int f2fs_migrate_page(struct address_space *mapping,
		struct page *newpage, struct page *page, enum migrate_mode mode)
{
	int rc, extra_count;
	struct f2fs_inode_info *fi = F2FS_I(mapping->host);
	bool atomic_written = IS_ATOMIC_WRITTEN_PAGE(page);

	BUG_ON(PageWriteback(page));

	/* migrating an atomic written page is safe with the inmem_lock hold */
	if (atomic_written) {
		if (mode != MIGRATE_SYNC)
			return -EBUSY;
		if (!mutex_trylock(&fi->inmem_lock))
			return -EAGAIN;
	}

	/* one extra reference was held for atomic_write page */
	extra_count = atomic_written ? 1 : 0;
	rc = migrate_page_move_mapping(mapping, newpage,
				page, mode, extra_count);
	if (rc != MIGRATEPAGE_SUCCESS) {
		if (atomic_written)
			mutex_unlock(&fi->inmem_lock);
		return rc;
	}

	if (atomic_written) {
		struct inmem_pages *cur;
		list_for_each_entry(cur, &fi->inmem_pages, list)
			if (cur->page == page) {
				cur->page = newpage;
				break;
			}
		mutex_unlock(&fi->inmem_lock);
		put_page(page);
		get_page(newpage);
	}

	if (PagePrivate(page)) {
		f2fs_set_page_private(newpage, page_private(page));
		f2fs_clear_page_private(page);
	}

	if (mode != MIGRATE_SYNC_NO_COPY)
		migrate_page_copy(newpage, page);
	else
		migrate_page_states(newpage, page);

	return MIGRATEPAGE_SUCCESS;
}
int f2fs_migrate_page(struct address_space *mapping,
		struct page *newpage, struct page *page, enum migrate_mode mode)
{
	int rc, extra_count;
	struct f2fs_inode_info *fi = F2FS_I(mapping->host);
	bool atomic_written = IS_ATOMIC_WRITTEN_PAGE(page);

	BUG_ON(PageWriteback(page));

	 
	if (atomic_written) {
		if (mode != MIGRATE_SYNC)
			return -EBUSY;
		if (!mutex_trylock(&fi->inmem_lock))
			return -EAGAIN;
	}

	 
	extra_count = atomic_written ? 1 : 0;
	rc = migrate_page_move_mapping(mapping, newpage,
				page, mode, extra_count);
	if (rc != MIGRATEPAGE_SUCCESS) {
		if (atomic_written)
			mutex_unlock(&fi->inmem_lock);
		return rc;
	}

	if (atomic_written) {
		struct inmem_pages *cur;
		list_for_each_entry(cur, &fi->inmem_pages, list)
			if (cur->page == page) {
				cur->page = newpage;
				break;
			}
		mutex_unlock(&fi->inmem_lock);
		put_page(page);
		get_page(newpage);
	}

	if (PagePrivate(page)) {
		f2fs_set_page_private(newpage, page_private(page));
		f2fs_clear_page_private(page);
	}

	if (mode != MIGRATE_SYNC_NO_COPY)
		migrate_page_copy(newpage, page);
	else
		migrate_page_states(newpage, page);

	return MIGRATEPAGE_SUCCESS;
}