fs/f2fs/checkpoint.c - kernel/msm-4.9 - Gitiles

 /*
  * fs/f2fs/checkpoint.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/bio.h>
 #include <linux/mpage.h>
 #include <linux/writeback.h>
 #include <linux/blkdev.h>
 #include <linux/f2fs_fs.h>
 #include <linux/pagevec.h>
 #include <linux/swap.h>

 #include "f2fs.h"
 #include "node.h"
 #include "segment.h"

 static struct kmem_cache *orphan_entry_slab;
 static struct kmem_cache *inode_entry_slab;

 /*
  * We guarantee no failure on the returned page.
  */
 struct page *grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
 {
 	struct address_space *mapping = sbi->meta_inode->i_mapping;
 	struct page *page = NULL;
 repeat:
 	page = grab_cache_page(mapping, index);
 	if (!page) {
 		cond_resched();
 		goto repeat;
 	}

 	/* We wait writeback only inside grab_meta_page() */
 	wait_on_page_writeback(page);
 	SetPageUptodate(page);
 	return page;
 }

 /*
  * We guarantee no failure on the returned page.
  */
 struct page *get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
 {
 	struct address_space *mapping = sbi->meta_inode->i_mapping;
 	struct page *page;
 repeat:
 	page = grab_cache_page(mapping, index);
 	if (!page) {
 		cond_resched();
 		goto repeat;
 	}
 	if (f2fs_readpage(sbi, page, index, READ_SYNC)) {
 		f2fs_put_page(page, 1);
 		goto repeat;
 	}
 	mark_page_accessed(page);

 	/* We do not allow returning an errorneous page */
 	return page;
 }

 static int f2fs_write_meta_page(struct page *page,
 				struct writeback_control *wbc)
 {
 	struct inode *inode = page->mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);

 	/* Should not write any meta pages, if any IO error was occurred */
 	if (wbc->for_reclaim ||
 			is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)) {
 		dec_page_count(sbi, F2FS_DIRTY_META);
 		wbc->pages_skipped++;
 		set_page_dirty(page);
 		return AOP_WRITEPAGE_ACTIVATE;
 	}

 	wait_on_page_writeback(page);

 	write_meta_page(sbi, page);
 	dec_page_count(sbi, F2FS_DIRTY_META);
 	unlock_page(page);
 	return 0;
 }

 static int f2fs_write_meta_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 written;

 	if (wbc->for_kupdate)
 		return 0;

 	if (get_pages(sbi, F2FS_DIRTY_META) == 0)
 		return 0;

 	/* if mounting is failed, skip writing node pages */
 	mutex_lock(&sbi->cp_mutex);
 	written = sync_meta_pages(sbi, META, bio_get_nr_vecs(bdev));
 	mutex_unlock(&sbi->cp_mutex);
 	wbc->nr_to_write -= written;
 	return 0;
 }

 long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
 						long nr_to_write)
 {
 	struct address_space *mapping = sbi->meta_inode->i_mapping;
 	pgoff_t index = 0, end = LONG_MAX;
 	struct pagevec pvec;
 	long nwritten = 0;
 	struct writeback_control wbc = {
 		.for_reclaim = 0,
 	};

 	pagevec_init(&pvec, 0);

 	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];
 			lock_page(page);
 			BUG_ON(page->mapping != mapping);
 			BUG_ON(!PageDirty(page));
 			clear_page_dirty_for_io(page);
 			if (f2fs_write_meta_page(page, &wbc)) {
 				unlock_page(page);
 				break;
 			}
 			if (nwritten++ >= nr_to_write)
 				break;
 		}
 		pagevec_release(&pvec);
 		cond_resched();
 	}

 	if (nwritten)
 		f2fs_submit_bio(sbi, type, nr_to_write == LONG_MAX);

 	return nwritten;
 }

 static int f2fs_set_meta_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_META);
 		return 1;
 	}
 	return 0;
 }

 const struct address_space_operations f2fs_meta_aops = {
 	.writepage	= f2fs_write_meta_page,
 	.writepages	= f2fs_write_meta_pages,
 	.set_page_dirty	= f2fs_set_meta_page_dirty,
 };

 int check_orphan_space(struct f2fs_sb_info *sbi)
 {
 	unsigned int max_orphans;
 	int err = 0;

 	/*
 	 * considering 512 blocks in a segment 5 blocks are needed for cp
 	 * and log segment summaries. Remaining blocks are used to keep
 	 * orphan entries with the limitation one reserved segment
 	 * for cp pack we can have max 1020*507 orphan entries
 	 */
 	max_orphans = (sbi->blocks_per_seg - 5) * F2FS_ORPHANS_PER_BLOCK;
 	mutex_lock(&sbi->orphan_inode_mutex);
 	if (sbi->n_orphans >= max_orphans)
 		err = -ENOSPC;
 	mutex_unlock(&sbi->orphan_inode_mutex);
 	return err;
 }

 void add_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
 {
 	struct list_head *head, *this;
 	struct orphan_inode_entry *new = NULL, *orphan = NULL;

 	mutex_lock(&sbi->orphan_inode_mutex);
 	head = &sbi->orphan_inode_list;
 	list_for_each(this, head) {
 		orphan = list_entry(this, struct orphan_inode_entry, list);
 		if (orphan->ino == ino)
 			goto out;
 		if (orphan->ino > ino)
 			break;
 		orphan = NULL;
 	}
 retry:
 	new = kmem_cache_alloc(orphan_entry_slab, GFP_ATOMIC);
 	if (!new) {
 		cond_resched();
 		goto retry;
 	}
 	new->ino = ino;

 	/* add new_oentry into list which is sorted by inode number */
 	if (orphan)
 		list_add(&new->list, this->prev);
 	else
 		list_add_tail(&new->list, head);

 	sbi->n_orphans++;
 out:
 	mutex_unlock(&sbi->orphan_inode_mutex);
 }

 void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
 {
 	struct list_head *this, *next, *head;
 	struct orphan_inode_entry *orphan;

 	mutex_lock(&sbi->orphan_inode_mutex);
 	head = &sbi->orphan_inode_list;
 	list_for_each_safe(this, next, head) {
 		orphan = list_entry(this, struct orphan_inode_entry, list);
 		if (orphan->ino == ino) {
 			list_del(&orphan->list);
 			kmem_cache_free(orphan_entry_slab, orphan);
 			sbi->n_orphans--;
 			break;
 		}
 	}
 	mutex_unlock(&sbi->orphan_inode_mutex);
 }

 static void recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
 {
 	struct inode *inode = f2fs_iget(sbi->sb, ino);
 	BUG_ON(IS_ERR(inode));
 	clear_nlink(inode);

