fs/f2fs/node.h - SHIFTPHONES/mainline/linux - Gitiles

 /*
  * fs/f2fs/node.h
  *
  * 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.
  */
 /* start node id of a node block dedicated to the given node id */
 #define	START_NID(nid) ((nid / NAT_ENTRY_PER_BLOCK) * NAT_ENTRY_PER_BLOCK)

 /* node block offset on the NAT area dedicated to the given start node id */
 #define	NAT_BLOCK_OFFSET(start_nid) (start_nid / NAT_ENTRY_PER_BLOCK)

 /* # of pages to perform synchronous readahead before building free nids */
 #define FREE_NID_PAGES	8
 #define MAX_FREE_NIDS	(NAT_ENTRY_PER_BLOCK * FREE_NID_PAGES)

 #define DEF_RA_NID_PAGES	0	/* # of nid pages to be readaheaded */

 /* maximum readahead size for node during getting data blocks */
 #define MAX_RA_NODE		128

 /* control the memory footprint threshold (10MB per 1GB ram) */
 #define DEF_RAM_THRESHOLD	1

 /* control dirty nats ratio threshold (default: 10% over max nid count) */
 #define DEF_DIRTY_NAT_RATIO_THRESHOLD		10
 /* control total # of nats */
 #define DEF_NAT_CACHE_THRESHOLD			100000

 /* vector size for gang look-up from nat cache that consists of radix tree */
 #define NATVEC_SIZE	64
 #define SETVEC_SIZE	32

 /* return value for read_node_page */
 #define LOCKED_PAGE	1

 /* For flag in struct node_info */
 enum {
 	IS_CHECKPOINTED,	/* is it checkpointed before? */
 	HAS_FSYNCED_INODE,	/* is the inode fsynced before? */
 	HAS_LAST_FSYNC,		/* has the latest node fsync mark? */
 	IS_DIRTY,		/* this nat entry is dirty? */
 };

 /*
  * For node information
  */
 struct node_info {
 	nid_t nid;		/* node id */
 	nid_t ino;		/* inode number of the node's owner */
 	block_t	blk_addr;	/* block address of the node */
 	unsigned char version;	/* version of the node */
 	unsigned char flag;	/* for node information bits */
 };

 struct nat_entry {
 	struct list_head list;	/* for clean or dirty nat list */
 	struct node_info ni;	/* in-memory node information */
 };

 #define nat_get_nid(nat)		(nat->ni.nid)
 #define nat_set_nid(nat, n)		(nat->ni.nid = n)
 #define nat_get_blkaddr(nat)		(nat->ni.blk_addr)
 #define nat_set_blkaddr(nat, b)		(nat->ni.blk_addr = b)
 #define nat_get_ino(nat)		(nat->ni.ino)
 #define nat_set_ino(nat, i)		(nat->ni.ino = i)
 #define nat_get_version(nat)		(nat->ni.version)
 #define nat_set_version(nat, v)		(nat->ni.version = v)

 #define inc_node_version(version)	(++version)

 static inline void copy_node_info(struct node_info *dst,
 						struct node_info *src)
 {
 	dst->nid = src->nid;
 	dst->ino = src->ino;
 	dst->blk_addr = src->blk_addr;
 	dst->version = src->version;
 	/* should not copy flag here */
 }

 static inline void set_nat_flag(struct nat_entry *ne,
 				unsigned int type, bool set)
 {
 	unsigned char mask = 0x01 << type;
 	if (set)
 		ne->ni.flag |= mask;
 	else
 		ne->ni.flag &= ~mask;
 }

 static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
 {
 	unsigned char mask = 0x01 << type;
 	return ne->ni.flag & mask;
 }

 static inline void nat_reset_flag(struct nat_entry *ne)
 {
 	/* these states can be set only after checkpoint was done */
 	set_nat_flag(ne, IS_CHECKPOINTED, true);
 	set_nat_flag(ne, HAS_FSYNCED_INODE, false);
 	set_nat_flag(ne, HAS_LAST_FSYNC, true);
 }

