Quoting "Toby Corkindale" <toby.corkindale@strategicdata.com.au>:
Essentially I was wondering whether you'd lose an entire file (or extent of a file) if the checksum fails, or whether you could still access the rest of the file but with just one block missing in the event of a bad sector.
It shouldn't be any different from a "normal" device error - you get an error when you are reading this block. I don't know the source code but I expect this error if you read sequentially. You may try to recover using random access and pointing to a block behind the broken one. I personally never bothered to do forensics on corrupted filesystems or disks or whatever. If it isn't mirrored and not backed up - it isn't important enough. Regards Peter