From: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"jmoyer@redhat.com" <jmoyer@redhat.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH v6 6/6] libnvdimm, btt: rework error clearing
Date: Thu, 24 Aug 2017 21:40:55 +0000 [thread overview]
Message-ID: <1503610260.2042.177.camel@hpe.com> (raw)
In-Reply-To: <x4960dcoetl.fsf@segfault.boston.devel.redhat.com>
On Thu, 2017-08-24 at 17:07 -0400, Jeff Moyer wrote:
> Dan Williams <dan.j.williams@intel.com> writes:
>
> > > > I hit an infinite clear loop when DSM Clear Uncorrectable Error
> > > > function fails. Haven't looked into the details, but I suspect
> > > > this unconditional retry is the cause of this.
> > >
> > > Thanks Toshi - that makes sense. I think the right thing to do
> > > would be if the DSM fails, return an EIO yes? (Or should we
> > > ignore the fact that there was an error, clear ->has_err, and let
> > > the write take its course (possibly generate a CMCI)
> > >
> > > It will still be in the badblock list, and for reads ->rw_bytes
> > > will still check and fail them.
> > >
> > > I'll send out a new series with a fix, but we really need to get
> > > a unit test for BTT error clearing, and I'm working on
> > > implementing the new error injection DSMs in libndctl and
> > > nfit_test to do that.
> > >
> >
> > I think as much as possible we should try to not fail writes. Leave
> > the badblock entry in place so that we get an error on the next
> > read. Upper-level software reacts more aggressively to write errors
> > than read errors.
>
> I don't think it's wise to lie about data integrity. If a write
> cannot be completed, it *needs* to fail. You can't make any
> assumptions about what applications will do with the result.
Agreed. pmem driver returns with EIO on write in this scenario as
well.
Thanks,
-Toshi
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next prev parent reply other threads:[~2017-08-24 21:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-22 22:19 [PATCH v6 0/6] BTT error clearing rework Vishal Verma
2017-08-22 22:19 ` [PATCH v6 1/6] btt: fix a missed NVDIMM_IO_ATOMIC case in the write path Vishal Verma
2017-08-22 22:19 ` [PATCH v6 2/6] btt: refactor map entry operations with macros Vishal Verma
2017-08-22 22:19 ` [PATCH v6 3/6] btt: ensure that flags were also unchanged during a map_read Vishal Verma
2017-08-22 22:19 ` [PATCH v6 4/6] btt: cache sector_size in arena_info Vishal Verma
2017-08-22 22:19 ` [PATCH v6 5/6] libnvdimm: fix potential deadlock while clearing errors Vishal Verma
2017-08-22 22:19 ` [PATCH v6 6/6] libnvdimm, btt: rework error clearing Vishal Verma
2017-08-23 17:23 ` Kani, Toshimitsu
2017-08-24 20:32 ` Verma, Vishal L
2017-08-24 20:36 ` Dan Williams
2017-08-24 21:07 ` Jeff Moyer
2017-08-24 21:40 ` Kani, Toshimitsu [this message]
2017-08-24 22:11 ` Dan Williams
2017-08-24 23:15 ` Verma, Vishal L
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