On Tue, Nov 24, 2015 at 12:10 PM, Verma, Vishal L <vishal.l.verma@xxxxxxxxx> wrote: > On Tue, 2015-11-24 at 14:14 -0500, Jeff Moyer wrote: >> >> I'm not sure whether it makes sense to continue without badblock >> management for the RAID code. I was hoping Neil would comment on >> that. >> >> -Jeff > > Not sure I follow? I believe I've kept all the badblocks functionality > RAID already had.. > > > On a related note, something I observed when testing with md: > > md's badblock list is per-device, and can be seen at: > /sys/block/md0/md/dev-pmem0/bad_blocks > > Now if we have badblocks in the gendisks too, there is also: > /sys/block/pmem0/bad_blocks > > The two are separate 'accounts' maintained by separate drivers (md for > the former, and pmem for the latter). This can potentially be > confusing.. > > Should we consolidate the two, i.e. make md (re)use the gendisk > badblocks for its purposes too? If we get agreement that tracking bad blocks at the gendisk is useful for more than just nvdimms then yes, I think it makes sense to move md bad_blocks to the gendisk layer. That is provided we can add a symlink to make the move transparent to existing md userspace tooling. The use cases I can envision being useful for other disks is: 1/ Bypassing / avoiding known bad blocks on disks / drivers that inject long completion latency for error handling. 2/ Simulating bad blocks for disks that can't store them locally. Similar to the md use case, if one encounters errors restoring a disk image from a backup it's useful to have the option to record the error in a bad block list and keep going. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
