/*

   * 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.h"

  #include <trace/events/f2fs.h>

  static struct kmem_cache *ino_entry_slab;

  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 = META_MAPPING(sbi);

  	struct page *page = NULL;
  repeat:

  	page = grab_cache_page(mapping, index);

  	if (!page) {
  		cond_resched();
  		goto repeat;
  	}

  	f2fs_wait_on_page_writeback(page, META);

  	SetPageUptodate(page);
  	return page;
  }

  /*

   * We guarantee no failure on the returned page.
   */

  static struct page *__get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index,
  							bool is_meta)

  {

  	struct address_space *mapping = META_MAPPING(sbi);

  	struct page *page;

  	struct f2fs_io_info fio = {

  		.sbi = sbi,

  		.type = META,
  		.rw = READ_SYNC | REQ_META | REQ_PRIO,
  		.blk_addr = index,

  		.encrypted_page = NULL,

  	};

  
  	if (unlikely(!is_meta))
  		fio.rw &= ~REQ_META;

  repeat:
  	page = grab_cache_page(mapping, index);
  	if (!page) {
  		cond_resched();
  		goto repeat;
  	}

  	if (PageUptodate(page))
  		goto out;

  	fio.page = page;

  	if (f2fs_submit_page_bio(&fio)) {
  		f2fs_put_page(page, 1);

  		goto repeat;

  	}

  	lock_page(page);

  	if (unlikely(page->mapping != mapping)) {

  		f2fs_put_page(page, 1);
  		goto repeat;
  	}

  
  	/*
  	 * if there is any IO error when accessing device, make our filesystem
  	 * readonly and make sure do not write checkpoint with non-uptodate
  	 * meta page.
  	 */
  	if (unlikely(!PageUptodate(page)))
  		f2fs_stop_checkpoint(sbi);

  out:

  	return page;
  }

  struct page *get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
  {
  	return __get_meta_page(sbi, index, true);
  }
  
  /* for POR only */
  struct page *get_tmp_page(struct f2fs_sb_info *sbi, pgoff_t index)
  {
  	return __get_meta_page(sbi, index, false);
  }

  bool is_valid_blkaddr(struct f2fs_sb_info *sbi, block_t blkaddr, int type)

  {
  	switch (type) {
  	case META_NAT:

  		break;

  	case META_SIT:

  		if (unlikely(blkaddr >= SIT_BLK_CNT(sbi)))
  			return false;
  		break;

  	case META_SSA:

  		if (unlikely(blkaddr >= MAIN_BLKADDR(sbi) ||
  			blkaddr < SM_I(sbi)->ssa_blkaddr))
  			return false;
  		break;

  	case META_CP:

  		if (unlikely(blkaddr >= SIT_I(sbi)->sit_base_addr ||
  			blkaddr < __start_cp_addr(sbi)))
  			return false;
  		break;

  	case META_POR:

  		if (unlikely(blkaddr >= MAX_BLKADDR(sbi) ||
  			blkaddr < MAIN_BLKADDR(sbi)))
  			return false;
  		break;

  	default:
  		BUG();
  	}

  
  	return true;

  }
  
  /*

   * Readahead CP/NAT/SIT/SSA pages

   */

  int ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
  							int type, bool sync)

  {
  	block_t prev_blk_addr = 0;
  	struct page *page;

  	block_t blkno = start;

  	struct f2fs_io_info fio = {

  		.sbi = sbi,

  		.type = META,

  		.rw = sync ? (READ_SYNC | REQ_META | REQ_PRIO) : READA,

  		.encrypted_page = NULL,

  	};

  	if (unlikely(type == META_POR))
  		fio.rw &= ~REQ_META;

  	for (; nrpages-- > 0; blkno++) {

  		if (!is_valid_blkaddr(sbi, blkno, type))
  			goto out;

  		switch (type) {
  		case META_NAT:

  			if (unlikely(blkno >=
  					NAT_BLOCK_OFFSET(NM_I(sbi)->max_nid)))

  				blkno = 0;

