diff --git a/MAINTAINERS b/MAINTAINERS
index fa309ab7ccb..7a58a25a6e7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3273,6 +3273,16 @@ F:	Documentation/filesystems/caching/
 F:	fs/fscache/
 F:	include/linux/fscache*.h
 
+F2FS FILE SYSTEM
+M:	Jaegeuk Kim <jaegeuk.kim@samsung.com>
+L:	linux-f2fs-devel@lists.sourceforge.net
+W:	http://en.wikipedia.org/wiki/F2FS
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git
+S:	Maintained
+F:	Documentation/filesystems/f2fs.txt
+F:	fs/f2fs/
+F:	include/linux/f2fs_fs.h
+
 FUJITSU FR-V (FRV) PORT
 M:	David Howells <dhowells@redhat.com>
 S:	Maintained
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 655aeabc1dd..3aa5ce7cab8 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -16,6 +16,7 @@
 #include <linux/backing-dev.h>
 #include <linux/blkdev.h>
 #include <linux/bio.h>
+#include <linux/prefetch.h>
 
 #include "f2fs.h"
 #include "node.h"
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index b4e24f32b54..951ed52748f 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -11,6 +11,7 @@
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
 #include "f2fs.h"
+#include "node.h"
 #include "acl.h"
 
 static unsigned long dir_blocks(struct inode *inode)
@@ -74,7 +75,7 @@ static unsigned long dir_block_index(unsigned int level, unsigned int idx)
 	return bidx;
 }
 
-static bool early_match_name(const char *name, int namelen,
+static bool early_match_name(const char *name, size_t namelen,
 			f2fs_hash_t namehash, struct f2fs_dir_entry *de)
 {
 	if (le16_to_cpu(de->name_len) != namelen)
@@ -87,7 +88,7 @@ static bool early_match_name(const char *name, int namelen,
 }
 
 static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
-			const char *name, int namelen, int *max_slots,
+			const char *name, size_t namelen, int *max_slots,
 			f2fs_hash_t namehash, struct page **res_page)
 {
 	struct f2fs_dir_entry *de;
@@ -126,7 +127,7 @@ found:
 }
 
 static struct f2fs_dir_entry *find_in_level(struct inode *dir,
-		unsigned int level, const char *name, int namelen,
+		unsigned int level, const char *name, size_t namelen,
 			f2fs_hash_t namehash, struct page **res_page)
 {
 	int s = GET_DENTRY_SLOTS(namelen);
@@ -181,7 +182,7 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 			struct qstr *child, struct page **res_page)
 {
 	const char *name = child->name;
-	int namelen = child->len;
+	size_t namelen = child->len;
 	unsigned long npages = dir_blocks(dir);
 	struct f2fs_dir_entry *de = NULL;
 	f2fs_hash_t name_hash;
@@ -308,6 +309,7 @@ static int init_inode_metadata(struct inode *inode, struct dentry *dentry)
 		ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
 		if (IS_ERR(ipage))
 			return PTR_ERR(ipage);
+		set_cold_node(inode, ipage);
 		init_dent_inode(dentry, ipage);
 		f2fs_put_page(ipage, 1);
 	}
@@ -381,7 +383,7 @@ int f2fs_add_link(struct dentry *dentry, struct inode *inode)
 	struct inode *dir = dentry->d_parent->d_inode;
 	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
 	const char *name = dentry->d_name.name;
-	int namelen = dentry->d_name.len;
+	size_t namelen = dentry->d_name.len;
 	struct page *dentry_page = NULL;
 	struct f2fs_dentry_block *dentry_blk = NULL;
 	int slots = GET_DENTRY_SLOTS(namelen);
@@ -540,13 +542,13 @@ int f2fs_make_empty(struct inode *inode, struct inode *parent)
 
 	de = &dentry_blk->dentry[0];
 	de->name_len = cpu_to_le16(1);
-	de->hash_code = 0;
+	de->hash_code = f2fs_dentry_hash(".", 1);
 	de->ino = cpu_to_le32(inode->i_ino);
 	memcpy(dentry_blk->filename[0], ".", 1);
 	set_de_type(de, inode);
 
