// SPDX-License-Identifier: GPL-2.0

  /*

   * fs/f2fs/checkpoint.c
   *
   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   *             http://www.samsung.com/

   */
  #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 *f2fs_inode_entry_slab;

  void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io)
  {

  	f2fs_build_fault_attr(sbi, 0, 0);

  	set_ckpt_flags(sbi, CP_ERROR_FLAG);

  	if (!end_io)

  		f2fs_flush_merged_writes(sbi);

  }

  /*

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

  struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)

  {

  	struct address_space *mapping = META_MAPPING(sbi);

  	struct page *page;

  repeat:

  	page = f2fs_grab_cache_page(mapping, index, false);

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

  	f2fs_wait_on_page_writeback(page, META, true, true);

  	if (!PageUptodate(page))
  		SetPageUptodate(page);

  	return 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,

  		.op = REQ_OP_READ,

  		.op_flags = REQ_META | REQ_PRIO,

  		.old_blkaddr = index,
  		.new_blkaddr = index,

  		.encrypted_page = NULL,

  		.is_por = !is_meta,

  	};

  	int err;

  
  	if (unlikely(!is_meta))

  		fio.op_flags &= ~REQ_META;

  repeat:

  	page = f2fs_grab_cache_page(mapping, index, false);

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

  	if (PageUptodate(page))
  		goto out;

  	fio.page = page;

  	err = f2fs_submit_page_bio(&fio);
  	if (err) {
  		f2fs_put_page(page, 1);
  		return ERR_PTR(err);

  	}

  	f2fs_update_iostat(sbi, FS_META_READ_IO, F2FS_BLKSIZE);

  	lock_page(page);

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

  		f2fs_put_page(page, 1);
  		goto repeat;
  	}

  	if (unlikely(!PageUptodate(page))) {

  		f2fs_put_page(page, 1);
  		return ERR_PTR(-EIO);

  	}

  out:

  	return page;
  }

  struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)

  {
  	return __get_meta_page(sbi, index, true);
  }

  struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index)

  {
  	struct page *page;
  	int count = 0;
  
  retry:
  	page = __get_meta_page(sbi, index, true);
  	if (IS_ERR(page)) {
  		if (PTR_ERR(page) == -EIO &&
  				++count <= DEFAULT_RETRY_IO_COUNT)
  			goto retry;

  		f2fs_stop_checkpoint(sbi, false);

  	}

  	return page;
  }

  /* for POR only */

  struct page *f2fs_get_tmp_page(struct f2fs_sb_info *sbi, pgoff_t index)

  {
  	return __get_meta_page(sbi, index, false);
  }

  static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr,
  							int type)
  {
  	struct seg_entry *se;
  	unsigned int segno, offset;
  	bool exist;
  
  	if (type != DATA_GENERIC_ENHANCE && type != DATA_GENERIC_ENHANCE_READ)
  		return true;
  
  	segno = GET_SEGNO(sbi, blkaddr);
  	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
  	se = get_seg_entry(sbi, segno);
  
  	exist = f2fs_test_bit(offset, se->cur_valid_map);
  	if (!exist && type == DATA_GENERIC_ENHANCE) {

  		f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d",
  			 blkaddr, exist);

  		set_sbi_flag(sbi, SBI_NEED_FSCK);
  		WARN_ON(1);
  	}
  	return exist;
  }

  bool f2fs_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;

  	case DATA_GENERIC:

  	case DATA_GENERIC_ENHANCE:
  	case DATA_GENERIC_ENHANCE_READ:

  		if (unlikely(blkaddr >= MAX_BLKADDR(sbi) ||

  				blkaddr < MAIN_BLKADDR(sbi))) {

  			f2fs_warn(sbi, "access invalid blkaddr:%u",
  				  blkaddr);

  			set_sbi_flag(sbi, SBI_NEED_FSCK);
  			WARN_ON(1);

  			return false;

  		} else {
  			return __is_bitmap_valid(sbi, blkaddr, type);

  		}

  		break;

  	case META_GENERIC:
  		if (unlikely(blkaddr < SEG0_BLKADDR(sbi) ||
  			blkaddr >= MAIN_BLKADDR(sbi)))
  			return false;
  		break;

  	default:
  		BUG();
  	}

  
  	return true;