 	/* truncate all the data during iput */
 	iput(inode);
 }

 int recover_orphan_inodes(struct f2fs_sb_info *sbi)
 {
 	block_t start_blk, orphan_blkaddr, i, j;

 	if (!is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG))
 		return 0;

 	sbi->por_doing = 1;
 	start_blk = __start_cp_addr(sbi) + 1;
 	orphan_blkaddr = __start_sum_addr(sbi) - 1;

 	for (i = 0; i < orphan_blkaddr; i++) {
 		struct page *page = get_meta_page(sbi, start_blk + i);
 		struct f2fs_orphan_block *orphan_blk;

 		orphan_blk = (struct f2fs_orphan_block *)page_address(page);
 		for (j = 0; j < le32_to_cpu(orphan_blk->entry_count); j++) {
 			nid_t ino = le32_to_cpu(orphan_blk->ino[j]);
 			recover_orphan_inode(sbi, ino);
 		}
 		f2fs_put_page(page, 1);
 	}
 	/* clear Orphan Flag */
 	clear_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG);
 	sbi->por_doing = 0;
 	return 0;
 }

 static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
 {
 	struct list_head *head, *this, *next;
 	struct f2fs_orphan_block *orphan_blk = NULL;
 	struct page *page = NULL;
 	unsigned int nentries = 0;
 	unsigned short index = 1;
 	unsigned short orphan_blocks;

 	orphan_blocks = (unsigned short)((sbi->n_orphans +
 		(F2FS_ORPHANS_PER_BLOCK - 1)) / F2FS_ORPHANS_PER_BLOCK);

 	mutex_lock(&sbi->orphan_inode_mutex);
 	head = &sbi->orphan_inode_list;

 	/* loop for each orphan inode entry and write them in Jornal block */
 	list_for_each_safe(this, next, head) {
 		struct orphan_inode_entry *orphan;

 		orphan = list_entry(this, struct orphan_inode_entry, list);

 		if (nentries == F2FS_ORPHANS_PER_BLOCK) {
 			/*
 			 * an orphan block is full of 1020 entries,
 			 * then we need to flush current orphan blocks
 			 * and bring another one in memory
 			 */
 			orphan_blk->blk_addr = cpu_to_le16(index);
 			orphan_blk->blk_count = cpu_to_le16(orphan_blocks);
 			orphan_blk->entry_count = cpu_to_le32(nentries);
 			set_page_dirty(page);
 			f2fs_put_page(page, 1);
 			index++;
 			start_blk++;
 			nentries = 0;
 			page = NULL;
 		}
 		if (page)
 			goto page_exist;

 		page = grab_meta_page(sbi, start_blk);
 		orphan_blk = (struct f2fs_orphan_block *)page_address(page);
 		memset(orphan_blk, 0, sizeof(*orphan_blk));
 page_exist:
 		orphan_blk->ino[nentries++] = cpu_to_le32(orphan->ino);
 	}
 	if (!page)
 		goto end;

 	orphan_blk->blk_addr = cpu_to_le16(index);
 	orphan_blk->blk_count = cpu_to_le16(orphan_blocks);
 	orphan_blk->entry_count = cpu_to_le32(nentries);
 	set_page_dirty(page);
 	f2fs_put_page(page, 1);
 end:
 	mutex_unlock(&sbi->orphan_inode_mutex);
 }

 static struct page *validate_checkpoint(struct f2fs_sb_info *sbi,
 				block_t cp_addr, unsigned long long *version)
 {
 	struct page *cp_page_1, *cp_page_2 = NULL;
 	unsigned long blk_size = sbi->blocksize;
 	struct f2fs_checkpoint *cp_block;
 	unsigned long long cur_version = 0, pre_version = 0;
 	unsigned int crc = 0;
 	size_t crc_offset;

 	/* Read the 1st cp block in this CP pack */
 	cp_page_1 = get_meta_page(sbi, cp_addr);

 	/* get the version number */
 	cp_block = (struct f2fs_checkpoint *)page_address(cp_page_1);
 	crc_offset = le32_to_cpu(cp_block->checksum_offset);
 	if (crc_offset >= blk_size)
 		goto invalid_cp1;

 	crc = *(unsigned int *)((unsigned char *)cp_block + crc_offset);
 	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
 		goto invalid_cp1;

 	pre_version = le64_to_cpu(cp_block->checkpoint_ver);

 	/* Read the 2nd cp block in this CP pack */
 	cp_addr += le32_to_cpu(cp_block->cp_pack_total_block_count) - 1;
 	cp_page_2 = get_meta_page(sbi, cp_addr);

 	cp_block = (struct f2fs_checkpoint *)page_address(cp_page_2);
 	crc_offset = le32_to_cpu(cp_block->checksum_offset);
 	if (crc_offset >= blk_size)
 		goto invalid_cp2;

 	crc = *(unsigned int *)((unsigned char *)cp_block + crc_offset);
 	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
 		goto invalid_cp2;

 	cur_version = le64_to_cpu(cp_block->checkpoint_ver);

 	if (cur_version == pre_version) {
 		*version = cur_version;
 		f2fs_put_page(cp_page_2, 1);
 		return cp_page_1;
 	}
 invalid_cp2:
 	f2fs_put_page(cp_page_2, 1);
 invalid_cp1:
 	f2fs_put_page(cp_page_1, 1);
 	return NULL;
 }

 int get_valid_checkpoint(struct f2fs_sb_info *sbi)
 {
 	struct f2fs_checkpoint *cp_block;
 	struct f2fs_super_block *fsb = sbi->raw_super;
 	struct page *cp1, *cp2, *cur_page;
 	unsigned long blk_size = sbi->blocksize;
 	unsigned long long cp1_version = 0, cp2_version = 0;
 	unsigned long long cp_start_blk_no;

 	sbi->ckpt = kzalloc(blk_size, GFP_KERNEL);
 	if (!sbi->ckpt)
 		return -ENOMEM;
 	/*
 	 * Finding out valid cp block involves read both
 	 * sets( cp pack1 and cp pack 2)
 	 */
 	cp_start_blk_no = le32_to_cpu(fsb->cp_blkaddr);
 	cp1 = validate_checkpoint(sbi, cp_start_blk_no, &cp1_version);

