Re: [PATCH] pmem: report error on clear poison failure

From: Kani, Toshimitsu
Date: Thu Oct 13 2016 - 14:44:35 EST

On Thu, 2016-10-13 at 09:01 -0700, Dan Williams wrote:
> On Thu, Oct 13, 2016 at 8:54 AM, Toshi Kani <toshi.kani@xxxxxxx>
> wrote:
> >
> > ACPI Clear Uncorrectable Error DSM function may fail or may be
> > unsupported on a platform.ÂÂpmem_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?ÂÂIf 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.