Is disk really bad if mkfs.ext4 -c -c reports errors?

[Chris Green]

I have been reformatting a disk which had a few corrupted files on it
with the following command:-

    mkfs.ext4 -c -c /dev/sdb1

(Yes, I know this destroys all the data, everything except the few
corrupted files has been copied off the disk)

The second pass of badblocks is reporting some errors.  Does this
indicate that the disk is dying?  

The problem is that the documentation doesn't really tell one what the
errors mean.  Do the reported errors get remapped using the bad blocks
list or are they errors which *can't* be remapped because the bad
blocks list is full?  Running SMART diagnostics tells me the disk
drive has no errors.

-- 
Chris Green