 	/* The second checkpoint pack should start at the next segment */
 	cp_start_blk_no += 1 << le32_to_cpu(fsb->log_blocks_per_seg);
 	cp2 = validate_checkpoint(sbi, cp_start_blk_no, &cp2_version);

 	if (cp1 && cp2) {
 		if (ver_after(cp2_version, cp1_version))
 			cur_page = cp2;
 		else
 			cur_page = cp1;
 	} else if (cp1) {
 		cur_page = cp1;
 	} else if (cp2) {
 		cur_page = cp2;
 	} else {
 		goto fail_no_cp;
 	}

 	cp_block = (struct f2fs_checkpoint *)page_address(cur_page);
 	memcpy(sbi->ckpt, cp_block, blk_size);

 	f2fs_put_page(cp1, 1);
 	f2fs_put_page(cp2, 1);
 	return 0;

 fail_no_cp:
 	kfree(sbi->ckpt);
 	return -EINVAL;
 }

 void set_dirty_dir_page(struct inode *inode, struct page *page)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 	struct list_head *head = &sbi->dir_inode_list;
 	struct dir_inode_entry *new;
 	struct list_head *this;

 	if (!S_ISDIR(inode->i_mode))
 		return;
 retry:
 	new = kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
 	if (!new) {
 		cond_resched();
 		goto retry;
 	}
 	new->inode = inode;
 	INIT_LIST_HEAD(&new->list);

 	spin_lock(&sbi->dir_inode_lock);
 	list_for_each(this, head) {
 		struct dir_inode_entry *entry;
 		entry = list_entry(this, struct dir_inode_entry, list);
 		if (entry->inode == inode) {
 			kmem_cache_free(inode_entry_slab, new);
 			goto out;
 		}
 	}
 	list_add_tail(&new->list, head);
 	sbi->n_dirty_dirs++;

 	BUG_ON(!S_ISDIR(inode->i_mode));
 out:
 	inc_page_count(sbi, F2FS_DIRTY_DENTS);
 	inode_inc_dirty_dents(inode);
 	SetPagePrivate(page);

 	spin_unlock(&sbi->dir_inode_lock);
 }

 void remove_dirty_dir_inode(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 	struct list_head *head = &sbi->dir_inode_list;
 	struct list_head *this;

 	if (!S_ISDIR(inode->i_mode))
 		return;

 	spin_lock(&sbi->dir_inode_lock);
 	if (atomic_read(&F2FS_I(inode)->dirty_dents))
 		goto out;

 	list_for_each(this, head) {
 		struct dir_inode_entry *entry;
 		entry = list_entry(this, struct dir_inode_entry, list);
 		if (entry->inode == inode) {
 			list_del(&entry->list);
 			kmem_cache_free(inode_entry_slab, entry);
 			sbi->n_dirty_dirs--;
 			break;
 		}
 	}
 out:
 	spin_unlock(&sbi->dir_inode_lock);
 }

 void sync_dirty_dir_inodes(struct f2fs_sb_info *sbi)
 {
 	struct list_head *head = &sbi->dir_inode_list;
 	struct dir_inode_entry *entry;
 	struct inode *inode;
 retry:
 	spin_lock(&sbi->dir_inode_lock);
 	if (list_empty(head)) {
 		spin_unlock(&sbi->dir_inode_lock);
 		return;
 	}
 	entry = list_entry(head->next, struct dir_inode_entry, list);
 	inode = igrab(entry->inode);
 	spin_unlock(&sbi->dir_inode_lock);
 	if (inode) {
 		filemap_flush(inode->i_mapping);
 		iput(inode);
 	} else {
 		/*
 		 * We should submit bio, since it exists several
 		 * wribacking dentry pages in the freeing inode.
 		 */
 		f2fs_submit_bio(sbi, DATA, true);
 	}
 	goto retry;
 }

 /*
  * Freeze all the FS-operations for checkpoint.
  */
 static void block_operations(struct f2fs_sb_info *sbi)
 {
 	int t;
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_ALL,
 		.nr_to_write = LONG_MAX,
 		.for_reclaim = 0,
 	};

 	/* Stop renaming operation */
 	mutex_lock_op(sbi, RENAME);
 	mutex_lock_op(sbi, DENTRY_OPS);

 retry_dents:
 	/* write all the dirty dentry pages */
 	sync_dirty_dir_inodes(sbi);

 	mutex_lock_op(sbi, DATA_WRITE);
 	if (get_pages(sbi, F2FS_DIRTY_DENTS)) {
 		mutex_unlock_op(sbi, DATA_WRITE);
 		goto retry_dents;
 	}

 	/* block all the operations */
 	for (t = DATA_NEW; t <= NODE_TRUNC; t++)
 		mutex_lock_op(sbi, t);

 	mutex_lock(&sbi->write_inode);

 	/*
 	 * POR: we should ensure that there is no dirty node pages
 	 * until finishing nat/sit flush.
 	 */
 retry:
 	sync_node_pages(sbi, 0, &wbc);

 	mutex_lock_op(sbi, NODE_WRITE);

 	if (get_pages(sbi, F2FS_DIRTY_NODES)) {
 		mutex_unlock_op(sbi, NODE_WRITE);
 		goto retry;
 	}
 	mutex_unlock(&sbi->write_inode);
 }

 static void unblock_operations(struct f2fs_sb_info *sbi)
 {
 	int t;
 	for (t = NODE_WRITE; t >= RENAME; t--)
 		mutex_unlock_op(sbi, t);
 }

 static void do_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
 	nid_t last_nid = 0;
 	block_t start_blk;
 	struct page *cp_page;
 	unsigned int data_sum_blocks, orphan_blocks;
 	unsigned int crc32 = 0;
 	void *kaddr;
 	int i;

 	/* Flush all the NAT/SIT pages */
 	while (get_pages(sbi, F2FS_DIRTY_META))
 		sync_meta_pages(sbi, META, LONG_MAX);

 	next_free_nid(sbi, &last_nid);

