ext4: use proper csum calculation in ext4_rename

In ext4_rename, when the old name is a dir, we need to
change ".." to its new parent and journal the change, so
with metadata_csum enabled, we have to re-calc the csum.

As the first block of the dir can be either a htree root
or a normal directory block and we have different csum
calculation for these 2 types, we have to choose the right
one in ext4_rename.

btw, it is found by xfstests 013.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Darrick J. Wong <djwong@us.ibm.com>

fs/ext4/namei.c

@@ -2918,8 +2918,15 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 		PARENT_INO(dir_bh->b_data, new_dir->i_sb->s_blocksize) =
 						cpu_to_le32(new_dir->i_ino);
 		BUFFER_TRACE(dir_bh, "call ext4_handle_dirty_metadata");
-		retval = ext4_handle_dirty_dirent_node(handle, old_inode,
-						       dir_bh);
+		if (is_dx(old_inode)) {
+			retval = ext4_handle_dirty_dx_node(handle,
+							   old_inode,
+							   dir_bh);
+		} else {
+			retval = ext4_handle_dirty_dirent_node(handle,
+							       old_inode,
+							       dir_bh);
+		}
 		if (retval) {
 			ext4_std_error(old_dir->i_sb, retval);
 			goto end_rename;