ext4: close struct file leak on EXT4_IOC_MOVE_EXT

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ext4/ioctl.c

@@ -258,7 +258,8 @@ group_extend_out:
 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
 			ext4_msg(sb, KERN_ERR,
 				 "Online defrag not supported with bigalloc");
-			return -EOPNOTSUPP;
+			err = -EOPNOTSUPP;
+			goto mext_out;
 		}
 
 		err = mnt_want_write_file(filp);