 	/*
 	 * modify checkpoint
 	 * version number is already updated
 	 */
 	ckpt->elapsed_time = cpu_to_le64(get_mtime(sbi));
 	ckpt->valid_block_count = cpu_to_le64(valid_user_blocks(sbi));
 	ckpt->free_segment_count = cpu_to_le32(free_segments(sbi));
 	for (i = 0; i < 3; i++) {
 		ckpt->cur_node_segno[i] =
 			cpu_to_le32(curseg_segno(sbi, i + CURSEG_HOT_NODE));
 		ckpt->cur_node_blkoff[i] =
 			cpu_to_le16(curseg_blkoff(sbi, i + CURSEG_HOT_NODE));
 		ckpt->alloc_type[i + CURSEG_HOT_NODE] =
 				curseg_alloc_type(sbi, i + CURSEG_HOT_NODE);
 	}
 	for (i = 0; i < 3; i++) {
 		ckpt->cur_data_segno[i] =
 			cpu_to_le32(curseg_segno(sbi, i + CURSEG_HOT_DATA));
 		ckpt->cur_data_blkoff[i] =
 			cpu_to_le16(curseg_blkoff(sbi, i + CURSEG_HOT_DATA));
 		ckpt->alloc_type[i + CURSEG_HOT_DATA] =
 				curseg_alloc_type(sbi, i + CURSEG_HOT_DATA);
 	}

 	ckpt->valid_node_count = cpu_to_le32(valid_node_count(sbi));
 	ckpt->valid_inode_count = cpu_to_le32(valid_inode_count(sbi));
 	ckpt->next_free_nid = cpu_to_le32(last_nid);

 	/* 2 cp  + n data seg summary + orphan inode blocks */
 	data_sum_blocks = npages_for_summary_flush(sbi);
 	if (data_sum_blocks < 3)
 		set_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);
 	else
 		clear_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);

 	orphan_blocks = (sbi->n_orphans + F2FS_ORPHANS_PER_BLOCK - 1)
 					/ F2FS_ORPHANS_PER_BLOCK;
 	ckpt->cp_pack_start_sum = cpu_to_le32(1 + orphan_blocks);

 	if (is_umount) {
 		set_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
 		ckpt->cp_pack_total_block_count = cpu_to_le32(2 +
 			data_sum_blocks + orphan_blocks + NR_CURSEG_NODE_TYPE);
 	} else {
 		clear_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
 		ckpt->cp_pack_total_block_count = cpu_to_le32(2 +
 			data_sum_blocks + orphan_blocks);
 	}

 	if (sbi->n_orphans)
 		set_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);
 	else
 		clear_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);

 	/* update SIT/NAT bitmap */
 	get_sit_bitmap(sbi, __bitmap_ptr(sbi, SIT_BITMAP));
 	get_nat_bitmap(sbi, __bitmap_ptr(sbi, NAT_BITMAP));

 	crc32 = f2fs_crc32(ckpt, le32_to_cpu(ckpt->checksum_offset));
 	*(__le32 *)((unsigned char *)ckpt +
 				le32_to_cpu(ckpt->checksum_offset))
 				= cpu_to_le32(crc32);

 	start_blk = __start_cp_addr(sbi);

 	/* write out checkpoint buffer at block 0 */
 	cp_page = grab_meta_page(sbi, start_blk++);
 	kaddr = page_address(cp_page);
 	memcpy(kaddr, ckpt, (1 << sbi->log_blocksize));
 	set_page_dirty(cp_page);
 	f2fs_put_page(cp_page, 1);

 	if (sbi->n_orphans) {
 		write_orphan_inodes(sbi, start_blk);
 		start_blk += orphan_blocks;
 	}

 	write_data_summaries(sbi, start_blk);
 	start_blk += data_sum_blocks;
 	if (is_umount) {
 		write_node_summaries(sbi, start_blk);
 		start_blk += NR_CURSEG_NODE_TYPE;
 	}

 	/* writeout checkpoint block */
 	cp_page = grab_meta_page(sbi, start_blk);
 	kaddr = page_address(cp_page);
 	memcpy(kaddr, ckpt, (1 << sbi->log_blocksize));
 	set_page_dirty(cp_page);
 	f2fs_put_page(cp_page, 1);

 	/* wait for previous submitted node/meta pages writeback */
 	while (get_pages(sbi, F2FS_WRITEBACK))
 		congestion_wait(BLK_RW_ASYNC, HZ / 50);

 	filemap_fdatawait_range(sbi->node_inode->i_mapping, 0, LONG_MAX);
 	filemap_fdatawait_range(sbi->meta_inode->i_mapping, 0, LONG_MAX);

 	/* update user_block_counts */
 	sbi->last_valid_block_count = sbi->total_valid_block_count;
 	sbi->alloc_valid_block_count = 0;

 	/* Here, we only have one bio having CP pack */
 	sync_meta_pages(sbi, META_FLUSH, LONG_MAX);

 	if (!is_set_ckpt_flags(ckpt, CP_ERROR_FLAG)) {
 		clear_prefree_segments(sbi);
 		F2FS_RESET_SB_DIRT(sbi);
 	}
 }

 /*
  * We guarantee that this checkpoint procedure should not fail.
  */
 void write_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
 	unsigned long long ckpt_ver;

 	mutex_lock(&sbi->cp_mutex);
 	block_operations(sbi);

 	f2fs_submit_bio(sbi, DATA, true);
 	f2fs_submit_bio(sbi, NODE, true);
 	f2fs_submit_bio(sbi, META, true);

 	/*
 	 * update checkpoint pack index
 	 * Increase the version number so that
 	 * SIT entries and seg summaries are written at correct place
 	 */
 	ckpt_ver = le64_to_cpu(ckpt->checkpoint_ver);
 	ckpt->checkpoint_ver = cpu_to_le64(++ckpt_ver);

 	/* write cached NAT/SIT entries to NAT/SIT area */
 	flush_nat_entries(sbi);
 	flush_sit_entries(sbi);

 	reset_victim_segmap(sbi);