  			/* get nat block addr */

  			fio.blk_addr = current_nat_addr(sbi,

  					blkno * NAT_ENTRY_PER_BLOCK);
  			break;
  		case META_SIT:
  			/* get sit block addr */

  			fio.blk_addr = current_sit_addr(sbi,

  					blkno * SIT_ENTRY_PER_BLOCK);

  			if (blkno != start && prev_blk_addr + 1 != fio.blk_addr)

  				goto out;

  			prev_blk_addr = fio.blk_addr;

  			break;

  		case META_SSA:

  		case META_CP:

  		case META_POR:

  			fio.blk_addr = blkno;

  			break;
  		default:
  			BUG();
  		}

  		page = grab_cache_page(META_MAPPING(sbi), fio.blk_addr);

  		if (!page)
  			continue;
  		if (PageUptodate(page)) {

  			f2fs_put_page(page, 1);
  			continue;
  		}

  		fio.page = page;
  		f2fs_submit_page_mbio(&fio);

  		f2fs_put_page(page, 0);
  	}
  out:
  	f2fs_submit_merged_bio(sbi, META, READ);
  	return blkno - start;
  }

  void ra_meta_pages_cond(struct f2fs_sb_info *sbi, pgoff_t index)
  {
  	struct page *page;
  	bool readahead = false;
  
  	page = find_get_page(META_MAPPING(sbi), index);
  	if (!page || (page && !PageUptodate(page)))
  		readahead = true;
  	f2fs_put_page(page, 0);
  
  	if (readahead)

  		ra_meta_pages(sbi, index, MAX_BIO_BLOCKS(sbi), META_POR, true);

  }

  static int f2fs_write_meta_page(struct page *page,
  				struct writeback_control *wbc)
  {

  	struct f2fs_sb_info *sbi = F2FS_P_SB(page);

  	trace_f2fs_writepage(page, META);

  	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))

  		goto redirty_out;

  	if (wbc->for_reclaim && page->index < GET_SUM_BLOCK(sbi, 0))

  		goto redirty_out;

  	if (unlikely(f2fs_cp_error(sbi)))

  		goto redirty_out;

  	f2fs_wait_on_page_writeback(page, META);

  	write_meta_page(sbi, page);
  	dec_page_count(sbi, F2FS_DIRTY_META);
  	unlock_page(page);

  	if (wbc->for_reclaim || unlikely(f2fs_cp_error(sbi)))

  		f2fs_submit_merged_bio(sbi, META, WRITE);

  	return 0;

  
  redirty_out:

  	redirty_page_for_writepage(wbc, page);

  	return AOP_WRITEPAGE_ACTIVATE;

  }
  
  static int f2fs_write_meta_pages(struct address_space *mapping,
  				struct writeback_control *wbc)
  {

  	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);

  	long diff, written;

  	trace_f2fs_writepages(mapping->host, wbc, META);

  	/* collect a number of dirty meta pages and write together */

  	if (wbc->for_kupdate ||
  		get_pages(sbi, F2FS_DIRTY_META) < nr_pages_to_skip(sbi, META))

  		goto skip_write;

  
  	/* if mounting is failed, skip writing node pages */
  	mutex_lock(&sbi->cp_mutex);

  	diff = nr_pages_to_write(sbi, META, wbc);
  	written = sync_meta_pages(sbi, META, wbc->nr_to_write);

  	mutex_unlock(&sbi->cp_mutex);

  	wbc->nr_to_write = max((long)0, wbc->nr_to_write - written - diff);

  	return 0;

  
  skip_write:
  	wbc->pages_skipped += get_pages(sbi, F2FS_DIRTY_META);
  	return 0;

