On Thu, Oct 13, 2016 at 06:16:29PM +0000, Kani, Toshimitsu wrote: > On Thu, 2016-10-13 at 10:22 -0700, Dan Williams wrote: > > On Thu, Oct 13, 2016 at 9:08 AM, Kani, Toshimitsu <toshi.k...@hpe.com > > > wrote: > > > > > > On Thu, 2016-10-13 at 09:01 -0700, Dan Williams wrote: > > > > > > > > On Thu, Oct 13, 2016 at 8:54 AM, Toshi Kani <toshi.k...@hpe.com> > > > > wrote: > > > > > > > > > > > > > > > ACPI Clear Uncorrectable Error DSM function may fail or may be > > > > > unsupported on a platform. pmem_clear_poison() returns without > > > > > clearing badblocks in such cases, which leads to a silent data > > > > > corruption. > > > > > > > > > > Change pmem_do_bvec() and pmem_clear_poison() to return -EIO > > > > > so that filesystem can log an error message. > > > > > > > > What's the silent data corruption scenario? If the clear poison > > > > fails I'm assuming that the poison will still be notified on the > > > > next > > > > read. > > > > > > I agree that the data is eventually read, but there is no guranteed > > > that when it is read soon enough, i.e. user might not access to the > > > data for a long time. > > > > ...but that's the same behavior for errors that we don't yet know > > about. That said, we indeed know that the write failed. I'd feel > > better about this patch if the justification / impact was clearer in > > the changelog, because "silent data corruption" is not the impact. > > Agreed. How about the following descritpion? > > === > ACPI Clear Uncorrectable Error DSM function may fail or may be > unsupported on a platform. pmem_clear_poison() returns without > clearing badblocks in such cases. This failure is detected at > the next read (-EIO). > > This behavior can lead to an issue when user keeps writing but > does not read immedicately. For instance, flight recorder file immediately
> may be only read when it is necessary for troubleshooting. > > Change pmem_do_bvec() and pmem_clear_poison() to return -EIO > so that filesystem can log an error message on a write error. > === > > Thanks, > -Toshi > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@lists.01.org > https://lists.01.org/mailman/listinfo/linux-nvdimm _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm