From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: George Spelvin <linux@horizon.com>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3] jbd2: Fix block tag checksum verification brokenness
Date: Mon, 3 Jun 2013 00:55:21 -0700 [thread overview]
Message-ID: <20130603075521.GA6088@blackbox.djwong.org> (raw)
In-Reply-To: <20130603021630.13790.qmail@science.horizon.com>
On Sun, Jun 02, 2013 at 10:16:30PM -0400, George Spelvin wrote:
> > Fortunately metadata checksumming is still "experimental" and not in a shipping
> > e2fsprogs, so there should be few users affected by this.
>
> Am I reading this patch correctly that this changes which half of
> the 32-bit checksum is stored on little-endian (e.g. x86) machines?
> Before, it stored the low 16 bits of cpu_to_be32(csum), meaning the
> high 16 bits of csum.
...unless you're using a BE system in which case it's the low 16 bits. :)
> Now, it's cpu_to_be16(csum32), which is the low 16 bits of csum32.
>
> It so happens that I have multiple metadata_csum file systems.
> (I enabled it a while ago on a machine where I wasn't sure if corruption
> was RAM or disk, and have been using it on SSE4.2 machines since.)
>
> Is there an upgrade path? Also, what's the corresponding e2fsprogs
> commit that supports this change?
The kernel patch fixes journal bogosity when moving a disk between big and
little endian systems. e2fsprogs didn't have the brokenness, so there's no
change needed. In theory you'd only hit this if you happened to crash an x86
box with an ext4 fs, move the disk to a ppc, and try to recover it there.
The upgrade path is to umount cleanly and reboot with a patched kernel while
hoping that you don't crash while rebooting. Sorry about the bumpy
metadata_csum ride.
--D
next prev parent reply other threads:[~2013-06-03 7:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-03 2:16 [PATCH v3] jbd2: Fix block tag checksum verification brokenness George Spelvin
2013-06-03 7:55 ` Darrick J. Wong [this message]
2013-06-04 0:40 ` Darrick J. Wong
2013-06-04 3:32 ` George Spelvin
-- strict thread matches above, loose matches on Subject: below --
2013-05-10 23:38 [PATCH v2] " Darrick J. Wong
2013-05-11 5:18 ` Andreas Dilger
2013-05-13 21:47 ` [PATCH v3] " Darrick J. Wong
2013-05-28 11:34 ` Theodore Ts'o
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=20130603075521.GA6088@blackbox.djwong.org \
--to=darrick.wong@oracle.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux@horizon.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).