 static inline void node_info_from_raw_nat(struct node_info *ni,
 						struct f2fs_nat_entry *raw_ne)
 {
 	ni->ino = le32_to_cpu(raw_ne->ino);
 	ni->blk_addr = le32_to_cpu(raw_ne->block_addr);
 	ni->version = raw_ne->version;
 }

 static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne,
 						struct node_info *ni)
 {
 	raw_ne->ino = cpu_to_le32(ni->ino);
 	raw_ne->block_addr = cpu_to_le32(ni->blk_addr);
 	raw_ne->version = ni->version;
 }

 static inline bool excess_dirty_nats(struct f2fs_sb_info *sbi)
 {
 	return NM_I(sbi)->dirty_nat_cnt >= NM_I(sbi)->max_nid *
 					NM_I(sbi)->dirty_nats_ratio / 100;
 }

 static inline bool excess_cached_nats(struct f2fs_sb_info *sbi)
 {
 	return NM_I(sbi)->nat_cnt >= DEF_NAT_CACHE_THRESHOLD;
 }

 enum mem_type {
 	FREE_NIDS,	/* indicates the free nid list */
 	NAT_ENTRIES,	/* indicates the cached nat entry */
 	DIRTY_DENTS,	/* indicates dirty dentry pages */
 	INO_ENTRIES,	/* indicates inode entries */
 	EXTENT_CACHE,	/* indicates extent cache */
 	BASE_CHECK,	/* check kernel status */
 };

 struct nat_entry_set {
 	struct list_head set_list;	/* link with other nat sets */
 	struct list_head entry_list;	/* link with dirty nat entries */
 	nid_t set;			/* set number*/
 	unsigned int entry_cnt;		/* the # of nat entries in set */
 };

 /*
  * For free nid mangement
  */
 enum nid_state {
 	NID_NEW,	/* newly added to free nid list */
 	NID_ALLOC	/* it is allocated */
 };

 struct free_nid {
 	struct list_head list;	/* for free node id list */
 	nid_t nid;		/* node id */
 	int state;		/* in use or not: NID_NEW or NID_ALLOC */
 };

 static inline void next_free_nid(struct f2fs_sb_info *sbi, nid_t *nid)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct free_nid *fnid;

 	spin_lock(&nm_i->nid_list_lock);
 	if (nm_i->nid_cnt[FREE_NID_LIST] <= 0) {
 		spin_unlock(&nm_i->nid_list_lock);
 		return;
 	}
 	fnid = list_first_entry(&nm_i->nid_list[FREE_NID_LIST],
 						struct free_nid, list);
 	*nid = fnid->nid;
 	spin_unlock(&nm_i->nid_list_lock);
 }

 /*
  * inline functions
  */
 static inline void get_nat_bitmap(struct f2fs_sb_info *sbi, void *addr)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);

 #ifdef CONFIG_F2FS_CHECK_FS
 	if (memcmp(nm_i->nat_bitmap, nm_i->nat_bitmap_mir,
 						nm_i->bitmap_size))
 		f2fs_bug_on(sbi, 1);
 #endif
 	memcpy(addr, nm_i->nat_bitmap, nm_i->bitmap_size);
 }

 static inline pgoff_t current_nat_addr(struct f2fs_sb_info *sbi, nid_t start)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	pgoff_t block_off;
 	pgoff_t block_addr;
 	int seg_off;

 	block_off = NAT_BLOCK_OFFSET(start);
 	seg_off = block_off >> sbi->log_blocks_per_seg;

 	block_addr = (pgoff_t)(nm_i->nat_blkaddr +
 		(seg_off << sbi->log_blocks_per_seg << 1) +
 		(block_off & (sbi->blocks_per_seg - 1)));

