On Wed, Feb 01, 2012 at 12:16:05PM -0600, James Bottomley wrote: > supplying protection information to user space isn't about the > application checking what's on disk .. there's automatic verification in > the chain to do that (both the HBA and the disk will check the > protection information on entry/exit and transfer). Supplying > protection information to userspace is about checking nothing went wrong > in the handoff between the end of the DIF stack and the application. Not sure if I got this right, but keeping protection information for in-ram pagecache and exposing it to userland somehow, to me sounds a bit of overkill as a concept. Then you should want that for anonymous memory too. If you copy the pagecache to a malloc()ed buffer and verify pagecache was consistent, but then the buffer is corrupt by hardware bitflip or software bug, then what's the point. Besides if this is getting exposed to userland and it's not hidden in the kernel (FS/Storage layers), userland could code its own verification logic without much added complexity. With CRC in hardware on the CPU it doesn't sound like a big cost to do it fully in userland and then you could run it on anonymous memory too if you need and not be dependent on hardware or filesystem details (well other than a a cpuid check at startup). -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
