+
+ vfs_lock_two_pages(src_page, dest_page);
+
+ /*
+ * Now that we've locked both pages, make sure they're still
+ * mapped to the file data we're interested in. If not,
+ * someone is invalidating pages on us and we lose.
+ */
+ if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
+ src_page->mapping != src->i_mapping ||
+ dest_page->mapping != dest->i_mapping) {
+ same = false;
+ goto unlock;
+ }
+