 #ifdef CONFIG_F2FS_CHECK_FS
 	if (f2fs_test_bit(block_off, nm_i->nat_bitmap) !=
 			f2fs_test_bit(block_off, nm_i->nat_bitmap_mir))
 		f2fs_bug_on(sbi, 1);
 #endif

 	if (f2fs_test_bit(block_off, nm_i->nat_bitmap))
 		block_addr += sbi->blocks_per_seg;

 	return block_addr;
 }

 static inline pgoff_t next_nat_addr(struct f2fs_sb_info *sbi,
 						pgoff_t block_addr)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);

 	block_addr -= nm_i->nat_blkaddr;
 	if ((block_addr >> sbi->log_blocks_per_seg) % 2)
 		block_addr -= sbi->blocks_per_seg;
 	else
 		block_addr += sbi->blocks_per_seg;

 	return block_addr + nm_i->nat_blkaddr;
 }

 static inline void set_to_next_nat(struct f2fs_nm_info *nm_i, nid_t start_nid)
 {
 	unsigned int block_off = NAT_BLOCK_OFFSET(start_nid);

 	f2fs_change_bit(block_off, nm_i->nat_bitmap);
 #ifdef CONFIG_F2FS_CHECK_FS
 	f2fs_change_bit(block_off, nm_i->nat_bitmap_mir);
 #endif
 }

 static inline nid_t ino_of_node(struct page *node_page)
 {
 	struct f2fs_node *rn = F2FS_NODE(node_page);
 	return le32_to_cpu(rn->footer.ino);
 }

 static inline nid_t nid_of_node(struct page *node_page)
 {
 	struct f2fs_node *rn = F2FS_NODE(node_page);
 	return le32_to_cpu(rn->footer.nid);
 }

 static inline unsigned int ofs_of_node(struct page *node_page)
 {
 	struct f2fs_node *rn = F2FS_NODE(node_page);
 	unsigned flag = le32_to_cpu(rn->footer.flag);
 	return flag >> OFFSET_BIT_SHIFT;
 }

 static inline __u64 cpver_of_node(struct page *node_page)
 {
 	struct f2fs_node *rn = F2FS_NODE(node_page);
 	return le64_to_cpu(rn->footer.cp_ver);
 }

 static inline block_t next_blkaddr_of_node(struct page *node_page)
 {
 	struct f2fs_node *rn = F2FS_NODE(node_page);
 	return le32_to_cpu(rn->footer.next_blkaddr);
 }

 static inline void fill_node_footer(struct page *page, nid_t nid,
 				nid_t ino, unsigned int ofs, bool reset)
 {
 	struct f2fs_node *rn = F2FS_NODE(page);
 	unsigned int old_flag = 0;

 	if (reset)
 		memset(rn, 0, sizeof(*rn));
 	else
 		old_flag = le32_to_cpu(rn->footer.flag);

 	rn->footer.nid = cpu_to_le32(nid);
 	rn->footer.ino = cpu_to_le32(ino);

 	/* should remain old flag bits such as COLD_BIT_SHIFT */
 	rn->footer.flag = cpu_to_le32((ofs << OFFSET_BIT_SHIFT) |
 					(old_flag & OFFSET_BIT_MASK));
 }

 static inline void copy_node_footer(struct page *dst, struct page *src)
 {
 	struct f2fs_node *src_rn = F2FS_NODE(src);
 	struct f2fs_node *dst_rn = F2FS_NODE(dst);
 	memcpy(&dst_rn->footer, &src_rn->footer, sizeof(struct node_footer));
 }

 static inline void fill_node_footer_blkaddr(struct page *page, block_t blkaddr)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
 	struct f2fs_node *rn = F2FS_NODE(page);
 	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
 	__u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);

 	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
 		__u64 crc = le32_to_cpu(*((__le32 *)
 				((unsigned char *)ckpt + crc_offset)));
 		cp_ver |= (crc << 32);
 	}
 	rn->footer.cp_ver = cpu_to_le64(cp_ver);
 	rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
 }

 static inline bool is_recoverable_dnode(struct page *page)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
 	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
 	__u64 cp_ver = cur_cp_version(ckpt);

 	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
 		__u64 crc = le32_to_cpu(*((__le32 *)
 				((unsigned char *)ckpt + crc_offset)));
 		cp_ver |= (crc << 32);
 	}
 	return cp_ver == cpver_of_node(page);
 }