  }
  
  /*

   * Readahead CP/NAT/SIT/SSA/POR pages

   */

  int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,

  							int type, bool sync)

  {

  	struct page *page;

  	block_t blkno = start;

  	struct f2fs_io_info fio = {

  		.sbi = sbi,

  		.type = META,

  		.op = REQ_OP_READ,

  		.op_flags = sync ? (REQ_META | REQ_PRIO) : REQ_RAHEAD,

  		.encrypted_page = NULL,

  		.in_list = false,

  		.is_por = (type == META_POR),

  	};

  	struct blk_plug plug;

  	int err;

  	if (unlikely(type == META_POR))

  		fio.op_flags &= ~REQ_META;

  	blk_start_plug(&plug);

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

  		if (!f2fs_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.new_blkaddr = current_nat_addr(sbi,

  					blkno * NAT_ENTRY_PER_BLOCK);
  			break;
  		case META_SIT:

  			if (unlikely(blkno >= TOTAL_SEGS(sbi)))
  				goto out;

  			/* get sit block addr */

  			fio.new_blkaddr = current_sit_addr(sbi,

  					blkno * SIT_ENTRY_PER_BLOCK);

  			break;

  		case META_SSA:

  		case META_CP:

  		case META_POR:

  			fio.new_blkaddr = blkno;

  			break;
  		default:
  			BUG();
  		}

  		page = f2fs_grab_cache_page(META_MAPPING(sbi),
  						fio.new_blkaddr, false);

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

  			f2fs_put_page(page, 1);
  			continue;
  		}

  		fio.page = page;

  		err = f2fs_submit_page_bio(&fio);
  		f2fs_put_page(page, err ? 1 : 0);

  
  		if (!err)
  			f2fs_update_iostat(sbi, FS_META_READ_IO, F2FS_BLKSIZE);

  	}
  out:

  	blk_finish_plug(&plug);

  	return blkno - start;
  }

  void f2fs_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 || !PageUptodate(page))

  		readahead = true;
  	f2fs_put_page(page, 0);
  
  	if (readahead)

  		f2fs_ra_meta_pages(sbi, index, BIO_MAX_PAGES, META_POR, true);

  }

  static int __f2fs_write_meta_page(struct page *page,
  				struct writeback_control *wbc,
  				enum iostat_type io_type)

  {

  	struct f2fs_sb_info *sbi = F2FS_P_SB(page);

  	trace_f2fs_writepage(page, META);

  	if (unlikely(f2fs_cp_error(sbi)))
  		goto redirty_out;

  	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;

  	f2fs_do_write_meta_page(sbi, page, io_type);

  	dec_page_count(sbi, F2FS_DIRTY_META);

  
  	if (wbc->for_reclaim)

  		f2fs_submit_merged_write_cond(sbi, NULL, page, 0, META);

  	unlock_page(page);

  	if (unlikely(f2fs_cp_error(sbi)))

  		f2fs_submit_merged_write(sbi, META);

  	return 0;

  
  redirty_out:

  	redirty_page_for_writepage(wbc, page);

  	return AOP_WRITEPAGE_ACTIVATE;

  }

  static int f2fs_write_meta_page(struct page *page,
  				struct writeback_control *wbc)
  {
  	return __f2fs_write_meta_page(page, wbc, FS_META_IO);
  }

  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;

  	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
  		goto skip_write;

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

  	if (wbc->sync_mode != WB_SYNC_ALL &&
  			get_pages(sbi, F2FS_DIRTY_META) <
  					nr_pages_to_skip(sbi, META))

  		goto skip_write;

  	/* if locked failed, cp will flush dirty pages instead */

  	if (!down_write_trylock(&sbi->cp_global_sem))

  		goto skip_write;

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

  	diff = nr_pages_to_write(sbi, META, wbc);

  	written = f2fs_sync_meta_pages(sbi, META, wbc->nr_to_write, FS_META_IO);

  	up_write(&sbi->cp_global_sem);

  	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);

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

  	return 0;

  }

  long f2fs_sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,

  				long nr_to_write, enum iostat_type io_type)

