == 0) {
+			step = 2;
+			break;
+		}
+	}
+
+	if (step < 2) {
+		step++;
+		goto next_step;
+	}
+
+	if (wrote)
+		f2fs_submit_bio(sbi, NODE, wbc->sync_mode == WB_SYNC_ALL);
+
+	return nwritten;
+}
+
+static int f2fs_write_node_page(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
+	nid_t nid;
+	unsigned int nofs;
+	block_t new_addr;
+	struct node_info ni;
+
+	if (wbc->for_reclaim) {
+		dec_page_count(sbi, F2FS_DIRTY_NODES);
+		wbc->pages_skipped++;
+		set_page_dirty(page);
+		return AOP_WRITEPAGE_ACTIVATE;
+	}
+
+	wait_on_page_writeback(page);
+
+	mutex_lock_op(sbi, NODE_WRITE);
+
+	/* get old block addr of this node page */
+	nid = nid_of_node(page);
+	nofs = ofs_of_node(page);
+	BUG_ON(page->index != nid);
+
+	get_node_info(sbi, nid, &ni);
+
+	/* This page is already truncated */
+	if (ni.blk_addr == NULL_ADDR)
+		return 0;
+
+	set_page_writeback(page);
+
+	/* insert node offset */
+	write_node_page(sbi, page, nid, ni.blk_addr, &new_addr);
+	set_node_addr(sbi, &ni, new_addr);
+	dec_page_count(sbi, F2FS_DIRTY_NODES);
+
+	mutex_unlock_op(sbi, NODE_WRITE);
+	unlock_page(page);
+	return 0;
+}
+
+static int f2fs_write_node_pages(struct address_space *mapping,
+			    struct writeback_control *wbc)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
+	struct block_device *bdev = sbi->sb->s_bdev;
+	long nr_to_write = wbc->nr_to_write;
+
+	if (wbc->for_kupdate)
+		return 0;
+
+	if (get_pages(sbi, F2FS_DIRTY_NODES) == 0)
+		return 0;
+
+	if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
+		write_checkpoint(sbi, false, false);
+		return 0;
+	}
+
+	/* if mounting is failed, skip writing node pages */
+	wbc->nr_to_write = bio_get_nr_vecs(bdev);
+	sync_node_pages(sbi, 0, wbc);
+	wbc->nr_to_write = nr_to_write -
+		(bio_get_nr_vecs(bdev) - wbc->nr_to_write);
+	return 0;
+}
+
+static int f2fs_set_node_page_dirty(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
+
+	SetPageUptodate(page);
+	if (!PageDirty(page)) {
+		__set_page_dirty_nobuffers(page);
+		inc_page_count(sbi, F2FS_DIRTY_NODES);
+		SetPagePrivate(page);
+		return 1;
+	}
+	return 0;
+}
+
+static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
+{
+	struct inode *inode = page->mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	if (PageDirty(page))
+		dec_page_count(sbi, F2FS_DIRTY_NODES);
+	ClearPagePrivate(page);
+}
+
+static int f2fs_release_node_page(struct page *page, gfp_t wait)
+{
+	ClearPagePrivate(page);
+	return 0;
+}
+
+/**
+ * Structure of the f2fs node operations
+ */
+const struct address_space_operations f2fs_node_aops = {
+	.writepage	= f2fs_write_node_page,
+	.writepages	= f2fs_write_node_pages,
+	.set_page_dirty	= f2fs_set_node_page_dirty,
+	.invalidatepage	= f2fs_invalidate_node_page,
+	.releasepage	= f2fs_release_node_page,
+};
+
+static struct free_nid *__lookup_free_nid_list(nid_t n, struct list_head *head)
+{
+	struct list_head *this;
+	struct free_nid *i = NULL;
+	list_for_each(this, head) {
+		i = list_entry(this, struct free_nid, list);
+		if (i->nid == n)
+			break;
+		i = NULL;
+	}
+	return i;
+}
+
+static void __del_from_free_nid_list(struct free_nid *i)
+{
+	list_del(&i->list);
+	kmem_cache_free(free_nid_slab, i);
+}
+
+static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
+{
+	struct free_nid *i;
+
+	if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
+		return 0;
+retry:
+	i = kmem_cache_alloc(free_nid_slab, GFP_NOFS);
+	if (!i) {
+		cond_resched();
+		goto retry;
+	}
+	i->nid = nid;