 /*
  * f2fs assigns the following node offsets described as (num).
  * N = NIDS_PER_BLOCK
  *
  *  Inode block (0)
  *    |- direct node (1)
  *    |- direct node (2)
  *    |- indirect node (3)
  *    |            `- direct node (4 => 4 + N - 1)
  *    |- indirect node (4 + N)
  *    |            `- direct node (5 + N => 5 + 2N - 1)
  *    `- double indirect node (5 + 2N)
  *                 `- indirect node (6 + 2N)
  *                       `- direct node
  *                 ......
  *                 `- indirect node ((6 + 2N) + x(N + 1))
  *                       `- direct node
  *                 ......
  *                 `- indirect node ((6 + 2N) + (N - 1)(N + 1))
  *                       `- direct node
  */
 static inline bool IS_DNODE(struct page *node_page)
 {
 	unsigned int ofs = ofs_of_node(node_page);

 	if (f2fs_has_xattr_block(ofs))
 		return false;

 	if (ofs == 3 || ofs == 4 + NIDS_PER_BLOCK ||
 			ofs == 5 + 2 * NIDS_PER_BLOCK)
 		return false;
 	if (ofs >= 6 + 2 * NIDS_PER_BLOCK) {
 		ofs -= 6 + 2 * NIDS_PER_BLOCK;
 		if (!((long int)ofs % (NIDS_PER_BLOCK + 1)))
 			return false;
 	}
 	return true;
 }

 static inline int set_nid(struct page *p, int off, nid_t nid, bool i)
 {
 	struct f2fs_node *rn = F2FS_NODE(p);

 	f2fs_wait_on_page_writeback(p, NODE, true);

 	if (i)
 		rn->i.i_nid[off - NODE_DIR1_BLOCK] = cpu_to_le32(nid);
 	else
 		rn->in.nid[off] = cpu_to_le32(nid);
 	return set_page_dirty(p);
 }

 static inline nid_t get_nid(struct page *p, int off, bool i)
 {
 	struct f2fs_node *rn = F2FS_NODE(p);

 	if (i)
 		return le32_to_cpu(rn->i.i_nid[off - NODE_DIR1_BLOCK]);
 	return le32_to_cpu(rn->in.nid[off]);
 }

 /*
  * Coldness identification:
  *  - Mark cold files in f2fs_inode_info
  *  - Mark cold node blocks in their node footer
  *  - Mark cold data pages in page cache
  */
 static inline int is_cold_data(struct page *page)
 {
 	return PageChecked(page);
 }

 static inline void set_cold_data(struct page *page)
 {
 	SetPageChecked(page);
 }

 static inline void clear_cold_data(struct page *page)
 {
 	ClearPageChecked(page);
 }

 static inline int is_node(struct page *page, int type)
 {
 	struct f2fs_node *rn = F2FS_NODE(page);
 	return le32_to_cpu(rn->footer.flag) & (1 << type);
 }

 #define is_cold_node(page)	is_node(page, COLD_BIT_SHIFT)
 #define is_fsync_dnode(page)	is_node(page, FSYNC_BIT_SHIFT)
 #define is_dent_dnode(page)	is_node(page, DENT_BIT_SHIFT)

 static inline int is_inline_node(struct page *page)
 {
 	return PageChecked(page);
 }

 static inline void set_inline_node(struct page *page)
 {
 	SetPageChecked(page);
 }

 static inline void clear_inline_node(struct page *page)
 {
 	ClearPageChecked(page);
 }

 static inline void set_cold_node(struct inode *inode, struct page *page)
 {
 	struct f2fs_node *rn = F2FS_NODE(page);
 	unsigned int flag = le32_to_cpu(rn->footer.flag);

 	if (S_ISDIR(inode->i_mode))
 		flag &= ~(0x1 << COLD_BIT_SHIFT);
 	else
 		flag |= (0x1 << COLD_BIT_SHIFT);
 	rn->footer.flag = cpu_to_le32(flag);
 }

 static inline void set_mark(struct page *page, int mark, int type)
 {
 	struct f2fs_node *rn = F2FS_NODE(page);
 	unsigned int flag = le32_to_cpu(rn->footer.flag);
 	if (mark)
 		flag |= (0x1 << type);
 	else
 		flag &= ~(0x1 << type);
 	rn->footer.flag = cpu_to_le32(flag);
 }
 #define set_dentry_mark(page, mark)	set_mark(page, mark, DENT_BIT_SHIFT)
 #define set_fsync_mark(page, mark)	set_mark(page, mark, FSYNC_BIT_SHIFT)
	/*
	* fs/f2fs/node.h
	*
	* 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.
	*/
	/* start node id of a node block dedicated to the given node id */
	#define START_NID(nid) ((nid / NAT_ENTRY_PER_BLOCK) * NAT_ENTRY_PER_BLOCK)