  {

  	struct address_space *mapping = META_MAPPING(sbi);

  	pgoff_t index = 0, prev = ULONG_MAX;

  	struct pagevec pvec;
  	long nwritten = 0;

  	int nr_pages;

  	struct writeback_control wbc = {
  		.for_reclaim = 0,
  	};

  	struct blk_plug plug;

  	pagevec_init(&pvec);

  	blk_start_plug(&plug);

  	while ((nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,

  				PAGECACHE_TAG_DIRTY))) {

  		int i;

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

  			if (prev == ULONG_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;
  			}

  			f2fs_wait_on_page_writeback(page, META, true, true);

  			if (!clear_page_dirty_for_io(page))
  				goto continue_unlock;

  			if (__f2fs_write_meta_page(page, &wbc, io_type)) {

  				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_write(sbi, type);

  	blk_finish_plug(&plug);

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

  	trace_f2fs_set_page_dirty(page, META);

  	if (!PageUptodate(page))
  		SetPageUptodate(page);

  	if (!PageDirty(page)) {

  		__set_page_dirty_nobuffers(page);

  		inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_META);

  		f2fs_set_page_private(page, 0);

  		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,

  #ifdef CONFIG_MIGRATION
  	.migratepage    = f2fs_migrate_page,
  #endif

  };

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

  {

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

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

  	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 (unlikely(radix_tree_insert(&im->ino_root, ino, e)))
  			f2fs_bug_on(sbi, 1);

  		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++;

  	}

  
  	if (type == FLUSH_INO)
  		f2fs_set_bit(devidx, (char *)&e->dirty_device);

  	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 f2fs_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, 0, type);

  }

  void f2fs_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, UPDATE_INO or TRANS_DIR_INO */

  bool f2fs_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 f2fs_release_ino_entry(struct f2fs_sb_info *sbi, bool all)

  {
  	struct ino_entry *e, *tmp;
  	int i;

  	for (i = all ? ORPHAN_INO : APPEND_INO; i < MAX_INO_ENTRY; 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);

  	}
  }

  void f2fs_set_dirty_device(struct f2fs_sb_info *sbi, nid_t ino,

  					unsigned int devidx, int type)
  {
  	__add_ino_entry(sbi, ino, devidx, type);
  }

  bool f2fs_is_dirty_device(struct f2fs_sb_info *sbi, nid_t ino,

  					unsigned int devidx, int type)
  {
  	struct inode_management *im = &sbi->im[type];
  	struct ino_entry *e;
  	bool is_dirty = false;
  
  	spin_lock(&im->ino_lock);
  	e = radix_tree_lookup(&im->ino_root, ino);
  	if (e && f2fs_test_bit(devidx, (char *)&e->dirty_device))
  		is_dirty = true;
  	spin_unlock(&im->ino_lock);
  	return is_dirty;
  }

  int f2fs_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 (time_to_inject(sbi, FAULT_ORPHAN)) {

  		spin_unlock(&im->ino_lock);

  		f2fs_show_injection_info(sbi, FAULT_ORPHAN);

  		return -ENOSPC;
  	}

  	if (unlikely(im->ino_num >= sbi->max_orphans))

  		err = -ENOSPC;

  	else

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

  	return err;
  }

  void f2fs_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 f2fs_add_orphan_inode(struct inode *inode)

  {

  	/* add new orphan ino entry into list */

  	__add_ino_entry(F2FS_I_SB(inode), inode->i_ino, 0, ORPHAN_INO);

  	f2fs_update_inode_page(inode);

  }

  void f2fs_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;

  	struct node_info ni;

  	int err;

  	inode = f2fs_iget_retry(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);
  	}

  	err = dquot_initialize(inode);

  	if (err) {
  		iput(inode);

  		goto err_out;

  	}

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

  	err = f2fs_get_node_info(sbi, ino, &ni);
  	if (err)
  		goto err_out;

  
  	/* ENOMEM was fully retried in f2fs_evict_inode. */
  	if (ni.blk_addr != NULL_ADDR) {

  		err = -EIO;
  		goto err_out;

  	}

  	return 0;

  
  err_out:
  	set_sbi_flag(sbi, SBI_NEED_FSCK);

  	f2fs_warn(sbi, "%s: orphan failed (ino=%x), run fsck to fix.",
  		  __func__, ino);

  	return err;

  }

  int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)

  {

  	block_t start_blk, orphan_blocks, i, j;

  	unsigned int s_flags = sbi->sb->s_flags;
  	int err = 0;