+	i->state = NID_NEW;
+
+	spin_lock(&nm_i->free_nid_list_lock);
+	if (__lookup_free_nid_list(nid, &nm_i->free_nid_list)) {
+		spin_unlock(&nm_i->free_nid_list_lock);
+		kmem_cache_free(free_nid_slab, i);
+		return 0;
+	}
+	list_add_tail(&i->list, &nm_i->free_nid_list);
+	nm_i->fcnt++;
+	spin_unlock(&nm_i->free_nid_list_lock);
+	return 1;
+}
+
+static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
+{
+	struct free_nid *i;
+	spin_lock(&nm_i->free_nid_list_lock);
+	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
+	if (i && i->state == NID_NEW) {
+		__del_from_free_nid_list(i);
+		nm_i->fcnt--;
+	}
+	spin_unlock(&nm_i->free_nid_list_lock);
+}
+
+static int scan_nat_page(struct f2fs_nm_info *nm_i,
+			struct page *nat_page, nid_t start_nid)
+{
+	struct f2fs_nat_block *nat_blk = page_address(nat_page);
+	block_t blk_addr;
+	int fcnt = 0;
+	int i;
+
+	/* 0 nid should not be used */
+	if (start_nid == 0)
+		++start_nid;
+
+	i = start_nid % NAT_ENTRY_PER_BLOCK;
+
+	for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
+		blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
+		BUG_ON(blk_addr == NEW_ADDR);
+		if (blk_addr == NULL_ADDR)
+			fcnt += add_free_nid(nm_i, start_nid);
+	}
+	return fcnt;
+}
+
+static void build_free_nids(struct f2fs_sb_info *sbi)
+{
+	struct free_nid *fnid, *next_fnid;
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	struct f2fs_summary_block *sum = curseg->sum_blk;
+	nid_t nid = 0;
+	bool is_cycled = false;
+	int fcnt = 0;
+	int i;
+
+	nid = nm_i->next_scan_nid;
+	nm_i->init_scan_nid = nid;
+
+	ra_nat_pages(sbi, nid);
+
+	while (1) {
+		struct page *page = get_current_nat_page(sbi, nid);
+
+		fcnt += scan_nat_page(nm_i, page, nid);
+		f2fs_put_page(page, 1);
+
+		nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK));
+
+		if (nid >= nm_i->max_nid) {
+			nid = 0;
+			is_cycled = true;
+		}
+		if (fcnt > MAX_FREE_NIDS)
+			break;
+		if (is_cycled && nm_i->init_scan_nid <= nid)
+			break;
+	}
+
+	nm_i->next_scan_nid = nid;
+
+	/* find free nids from current sum_pages */
+	mutex_lock(&curseg->curseg_mutex);
+	for (i = 0; i < nats_in_cursum(sum); i++) {
+		block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr);
+		nid = le32_to_cpu(nid_in_journal(sum, i));
+		if (addr == NULL_ADDR)
+			add_free_nid(nm_i, nid);
+		else
+			remove_free_nid(nm_i, nid);
+	}
+	mutex_unlock(&curseg->curseg_mutex);
+
+	/* remove the free nids from current allocated nids */
+	list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list) {
+		struct nat_entry *ne;
+
+		read_lock(&nm_i->nat_tree_lock);
+		ne = __lookup_nat_cache(nm_i, fnid->nid);
+		if (ne && nat_get_blkaddr(ne) != NULL_ADDR)
+			remove_free_nid(nm_i, fnid->nid);
+		read_unlock(&nm_i->nat_tree_lock);
+	}
+}
+
+/*
+ * If this function returns success, caller can obtain a new nid
+ * from second parameter of this function.
+ * The returned nid could be used ino as well as nid when inode is created.
+ */
+bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct free_nid *i = NULL;
+	struct list_head *this;
+retry:
+	mutex_lock(&nm_i->build_lock);
+	if (!nm_i->fcnt) {
+		/* scan NAT in order to build free nid list */
+		build_free_nids(sbi);
+		if (!nm_i->fcnt) {
+			mutex_unlock(&nm_i->build_lock);
+			return false;
+		}
+	}
+	mutex_unlock(&nm_i->build_lock);
+
+	/*
+	 * We check fcnt again since previous check is racy as
+	 * we didn't hold free_nid_list_lock. So other thread
+	 * could consume all of free nids.