 	de = &dentry_blk->dentry[1];
-	de->hash_code = 0;
+	de->hash_code = f2fs_dentry_hash("..", 2);
 	de->name_len = cpu_to_le16(2);
 	de->ino = cpu_to_le32(parent->i_ino);
 	memcpy(dentry_blk->filename[1], "..", 2);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a18d63db2fb..13c6dfbb718 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -881,7 +881,7 @@ int f2fs_sync_fs(struct super_block *, int);
 /*
  * hash.c
  */
-f2fs_hash_t f2fs_dentry_hash(const char *, int);
+f2fs_hash_t f2fs_dentry_hash(const char *, size_t);
 
 /*
  * node.c
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f9e085dfb1f..7f9ea9271eb 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -160,15 +160,17 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	if (need_to_sync_dir(sbi, inode))
 		need_cp = true;
 
-	f2fs_write_inode(inode, NULL);
-
 	if (need_cp) {
 		/* all the dirty node pages should be flushed for POR */
 		ret = f2fs_sync_fs(inode->i_sb, 1);
 		clear_inode_flag(F2FS_I(inode), FI_NEED_CP);
 	} else {
-		while (sync_node_pages(sbi, inode->i_ino, &wbc) == 0)
-			f2fs_write_inode(inode, NULL);
+		/* if there is no written node page, write its inode page */
+		while (!sync_node_pages(sbi, inode->i_ino, &wbc)) {
+			ret = f2fs_write_inode(inode, NULL);
+			if (ret)
+				goto out;
+		}
 		filemap_fdatawait_range(sbi->node_inode->i_mapping,
 							0, LONG_MAX);
 	}
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 644aa380827..b0ec721e984 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -390,9 +390,7 @@ next_step:
 		}
 
 		err = check_valid_map(sbi, segno, off);
-		if (err == GC_ERROR)
-			return err;
-		else if (err == GC_NEXT)
+		if (err == GC_NEXT)
 			continue;
 
 		if (initial) {
@@ -430,28 +428,22 @@ next_step:
  */
 block_t start_bidx_of_node(unsigned int node_ofs)
 {
-	block_t start_bidx;
-	unsigned int bidx, indirect_blks;
-	int dec;
+	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
+	unsigned int bidx;
 
-	indirect_blks = 2 * NIDS_PER_BLOCK + 4;
+	if (node_ofs == 0)
+		return 0;
 
-	start_bidx = 1;
-	if (node_ofs == 0) {
-		start_bidx = 0;
-	} else if (node_ofs <= 2) {
+	if (node_ofs <= 2) {
 		bidx = node_ofs - 1;
 	} else if (node_ofs <= indirect_blks) {
-		dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
+		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 		bidx = node_ofs - 2 - dec;
 	} else {
-		dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
+		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 		bidx = node_ofs - 5 - dec;
 	}
-
-	if (start_bidx)
-		start_bidx = bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
-	return start_bidx;
+	return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
 }
 
 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
@@ -556,9 +548,7 @@ next_step:
 		}
 
 		err = check_valid_map(sbi, segno, off);
-		if (err == GC_ERROR)
-			goto stop;
-		else if (err == GC_NEXT)
+		if (err == GC_NEXT)
 			continue;
 
 		if (phase == 0) {
@@ -568,9 +558,7 @@ next_step:
 
 		/* Get an inode by ino with checking validity */
 		err = check_dnode(sbi, entry, &dni, start_addr + off, &nofs);
-		if (err == GC_ERROR)
-			goto stop;
-		else if (err == GC_NEXT)
+		if (err == GC_NEXT)
 			continue;
 
 		if (phase == 1) {
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index a60f04200f8..6eb8d269b53 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -42,7 +42,7 @@ static void TEA_transform(unsigned int buf[4], unsigned int const in[])
 	buf[1] += b1;
 }
 
-static void str2hashbuf(const char *msg, int len, unsigned int *buf, int num)
+static void str2hashbuf(const char *msg, size_t len, unsigned int *buf, int num)
 {
 	unsigned pad, val;
 	int i;
@@ -69,13 +69,17 @@ static void str2hashbuf(const char *msg, int len, unsigned int *buf, int num)
 		*buf++ = pad;
 }
 