  #ifdef CONFIG_QUOTA
  	int quota_enabled;
  #endif

  	if (!is_set_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG))

  		return 0;

  	if (bdev_read_only(sbi->sb->s_bdev)) {

  		f2fs_info(sbi, "write access unavailable, skipping orphan cleanup");

  		return 0;
  	}

  	if (s_flags & SB_RDONLY) {

  		f2fs_info(sbi, "orphan cleanup on readonly fs");

  		sbi->sb->s_flags &= ~SB_RDONLY;

  	}
  
  #ifdef CONFIG_QUOTA
  	/* Needed for iput() to work correctly and not trash data */

  	sbi->sb->s_flags |= SB_ACTIVE;

  	/*
  	 * Turn on quotas which were not enabled for read-only mounts if
  	 * filesystem has quota feature, so that they are updated correctly.
  	 */

  	quota_enabled = f2fs_enable_quota_files(sbi, s_flags & SB_RDONLY);

  #endif

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

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

  	f2fs_ra_meta_pages(sbi, start_blk, orphan_blocks, META_CP, true);

  	for (i = 0; i < orphan_blocks; i++) {

  		struct page *page;

  		struct f2fs_orphan_block *orphan_blk;

  		page = f2fs_get_meta_page(sbi, start_blk + i);
  		if (IS_ERR(page)) {
  			err = PTR_ERR(page);
  			goto out;
  		}

  		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);

  				goto out;

  			}

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

  	clear_ckpt_flags(sbi, CP_ORPHAN_PRESENT_FLAG);

  out:

  	set_sbi_flag(sbi, SBI_IS_RECOVERED);

  #ifdef CONFIG_QUOTA
  	/* Turn quotas off */

  	if (quota_enabled)
  		f2fs_quota_off_umount(sbi->sb);

  #endif

  	sbi->sb->s_flags = s_flags; /* Restore SB_RDONLY status */

  
  	return err;

  }
  
  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 = f2fs_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 __u32 f2fs_checkpoint_chksum(struct f2fs_sb_info *sbi,
  						struct f2fs_checkpoint *ckpt)
  {
  	unsigned int chksum_ofs = le32_to_cpu(ckpt->checksum_offset);
  	__u32 chksum;
  
  	chksum = f2fs_crc32(sbi, ckpt, chksum_ofs);
  	if (chksum_ofs < CP_CHKSUM_OFFSET) {
  		chksum_ofs += sizeof(chksum);
  		chksum = f2fs_chksum(sbi, chksum, (__u8 *)ckpt + chksum_ofs,
  						F2FS_BLKSIZE - chksum_ofs);
  	}
  	return chksum;
  }

  static int get_checkpoint_version(struct f2fs_sb_info *sbi, block_t cp_addr,
  		struct f2fs_checkpoint **cp_block, struct page **cp_page,
  		unsigned long long *version)

  {

  	size_t crc_offset = 0;

  	__u32 crc;

  	*cp_page = f2fs_get_meta_page(sbi, cp_addr);

  	if (IS_ERR(*cp_page))
  		return PTR_ERR(*cp_page);

  	*cp_block = (struct f2fs_checkpoint *)page_address(*cp_page);

  	crc_offset = le32_to_cpu((*cp_block)->checksum_offset);

  	if (crc_offset < CP_MIN_CHKSUM_OFFSET ||
  			crc_offset > CP_CHKSUM_OFFSET) {

  		f2fs_put_page(*cp_page, 1);

  		f2fs_warn(sbi, "invalid crc_offset: %zu", crc_offset);

  		return -EINVAL;
  	}

  	crc = f2fs_checkpoint_chksum(sbi, *cp_block);
  	if (crc != cur_cp_crc(*cp_block)) {

  		f2fs_put_page(*cp_page, 1);

  		f2fs_warn(sbi, "invalid crc value");

  		return -EINVAL;
  	}

  	*version = cur_cp_version(*cp_block);
  	return 0;
  }

  static struct page *validate_checkpoint(struct f2fs_sb_info *sbi,
  				block_t cp_addr, unsigned long long *version)
  {
  	struct page *cp_page_1 = NULL, *cp_page_2 = NULL;
  	struct f2fs_checkpoint *cp_block = NULL;
  	unsigned long long cur_version = 0, pre_version = 0;
  	int err;

  	err = get_checkpoint_version(sbi, cp_addr, &cp_block,
  					&cp_page_1, version);
  	if (err)

  		return NULL;

  
  	if (le32_to_cpu(cp_block->cp_pack_total_block_count) >
  					sbi->blocks_per_seg) {

  		f2fs_warn(sbi, "invalid cp_pack_total_block_count:%u",
  			  le32_to_cpu(cp_block->cp_pack_total_block_count));

  		goto invalid_cp;