  }
  
  long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
  						long nr_to_write)
  {

  	struct address_space *mapping = META_MAPPING(sbi);

  	pgoff_t index = 0, end = LONG_MAX, prev = 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 (unlikely(nr_pages == 0))

  			break;
  
  		for (i = 0; i < nr_pages; i++) {
  			struct page *page = pvec.pages[i];

  			if (prev == LONG_MAX)
  				prev = page->index - 1;
  			if (nr_to_write != LONG_MAX && page->index != prev + 1) {
  				pagevec_release(&pvec);
  				goto stop;
  			}

  			lock_page(page);

  
  			if (unlikely(page->mapping != mapping)) {
  continue_unlock:
  				unlock_page(page);
  				continue;
  			}
  			if (!PageDirty(page)) {
  				/* someone wrote it for us */
  				goto continue_unlock;
  			}
  
  			if (!clear_page_dirty_for_io(page))
  				goto continue_unlock;

  			if (mapping->a_ops->writepage(page, &wbc)) {

  				unlock_page(page);
  				break;
  			}

  			nwritten++;

  			prev = page->index;

  			if (unlikely(nwritten >= nr_to_write))

  				break;
  		}
  		pagevec_release(&pvec);
  		cond_resched();
  	}

  stop:

  	if (nwritten)

  		f2fs_submit_merged_bio(sbi, type, WRITE);

  
  	return nwritten;
  }
  
  static int f2fs_set_meta_page_dirty(struct page *page)
  {

  	trace_f2fs_set_page_dirty(page, META);

  	SetPageUptodate(page);
  	if (!PageDirty(page)) {
  		__set_page_dirty_nobuffers(page);

  		inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_META);

  		SetPagePrivate(page);

  		f2fs_trace_pid(page);

  		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,

  	.invalidatepage = f2fs_invalidate_page,
  	.releasepage	= f2fs_release_page,

  };

  static void __add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

  {

  	struct inode_management *im = &sbi->im[type];

  	struct ino_entry *e, *tmp;
  
  	tmp = f2fs_kmem_cache_alloc(ino_entry_slab, GFP_NOFS);

  retry:

  	radix_tree_preload(GFP_NOFS | __GFP_NOFAIL);

  	spin_lock(&im->ino_lock);

  	e = radix_tree_lookup(&im->ino_root, ino);

  	if (!e) {

  		e = tmp;

  		if (radix_tree_insert(&im->ino_root, ino, e)) {
  			spin_unlock(&im->ino_lock);

  			radix_tree_preload_end();

  			goto retry;
  		}
  		memset(e, 0, sizeof(struct ino_entry));
  		e->ino = ino;

  		list_add_tail(&e->list, &im->ino_list);

  		if (type != ORPHAN_INO)

  			im->ino_num++;

  	}

  	spin_unlock(&im->ino_lock);

  	radix_tree_preload_end();

  
  	if (e != tmp)
  		kmem_cache_free(ino_entry_slab, tmp);

  }

  static void __remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

  {

  	struct inode_management *im = &sbi->im[type];

  	struct ino_entry *e;

  	spin_lock(&im->ino_lock);
  	e = radix_tree_lookup(&im->ino_root, ino);

  	if (e) {
  		list_del(&e->list);

  		radix_tree_delete(&im->ino_root, ino);
  		im->ino_num--;
  		spin_unlock(&im->ino_lock);

  		kmem_cache_free(ino_entry_slab, e);
  		return;

  	}

  	spin_unlock(&im->ino_lock);

  }

  void add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

  {
  	/* add new dirty ino entry into list */
  	__add_ino_entry(sbi, ino, type);
  }

  void remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)

  {
  	/* remove dirty ino entry from list */
  	__remove_ino_entry(sbi, ino, type);
  }
  
  /* mode should be APPEND_INO or UPDATE_INO */
  bool exist_written_data(struct f2fs_sb_info *sbi, nid_t ino, int mode)
  {

  	struct inode_management *im = &sbi->im[mode];

  	struct ino_entry *e;

  
  	spin_lock(&im->ino_lock);
  	e = radix_tree_lookup(&im->ino_root, ino);
  	spin_unlock(&im->ino_lock);

  	return e ? true : false;
  }

  void release_ino_entry(struct f2fs_sb_info *sbi)