+	 */
+	spin_lock(&nm_i->free_nid_list_lock);
+	if (!nm_i->fcnt) {
+		spin_unlock(&nm_i->free_nid_list_lock);
+		goto retry;
+	}
+
+	BUG_ON(list_empty(&nm_i->free_nid_list));
+	list_for_each(this, &nm_i->free_nid_list) {
+		i = list_entry(this, struct free_nid, list);
+		if (i->state == NID_NEW)
+			break;
+	}
+
+	BUG_ON(i->state != NID_NEW);
+	*nid = i->nid;
+	i->state = NID_ALLOC;
+	nm_i->fcnt--;
+	spin_unlock(&nm_i->free_nid_list_lock);
+	return true;
+}
+
+/**
+ * alloc_nid() should be called prior to this function.
+ */
+void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct free_nid *i;
+
+	spin_lock(&nm_i->free_nid_list_lock);
+	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
+	if (i) {
+		BUG_ON(i->state != NID_ALLOC);
+		__del_from_free_nid_list(i);
+	}
+	spin_unlock(&nm_i->free_nid_list_lock);
+}
+
+/**
+ * alloc_nid() should be called prior to this function.
+ */
+void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
+{
+	alloc_nid_done(sbi, nid);
+	add_free_nid(NM_I(sbi), nid);
+}
+
+void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
+		struct f2fs_summary *sum, struct node_info *ni,
+		block_t new_blkaddr)
+{
+	rewrite_node_page(sbi, page, sum, ni->blk_addr, new_blkaddr);
+	set_node_addr(sbi, ni, new_blkaddr);
+	clear_node_page_dirty(page);
+}
+
+int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
+{
+	struct address_space *mapping = sbi->node_inode->i_mapping;
+	struct f2fs_node *src, *dst;
+	nid_t ino = ino_of_node(page);
+	struct node_info old_ni, new_ni;
+	struct page *ipage;
+
+	ipage = grab_cache_page(mapping, ino);
+	if (!ipage)
+		return -ENOMEM;
+
+	/* Should not use this inode  from free nid list */
+	remove_free_nid(NM_I(sbi), ino);
+
+	get_node_info(sbi, ino, &old_ni);
+	SetPageUptodate(ipage);
+	fill_node_footer(ipage, ino, ino, 0, true);
+
+	src = (struct f2fs_node *)page_address(page);
+	dst = (struct f2fs_node *)page_address(ipage);
+
+	memcpy(dst, src, (unsigned long)&src->i.i_ext - (unsigned long)&src->i);
+	dst->i.i_size = 0;
+	dst->i.i_blocks = 1;
+	dst->i.i_links = 1;
+	dst->i.i_xattr_nid = 0;
+
+	new_ni = old_ni;
+	new_ni.ino = ino;
+
+	set_node_addr(sbi, &new_ni, NEW_ADDR);
+	inc_valid_inode_count(sbi);
+
+	f2fs_put_page(ipage, 1);
+	return 0;
+}
+
+int restore_node_summary(struct f2fs_sb_info *sbi,
+			unsigned int segno, struct f2fs_summary_block *sum)
+{
+	struct f2fs_node *rn;
+	struct f2fs_summary *sum_entry;
+	struct page *page;
+	block_t addr;
+	int i, last_offset;
+
+	/* alloc temporal page for read node */
+	page = alloc_page(GFP_NOFS | __GFP_ZERO);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	lock_page(page);
+
+	/* scan the node segment */
+	last_offset = sbi->blocks_per_seg;
+	addr = START_BLOCK(sbi, segno);
+	sum_entry = &sum->entries[0];
+
+	for (i = 0; i < last_offset; i++, sum_entry++) {
+		if (f2fs_readpage(sbi, page, addr, READ_SYNC))
+			goto out;
+
+		rn = (struct f2fs_node *)page_address(page);
+		sum_entry->nid = rn->footer.nid;
+		sum_entry->version = 0;
+		sum_entry->ofs_in_node = 0;
+		addr++;
+
+		/*
+		 * In order to read next node page,
+		 * we must clear PageUptodate flag.
