ext4: don't dereference null pointer when make_indexed_dir() fails

Fix for a null pointer bug found while running punch hole tests

Signed-off-by: Allison Henderson <[e-mail]>
Signed-off-by: "Theodore Ts'o" <[e-mail]>

fs/ext4/namei.c

···
 	frame->at = entries;
 	frame->bh = bh;
 	bh = bh2;
+
+	ext4_handle_dirty_metadata(handle, dir, frame->bh);
+	ext4_handle_dirty_metadata(handle, dir, bh);
+
 	de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
 	if (!de) {
 		/*
···
 		 * with corrupted filesystem.
 		 */
 		ext4_mark_inode_dirty(handle, dir);
-		ext4_handle_dirty_metadata(handle, dir, frame->bh);
-		ext4_handle_dirty_metadata(handle, dir, bh);
 		dx_release(frames);
 		return retval;
 	}