  {
  	struct ino_entry *e, *tmp;
  	int i;
  
  	for (i = APPEND_INO; i <= UPDATE_INO; i++) {

  		struct inode_management *im = &sbi->im[i];
  
  		spin_lock(&im->ino_lock);
  		list_for_each_entry_safe(e, tmp, &im->ino_list, list) {

  			list_del(&e->list);

  			radix_tree_delete(&im->ino_root, e->ino);

  			kmem_cache_free(ino_entry_slab, e);

  			im->ino_num--;

  		}

  		spin_unlock(&im->ino_lock);

  	}
  }

  int acquire_orphan_inode(struct f2fs_sb_info *sbi)

  {

  	struct inode_management *im = &sbi->im[ORPHAN_INO];

  	int err = 0;

  	spin_lock(&im->ino_lock);
  	if (unlikely(im->ino_num >= sbi->max_orphans))

  		err = -ENOSPC;

  	else

  		im->ino_num++;
  	spin_unlock(&im->ino_lock);

  	return err;
  }

  void release_orphan_inode(struct f2fs_sb_info *sbi)
  {

  	struct inode_management *im = &sbi->im[ORPHAN_INO];
  
  	spin_lock(&im->ino_lock);
  	f2fs_bug_on(sbi, im->ino_num == 0);
  	im->ino_num--;
  	spin_unlock(&im->ino_lock);

  }

  void add_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
  {

  	/* add new orphan ino entry into list */

  	__add_ino_entry(sbi, ino, ORPHAN_INO);

  }
  
  void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
  {

  	/* remove orphan entry from orphan list */

  	__remove_ino_entry(sbi, ino, ORPHAN_INO);

  }

  static int recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)

  {

  	struct inode *inode;
  
  	inode = f2fs_iget(sbi->sb, ino);
  	if (IS_ERR(inode)) {
  		/*
  		 * there should be a bug that we can't find the entry
  		 * to orphan inode.
  		 */
  		f2fs_bug_on(sbi, PTR_ERR(inode) == -ENOENT);
  		return PTR_ERR(inode);
  	}

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

  	return 0;

  }

  int recover_orphan_inodes(struct f2fs_sb_info *sbi)

  {

  	block_t start_blk, orphan_blocks, i, j;

  	int err;

  	if (!is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG))

  		return 0;

  	start_blk = __start_cp_addr(sbi) + 1 + __cp_payload(sbi);

  	orphan_blocks = __start_sum_addr(sbi) - 1 - __cp_payload(sbi);

  	ra_meta_pages(sbi, start_blk, orphan_blocks, META_CP, true);

  	for (i = 0; i < orphan_blocks; 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]);

  			err = recover_orphan_inode(sbi, ino);
  			if (err) {
  				f2fs_put_page(page, 1);

  				return err;
  			}

  		}
  		f2fs_put_page(page, 1);
  	}
  	/* clear Orphan Flag */

  	clear_ckpt_flags(F2FS_CKPT(sbi), CP_ORPHAN_PRESENT_FLAG);

  	return 0;

  }
  
  static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
  {

  	struct list_head *head;

  	struct f2fs_orphan_block *orphan_blk = NULL;

  	unsigned int nentries = 0;

  	unsigned short index = 1;

  	unsigned short orphan_blocks;

  	struct page *page = NULL;

  	struct ino_entry *orphan = NULL;

  	struct inode_management *im = &sbi->im[ORPHAN_INO];

  	orphan_blocks = GET_ORPHAN_BLOCKS(im->ino_num);

  	/*
  	 * we don't need to do spin_lock(&im->ino_lock) here, since all the
  	 * orphan inode operations are covered under f2fs_lock_op().
  	 * And, spin_lock should be avoided due to page operations below.
  	 */

  	head = &im->ino_list;

  
  	/* loop for each orphan inode entry and write them in Jornal block */

  	list_for_each_entry(orphan, head, list) {
  		if (!page) {

  			page = grab_meta_page(sbi, start_blk++);

  			orphan_blk =
  				(struct f2fs_orphan_block *)page_address(page);
  			memset(orphan_blk, 0, sizeof(*orphan_blk));
  		}

  		orphan_blk->ino[nentries++] = cpu_to_le32(orphan->ino);

