f2fs: fix to clear private data in page

Private data in page should be removed during ->releasepage or
->invalidatepage, otherwise garbage data would be remained in that page.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1723,6 +1723,7 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
 	if (IS_ATOMIC_WRITTEN_PAGE(page))
 		return;
 
+	set_page_private(page, 0);
 	ClearPagePrivate(page);
 }
 
@@ -1736,6 +1737,7 @@ int f2fs_release_page(struct page *page, gfp_t wait)
 	if (IS_ATOMIC_WRITTEN_PAGE(page))
 		return 0;
 
+	set_page_private(page, 0);
 	ClearPagePrivate(page);
 	return 1;
 }