On Wed, Jul 04, 2012 at 12:07:52AM +0400, James Bottomley wrote: > > The reason for the try_rc_10_first flag is that some devices return > > bogus data in response to RC16. Like, an 800 GB device claiming to > > have 3 exabytes. > > So we could easily send both and only believe RC10 if the device is > under 2TB. However, what about all the extra flags we read out of RC16, > like trim, large sector size and DIF capability? If the device lies > about its capacity, won't we get bogus values for those as well, which > is going to cause other screw ups? I think the necessary algorithm is simpler than that: Send RC10 (unless the device supports PI, in which case it's probably enterprisey and well-tested) Send RC16 If RC10 capacity agrees with RC16 capacity, use extra RC16 data. (for values of "agrees with" that include the "-1 to use RC16" indicator) Sure, it's one extra command, but really, who cares? -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: 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