+		 */
+		ClearPageUptodate(page);
+	}
+out:
+	unlock_page(page);
+	__free_pages(page, 0);
+	return 0;
+}
+
+static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	struct f2fs_summary_block *sum = curseg->sum_blk;
+	int i;
+
+	mutex_lock(&curseg->curseg_mutex);
+
+	if (nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES) {
+		mutex_unlock(&curseg->curseg_mutex);
+		return false;
+	}
+
+	for (i = 0; i < nats_in_cursum(sum); i++) {
+		struct nat_entry *ne;
+		struct f2fs_nat_entry raw_ne;
+		nid_t nid = le32_to_cpu(nid_in_journal(sum, i));
+
+		raw_ne = nat_in_journal(sum, i);
+retry:
+		write_lock(&nm_i->nat_tree_lock);
+		ne = __lookup_nat_cache(nm_i, nid);
+		if (ne) {
+			__set_nat_cache_dirty(nm_i, ne);
+			write_unlock(&nm_i->nat_tree_lock);
+			continue;
+		}
+		ne = grab_nat_entry(nm_i, nid);
+		if (!ne) {
+			write_unlock(&nm_i->nat_tree_lock);
+			goto retry;
+		}
+		nat_set_blkaddr(ne, le32_to_cpu(raw_ne.block_addr));
+		nat_set_ino(ne, le32_to_cpu(raw_ne.ino));
+		nat_set_version(ne, raw_ne.version);
+		__set_nat_cache_dirty(nm_i, ne);
+		write_unlock(&nm_i->nat_tree_lock);
+	}
+	update_nats_in_cursum(sum, -i);
+	mutex_unlock(&curseg->curseg_mutex);
+	return true;
+}
+
+/**
+ * This function is called during the checkpointing process.
+ */
+void flush_nat_entries(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
+	struct f2fs_summary_block *sum = curseg->sum_blk;
+	struct list_head *cur, *n;
+	struct page *page = NULL;
+	struct f2fs_nat_block *nat_blk = NULL;
+	nid_t start_nid = 0, end_nid = 0;
+	bool flushed;
+
+	flushed = flush_nats_in_journal(sbi);
+
+	if (!flushed)
+		mutex_lock(&curseg->curseg_mutex);
+
+	/* 1) flush dirty nat caches */
+	list_for_each_safe(cur, n, &nm_i->dirty_nat_entries) {
+		struct nat_entry *ne;
+		nid_t nid;
+		struct f2fs_nat_entry raw_ne;
+		int offset = -1;
+		block_t old_blkaddr, new_blkaddr;
+
+		ne = list_entry(cur, struct nat_entry, list);
+		nid = nat_get_nid(ne);
+
+		if (nat_get_blkaddr(ne) == NEW_ADDR)
+			continue;
+		if (flushed)
+			goto to_nat_page;
+
+		/* if there is room for nat enries in curseg->sumpage */
+		offset = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 1);
+		if (offset >= 0) {
+			raw_ne = nat_in_journal(sum, offset);
+			old_blkaddr = le32_to_cpu(raw_ne.block_addr);
+			goto flush_now;
+		}
+to_nat_page:
+		if (!page || (start_nid > nid || nid > end_nid)) {
+			if (page) {
+				f2fs_put_page(page, 1);
+				page = NULL;
+			}
+			start_nid = START_NID(nid);
+			end_nid = start_nid + NAT_ENTRY_PER_BLOCK - 1;
+
+			/*
+			 * get nat block with dirty flag, increased reference
+			 * count, mapped and lock
+			 */
+			page = get_next_nat_page(sbi, start_nid);
+			nat_blk = page_address(page);
+		}
+
+		BUG_ON(!nat_blk);
+		raw_ne = nat_blk->entries[nid - start_nid];
+		old_blkaddr = le32_to_cpu(raw_ne.block_addr);
+flush_now:
+		new_blkaddr = nat_get_blkaddr(ne);
+
+		raw_ne.ino = cpu_to_le32(nat_get_ino(ne));
+		raw_ne.block_addr = cpu_to_le32(new_blkaddr);
+		raw_ne.version = nat_get_version(ne);
+
+		if (offset < 0) {
+			nat_blk->entries[nid - start_nid] = raw_ne;
+		} else {
+			nat_in_journal(sum, offset) = raw_ne;
+			nid_in_journal(sum, offset) = cpu_to_le32(nid);
+		}
+
+		if (nat_get_blkaddr(ne) == NULL_ADDR) {
+			write_lock(&nm_i->nat_tree_lock);
+			__del_from_nat_cache(nm_i, ne);
+			write_unlock(&nm_i->nat_tree_lock);
+
+			/* We can reuse this freed nid at this point */