	/* node block offset on the NAT area dedicated to the given start node id */
	#define NAT_BLOCK_OFFSET(start_nid) (start_nid / NAT_ENTRY_PER_BLOCK)

	/* # of pages to perform synchronous readahead before building free nids */
	#define FREE_NID_PAGES 8
	#define MAX_FREE_NIDS (NAT_ENTRY_PER_BLOCK * FREE_NID_PAGES)

	#define DEF_RA_NID_PAGES 0 /* # of nid pages to be readaheaded */

	/* maximum readahead size for node during getting data blocks */
	#define MAX_RA_NODE 128

	/* control the memory footprint threshold (10MB per 1GB ram) */
	#define DEF_RAM_THRESHOLD 1

	/* control dirty nats ratio threshold (default: 10% over max nid count) */
	#define DEF_DIRTY_NAT_RATIO_THRESHOLD 10
	/* control total # of nats */
	#define DEF_NAT_CACHE_THRESHOLD 100000

	/* vector size for gang look-up from nat cache that consists of radix tree */
	#define NATVEC_SIZE 64
	#define SETVEC_SIZE 32

	/* return value for read_node_page */
	#define LOCKED_PAGE 1

	/* For flag in struct node_info */
	enum {
	IS_CHECKPOINTED, /* is it checkpointed before? */
	HAS_FSYNCED_INODE, /* is the inode fsynced before? */
	HAS_LAST_FSYNC, /* has the latest node fsync mark? */
	IS_DIRTY, /* this nat entry is dirty? */
	};

	/*
	* For node information
	*/
	struct node_info {
	nid_t nid; /* node id */
	nid_t ino; /* inode number of the node's owner */
	block_t blk_addr; /* block address of the node */
	unsigned char version; /* version of the node */
	unsigned char flag; /* for node information bits */
	};

	struct nat_entry {
	struct list_head list; /* for clean or dirty nat list */
	struct node_info ni; /* in-memory node information */
	};

	#define nat_get_nid(nat) (nat->ni.nid)
	#define nat_set_nid(nat, n) (nat->ni.nid = n)
	#define nat_get_blkaddr(nat) (nat->ni.blk_addr)
	#define nat_set_blkaddr(nat, b) (nat->ni.blk_addr = b)
	#define nat_get_ino(nat) (nat->ni.ino)
	#define nat_set_ino(nat, i) (nat->ni.ino = i)
	#define nat_get_version(nat) (nat->ni.version)
	#define nat_set_version(nat, v) (nat->ni.version = v)

	#define inc_node_version(version) (++version)

	static inline void copy_node_info(struct node_info *dst,
	struct node_info *src)
	{
	dst->nid = src->nid;
	dst->ino = src->ino;
	dst->blk_addr = src->blk_addr;
	dst->version = src->version;
	/* should not copy flag here */
	}

	static inline void set_nat_flag(struct nat_entry *ne,
	unsigned int type, bool set)
	{
	unsigned char mask = 0x01 << type;
	if (set)
	ne->ni.flag \|= mask;
	else
	ne->ni.flag &= ~mask;
	}

	static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
	{
	unsigned char mask = 0x01 << type;
	return ne->ni.flag & mask;
	}

	static inline void nat_reset_flag(struct nat_entry *ne)
	{
	/* these states can be set only after checkpoint was done */
	set_nat_flag(ne, IS_CHECKPOINTED, true);
	set_nat_flag(ne, HAS_FSYNCED_INODE, false);
	set_nat_flag(ne, HAS_LAST_FSYNC, true);
	}

