f2fs: add checkpoint operations

This adds functions required by the checkpoint operations.

Basically, f2fs adopts a roll-back model with checkpoint blocks written in the
CP area. The checkpoint procedure includes as follows.

- write_checkpoint()
1. block_operations() freezes VFS calls.
2. submit cached bios.
3. flush_nat_entries() writes NAT pages updated by dirty NAT entries.
4. flush_sit_entries() writes SIT pages updated by dirty SIT entries.
5. do_checkpoint() writes,
  - checkpoint block (#0)
  - orphan inode blocks
  - summary blocks made by active logs
  - checkpoint block (copy of #0)
6. unblock_opeations()

In order to provide an address space for meta pages, f2fs_sb_info has a special
inode, namely meta_inode. This patch also adds the address space operations for
meta_inode.
Signed-off-by: Chul Lee <chur.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/checkpoint.c

+/**
+ * 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);
+	int err;
+
+	wait_on_page_writeback(page);
+
+	err = write_meta_page(sbi, page, wbc);
+	if (err) {
+		wbc->pages_skipped++;
+		set_page_dirty(page);
+	}
+
+	dec_page_count(sbi, F2FS_DIRTY_META);
+
+	/* In this case, we should not unlock this page */
+	if (err != AOP_WRITEPAGE_ACTIVATE)
+		unlock_page(page);
+	return err;
+}
+
+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);
+			f2fs_write_meta_page(page, &wbc);
+			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);
+		F2FS_SET_SB_DIRT(sbi);
+		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;
+	INIT_LIST_HEAD(&new->list);
+
+	/* add new_oentry into list which is sorted by inode number */
+	if (orphan) {
+		struct orphan_inode_entry *prev;
+
+		/* get previous entry */
+		prev = list_entry(orphan->list.prev, typeof(*prev), list);
+		if (&prev->list != head)
+			/* insert new orphan inode entry */
+			list_add(&new->list, &prev->list);
+		else
+			list_add(&new->list, head);
+	} 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 (!(F2FS_CKPT(sbi)->ckpt_flags & 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 */
+	F2FS_CKPT(sbi)->ckpt_flags &= (~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 += le64_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.
+ */
+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;
+	void *kaddr;
+	__u32 crc32 = 0;
+	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)
+		ckpt->ckpt_flags |= CP_COMPACT_SUM_FLAG;
+	else
+		ckpt->ckpt_flags &= (~CP_COMPACT_SUM_FLAG);
+
+	orphan_blocks = (sbi->n_orphans + F2FS_ORPHANS_PER_BLOCK - 1)
+					/ F2FS_ORPHANS_PER_BLOCK;
+	ckpt->cp_pack_start_sum = 1 + orphan_blocks;
+	ckpt->cp_pack_total_block_count = 2 + data_sum_blocks + orphan_blocks;
+
+	if (is_umount) {
+		ckpt->ckpt_flags |= CP_UMOUNT_FLAG;
+		ckpt->cp_pack_total_block_count += NR_CURSEG_NODE_TYPE;
+	} else {
+		ckpt->ckpt_flags &= (~CP_UMOUNT_FLAG);
+	}
+
+	if (sbi->n_orphans)
+		ckpt->ckpt_flags |= CP_ORPHAN_PRESENT_FLAG;
+	else
+		ckpt->ckpt_flags &= (~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));
+	*(__u32 *)((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 */
+	if (sbi->ckpt->ckpt_flags & CP_ERROR_FLAG)
+		sbi->sb->s_flags |= MS_RDONLY;
+	else
+		sync_meta_pages(sbi, META_FLUSH, LONG_MAX);
+
+	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 blocked, bool is_umount)
+{
+	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
+	unsigned long long ckpt_ver;
+
+	if (!blocked) {
+		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 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);
+}