diff --git a/mm/migrate.c b/mm/migrate.c
index 4e0eccca5e265ac19bc507a171a2f720d27f8c21..449d77d409f52622bbf825b7fd17d43df7ff5fbf 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -383,7 +383,14 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
 
 	if (PageDirty(page)) {
 		clear_page_dirty_for_io(page);
-		set_page_dirty(newpage);
+		/*
+		 * Want to mark the page and the radix tree as dirty, and
+		 * redo the accounting that clear_page_dirty_for_io undid,
+		 * but we can't use set_page_dirty because that function
+		 * is actually a signal that all of the page has become dirty.
+		 * Wheras only part of our page may be dirty.
+		 */
+		__set_page_dirty_nobuffers(newpage);
  	}
 
 #ifdef CONFIG_SWAP