	static inline void node_info_from_raw_nat(struct node_info *ni,
	struct f2fs_nat_entry *raw_ne)
	{
	ni->ino = le32_to_cpu(raw_ne->ino);
	ni->blk_addr = le32_to_cpu(raw_ne->block_addr);
	ni->version = raw_ne->version;
	}

	static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne,
	struct node_info *ni)
	{
	raw_ne->ino = cpu_to_le32(ni->ino);
	raw_ne->block_addr = cpu_to_le32(ni->blk_addr);
	raw_ne->version = ni->version;
	}

	static inline bool excess_dirty_nats(struct f2fs_sb_info *sbi)
	{
	return NM_I(sbi)->dirty_nat_cnt >= NM_I(sbi)->max_nid *
	NM_I(sbi)->dirty_nats_ratio / 100;
	}

	static inline bool excess_cached_nats(struct f2fs_sb_info *sbi)
	{
	return NM_I(sbi)->nat_cnt >= DEF_NAT_CACHE_THRESHOLD;
	}

	enum mem_type {
	FREE_NIDS, /* indicates the free nid list */
	NAT_ENTRIES, /* indicates the cached nat entry */
	DIRTY_DENTS, /* indicates dirty dentry pages */
	INO_ENTRIES, /* indicates inode entries */
	EXTENT_CACHE, /* indicates extent cache */
	BASE_CHECK, /* check kernel status */
	};

	struct nat_entry_set {
	struct list_head set_list; /* link with other nat sets */
	struct list_head entry_list; /* link with dirty nat entries */
	nid_t set; /* set number*/
	unsigned int entry_cnt; /* the # of nat entries in set */
	};

	/*
	* For free nid mangement
	*/
	enum nid_state {
	NID_NEW, /* newly added to free nid list */
	NID_ALLOC /* it is allocated */
	};

	struct free_nid {
	struct list_head list; /* for free node id list */
	nid_t nid; /* node id */
	int state; /* in use or not: NID_NEW or NID_ALLOC */
	};

	static inline void next_free_nid(struct f2fs_sb_info sbi, nid_t nid)
	{
	struct f2fs_nm_info *nm_i = NM_I(sbi);
	struct free_nid *fnid;

	spin_lock(&nm_i->nid_list_lock);
	if (nm_i->nid_cnt[FREE_NID_LIST] <= 0) {
	spin_unlock(&nm_i->nid_list_lock);
	return;
	}
	fnid = list_first_entry(&nm_i->nid_list[FREE_NID_LIST],
	struct free_nid, list);
	*nid = fnid->nid;
	spin_unlock(&nm_i->nid_list_lock);
	}

	/*
	* inline functions
	*/
	static inline void get_nat_bitmap(struct f2fs_sb_info sbi, void addr)
	{
	struct f2fs_nm_info *nm_i = NM_I(sbi);

	#ifdef CONFIG_F2FS_CHECK_FS
	if (memcmp(nm_i->nat_bitmap, nm_i->nat_bitmap_mir,
	nm_i->bitmap_size))
	f2fs_bug_on(sbi, 1);
	#endif
	memcpy(addr, nm_i->nat_bitmap, nm_i->bitmap_size);
	}

	static inline pgoff_t current_nat_addr(struct f2fs_sb_info *sbi, nid_t start)
	{
	struct f2fs_nm_info *nm_i = NM_I(sbi);
	pgoff_t block_off;
	pgoff_t block_addr;
	int seg_off;

	block_off = NAT_BLOCK_OFFSET(start);
	seg_off = block_off >> sbi->log_blocks_per_seg;

	block_addr = (pgoff_t)(nm_i->nat_blkaddr +
	(seg_off << sbi->log_blocks_per_seg << 1) +
	(block_off & (sbi->blocks_per_seg - 1)));