  		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++;

  			nentries = 0;
  			page = NULL;
  		}

  	}

  	if (page) {
  		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);

  	}

  }
  
  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(*((__le32 *)((unsigned char *)cp_block + crc_offset)));

  	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
  		goto invalid_cp1;

  	pre_version = cur_cp_version(cp_block);

  
  	/* 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(*((__le32 *)((unsigned char *)cp_block + crc_offset)));

  	if (!f2fs_crc_valid(crc, cp_block, crc_offset))
  		goto invalid_cp2;

  	cur_version = cur_cp_version(cp_block);

  
  	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;

  	unsigned int cp_blks = 1 + __cp_payload(sbi);

  	block_t cp_blk_no;
  	int i;

  	sbi->ckpt = kzalloc(cp_blks * 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 += ((unsigned long long)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);

  	if (cp_blks <= 1)
  		goto done;
  
  	cp_blk_no = le32_to_cpu(fsb->cp_blkaddr);
  	if (cur_page == cp2)
  		cp_blk_no += 1 << le32_to_cpu(fsb->log_blocks_per_seg);
  
  	for (i = 1; i < cp_blks; i++) {
  		void *sit_bitmap_ptr;
  		unsigned char *ckpt = (unsigned char *)sbi->ckpt;
  
  		cur_page = get_meta_page(sbi, cp_blk_no + i);
  		sit_bitmap_ptr = page_address(cur_page);
  		memcpy(ckpt + i * blk_size, sit_bitmap_ptr, blk_size);
  		f2fs_put_page(cur_page, 1);
  	}
  done:

  	f2fs_put_page(cp1, 1);
  	f2fs_put_page(cp2, 1);
  	return 0;
  
  fail_no_cp:
  	kfree(sbi->ckpt);
  	return -EINVAL;
  }

  static void __add_dirty_inode(struct inode *inode, enum inode_type type)

  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	struct f2fs_inode_info *fi = F2FS_I(inode);

  	int flag = (type == DIR_INODE) ? FI_DIRTY_DIR : FI_DIRTY_FILE;

  	if (is_inode_flag_set(fi, flag))

  		return;

  	set_inode_flag(fi, flag);
  	list_add_tail(&fi->dirty_list, &sbi->inode_list[type]);

  	stat_inc_dirty_inode(sbi, type);

  }

  static void __remove_dirty_inode(struct inode *inode, enum inode_type type)

  {

  	struct f2fs_inode_info *fi = F2FS_I(inode);

  	int flag = (type == DIR_INODE) ? FI_DIRTY_DIR : FI_DIRTY_FILE;

  
  	if (get_dirty_pages(inode) ||

  			!is_inode_flag_set(F2FS_I(inode), flag))

  		return;
  
  	list_del_init(&fi->dirty_list);

  	clear_inode_flag(fi, flag);

  	stat_dec_dirty_inode(F2FS_I_SB(inode), type);

  }

  void update_dirty_page(struct inode *inode, struct page *page)

  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	enum inode_type type = S_ISDIR(inode->i_mode) ? DIR_INODE : FILE_INODE;

  	if (!S_ISDIR(inode->i_mode) && !S_ISREG(inode->i_mode) &&
  			!S_ISLNK(inode->i_mode))

  		return;

  	spin_lock(&sbi->inode_lock[type]);
  	__add_dirty_inode(inode, type);

  	inode_inc_dirty_pages(inode);

  	spin_unlock(&sbi->inode_lock[type]);

  	SetPagePrivate(page);

  	f2fs_trace_pid(page);

  }
  
  void add_dirty_dir_inode(struct inode *inode)
  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	spin_lock(&sbi->inode_lock[DIR_INODE]);
  	__add_dirty_inode(inode, DIR_INODE);
  	spin_unlock(&sbi->inode_lock[DIR_INODE]);

  }

  void remove_dirty_inode(struct inode *inode)

