From: Sami Tolvanen <samitolvanen@google.com>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Milan Broz <mbroz@redhat.com>,
device-mapper development <dm-devel@redhat.com>,
Mandeep Baines <msb@chromium.org>, Will Drewry <wad@chromium.org>,
Kees Cook <keescook@chromium.org>,
Mike Snitzer <snitzer@redhat.com>,
linux-kernel@vger.kernel.org, Alasdair Kergon <agk@redhat.com>,
Mark Salyzyn <salyzyn@google.com>
Subject: Re: [PATCH 0/4] dm verity: add support for error correction
Date: Fri, 6 Nov 2015 19:06:34 +0000 [thread overview]
Message-ID: <20151106190634.GA2813@google.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1511061201520.5619@file01.intranet.prod.int.rdu2.redhat.com>
On Fri, Nov 06, 2015 at 12:23:29PM -0500, Mikulas Patocka wrote:
> I'm also wondering what is this patch useful for. Disks and flash
> controllers have their own error detection and correction
I think I addressed this earlier. Some storage devices are able to
correct bit flips, but don't have enough redundancy to correct larger
errors. Using this patch set we can correct N MiB of consecutive
corruption anywhere on the partition with the same amount of storage
overhead.
> Another point - if the read-only system partition is experiencing some
> errors, than the read-write partition will probably have errors too
On mobile devices, errors in read-only partitions often lead to
bricked devices while errors in the read-write parts might only lead
to lost cat photos. There are situations where people would prefer to
have a working phone even if it fails to store some of their data.
> Do you have some real case where such error corrections
> increase longevity of some device?
Yes, there have been several cases where read-only partition errors
have rendered a device unusable. The sheer volume of mobile devices
means that even if a tiny fraction of them suffer from such a problem,
it's going to affect a large number of people.
> But you can take raid5 in read-only mode, put it on several partitions
> protected with dm-verity and you get decent error correction
I agree. Unfortunately, we don't currently have the luxury of using
raid on mobile devices.
Sami
next prev parent reply other threads:[~2015-11-06 19:06 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 2:02 [PATCH 0/4] dm verity: add support for error correction Sami Tolvanen
2015-11-05 2:02 ` [PATCH 1/4] dm verity: clean up duplicate hashing code Sami Tolvanen
2015-11-17 22:32 ` Kees Cook
2015-11-05 2:02 ` [PATCH 2/4] dm verity: separate function for parsing opt args Sami Tolvanen
2015-11-17 22:33 ` Kees Cook
2015-12-02 20:16 ` Mike Snitzer
2015-11-05 2:02 ` [PATCH 3/4] dm verity: add support for forward error correction Sami Tolvanen
2015-11-05 5:36 ` kbuild test robot
2015-11-05 22:06 ` kbuild test robot
2015-11-05 2:02 ` [PATCH 4/4] dm verity: ignore zero blocks Sami Tolvanen
2015-11-05 22:13 ` kbuild test robot
2015-11-05 7:34 ` [PATCH 0/4] dm verity: add support for error correction Milan Broz
2015-11-05 17:33 ` Sami Tolvanen
2015-11-09 16:37 ` Mike Snitzer
2015-11-09 19:19 ` Sami Tolvanen
2015-11-09 19:58 ` Mike Snitzer
2015-11-12 10:30 ` Milan Broz
2015-12-03 9:36 ` Sami Tolvanen
2015-11-12 18:50 ` Mikulas Patocka
2015-12-03 9:33 ` Sami Tolvanen
2015-12-02 20:22 ` Mike Snitzer
2015-12-03 9:11 ` Sami Tolvanen
2015-11-06 17:23 ` Mikulas Patocka
2015-11-06 19:06 ` Sami Tolvanen [this message]
2015-11-06 19:20 ` [dm-devel] " Zdenek Kabelac
2015-11-06 20:27 ` Sami Tolvanen
2015-11-06 21:05 ` Zdenek Kabelac
2015-11-06 21:23 ` Sami Tolvanen
2015-11-07 15:29 ` Mikulas Patocka
2015-11-07 15:20 ` Mikulas Patocka
2015-11-07 15:18 ` Mikulas Patocka
2015-11-09 15:06 ` Austin S Hemmelgarn
2015-12-03 14:26 ` [PATCH v2 0/2] " Sami Tolvanen
2015-12-03 14:26 ` [PATCH v2 1/2] dm verity: add support for forward " Sami Tolvanen
2015-12-03 14:26 ` [PATCH v2 2/2] dm verity: ignore zero blocks Sami Tolvanen
2015-12-03 19:54 ` [PATCH v2 0/2] dm verity: add support for error correction Mike Snitzer
2015-12-03 23:05 ` Mike Snitzer
2015-12-04 10:03 ` Sami Tolvanen
2015-12-04 21:09 ` Mike Snitzer
2015-12-07 13:21 ` Sami Tolvanen
2015-12-07 14:58 ` Mike Snitzer
2015-12-07 16:31 ` Sami Tolvanen
2015-12-07 18:07 ` Milan Broz
2015-12-07 19:07 ` Mike Snitzer
2015-12-08 10:18 ` Sami Tolvanen
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=20151106190634.GA2813@google.com \
--to=samitolvanen@google.com \
--cc=agk@redhat.com \
--cc=dm-devel@redhat.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mbroz@redhat.com \
--cc=mpatocka@redhat.com \
--cc=msb@chromium.org \
--cc=salyzyn@google.com \
--cc=snitzer@redhat.com \
--cc=wad@chromium.org \
/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).