	#ifdef CONFIG_F2FS_CHECK_FS
	if (f2fs_test_bit(block_off, nm_i->nat_bitmap) !=
	f2fs_test_bit(block_off, nm_i->nat_bitmap_mir))
	f2fs_bug_on(sbi, 1);
	#endif

	if (f2fs_test_bit(block_off, nm_i->nat_bitmap))
	block_addr += sbi->blocks_per_seg;

	return block_addr;
	}

	static inline pgoff_t next_nat_addr(struct f2fs_sb_info *sbi,
	pgoff_t block_addr)
	{
	struct f2fs_nm_info *nm_i = NM_I(sbi);

	block_addr -= nm_i->nat_blkaddr;
	if ((block_addr >> sbi->log_blocks_per_seg) % 2)
	block_addr -= sbi->blocks_per_seg;
	else
	block_addr += sbi->blocks_per_seg;

	return block_addr + nm_i->nat_blkaddr;
	}

	static inline void set_to_next_nat(struct f2fs_nm_info *nm_i, nid_t start_nid)
	{
	unsigned int block_off = NAT_BLOCK_OFFSET(start_nid);

	f2fs_change_bit(block_off, nm_i->nat_bitmap);
	#ifdef CONFIG_F2FS_CHECK_FS
	f2fs_change_bit(block_off, nm_i->nat_bitmap_mir);
	#endif
	}

	static inline nid_t ino_of_node(struct page *node_page)
	{
	struct f2fs_node *rn = F2FS_NODE(node_page);
	return le32_to_cpu(rn->footer.ino);
	}

	static inline nid_t nid_of_node(struct page *node_page)
	{
	struct f2fs_node *rn = F2FS_NODE(node_page);
	return le32_to_cpu(rn->footer.nid);
	}

	static inline unsigned int ofs_of_node(struct page *node_page)
	{
	struct f2fs_node *rn = F2FS_NODE(node_page);
	unsigned flag = le32_to_cpu(rn->footer.flag);
	return flag >> OFFSET_BIT_SHIFT;
	}

	static inline __u64 cpver_of_node(struct page *node_page)
	{
	struct f2fs_node *rn = F2FS_NODE(node_page);
	return le64_to_cpu(rn->footer.cp_ver);
	}

	static inline block_t next_blkaddr_of_node(struct page *node_page)
	{
	struct f2fs_node *rn = F2FS_NODE(node_page);
	return le32_to_cpu(rn->footer.next_blkaddr);
	}

	static inline void fill_node_footer(struct page *page, nid_t nid,
	nid_t ino, unsigned int ofs, bool reset)
	{
	struct f2fs_node *rn = F2FS_NODE(page);
	unsigned int old_flag = 0;

	if (reset)
	memset(rn, 0, sizeof(*rn));
	else
	old_flag = le32_to_cpu(rn->footer.flag);

	rn->footer.nid = cpu_to_le32(nid);
	rn->footer.ino = cpu_to_le32(ino);

	/* should remain old flag bits such as COLD_BIT_SHIFT */
	rn->footer.flag = cpu_to_le32((ofs << OFFSET_BIT_SHIFT) \|
	(old_flag & OFFSET_BIT_MASK));
	}

	static inline void copy_node_footer(struct page dst, struct page src)
	{
	struct f2fs_node *src_rn = F2FS_NODE(src);
	struct f2fs_node *dst_rn = F2FS_NODE(dst);
	memcpy(&dst_rn->footer, &src_rn->footer, sizeof(struct node_footer));
	}

	static inline void fill_node_footer_blkaddr(struct page *page, block_t blkaddr)
	{
	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
	struct f2fs_node *rn = F2FS_NODE(page);
	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
	__u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);

	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
	__u64 crc = le32_to_cpu(((__le32 )
	((unsigned char *)ckpt + crc_offset)));
	cp_ver \|= (crc << 32);
	}
	rn->footer.cp_ver = cpu_to_le64(cp_ver);
	rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
	}

	static inline bool is_recoverable_dnode(struct page *page)
	{
	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
	__u64 cp_ver = cur_cp_version(ckpt);

	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
	__u64 crc = le32_to_cpu(((__le32 )
	((unsigned char *)ckpt + crc_offset)));
	cp_ver \|= (crc << 32);
	}
	return cp_ver == cpver_of_node(page);
	}