-f2fs_hash_t f2fs_dentry_hash(const char *name, int len)
+f2fs_hash_t f2fs_dentry_hash(const char *name, size_t len)
 {
-	__u32 hash, minor_hash;
+	__u32 hash;
 	f2fs_hash_t f2fs_hash;
 	const char *p;
 	__u32 in[8], buf[4];
 
+	if ((len <= 2) && (name[0] == '.') &&
+		(name[1] == '.' || name[1] == '\0'))
+		return 0;
+
 	/* Initialize the default seed for the hash checksum functions */
 	buf[0] = 0x67452301;
 	buf[1] = 0xefcdab89;
@@ -83,15 +87,15 @@ f2fs_hash_t f2fs_dentry_hash(const char *name, int len)
 	buf[3] = 0x10325476;
 
 	p = name;
-	while (len > 0) {
+	while (1) {
 		str2hashbuf(p, len, in, 4);
 		TEA_transform(buf, in);
-		len -= 16;
 		p += 16;
+		if (len <= 16)
+			break;
+		len -= 16;
 	}
 	hash = buf[0];
-	minor_hash = buf[1];
-
 	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
 	return f2fs_hash;
 }
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index df5fb381ebf..bf20b4d0321 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -203,6 +203,7 @@ void update_inode(struct inode *inode, struct page *node_page)
 	ri->i_flags = cpu_to_le32(F2FS_I(inode)->i_flags);
 	ri->i_pino = cpu_to_le32(F2FS_I(inode)->i_pino);
 	ri->i_generation = cpu_to_le32(inode->i_generation);
+	set_cold_node(inode, node_page);
 	set_page_dirty(node_page);
 }
 
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 89b7675dc37..1a49b881bac 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -77,8 +77,8 @@ fail:
 
 static int is_multimedia_file(const unsigned char *s, const char *sub)
 {
-	int slen = strlen(s);
-	int sublen = strlen(sub);
+	size_t slen = strlen(s);
+	size_t sublen = strlen(sub);
 	int ret;
 
 	if (sublen > slen)
@@ -123,6 +123,8 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	nid_t ino = 0;
 	int err;
 
+	f2fs_balance_fs(sbi);
+
 	inode = f2fs_new_inode(dir, mode);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -144,8 +146,6 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	if (!sbi->por_doing)
 		d_instantiate(dentry, inode);
 	unlock_new_inode(inode);
-
-	f2fs_balance_fs(sbi);
 	return 0;
 out:
 	clear_nlink(inode);
@@ -163,6 +163,8 @@ static int f2fs_link(struct dentry *old_dentry, struct inode *dir,
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	int err;
 
+	f2fs_balance_fs(sbi);
+
 	inode->i_ctime = CURRENT_TIME;
 	atomic_inc(&inode->i_count);
 
@@ -172,8 +174,6 @@ static int f2fs_link(struct dentry *old_dentry, struct inode *dir,
 		goto out;
 
 	d_instantiate(dentry, inode);
-
-	f2fs_balance_fs(sbi);
 	return 0;
 out:
 	clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
@@ -223,6 +223,8 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 	struct page *page;
 	int err = -ENOENT;
 
+	f2fs_balance_fs(sbi);
+
 	de = f2fs_find_entry(dir, &dentry->d_name, &page);
 	if (!de)
 		goto fail;
@@ -238,7 +240,6 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 
 	/* In order to evict this inode,  we set it dirty */
 	mark_inode_dirty(inode);
-	f2fs_balance_fs(sbi);
 fail:
 	return err;
 }
@@ -249,9 +250,11 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 	struct super_block *sb = dir->i_sb;
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	struct inode *inode;
-	unsigned symlen = strlen(symname) + 1;
+	size_t symlen = strlen(symname) + 1;
 	int err;
 
+	f2fs_balance_fs(sbi);
+
 	inode = f2fs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -268,9 +271,6 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 
 	d_instantiate(dentry, inode);
 	unlock_new_inode(inode);
-
-	f2fs_balance_fs(sbi);
-
 	return err;
 out:
 	clear_nlink(inode);
@@ -286,6 +286,8 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	struct inode *inode;
 	int err;
 