+			add_free_nid(NM_I(sbi), nid);
+		} else {
+			write_lock(&nm_i->nat_tree_lock);
+			__clear_nat_cache_dirty(nm_i, ne);
+			ne->checkpointed = true;
+			write_unlock(&nm_i->nat_tree_lock);
+		}
+	}
+	if (!flushed)
+		mutex_unlock(&curseg->curseg_mutex);
+	f2fs_put_page(page, 1);
+
+	/* 2) shrink nat caches if necessary */
+	try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
+}
+
+static int init_node_manager(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	unsigned char *version_bitmap;
+	unsigned int nat_segs, nat_blocks;
+
+	nm_i->nat_blkaddr = le32_to_cpu(sb_raw->nat_blkaddr);
+
+	/* segment_count_nat includes pair segment so divide to 2. */
+	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
+	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
+	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
+	nm_i->fcnt = 0;
+	nm_i->nat_cnt = 0;
+
+	INIT_LIST_HEAD(&nm_i->free_nid_list);
+	INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
+	INIT_LIST_HEAD(&nm_i->nat_entries);
+	INIT_LIST_HEAD(&nm_i->dirty_nat_entries);
+
+	mutex_init(&nm_i->build_lock);
+	spin_lock_init(&nm_i->free_nid_list_lock);
+	rwlock_init(&nm_i->nat_tree_lock);
+
+	nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
+	nm_i->init_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
+	nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
+
+	nm_i->nat_bitmap = kzalloc(nm_i->bitmap_size, GFP_KERNEL);
+	if (!nm_i->nat_bitmap)
+		return -ENOMEM;
+	version_bitmap = __bitmap_ptr(sbi, NAT_BITMAP);
+	if (!version_bitmap)
+		return -EFAULT;
+
+	/* copy version bitmap */
+	memcpy(nm_i->nat_bitmap, version_bitmap, nm_i->bitmap_size);
+	return 0;
+}
+
+int build_node_manager(struct f2fs_sb_info *sbi)
+{
+	int err;
+
+	sbi->nm_info = kzalloc(sizeof(struct f2fs_nm_info), GFP_KERNEL);
+	if (!sbi->nm_info)
+		return -ENOMEM;
+
+	err = init_node_manager(sbi);
+	if (err)
+		return err;
+
+	build_free_nids(sbi);
+	return 0;
+}
+
+void destroy_node_manager(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_nm_info *nm_i = NM_I(sbi);
+	struct free_nid *i, *next_i;
+	struct nat_entry *natvec[NATVEC_SIZE];
+	nid_t nid = 0;
+	unsigned int found;
+
+	if (!nm_i)
+		return;
+
+	/* destroy free nid list */
+	spin_lock(&nm_i->free_nid_list_lock);
+	list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
+		BUG_ON(i->state == NID_ALLOC);
+		__del_from_free_nid_list(i);
+		nm_i->fcnt--;
+	}
+	BUG_ON(nm_i->fcnt);
+	spin_unlock(&nm_i->free_nid_list_lock);
+
+	/* destroy nat cache */
+	write_lock(&nm_i->nat_tree_lock);
+	while ((found = __gang_lookup_nat_cache(nm_i,
+					nid, NATVEC_SIZE, natvec))) {
+		unsigned idx;
+		for (idx = 0; idx < found; idx++) {
+			struct nat_entry *e = natvec[idx];
+			nid = nat_get_nid(e) + 1;
+			__del_from_nat_cache(nm_i, e);
+		}
+	}
+	BUG_ON(nm_i->nat_cnt);
+	write_unlock(&nm_i->nat_tree_lock);
+
+	kfree(nm_i->nat_bitmap);
+	sbi->nm_info = NULL;
+	kfree(nm_i);
+}
+
+int create_node_manager_caches(void)
+{
+	nat_entry_slab = f2fs_kmem_cache_create("nat_entry",
+			sizeof(struct nat_entry), NULL);
+	if (!nat_entry_slab)
+		return -ENOMEM;
+
+	free_nid_slab = f2fs_kmem_cache_create("free_nid",
+			sizeof(struct free_nid), NULL);
+	if (!free_nid_slab) {
+		kmem_cache_destroy(nat_entry_slab);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void destroy_node_manager_caches(void)
+{
+	kmem_cache_destroy(free_nid_slab);
+	kmem_cache_destroy(nat_entry_slab);
+}