  	}

  	pre_version = *version;

  	cp_addr += le32_to_cpu(cp_block->cp_pack_total_block_count) - 1;
  	err = get_checkpoint_version(sbi, cp_addr, &cp_block,
  					&cp_page_2, version);
  	if (err)

  		goto invalid_cp;

  	cur_version = *version;

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

  	f2fs_put_page(cp_page_2, 1);

  invalid_cp:

  	f2fs_put_page(cp_page_1, 1);
  	return NULL;
  }

  int f2fs_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;

  	int err;

  	sbi->ckpt = f2fs_kvzalloc(sbi, array_size(blk_size, cp_blks),
  				  GFP_KERNEL);

  	if (!sbi->ckpt)
  		return -ENOMEM;
  	/*
  	 * Finding out valid cp block involves read both

  	 * sets( cp pack 1 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 {

  		err = -EFSCORRUPTED;

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

  	if (cur_page == cp1)
  		sbi->cur_cp_pack = 1;
  	else
  		sbi->cur_cp_pack = 2;

  	/* Sanity checking of checkpoint */

  	if (f2fs_sanity_check_ckpt(sbi)) {
  		err = -EFSCORRUPTED;

  		goto free_fail_no_cp;

  	}

  	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 = f2fs_get_meta_page(sbi, cp_blk_no + i);

  		if (IS_ERR(cur_page)) {
  			err = PTR_ERR(cur_page);

  			goto free_fail_no_cp;

  		}

  		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;

  free_fail_no_cp:
  	f2fs_put_page(cp1, 1);
  	f2fs_put_page(cp2, 1);

  fail_no_cp:

  	kvfree(sbi->ckpt);

  	return err;

  }

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

  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

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

  	if (is_inode_flag_set(inode, flag))

  		return;

  	set_inode_flag(inode, flag);

  	if (!f2fs_is_volatile_file(inode))
  		list_add_tail(&F2FS_I(inode)->dirty_list,
  						&sbi->inode_list[type]);

  	stat_inc_dirty_inode(sbi, type);

  }

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

  {

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

  	if (get_dirty_pages(inode) || !is_inode_flag_set(inode, flag))

  		return;

  	list_del_init(&F2FS_I(inode)->dirty_list);
  	clear_inode_flag(inode, flag);

  	stat_dec_dirty_inode(F2FS_I_SB(inode), type);

  }

  void f2fs_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]);
  	if (type != FILE_INODE || test_opt(sbi, DATA_FLUSH))

  		__add_dirty_inode(inode, type);

  	inode_inc_dirty_pages(inode);

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

  	f2fs_set_page_private(page, 0);

  	f2fs_trace_pid(page);

  }

  void f2fs_remove_dirty_inode(struct inode *inode)

  {

  	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;

  	if (type == FILE_INODE && !test_opt(sbi, DATA_FLUSH))
  		return;

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

  }

  int f2fs_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);

  	unsigned long ino = 0;

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

  		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_first_entry(head, struct f2fs_inode_info, dirty_list);

  	inode = igrab(&fi->vfs_inode);

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

  	if (inode) {

  		unsigned long cur_ino = inode->i_ino;

  		F2FS_I(inode)->cp_task = current;

  		filemap_fdatawrite(inode->i_mapping);

  		F2FS_I(inode)->cp_task = NULL;

  		iput(inode);

  		/* We need to give cpu to another writers. */

  		if (ino == cur_ino)

  			cond_resched();

  		else

  			ino = cur_ino;

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

  		f2fs_submit_merged_write(sbi, DATA);

  		cond_resched();

