I had a similar problem a few weeks back and used tar to locate the
file.
        tar -cf /dev/null /filesystem

- stops and reports the filename.

Dominic J Hulewicz writes:
 > One of our NetBSD hosts is reporting a disk input/output error during
 > a routine filesystem backup (dump). I want to find out what file is
 > causing this, but the error report only gives reference to a block
 > number.
 > 
 > Does anyone know how I can find out what inode or file is using a
 > particular block ?
 > 
 > 
 > 	Regards,
 > 		Dom.
 > -- 
 >   Dominic J. Hulewicz - mailto:dom@inta.net - http://www.intanet.com/dom

-- 
------------------------------------------------------------
Rex McMaster                            rmcm@compsoft.com.au 
                                   rex@mcmaster.wattle.id.au
     PGP Public key: http://www.compsoft.com.au/~rmcm/pgp-pk