  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	struct f2fs_inode_info *fi = F2FS_I(inode);

  	enum inode_type type = S_ISDIR(inode->i_mode) ? DIR_INODE : FILE_INODE;

  	if (!S_ISDIR(inode->i_mode) && !S_ISREG(inode->i_mode) &&
  			!S_ISLNK(inode->i_mode))

  		return;

  	spin_lock(&sbi->inode_lock[type]);
  	__remove_dirty_inode(inode, type);
  	spin_unlock(&sbi->inode_lock[type]);

  
  	/* Only from the recovery routine */

  	if (is_inode_flag_set(fi, FI_DELAY_IPUT)) {
  		clear_inode_flag(fi, FI_DELAY_IPUT);

  		iput(inode);

  	}

  }

  int sync_dirty_inodes(struct f2fs_sb_info *sbi, enum inode_type type)

  {

  	struct list_head *head;

  	struct inode *inode;

  	struct f2fs_inode_info *fi;

  	bool is_dir = (type == DIR_INODE);
  
  	trace_f2fs_sync_dirty_inodes_enter(sbi->sb, is_dir,
  				get_pages(sbi, is_dir ?
  				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA));

  retry:

  	if (unlikely(f2fs_cp_error(sbi)))

  		return -EIO;

  	spin_lock(&sbi->inode_lock[type]);

  	head = &sbi->inode_list[type];

  	if (list_empty(head)) {

  		spin_unlock(&sbi->inode_lock[type]);

  		trace_f2fs_sync_dirty_inodes_exit(sbi->sb, is_dir,
  				get_pages(sbi, is_dir ?
  				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA));

  		return 0;

  	}

  	fi = list_entry(head->next, struct f2fs_inode_info, dirty_list);
  	inode = igrab(&fi->vfs_inode);

  	spin_unlock(&sbi->inode_lock[type]);

  	if (inode) {

  		filemap_fdatawrite(inode->i_mapping);

  		iput(inode);
  	} else {
  		/*
  		 * We should submit bio, since it exists several
  		 * wribacking dentry pages in the freeing inode.
  		 */

  		f2fs_submit_merged_bio(sbi, DATA, WRITE);

  		cond_resched();

  	}
  	goto retry;
  }

  /*

   * Freeze all the FS-operations for checkpoint.
   */

  static int 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;

  	int err = 0;

  
  	blk_start_plug(&plug);

  retry_flush_dents:

  	f2fs_lock_all(sbi);

  	/* write all the dirty dentry pages */

  	if (get_pages(sbi, F2FS_DIRTY_DENTS)) {

  		f2fs_unlock_all(sbi);

  		err = sync_dirty_inodes(sbi, DIR_INODE);
  		if (err)

  			goto out;

  		goto retry_flush_dents;

  	}

  	/*

  	 * POR: we should ensure that there are no dirty node pages

  	 * until finishing nat/sit flush.
  	 */

  retry_flush_nodes:

  	down_write(&sbi->node_write);

  
  	if (get_pages(sbi, F2FS_DIRTY_NODES)) {

  		up_write(&sbi->node_write);

  		err = sync_node_pages(sbi, 0, &wbc);
  		if (err) {

  			f2fs_unlock_all(sbi);

  			goto out;
  		}

  		goto retry_flush_nodes;

  	}

  out:

  	blk_finish_plug(&plug);

  	return err;

  }
  
  static void unblock_operations(struct f2fs_sb_info *sbi)
  {

  	up_write(&sbi->node_write);

  	f2fs_unlock_all(sbi);

  }

  static void wait_on_all_pages_writeback(struct f2fs_sb_info *sbi)
  {
  	DEFINE_WAIT(wait);
  
  	for (;;) {
  		prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE);
  
  		if (!get_pages(sbi, F2FS_WRITEBACK))
  			break;
  
  		io_schedule();
  	}
  	finish_wait(&sbi->cp_wait, &wait);
  }

  static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)

  {
  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);

