Messages in this thread | | | Date | Wed, 26 Apr 2006 16:35:36 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] drivers/scsi/sd.c: fix uninitialized variable in handling medium errors |
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Mark Lord <lkml@rtr.ca> wrote: > > > That's if we think -stable needs this fixed. > > Let's say a bunch of read bio's get coalesced into a single > 200+ sector request. This then fails on one single bad sector > out of the 200+. Without the patch, there is a very good chance > that sd.c will simply fail the entire request, all 200+ sectors. > > With the patch, it will fail the first block, and then retry > the remaining blocks. And repeat this until something works, > or until everything has failed one by one.
Yowch. I have the feeling that this'll take our EIO-handling time from far-too-long to far-too-long*200.
I am still traumatised by my recent ten-minute wait for a dodgy DVD to become ejectable.
I don't think -stable needs this, personally.
> Better, but still not the best. > > What I need to have happen when a request is failed due to bad-media, > is have it split the request into a sequence of single-block requests > that are passed to the LLD one at a time. The ones with real bad > sectors will then be independently failed, and the rest will get done. > > Much better. Much more complex. > > I'm thinking about something like that, just not sure whether to put it > (initially) in libata, sd.c, or the block layer.
block, I suspect. My DVD trauma was IDE-induced. Jens is mulling the problem - I'd suggest you coordinate with him.
It would be a good thing to fix.
It's moderately hard to test, though. Easy enough for DVDs and CDs, but it's harder to take a marker pen to a hard drive. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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