On Mon, Oct 10, 2016 at 09:47:04PM +0100, Anthony Youngman wrote:

with a list of all blocks that failed to copy. Then we need to patch the 
low-level disk access code so that it reads this list of "bad blocks" 
and returns a read error if any attempt is made to read one. If a block 

hdparm has that feature to mark sectors as bad (--make-bad-sector).
not sure how that behaves on a re-write by md. I never tried it myself.

Maybe you could also do something with device mapper. It does have 
an error target, and then there's the overlay. I wish dmsetup had 
some profiles/shortcuts/reciped to make creation of such device mapper 
tidbits easier or another common tool for those device mapper tricks...

Regards
Andreas Klauer