  	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);

  	struct f2fs_nm_info *nm_i = NM_I(sbi);

  	unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num;

  	nid_t last_nid = nm_i->next_scan_nid;

  	block_t start_blk;

  	unsigned int data_sum_blocks, orphan_blocks;

  	__u32 crc32 = 0;

  	int i;

  	int cp_payload_blks = __cp_payload(sbi);

  	block_t discard_blk = NEXT_FREE_BLKADDR(sbi, curseg);
  	bool invalidate = false;

  	/*
  	 * This avoids to conduct wrong roll-forward operations and uses
  	 * metapages, so should be called prior to sync_meta_pages below.
  	 */

  	if (discard_next_dnode(sbi, discard_blk))
  		invalidate = true;

  
  	/* Flush all the NAT/SIT pages */

  	while (get_pages(sbi, F2FS_DIRTY_META)) {

  		sync_meta_pages(sbi, META, LONG_MAX);

  		if (unlikely(f2fs_cp_error(sbi)))

  			return -EIO;

  	}

  
  	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 < NR_CURSEG_NODE_TYPE; 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 < NR_CURSEG_DATA_TYPE; 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, false);

  	if (data_sum_blocks < NR_CURSEG_DATA_TYPE)

  		set_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);

  	else

  		clear_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);

  	orphan_blocks = GET_ORPHAN_BLOCKS(orphan_num);

  	ckpt->cp_pack_start_sum = cpu_to_le32(1 + cp_payload_blks +
  			orphan_blocks);

  	if (__remain_node_summaries(cpc->reason))

  		ckpt->cp_pack_total_block_count = cpu_to_le32(F2FS_CP_PACKS+

  				cp_payload_blks + data_sum_blocks +
  				orphan_blocks + NR_CURSEG_NODE_TYPE);

  	else

  		ckpt->cp_pack_total_block_count = cpu_to_le32(F2FS_CP_PACKS +

  				cp_payload_blks + data_sum_blocks +
  				orphan_blocks);

  
  	if (cpc->reason == CP_UMOUNT)
  		set_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
  	else
  		clear_ckpt_flags(ckpt, CP_UMOUNT_FLAG);
  
  	if (cpc->reason == CP_FASTBOOT)
  		set_ckpt_flags(ckpt, CP_FASTBOOT_FLAG);
  	else
  		clear_ckpt_flags(ckpt, CP_FASTBOOT_FLAG);

  	if (orphan_num)

  		set_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);

  	else

  		clear_ckpt_flags(ckpt, CP_ORPHAN_PRESENT_FLAG);

  	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))

  		set_ckpt_flags(ckpt, CP_FSCK_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);

  	/* need to wait for end_io results */
  	wait_on_all_pages_writeback(sbi);
  	if (unlikely(f2fs_cp_error(sbi)))

  		return -EIO;

  	/* write out checkpoint buffer at block 0 */

  	update_meta_page(sbi, ckpt, start_blk++);
  
  	for (i = 1; i < 1 + cp_payload_blks; i++)
  		update_meta_page(sbi, (char *)ckpt + i * F2FS_BLKSIZE,
  							start_blk++);

  	if (orphan_num) {

  		write_orphan_inodes(sbi, start_blk);
  		start_blk += orphan_blocks;
  	}
  
  	write_data_summaries(sbi, start_blk);
  	start_blk += data_sum_blocks;

  	if (__remain_node_summaries(cpc->reason)) {

  		write_node_summaries(sbi, start_blk);
  		start_blk += NR_CURSEG_NODE_TYPE;
  	}
  
  	/* writeout checkpoint block */

  	update_meta_page(sbi, ckpt, start_blk);

  
  	/* wait for previous submitted node/meta pages writeback */

  	wait_on_all_pages_writeback(sbi);

  	if (unlikely(f2fs_cp_error(sbi)))

  		return -EIO;

  	filemap_fdatawait_range(NODE_MAPPING(sbi), 0, LONG_MAX);

  	filemap_fdatawait_range(META_MAPPING(sbi), 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);