 	/* unlock all the fs_lock[] in do_checkpoint() */
 	do_checkpoint(sbi, is_umount);

 	unblock_operations(sbi);
 	mutex_unlock(&sbi->cp_mutex);
 }

 void init_orphan_info(struct f2fs_sb_info *sbi)
 {
 	mutex_init(&sbi->orphan_inode_mutex);
 	INIT_LIST_HEAD(&sbi->orphan_inode_list);
 	sbi->n_orphans = 0;
 }

 int __init create_checkpoint_caches(void)
 {
 	orphan_entry_slab = f2fs_kmem_cache_create("f2fs_orphan_entry",
 			sizeof(struct orphan_inode_entry), NULL);
 	if (unlikely(!orphan_entry_slab))
 		return -ENOMEM;
 	inode_entry_slab = f2fs_kmem_cache_create("f2fs_dirty_dir_entry",
 			sizeof(struct dir_inode_entry), NULL);
 	if (unlikely(!inode_entry_slab)) {
 		kmem_cache_destroy(orphan_entry_slab);
 		return -ENOMEM;
 	}
 	return 0;
 }

 void destroy_checkpoint_caches(void)
 {
 	kmem_cache_destroy(orphan_entry_slab);
 	kmem_cache_destroy(inode_entry_slab);
 }
	/*
	* fs/f2fs/checkpoint.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/bio.h>
	#include <linux/mpage.h>
	#include <linux/writeback.h>
	#include <linux/blkdev.h>
	#include <linux/f2fs_fs.h>
	#include <linux/pagevec.h>
	#include <linux/swap.h>

	#include "f2fs.h"
	#include "node.h"
	#include "segment.h"

	static struct kmem_cache *orphan_entry_slab;
	static struct kmem_cache *inode_entry_slab;

	/*
	* We guarantee no failure on the returned page.
	*/
	struct page grab_meta_page(struct f2fs_sb_info sbi, pgoff_t index)
	{
	struct address_space *mapping = sbi->meta_inode->i_mapping;
	struct page *page = NULL;
	repeat:
	page = grab_cache_page(mapping, index);
	if (!page) {
	cond_resched();
	goto repeat;
	}

	/* We wait writeback only inside grab_meta_page() */
	wait_on_page_writeback(page);
	SetPageUptodate(page);
	return page;
	}

	/*
	* We guarantee no failure on the returned page.
	*/
	struct page get_meta_page(struct f2fs_sb_info sbi, pgoff_t index)
	{
	struct address_space *mapping = sbi->meta_inode->i_mapping;
	struct page *page;
	repeat:
	page = grab_cache_page(mapping, index);
	if (!page) {
	cond_resched();
	goto repeat;
	}
	if (f2fs_readpage(sbi, page, index, READ_SYNC)) {
	f2fs_put_page(page, 1);
	goto repeat;
	}
	mark_page_accessed(page);

	/* We do not allow returning an errorneous page */
	return page;
	}

	static int f2fs_write_meta_page(struct page *page,
	struct writeback_control *wbc)
	{
	struct inode *inode = page->mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);

	/* Should not write any meta pages, if any IO error was occurred */
	if (wbc->for_reclaim \|\|
	is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)) {
	dec_page_count(sbi, F2FS_DIRTY_META);
	wbc->pages_skipped++;
	set_page_dirty(page);
	return AOP_WRITEPAGE_ACTIVATE;
	}

	wait_on_page_writeback(page);

	write_meta_page(sbi, page);
	dec_page_count(sbi, F2FS_DIRTY_META);
	unlock_page(page);
	return 0;
	}

	static int f2fs_write_meta_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 written;

	if (wbc->for_kupdate)
	return 0;

	if (get_pages(sbi, F2FS_DIRTY_META) == 0)
	return 0;

	/* if mounting is failed, skip writing node pages */
	mutex_lock(&sbi->cp_mutex);
	written = sync_meta_pages(sbi, META, bio_get_nr_vecs(bdev));
	mutex_unlock(&sbi->cp_mutex);
	wbc->nr_to_write -= written;
	return 0;
	}

	long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
	long nr_to_write)
	{
	struct address_space *mapping = sbi->meta_inode->i_mapping;
	pgoff_t index = 0, end = LONG_MAX;
	struct pagevec pvec;
	long nwritten = 0;
	struct writeback_control wbc = {
	.for_reclaim = 0,
	};

	pagevec_init(&pvec, 0);

	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];
	lock_page(page);
	BUG_ON(page->mapping != mapping);
	BUG_ON(!PageDirty(page));
	clear_page_dirty_for_io(page);
	if (f2fs_write_meta_page(page, &wbc)) {
	unlock_page(page);
	break;
	}
	if (nwritten++ >= nr_to_write)
	break;
	}
	pagevec_release(&pvec);
	cond_resched();
	}

	if (nwritten)
	f2fs_submit_bio(sbi, type, nr_to_write == LONG_MAX);

	return nwritten;
	}

	static int f2fs_set_meta_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_META);
	return 1;
	}
	return 0;
	}

	const struct address_space_operations f2fs_meta_aops = {
	.writepage = f2fs_write_meta_page,
	.writepages = f2fs_write_meta_pages,
	.set_page_dirty = f2fs_set_meta_page_dirty,
	};

	int check_orphan_space(struct f2fs_sb_info *sbi)
	{
	unsigned int max_orphans;
	int err = 0;

	/*
	* considering 512 blocks in a segment 5 blocks are needed for cp
	* and log segment summaries. Remaining blocks are used to keep
	* orphan entries with the limitation one reserved segment
	* for cp pack we can have max 1020*507 orphan entries
	*/
	max_orphans = (sbi->blocks_per_seg - 5) * F2FS_ORPHANS_PER_BLOCK;
	mutex_lock(&sbi->orphan_inode_mutex);
	if (sbi->n_orphans >= max_orphans)
	err = -ENOSPC;
	mutex_unlock(&sbi->orphan_inode_mutex);
	return err;
	}

	void add_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
	{
	struct list_head head, this;
	struct orphan_inode_entry new = NULL, orphan = NULL;

	mutex_lock(&sbi->orphan_inode_mutex);
	head = &sbi->orphan_inode_list;
	list_for_each(this, head) {
	orphan = list_entry(this, struct orphan_inode_entry, list);
	if (orphan->ino == ino)
	goto out;
	if (orphan->ino > ino)
	break;
	orphan = NULL;
	}
	retry:
	new = kmem_cache_alloc(orphan_entry_slab, GFP_ATOMIC);
	if (!new) {
	cond_resched();
	goto retry;
	}
	new->ino = ino;

