Currently dio read also goes to verify checksum if -EIO has been returned,
although it usually fails on checksum, it's not necessary at all, we could
directly check if there is another copy to read.

And with this, the behavior of dio read is now consistent with that of
buffered read.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ use bool for uptodate ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>