/*
 * 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"
#include <trace/events/f2fs.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 (PageUptodate(page))
                goto out;

        if (f2fs_readpage(sbi, page, index, READ_SYNC))
                goto repeat;

        lock_page(page);
        if (page->mapping != mapping) {
                f2fs_put_page(page, 1);
                goto repeat;
        }
out:
        mark_page_accessed(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;
        size_t crc_offset;
        __u32 crc = 0;

        /* 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 = le32_to_cpu(*((__u32 *)((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 = le32_to_cpu(*((__u32 *)((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;
}

static int __add_dirty_inode(struct inode *inode, struct dir_inode_entry *new)
{
        struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
        struct list_head *head = &sbi->dir_inode_list;
        struct list_head *this;

        list_for_each(this, head) {
                struct dir_inode_entry *entry;
                entry = list_entry(this, struct dir_inode_entry, list);
                if (entry->inode == inode)
                        return -EEXIST;
        }
        list_add_tail(&new->list, head);
#ifdef CONFIG_F2FS_STAT_FS
        sbi->n_dirty_dirs++;
#endif
        return 0;
}

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

        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);
        if (__add_dirty_inode(inode, new))
                kmem_cache_free(inode_entry_slab, new);

        inc_page_count(sbi, F2FS_DIRTY_DENTS);
        inode_inc_dirty_dents(inode);
        SetPagePrivate(page);
        spin_unlock(&sbi->dir_inode_lock);
}

void add_dirty_dir_inode(struct inode *inode)
{
        struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
        struct dir_inode_entry *new;
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);
        if (__add_dirty_inode(inode, new))
                kmem_cache_free(inode_entry_slab, new);
        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)) {
                spin_unlock(&sbi->dir_inode_lock);
                return;
        }

        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);
#ifdef CONFIG_F2FS_STAT_FS
                        sbi->n_dirty_dirs--;
#endif
                        break;
                }
        }
        spin_unlock(&sbi->dir_inode_lock);

        /* Only from the recovery routine */
        if (is_inode_flag_set(F2FS_I(inode), FI_DELAY_IPUT)) {
                clear_inode_flag(F2FS_I(inode), FI_DELAY_IPUT);
                iput(inode);
        }
}

struct inode *check_dirty_dir_inode(struct f2fs_sb_info *sbi, nid_t ino)
{
        struct list_head *head = &sbi->dir_inode_list;
        struct list_head *this;
        struct inode *inode = NULL;

        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->i_ino == ino) {
                        inode = entry->inode;
                        break;
                }
        }
        spin_unlock(&sbi->dir_inode_lock);
        return inode;
}

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)
{
        struct writeback_control wbc = {
                .sync_mode = WB_SYNC_ALL,
                .nr_to_write = LONG_MAX,
                .for_reclaim = 0,
        };
        struct blk_plug plug;

        blk_start_plug(&plug);

retry_flush_dents:
        mutex_lock_all(sbi);

        /* write all the dirty dentry pages */
        if (get_pages(sbi, F2FS_DIRTY_DENTS)) {
                mutex_unlock_all(sbi);
                sync_dirty_dir_inodes(sbi);
                goto retry_flush_dents;
        }

        /*
         * POR: we should ensure that there is no dirty node pages
         * until finishing nat/sit flush.
         */
retry_flush_nodes:
        mutex_lock(&sbi->node_write);

        if (get_pages(sbi, F2FS_DIRTY_NODES)) {
                mutex_unlock(&sbi->node_write);
                sync_node_pages(sbi, 0, &wbc);
                goto retry_flush_nodes;
        }
        blk_finish_plug(&plug);
}

static void unblock_operations(struct f2fs_sb_info *sbi)
{
        mutex_unlock(&sbi->node_write);
        mutex_unlock_all(sbi);
}

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;
        __u32 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;

        trace_f2fs_write_checkpoint(sbi->sb, is_umount, "start block_ops");

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

        trace_f2fs_write_checkpoint(sbi->sb, is_umount, "finish block_ops");

        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);

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

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

        trace_f2fs_write_checkpoint(sbi->sb, is_umount, "finish checkpoint");
}

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);
}