f2fs: check PageWriteback flag for ordered case

For all ordered cases in f2fs_wait_on_page_writeback(), we need to
check PageWriteback status, so let's clean up to relocate the check
into f2fs_wait_on_page_writeback().

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 5401ea5..f955cd3 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -44,7 +44,7 @@
 		cond_resched();
 		goto repeat;
 	}
-	f2fs_wait_on_page_writeback(page, META, true);
+	f2fs_wait_on_page_writeback(page, META, true, true);
 	if (!PageUptodate(page))
 		SetPageUptodate(page);
 	return page;
@@ -370,9 +370,8 @@
 				goto continue_unlock;
 			}
 
-			f2fs_wait_on_page_writeback(page, META, true);
+			f2fs_wait_on_page_writeback(page, META, true, true);
 
-			BUG_ON(PageWriteback(page));
 			if (!clear_page_dirty_for_io(page))
 				goto continue_unlock;
 
@@ -1290,8 +1289,7 @@
 	struct page *page = f2fs_grab_meta_page(sbi, blk_addr);
 	int err;
 
-	f2fs_wait_on_page_writeback(page, META, true);
-	f2fs_bug_on(sbi, PageWriteback(page));
+	f2fs_wait_on_page_writeback(page, META, true, true);
 
 	memcpy(page_address(page), src, PAGE_SIZE);