	/* add new_oentry into list which is sorted by inode number */
	if (orphan)
	list_add(&new->list, this->prev);
	else
	list_add_tail(&new->list, head);

	sbi->n_orphans++;
	out:
	mutex_unlock(&sbi->orphan_inode_mutex);
	}

	void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
	{
	struct list_head this, next, *head;
	struct orphan_inode_entry *orphan;

	mutex_lock(&sbi->orphan_inode_mutex);
	head = &sbi->orphan_inode_list;
	list_for_each_safe(this, next, head) {
	orphan = list_entry(this, struct orphan_inode_entry, list);
	if (orphan->ino == ino) {
	list_del(&orphan->list);
	kmem_cache_free(orphan_entry_slab, orphan);
	sbi->n_orphans--;
	break;
	}
	}
	mutex_unlock(&sbi->orphan_inode_mutex);
	}

	static void recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
	{
	struct inode *inode = f2fs_iget(sbi->sb, ino);
	BUG_ON(IS_ERR(inode));
	clear_nlink(inode);

	/* truncate all the data during iput */
	iput(inode);
	}

	int recover_orphan_inodes(struct f2fs_sb_info *sbi)
	{
	block_t start_blk, orphan_blkaddr, i, j;

	if (!is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG))
	return 0;

	sbi->por_doing = 1;
	start_blk = __start_cp_addr(sbi) + 1;
	orphan_blkaddr = __start_sum_addr(sbi) - 1;

	for (i = 0; i < orphan_blkaddr; i++) {
	struct page *page = get_meta_page(sbi, start_blk + i);
	struct f2fs_orphan_block *orphan_blk;

	orphan_blk = (struct f2fs_orphan_block *)page_address(page);
	for (j = 0; j < le32_to_cpu(orphan_blk->entry_count); j++) {
	nid_t ino = le32_to_cpu(orphan_blk->ino[j]);
	recover_orphan_inode(sbi, ino);
	}
	f2fs_put_page(page, 1);
	}
	/* clear Orphan Flag */
	clear_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG);
	sbi->por_doing = 0;
	return 0;
	}

	static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
	{
	struct list_head head, this, *next;
	struct f2fs_orphan_block *orphan_blk = NULL;
	struct page *page = NULL;
	unsigned int nentries = 0;
	unsigned short index = 1;
	unsigned short orphan_blocks;

	orphan_blocks = (unsigned short)((sbi->n_orphans +
	(F2FS_ORPHANS_PER_BLOCK - 1)) / F2FS_ORPHANS_PER_BLOCK);

	mutex_lock(&sbi->orphan_inode_mutex);
	head = &sbi->orphan_inode_list;

	/* loop for each orphan inode entry and write them in Jornal block */
	list_for_each_safe(this, next, head) {
	struct orphan_inode_entry *orphan;

	orphan = list_entry(this, struct orphan_inode_entry, list);

	if (nentries == F2FS_ORPHANS_PER_BLOCK) {
	/*
	* an orphan block is full of 1020 entries,
	* then we need to flush current orphan blocks
	* and bring another one in memory
	*/
	orphan_blk->blk_addr = cpu_to_le16(index);
	orphan_blk->blk_count = cpu_to_le16(orphan_blocks);
	orphan_blk->entry_count = cpu_to_le32(nentries);
	set_page_dirty(page);
	f2fs_put_page(page, 1);
	index++;
	start_blk++;
	nentries = 0;
	page = NULL;
	}
	if (page)
	goto page_exist;

	page = grab_meta_page(sbi, start_blk);
	orphan_blk = (struct f2fs_orphan_block *)page_address(page);
	memset(orphan_blk, 0, sizeof(*orphan_blk));
	page_exist:
	orphan_blk->ino[nentries++] = cpu_to_le32(orphan->ino);
	}
	if (!page)
	goto end;

	orphan_blk->blk_addr = cpu_to_le16(index);
	orphan_blk->blk_count = cpu_to_le16(orphan_blocks);
	orphan_blk->entry_count = cpu_to_le32(nentries);
	set_page_dirty(page);
	f2fs_put_page(page, 1);
	end:
	mutex_unlock(&sbi->orphan_inode_mutex);
	}

	static struct page validate_checkpoint(struct f2fs_sb_info sbi,
	block_t cp_addr, unsigned long long *version)
	{
	struct page cp_page_1, cp_page_2 = NULL;
	unsigned long blk_size = sbi->blocksize;
	struct f2fs_checkpoint *cp_block;
	unsigned long long cur_version = 0, pre_version = 0;
	unsigned int crc = 0;
	size_t crc_offset;

	/* Read the 1st cp block in this CP pack */
	cp_page_1 = get_meta_page(sbi, cp_addr);

	/* get the version number */
	cp_block = (struct f2fs_checkpoint *)page_address(cp_page_1);
	crc_offset = le32_to_cpu(cp_block->checksum_offset);
	if (crc_offset >= blk_size)
	goto invalid_cp1;

	crc = (unsigned int )((unsigned char *)cp_block + crc_offset);
	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
	goto invalid_cp1;

	pre_version = le64_to_cpu(cp_block->checkpoint_ver);

	/* Read the 2nd cp block in this CP pack */
	cp_addr += le32_to_cpu(cp_block->cp_pack_total_block_count) - 1;
	cp_page_2 = get_meta_page(sbi, cp_addr);

	cp_block = (struct f2fs_checkpoint *)page_address(cp_page_2);
	crc_offset = le32_to_cpu(cp_block->checksum_offset);
	if (crc_offset >= blk_size)
	goto invalid_cp2;

	crc = (unsigned int )((unsigned char *)cp_block + crc_offset);
	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
	goto invalid_cp2;

	cur_version = le64_to_cpu(cp_block->checkpoint_ver);

	if (cur_version == pre_version) {
	*version = cur_version;
	f2fs_put_page(cp_page_2, 1);
	return cp_page_1;
	}
	invalid_cp2:
	f2fs_put_page(cp_page_2, 1);
	invalid_cp1:
	f2fs_put_page(cp_page_1, 1);
	return NULL;
	}

	int get_valid_checkpoint(struct f2fs_sb_info *sbi)
	{
	struct f2fs_checkpoint *cp_block;
	struct f2fs_super_block *fsb = sbi->raw_super;
	struct page cp1, cp2, *cur_page;
	unsigned long blk_size = sbi->blocksize;
	unsigned long long cp1_version = 0, cp2_version = 0;
	unsigned long long cp_start_blk_no;

	sbi->ckpt = kzalloc(blk_size, GFP_KERNEL);
	if (!sbi->ckpt)
	return -ENOMEM;
	/*
	* Finding out valid cp block involves read both
	* sets( cp pack1 and cp pack 2)
	*/
	cp_start_blk_no = le32_to_cpu(fsb->cp_blkaddr);
	cp1 = validate_checkpoint(sbi, cp_start_blk_no, &cp1_version);