+	f2fs_balance_fs(sbi);
+
 	inode = f2fs_new_inode(dir, S_IFDIR | mode);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -305,7 +307,6 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	d_instantiate(dentry, inode);
 	unlock_new_inode(inode);
 
-	f2fs_balance_fs(sbi);
 	return 0;
 
 out_fail:
@@ -336,6 +337,8 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry,
 	if (!new_valid_dev(rdev))
 		return -EINVAL;
 
+	f2fs_balance_fs(sbi);
+
 	inode = f2fs_new_inode(dir, mode);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -350,9 +353,6 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry,
 	alloc_nid_done(sbi, inode->i_ino);
 	d_instantiate(dentry, inode);
 	unlock_new_inode(inode);
-
-	f2fs_balance_fs(sbi);
-
 	return 0;
 out:
 	clear_nlink(inode);
@@ -376,6 +376,8 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	struct f2fs_dir_entry *new_entry;
 	int err = -ENOENT;
 
+	f2fs_balance_fs(sbi);
+
 	old_entry = f2fs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 	if (!old_entry)
 		goto out;
@@ -441,8 +443,6 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	}
 
 	mutex_unlock_op(sbi, RENAME);
-
-	f2fs_balance_fs(sbi);
 	return 0;
 
 out_dir:
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 19870361497..5066bfd256c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -484,12 +484,14 @@ static void truncate_node(struct dnode_of_data *dn)
 	struct node_info ni;
 
 	get_node_info(sbi, dn->nid, &ni);
+	if (dn->inode->i_blocks == 0) {
+		BUG_ON(ni.blk_addr != NULL_ADDR);
+		goto invalidate;
+	}
 	BUG_ON(ni.blk_addr == NULL_ADDR);
 
-	if (ni.blk_addr != NULL_ADDR)
-		invalidate_blocks(sbi, ni.blk_addr);
-
 	/* Deallocate node address */
+	invalidate_blocks(sbi, ni.blk_addr);
 	dec_valid_node_count(sbi, dn->inode, 1);
 	set_node_addr(sbi, &ni, NULL_ADDR);
 
@@ -499,7 +501,7 @@ static void truncate_node(struct dnode_of_data *dn)
 	} else {
 		sync_inode_page(dn);
 	}
-
+invalidate:
 	clear_node_page_dirty(dn->node_page);
 	F2FS_SET_SB_DIRT(sbi);
 
@@ -768,20 +770,12 @@ int remove_inode_page(struct inode *inode)
 		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();
-	}
+	/* 0 is possible, after f2fs_new_inode() is failed */
+	BUG_ON(inode->i_blocks != 0 && inode->i_blocks != 1);
+	set_new_dnode(&dn, inode, page, page, ino);
+	truncate_node(&dn);
+
 	mutex_unlock_op(sbi, NODE_TRUNC);
 	return 0;
 }
@@ -834,17 +828,18 @@ struct page *new_node_page(struct dnode_of_data *dn, unsigned int ofs)
 		goto fail;
 	}
 	set_node_addr(sbi, &new_ni, NEW_ADDR);
+	set_cold_node(dn->inode, page);
 
 	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:
+	clear_node_page_dirty(page);
 	f2fs_put_page(page, 1);
 	return ERR_PTR(err);
 }
@@ -1093,7 +1088,6 @@ static int f2fs_write_node_page(struct page *page,
 {
 	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;
 
@@ -1110,7 +1104,6 @@ static int f2fs_write_node_page(struct page *page,
 
 	/* 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);
@@ -1571,7 +1564,7 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
 		nid_t nid;
 		struct f2fs_nat_entry raw_ne;
 		int offset = -1;
-		block_t old_blkaddr, new_blkaddr;
+		block_t new_blkaddr;
 
 		ne = list_entry(cur, struct nat_entry, list);
 		nid = nat_get_nid(ne);
@@ -1585,7 +1578,6 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
 		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:
@@ -1607,7 +1599,6 @@ to_nat_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);
 