	/*
	* f2fs assigns the following node offsets described as (num).
	* N = NIDS_PER_BLOCK
	*
	* Inode block (0)
	* \|- direct node (1)
	* \|- direct node (2)
	* \|- indirect node (3)
	* \| `- direct node (4 => 4 + N - 1)
	* \|- indirect node (4 + N)
	* \| `- direct node (5 + N => 5 + 2N - 1)
	* `- double indirect node (5 + 2N)
	* `- indirect node (6 + 2N)
	* `- direct node
	* ......
	* `- indirect node ((6 + 2N) + x(N + 1))
	* `- direct node
	* ......
	* `- indirect node ((6 + 2N) + (N - 1)(N + 1))
	* `- direct node
	*/
	static inline bool IS_DNODE(struct page *node_page)
	{
	unsigned int ofs = ofs_of_node(node_page);

	if (f2fs_has_xattr_block(ofs))
	return false;

	if (ofs == 3 \|\| ofs == 4 + NIDS_PER_BLOCK \|\|
	ofs == 5 + 2 * NIDS_PER_BLOCK)
	return false;
	if (ofs >= 6 + 2 * NIDS_PER_BLOCK) {
	ofs -= 6 + 2 * NIDS_PER_BLOCK;
	if (!((long int)ofs % (NIDS_PER_BLOCK + 1)))
	return false;
	}
	return true;
	}

	static inline int set_nid(struct page *p, int off, nid_t nid, bool i)
	{
	struct f2fs_node *rn = F2FS_NODE(p);

	f2fs_wait_on_page_writeback(p, NODE, true);

	if (i)
	rn->i.i_nid[off - NODE_DIR1_BLOCK] = cpu_to_le32(nid);
	else
	rn->in.nid[off] = cpu_to_le32(nid);
	return set_page_dirty(p);
	}

	static inline nid_t get_nid(struct page *p, int off, bool i)
	{
	struct f2fs_node *rn = F2FS_NODE(p);

	if (i)
	return le32_to_cpu(rn->i.i_nid[off - NODE_DIR1_BLOCK]);
	return le32_to_cpu(rn->in.nid[off]);
	}

	/*
	* Coldness identification:
	* - Mark cold files in f2fs_inode_info
	* - Mark cold node blocks in their node footer
	* - Mark cold data pages in page cache
	*/
	static inline int is_cold_data(struct page *page)
	{
	return PageChecked(page);
	}

	static inline void set_cold_data(struct page *page)
	{
	SetPageChecked(page);
	}

	static inline void clear_cold_data(struct page *page)
	{
	ClearPageChecked(page);
	}

	static inline int is_node(struct page *page, int type)
	{
	struct f2fs_node *rn = F2FS_NODE(page);
	return le32_to_cpu(rn->footer.flag) & (1 << type);
	}

	#define is_cold_node(page) is_node(page, COLD_BIT_SHIFT)
	#define is_fsync_dnode(page) is_node(page, FSYNC_BIT_SHIFT)
	#define is_dent_dnode(page) is_node(page, DENT_BIT_SHIFT)

	static inline int is_inline_node(struct page *page)
	{
	return PageChecked(page);
	}

	static inline void set_inline_node(struct page *page)
	{
	SetPageChecked(page);
	}

	static inline void clear_inline_node(struct page *page)
	{
	ClearPageChecked(page);
	}

	static inline void set_cold_node(struct inode inode, struct page page)
	{
	struct f2fs_node *rn = F2FS_NODE(page);
	unsigned int flag = le32_to_cpu(rn->footer.flag);

	if (S_ISDIR(inode->i_mode))
	flag &= ~(0x1 << COLD_BIT_SHIFT);
	else
	flag \|= (0x1 << COLD_BIT_SHIFT);
	rn->footer.flag = cpu_to_le32(flag);
	}

	static inline void set_mark(struct page *page, int mark, int type)
	{
	struct f2fs_node *rn = F2FS_NODE(page);
	unsigned int flag = le32_to_cpu(rn->footer.flag);
	if (mark)
	flag \|= (0x1 << type);
	else
	flag &= ~(0x1 << type);
	rn->footer.flag = cpu_to_le32(flag);
	}
	#define set_dentry_mark(page, mark) set_mark(page, mark, DENT_BIT_SHIFT)
	#define set_fsync_mark(page, mark) set_mark(page, mark, FSYNC_BIT_SHIFT)