Mark Lord <lkml@xxxxxx> 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. - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