	/* The second checkpoint pack should start at the next segment */
	cp_start_blk_no += 1 << le32_to_cpu(fsb->log_blocks_per_seg);
	cp2 = validate_checkpoint(sbi, cp_start_blk_no, &cp2_version);

	if (cp1 && cp2) {
	if (ver_after(cp2_version, cp1_version))
	cur_page = cp2;
	else
	cur_page = cp1;
	} else if (cp1) {
	cur_page = cp1;
	} else if (cp2) {
	cur_page = cp2;
	} else {
	goto fail_no_cp;
	}

	cp_block = (struct f2fs_checkpoint *)page_address(cur_page);
	memcpy(sbi->ckpt, cp_block, blk_size);

	f2fs_put_page(cp1, 1);
	f2fs_put_page(cp2, 1);
	return 0;

	fail_no_cp:
	kfree(sbi->ckpt);
	return -EINVAL;
	}

	void set_dirty_dir_page(struct inode inode, struct page page)
	{
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct list_head *head = &sbi->dir_inode_list;
	struct dir_inode_entry *new;
	struct list_head *this;

	if (!S_ISDIR(inode->i_mode))
	return;
	retry:
	new = kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
	if (!new) {
	cond_resched();
	goto retry;
	}
	new->inode = inode;
	INIT_LIST_HEAD(&new->list);

	spin_lock(&sbi->dir_inode_lock);
	list_for_each(this, head) {
	struct dir_inode_entry *entry;
	entry = list_entry(this, struct dir_inode_entry, list);
	if (entry->inode == inode) {
	kmem_cache_free(inode_entry_slab, new);
	goto out;
	}
	}
	list_add_tail(&new->list, head);
	sbi->n_dirty_dirs++;

	BUG_ON(!S_ISDIR(inode->i_mode));
	out:
	inc_page_count(sbi, F2FS_DIRTY_DENTS);
	inode_inc_dirty_dents(inode);
	SetPagePrivate(page);

	spin_unlock(&sbi->dir_inode_lock);
	}

	void remove_dirty_dir_inode(struct inode *inode)
	{
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct list_head *head = &sbi->dir_inode_list;
	struct list_head *this;

	if (!S_ISDIR(inode->i_mode))
	return;

	spin_lock(&sbi->dir_inode_lock);
	if (atomic_read(&F2FS_I(inode)->dirty_dents))
	goto out;

	list_for_each(this, head) {
	struct dir_inode_entry *entry;
	entry = list_entry(this, struct dir_inode_entry, list);
	if (entry->inode == inode) {
	list_del(&entry->list);
	kmem_cache_free(inode_entry_slab, entry);
	sbi->n_dirty_dirs--;
	break;
	}
	}
	out:
	spin_unlock(&sbi->dir_inode_lock);
	}

	void sync_dirty_dir_inodes(struct f2fs_sb_info *sbi)
	{
	struct list_head *head = &sbi->dir_inode_list;
	struct dir_inode_entry *entry;
	struct inode *inode;
	retry:
	spin_lock(&sbi->dir_inode_lock);
	if (list_empty(head)) {
	spin_unlock(&sbi->dir_inode_lock);
	return;
	}
	entry = list_entry(head->next, struct dir_inode_entry, list);
	inode = igrab(entry->inode);
	spin_unlock(&sbi->dir_inode_lock);
	if (inode) {
	filemap_flush(inode->i_mapping);
	iput(inode);
	} else {
	/*
	* We should submit bio, since it exists several
	* wribacking dentry pages in the freeing inode.
	*/
	f2fs_submit_bio(sbi, DATA, true);
	}
	goto retry;
	}

	/*
	* Freeze all the FS-operations for checkpoint.
	*/
	static void block_operations(struct f2fs_sb_info *sbi)
	{
	int t;
	struct writeback_control wbc = {
	.sync_mode = WB_SYNC_ALL,
	.nr_to_write = LONG_MAX,
	.for_reclaim = 0,
	};

	/* Stop renaming operation */
	mutex_lock_op(sbi, RENAME);
	mutex_lock_op(sbi, DENTRY_OPS);

	retry_dents:
	/* write all the dirty dentry pages */
	sync_dirty_dir_inodes(sbi);

	mutex_lock_op(sbi, DATA_WRITE);
	if (get_pages(sbi, F2FS_DIRTY_DENTS)) {
	mutex_unlock_op(sbi, DATA_WRITE);
	goto retry_dents;
	}

	/* block all the operations */
	for (t = DATA_NEW; t <= NODE_TRUNC; t++)
	mutex_lock_op(sbi, t);

	mutex_lock(&sbi->write_inode);

	/*
	* POR: we should ensure that there is no dirty node pages
	* until finishing nat/sit flush.
	*/
	retry:
	sync_node_pages(sbi, 0, &wbc);

	mutex_lock_op(sbi, NODE_WRITE);

	if (get_pages(sbi, F2FS_DIRTY_NODES)) {
	mutex_unlock_op(sbi, NODE_WRITE);
	goto retry;
	}
	mutex_unlock(&sbi->write_inode);
	}

	static void unblock_operations(struct f2fs_sb_info *sbi)
	{
	int t;
	for (t = NODE_WRITE; t >= RENAME; t--)
	mutex_unlock_op(sbi, t);
	}

	static void do_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
	{
	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
	nid_t last_nid = 0;
	block_t start_blk;
	struct page *cp_page;
	unsigned int data_sum_blocks, orphan_blocks;
	unsigned int crc32 = 0;
	void *kaddr;
	int i;

	/* Flush all the NAT/SIT pages */
	while (get_pages(sbi, F2FS_DIRTY_META))
	sync_meta_pages(sbi, META, LONG_MAX);

	next_free_nid(sbi, &last_nid);

