Re: ata_eh_link_autopsy: Bug?

[Mark Lord <kernel@xxxxxxxxxxxx>]

On 12-05-01 05:58 PM, Tejun Heo wrote:
> On Tue, May 01, 2012 at 04:27:00PM -0400, Mark Lord wrote:
>> MMmm.. even that isn't good enough, because the first ATA_QCFLAG_IO test
>> bypasses the rest of that logic and triggers unconditional retries.  Ugh.
> 
> Hmmm... the unconditional retry on ATA_QCFLAG_IO is intenttional so
> that known good requests from FS are guaranteed to be retried no
> matter how whacky the underlying device is.  I'm not sure whether that
> was a good decision tho.  Maybe we should trust the hardware a bit
> more.  So, I'm not necessarily against changing it.

With multi-terabyte drives being commonplace now, bad sectors seem
to be a more frequent occurrence than I can remember from the past.

And when libata stumbles across a bad sector, it literally hangs the
machine for _minutes_ doing retries.  I have never seen a retry make
any difference whatsoever on a bad sector read.  New, old, or ancient hardware.

Cheers
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