From: Dan Williams <dan.j.williams@intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>,
Ming Lei <ming.lei@redhat.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Hannes Reinecke <hare@suse.de>, Jens Axboe <axboe@kernel.dk>,
kernel test robot <lkp@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-block@vger.kernel.org
Subject: Re: [PATCH] libnvdimm: Let revalidate_disk() revalidate region read-only
Date: Tue, 9 Mar 2021 08:36:53 -0800 [thread overview]
Message-ID: <CAPcyv4iQShzBxyZcn+H=2DGnnpifaV_e=5yBaGA1sF+ESS0jAQ@mail.gmail.com> (raw)
In-Reply-To: <20210309073110.GA3140@lst.de>
On Mon, Mar 8, 2021 at 11:31 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, Mar 08, 2021 at 10:54:22PM -0800, Dan Williams wrote:
> > Previous kernels allowed the BLKROSET to override the disk's read-only
> > status. With that situation fixed the pmem driver needs to rely on
> > revalidate_disk() to clear the disk read-only status after the host
> > region has been marked read-write.
> >
> > Recall that when libnvdimm determines that the persistent memory has
> > lost persistence (for example lack of energy to flush from DRAM to FLASH
> > on an NVDIMM-N device) it marks the region read-only, but that state can
> > be overridden by the user via:
> >
> > echo 0 > /sys/bus/nd/devices/regionX/read_only
> >
> > ...to date there is no notification that the region has restored
> > persistence, so the user override is the only recovery.
>
> I've just resent my series to kill of ->revalidate_disk for good, so this
> obvious makes me a little unhappy. Given that ->revalidate_disk
> only ends up beeing called from the same path that ->open is called,
> why can't you just hook this up from the open method?
>
> Also any reason the sysfs attribute can't just directly propagate the
> information to the disk?
I should have assumed that revalidate_disk() was on the chopping
block. Let me take a look at just propagating from the region update
down to all affected disks. There's already a notification path for
regions to communicate badblocks, should be straightforward to reuse
for read-only updates.
prev parent reply other threads:[~2021-03-09 16:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 6:54 [PATCH] libnvdimm: Let revalidate_disk() revalidate region read-only Dan Williams
2021-03-09 7:31 ` Christoph Hellwig
2021-03-09 16:36 ` Dan Williams [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAPcyv4iQShzBxyZcn+H=2DGnnpifaV_e=5yBaGA1sF+ESS0jAQ@mail.gmail.com' \
--to=dan.j.williams@intel.com \
--cc=axboe@kernel.dk \
--cc=hare@suse.de \
--cc=hch@lst.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=lkp@intel.com \
--cc=martin.petersen@oracle.com \
--cc=ming.lei@redhat.com \
--cc=vishal.l.verma@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).