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index b07e9b6ef37..b571fee677d 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -144,14 +144,15 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
 				goto out;
 			}
 
-			INIT_LIST_HEAD(&entry->list);
-			list_add_tail(&entry->list, head);
-
 			entry->inode = f2fs_iget(sbi->sb, ino_of_node(page));
 			if (IS_ERR(entry->inode)) {
 				err = PTR_ERR(entry->inode);
+				kmem_cache_free(fsync_entry_slab, entry);
 				goto out;
 			}
+
+			INIT_LIST_HEAD(&entry->list);
+			list_add_tail(&entry->list, head);
 			entry->blkaddr = blkaddr;
 		}
 		if (IS_INODE(page)) {
@@ -228,6 +229,9 @@ static void check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
 
 	/* Deallocate previous index in the node page */
 	inode = f2fs_iget_nowait(sbi->sb, ino);
+	if (IS_ERR(inode))
+		return;
+
 	truncate_hole(inode, bidx, bidx + 1);
 	iput(inode);
 }
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1b26e4ea101..de6240922b0 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -12,54 +12,23 @@
 #include <linux/f2fs_fs.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/prefetch.h>
 #include <linux/vmalloc.h>
 
 #include "f2fs.h"
 #include "segment.h"
 #include "node.h"
 
-static int need_to_flush(struct f2fs_sb_info *sbi)
-{
-	unsigned int pages_per_sec = (1 << sbi->log_blocks_per_seg) *
-			sbi->segs_per_sec;
-	int node_secs = ((get_pages(sbi, F2FS_DIRTY_NODES) + pages_per_sec - 1)
-		>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
-	int dent_secs = ((get_pages(sbi, F2FS_DIRTY_DENTS) + pages_per_sec - 1)
-		>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
-
-	if (sbi->por_doing)
-		return 0;
-
-	if (free_sections(sbi) <= (node_secs + 2 * dent_secs +
-						reserved_sections(sbi)))
-		return 1;
-	return 0;
-}
-
 /*
  * This function balances dirty node and dentry pages.
  * In addition, it controls garbage collection.
  */
 void f2fs_balance_fs(struct f2fs_sb_info *sbi)
 {
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-		.nr_to_write = LONG_MAX,
-		.for_reclaim = 0,
-	};
-
-	if (sbi->por_doing)
-		return;
-
 	/*
-	 * We should do checkpoint when there are so many dirty node pages
-	 * with enough free segments. After then, we should do GC.
+	 * We should do GC or end up with checkpoint, if there are so many dirty
+	 * dir/node pages without enough free segments.
 	 */
-	if (need_to_flush(sbi)) {
-		sync_dirty_dir_inodes(sbi);
-		sync_node_pages(sbi, 0, &wbc);
-	}
-
 	if (has_not_enough_free_secs(sbi)) {
 		mutex_lock(&sbi->gc_mutex);
 		f2fs_gc(sbi, 1);
@@ -631,7 +600,6 @@ static void f2fs_end_io_write(struct bio *bio, int err)
 			if (page->mapping)
 				set_bit(AS_EIO, &page->mapping->flags);
 			set_ckpt_flags(p->sbi->ckpt, CP_ERROR_FLAG);
-			set_page_dirty(page);
 		}
 		end_page_writeback(page);
 		dec_page_count(p->sbi, F2FS_WRITEBACK);
@@ -791,11 +759,10 @@ static int __get_segment_type(struct page *page, enum page_type p_type)
 		return __get_segment_type_2(page, p_type);
 	case 4:
 		return __get_segment_type_4(page, p_type);
-	case 6:
-		return __get_segment_type_6(page, p_type);
-	default:
-		BUG();
 	}
+	/* NR_CURSEG_TYPE(6) logs by default */
+	BUG_ON(sbi->active_logs != NR_CURSEG_TYPE);
+	return __get_segment_type_6(page, p_type);
 }
 
 static void do_write_page(struct f2fs_sb_info *sbi, struct page *page,
@@ -1608,7 +1575,6 @@ static int build_dirty_segmap(struct f2fs_sb_info *sbi)
 