  	}
  	goto retry;
  }

  int f2fs_sync_inode_meta(struct f2fs_sb_info *sbi)
  {
  	struct list_head *head = &sbi->inode_list[DIRTY_META];
  	struct inode *inode;
  	struct f2fs_inode_info *fi;
  	s64 total = get_pages(sbi, F2FS_DIRTY_IMETA);
  
  	while (total--) {
  		if (unlikely(f2fs_cp_error(sbi)))
  			return -EIO;
  
  		spin_lock(&sbi->inode_lock[DIRTY_META]);
  		if (list_empty(head)) {
  			spin_unlock(&sbi->inode_lock[DIRTY_META]);
  			return 0;
  		}

  		fi = list_first_entry(head, struct f2fs_inode_info,

  							gdirty_list);
  		inode = igrab(&fi->vfs_inode);
  		spin_unlock(&sbi->inode_lock[DIRTY_META]);
  		if (inode) {

  			sync_inode_metadata(inode, 0);
  
  			/* it's on eviction */
  			if (is_inode_flag_set(inode, FI_DIRTY_INODE))

  				f2fs_update_inode_page(inode);

  			iput(inode);
  		}

  	}

  	return 0;
  }

  static void __prepare_cp_block(struct f2fs_sb_info *sbi)
  {
  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
  	struct f2fs_nm_info *nm_i = NM_I(sbi);
  	nid_t last_nid = nm_i->next_scan_nid;
  
  	next_free_nid(sbi, &last_nid);
  	ckpt->valid_block_count = cpu_to_le64(valid_user_blocks(sbi));
  	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);
  }

  static bool __need_flush_quota(struct f2fs_sb_info *sbi)
  {

  	bool ret = false;

  	if (!is_journalled_quota(sbi))
  		return false;

  
  	down_write(&sbi->quota_sem);
  	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) {
  		ret = false;
  	} else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) {
  		ret = false;
  	} else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH)) {
  		clear_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
  		ret = true;
  	} else if (get_pages(sbi, F2FS_DIRTY_QDATA)) {
  		ret = true;
  	}
  	up_write(&sbi->quota_sem);
  	return ret;

  }

  /*

   * 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,
  	};

  	int err = 0, cnt = 0;

  	/*
  	 * Let's flush inline_data in dirty node pages.
  	 */
  	f2fs_flush_inline_data(sbi);

  retry_flush_quotas:

  	f2fs_lock_all(sbi);

  	if (__need_flush_quota(sbi)) {
  		int locked;
  
  		if (++cnt > DEFAULT_RETRY_QUOTA_FLUSH_COUNT) {
  			set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);

  			set_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);

  			goto retry_flush_dents;
  		}

  		f2fs_unlock_all(sbi);

  
  		/* only failed during mount/umount/freeze/quotactl */
  		locked = down_read_trylock(&sbi->sb->s_umount);
  		f2fs_quota_sync(sbi->sb, -1);
  		if (locked)
  			up_read(&sbi->sb->s_umount);

  		cond_resched();
  		goto retry_flush_quotas;
  	}
  
  retry_flush_dents:

  	/* write all the dirty dentry pages */

  	if (get_pages(sbi, F2FS_DIRTY_DENTS)) {

  		f2fs_unlock_all(sbi);

  		err = f2fs_sync_dirty_inodes(sbi, DIR_INODE);

  		if (err)

  			return err;

  		cond_resched();

  		goto retry_flush_quotas;

  	}

  	/*
  	 * POR: we should ensure that there are no dirty node pages
  	 * until finishing nat/sit flush. inode->i_blocks can be updated.
  	 */
  	down_write(&sbi->node_change);

  	if (get_pages(sbi, F2FS_DIRTY_IMETA)) {

  		up_write(&sbi->node_change);

  		f2fs_unlock_all(sbi);
  		err = f2fs_sync_inode_meta(sbi);
  		if (err)

  			return err;

  		cond_resched();

  		goto retry_flush_quotas;

  	}

  retry_flush_nodes:

  	down_write(&sbi->node_write);

  
  	if (get_pages(sbi, F2FS_DIRTY_NODES)) {

  		up_write(&sbi->node_write);

  		atomic_inc(&sbi->wb_sync_req[NODE]);

  		err = f2fs_sync_node_pages(sbi, &wbc, false, FS_CP_NODE_IO);

  		atomic_dec(&sbi->wb_sync_req[NODE]);