  	/* wait for previous submitted meta pages writeback */
  	wait_on_all_pages_writeback(sbi);

  	/*
  	 * invalidate meta page which is used temporarily for zeroing out
  	 * block at the end of warm node chain.
  	 */
  	if (invalidate)
  		invalidate_mapping_pages(META_MAPPING(sbi), discard_blk,
  								discard_blk);

  	release_ino_entry(sbi);

  
  	if (unlikely(f2fs_cp_error(sbi)))

  		return -EIO;

  	clear_prefree_segments(sbi, cpc);

  	clear_sbi_flag(sbi, SBI_IS_DIRTY);

  
  	return 0;

  }

  /*

   * We guarantee that this checkpoint procedure will not fail.

   */

  int write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)

  {
  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
  	unsigned long long ckpt_ver;

  	int err = 0;

  	mutex_lock(&sbi->cp_mutex);

  	if (!is_sbi_flag_set(sbi, SBI_IS_DIRTY) &&

  		(cpc->reason == CP_FASTBOOT || cpc->reason == CP_SYNC ||
  		(cpc->reason == CP_DISCARD && !sbi->discard_blks)))

  		goto out;

  	if (unlikely(f2fs_cp_error(sbi))) {
  		err = -EIO;

  		goto out;

  	}
  	if (f2fs_readonly(sbi->sb)) {
  		err = -EROFS;

  		goto out;

  	}

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

  	err = block_operations(sbi);
  	if (err)

  		goto out;

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

  	f2fs_submit_merged_bio(sbi, DATA, WRITE);
  	f2fs_submit_merged_bio(sbi, NODE, WRITE);
  	f2fs_submit_merged_bio(sbi, META, WRITE);

  
  	/*
  	 * update checkpoint pack index
  	 * Increase the version number so that
  	 * SIT entries and seg summaries are written at correct place
  	 */

  	ckpt_ver = cur_cp_version(ckpt);

  	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, cpc);

  	/* unlock all the fs_lock[] in do_checkpoint() */

  	err = do_checkpoint(sbi, cpc);

  
  	unblock_operations(sbi);

  	stat_inc_cp_count(sbi->stat_info);

  
  	if (cpc->reason == CP_RECOVERY)
  		f2fs_msg(sbi->sb, KERN_NOTICE,
  			"checkpoint: version = %llx", ckpt_ver);

  
  	/* do checkpoint periodically */

  	f2fs_update_time(sbi, CP_TIME);

  	trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish checkpoint");

  out:
  	mutex_unlock(&sbi->cp_mutex);

  	return err;

  }

  void init_ino_entry_info(struct f2fs_sb_info *sbi)

  {

  	int i;
  
  	for (i = 0; i < MAX_INO_ENTRY; i++) {

  		struct inode_management *im = &sbi->im[i];
  
  		INIT_RADIX_TREE(&im->ino_root, GFP_ATOMIC);
  		spin_lock_init(&im->ino_lock);
  		INIT_LIST_HEAD(&im->ino_list);
  		im->ino_num = 0;

  	}

  	sbi->max_orphans = (sbi->blocks_per_seg - F2FS_CP_PACKS -

  			NR_CURSEG_TYPE - __cp_payload(sbi)) *
  				F2FS_ORPHANS_PER_BLOCK;

  }

  int __init create_checkpoint_caches(void)

  {

  	ino_entry_slab = f2fs_kmem_cache_create("f2fs_ino_entry",
  			sizeof(struct ino_entry));
  	if (!ino_entry_slab)

  		return -ENOMEM;

  	inode_entry_slab = f2fs_kmem_cache_create("f2fs_inode_entry",
  			sizeof(struct inode_entry));

  	if (!inode_entry_slab) {

  		kmem_cache_destroy(ino_entry_slab);

  		return -ENOMEM;
  	}
  	return 0;
  }
  
  void destroy_checkpoint_caches(void)
  {

  	kmem_cache_destroy(ino_entry_slab);

  	kmem_cache_destroy(inode_entry_slab);
  }