 	for (i = 0; i < NR_DIRTY_TYPE; i++) {
 		dirty_i->dirty_segmap[i] = kzalloc(bitmap_size, GFP_KERNEL);
-		dirty_i->nr_dirty[i] = 0;
 		if (!dirty_i->dirty_segmap[i])
 			return -ENOMEM;
 	}
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 0948405af6f..66a288a52fd 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -459,7 +459,20 @@ static inline int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
 
 static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi)
 {
-	return free_sections(sbi) <= reserved_sections(sbi);
+	unsigned int pages_per_sec = (1 << sbi->log_blocks_per_seg) *
+			sbi->segs_per_sec;
+	int node_secs = ((get_pages(sbi, F2FS_DIRTY_NODES) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+	int dent_secs = ((get_pages(sbi, F2FS_DIRTY_DENTS) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+
+	if (sbi->por_doing)
+		return false;
+
+	if (free_sections(sbi) <= (node_secs + 2 * dent_secs +
+						reserved_sections(sbi)))
+		return true;
+	return false;
 }
 
 static inline int utilization(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 13867322cf5..08a94c814bd 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -119,7 +119,6 @@ static void f2fs_put_super(struct super_block *sb)
 int f2fs_sync_fs(struct super_block *sb, int sync)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
-	int ret = 0;
 
 	if (!sbi->s_dirty && !get_pages(sbi, F2FS_DIRTY_NODES))
 		return 0;
@@ -127,7 +126,7 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
 	if (sync)
 		write_checkpoint(sbi, false, false);
 
-	return ret;
+	return 0;
 }
 
 static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
@@ -148,8 +147,8 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_bfree = buf->f_blocks - valid_user_blocks(sbi) - ovp_count;
 	buf->f_bavail = user_block_count - valid_user_blocks(sbi);
 
-	buf->f_files = valid_inode_count(sbi);
-	buf->f_ffree = sbi->total_node_count - valid_node_count(sbi);
+	buf->f_files = sbi->total_node_count;
+	buf->f_ffree = sbi->total_node_count - valid_inode_count(sbi);
 
 	buf->f_namelen = F2FS_MAX_NAME_LEN;
 	buf->f_fsid.val[0] = (u32)id;
@@ -302,7 +301,7 @@ static int parse_options(struct f2fs_sb_info *sbi, char *options)
 		case Opt_active_logs:
 			if (args->from && match_int(args, &arg))
 				return -EINVAL;
-			if (arg != 2 && arg != 4 && arg != 6)
+			if (arg != 2 && arg != 4 && arg != NR_CURSEG_TYPE)
 				return -EINVAL;
 			sbi->active_logs = arg;
 			break;
@@ -528,8 +527,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* if there are nt orphan nodes free them */
 	err = -EINVAL;
-	if (!is_set_ckpt_flags(F2FS_CKPT(sbi), CP_UMOUNT_FLAG) &&
-				recover_orphan_inodes(sbi))
+	if (recover_orphan_inodes(sbi))
 		goto free_node_inode;
 
 	/* read root inode and dentry */
@@ -548,8 +546,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* recover fsynced data */
-	if (!is_set_ckpt_flags(F2FS_CKPT(sbi), CP_UMOUNT_FLAG) &&
-				!test_opt(sbi, DISABLE_ROLL_FORWARD))
+	if (!test_opt(sbi, DISABLE_ROLL_FORWARD))
 		recover_fsync_data(sbi);
 
 	/* After POR, we can run background GC thread */
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 7d52e8dc0c5..940136a3d3a 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -208,7 +208,7 @@ int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
 	struct page *page;
 	void *base_addr;
 	int error = 0, found = 0;
-	int value_len, name_len;
+	size_t value_len, name_len;
 
 	if (name == NULL)
 		return -EINVAL;
@@ -304,7 +304,8 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
 	struct f2fs_xattr_entry *here, *last;
 	struct page *page;
 	void *base_addr;
-	int error, found, free, name_len, newsize;
+	int error, found, free, newsize;
+	size_t name_len;
 	char *pval;
 
 	if (name == NULL)