How to mark bad blocks without formatting

["J.S.Sahambi" <jsahambi@iitg.ernet.in>]

On my machine I have a 40 GB hard disk. I executed badblocks command on 
one (/dev/hda8) of the partitions and it found two bad blocks.

How do I know if these blocks have been used by any file or not?

And how to mark these bad blocks without formatting the partition so 
that they are not used by the system?

I am using 2.4.19 and all parititions are ext3.

Thanks
J S Sahambi