	/*
	* modify checkpoint
	* version number is already updated
	*/
	ckpt->elapsed_time = cpu_to_le64(get_mtime(sbi));
	ckpt->valid_block_count = cpu_to_le64(valid_user_blocks(sbi));
	ckpt->free_segment_count = cpu_to_le32(free_segments(sbi));
	for (i = 0; i < 3; i++) {
	ckpt->cur_node_segno[i] =
	cpu_to_le32(curseg_segno(sbi, i + CURSEG_HOT_NODE));
	ckpt->cur_node_blkoff[i] =
	cpu_to_le16(curseg_blkoff(sbi, i + CURSEG_HOT_NODE));
	ckpt->alloc_type[i + CURSEG_HOT_NODE] =
	curseg_alloc_type(sbi, i + CURSEG_HOT_NODE);
	}
	for (i = 0; i < 3; i++) {
	ckpt->cur_data_segno[i] =
	cpu_to_le32(curseg_segno(sbi, i + CURSEG_HOT_DATA));
	ckpt->cur_data_blkoff[i] =
	cpu_to_le16(curseg_blkoff(sbi, i + CURSEG_HOT_DATA));
	ckpt->alloc_type[i + CURSEG_HOT_DATA] =
	curseg_alloc_type(sbi, i + CURSEG_HOT_DATA);
	}

	ckpt->valid_node_count = cpu_to_le32(valid_node_count(sbi));
	ckpt->valid_inode_count = cpu_to_le32(valid_inode_count(sbi));
	ckpt->next_free_nid = cpu_to_le32(last_nid);

	/* 2 cp + n data seg summary + orphan inode blocks */
	data_sum_blocks = npages_for_summary_flush(sbi);
	if (data_sum_blocks < 3)
	set_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);
	else
	clear_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);

	orphan_blocks = (sbi->n_orphans + F2FS_ORPHANS_PER_BLOCK - 1)
	/ F2FS_ORPHANS_PER_BLOCK;
	ckpt->cp_pack_start_sum = cpu_to_le32(1 + orphan_blocks);

	if (is_umount) {
	set_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
	ckpt->cp_pack_total_block_count = cpu_to_le32(2 +
	data_sum_blocks + orphan_blocks + NR_CURSEG_NODE_TYPE);
	} else {
	clear_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
	ckpt->cp_pack_total_block_count = cpu_to_le32(2 +
	data_sum_blocks + orphan_blocks);
	}

	if (sbi->n_orphans)
	set_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);
	else
	clear_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);

	/* update SIT/NAT bitmap */
	get_sit_bitmap(sbi, __bitmap_ptr(sbi, SIT_BITMAP));
	get_nat_bitmap(sbi, __bitmap_ptr(sbi, NAT_BITMAP));

	crc32 = f2fs_crc32(ckpt, le32_to_cpu(ckpt->checksum_offset));
	(__le32 )((unsigned char *)ckpt +
	le32_to_cpu(ckpt->checksum_offset))
	= cpu_to_le32(crc32);

	start_blk = __start_cp_addr(sbi);

	/* write out checkpoint buffer at block 0 */
	cp_page = grab_meta_page(sbi, start_blk++);
	kaddr = page_address(cp_page);
	memcpy(kaddr, ckpt, (1 << sbi->log_blocksize));
	set_page_dirty(cp_page);
	f2fs_put_page(cp_page, 1);

	if (sbi->n_orphans) {
	write_orphan_inodes(sbi, start_blk);
	start_blk += orphan_blocks;
	}

	write_data_summaries(sbi, start_blk);
	start_blk += data_sum_blocks;
	if (is_umount) {
	write_node_summaries(sbi, start_blk);
	start_blk += NR_CURSEG_NODE_TYPE;
	}

	/* writeout checkpoint block */
	cp_page = grab_meta_page(sbi, start_blk);
	kaddr = page_address(cp_page);
	memcpy(kaddr, ckpt, (1 << sbi->log_blocksize));
	set_page_dirty(cp_page);
	f2fs_put_page(cp_page, 1);

	/* wait for previous submitted node/meta pages writeback */
	while (get_pages(sbi, F2FS_WRITEBACK))
	congestion_wait(BLK_RW_ASYNC, HZ / 50);

	filemap_fdatawait_range(sbi->node_inode->i_mapping, 0, LONG_MAX);
	filemap_fdatawait_range(sbi->meta_inode->i_mapping, 0, LONG_MAX);

	/* update user_block_counts */
	sbi->last_valid_block_count = sbi->total_valid_block_count;
	sbi->alloc_valid_block_count = 0;

	/* Here, we only have one bio having CP pack */
	sync_meta_pages(sbi, META_FLUSH, LONG_MAX);

	if (!is_set_ckpt_flags(ckpt, CP_ERROR_FLAG)) {
	clear_prefree_segments(sbi);
	F2FS_RESET_SB_DIRT(sbi);
	}
	}

	/*
	* We guarantee that this checkpoint procedure should not fail.
	*/
	void write_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
	{
	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
	unsigned long long ckpt_ver;

	mutex_lock(&sbi->cp_mutex);
	block_operations(sbi);

	f2fs_submit_bio(sbi, DATA, true);
	f2fs_submit_bio(sbi, NODE, true);
	f2fs_submit_bio(sbi, META, true);

	/*
	* update checkpoint pack index
	* Increase the version number so that
	* SIT entries and seg summaries are written at correct place
	*/
	ckpt_ver = le64_to_cpu(ckpt->checkpoint_ver);
	ckpt->checkpoint_ver = cpu_to_le64(++ckpt_ver);

	/* write cached NAT/SIT entries to NAT/SIT area */
	flush_nat_entries(sbi);
	flush_sit_entries(sbi);

	reset_victim_segmap(sbi);

	/* unlock all the fs_lock[] in do_checkpoint() */
	do_checkpoint(sbi, is_umount);

	unblock_operations(sbi);
	mutex_unlock(&sbi->cp_mutex);
	}

	void init_orphan_info(struct f2fs_sb_info *sbi)
	{
	mutex_init(&sbi->orphan_inode_mutex);
	INIT_LIST_HEAD(&sbi->orphan_inode_list);
	sbi->n_orphans = 0;
	}

	int __init create_checkpoint_caches(void)
	{
	orphan_entry_slab = f2fs_kmem_cache_create("f2fs_orphan_entry",
	sizeof(struct orphan_inode_entry), NULL);
	if (unlikely(!orphan_entry_slab))
	return -ENOMEM;
	inode_entry_slab = f2fs_kmem_cache_create("f2fs_dirty_dir_entry",
	sizeof(struct dir_inode_entry), NULL);
	if (unlikely(!inode_entry_slab)) {
	kmem_cache_destroy(orphan_entry_slab);
	return -ENOMEM;
	}
	return 0;
	}

	void destroy_checkpoint_caches(void)
	{
	kmem_cache_destroy(orphan_entry_slab);
	kmem_cache_destroy(inode_entry_slab);
	}