From: Eric Sandeen <sandeen@sandeen.net>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-xfs@vger.kernel.org, David Teigland <teigland@redhat.com>
Subject: Re: dm-writecache issue
Date: Tue, 18 Sep 2018 10:27:20 -0500 [thread overview]
Message-ID: <128a77fc-dbcb-278f-115c-da4a3d63e58f@sandeen.net> (raw)
In-Reply-To: <b3a162a8-7c2b-8a66-6f11-2abff3381690@sandeen.net>
On 9/18/18 10:04 AM, Eric Sandeen wrote:
> I cannot help but believe that ext4 occasionally
> gets harmed by this choice, because it's absolutely possible that a 4k
> metadata write gets only partly-persisted if power fails on a 512/512 disk,
> for example. In practice it seems to generally work out ok, but it is going
> beyond what the device says it can guarantee.
(this may be a bit uninformed on my part, Darrick reminds me that jbd2's
careful use of cache flushing & FUA probably means that it won't get burned
by a partial 4k metadata update if the power fails.)
I'll stop for now and see if Dave wants to chime in on xfs's reliance on
the actual atomic IO size for metadata IO. ;)
Thanks,
-Eric
next prev parent reply other threads:[~2018-09-18 21:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180911221147.GA23308@redhat.com>
2018-09-18 11:46 ` dm-writecache issue Mikulas Patocka
2018-09-18 12:32 ` Dave Chinner
2018-09-18 12:48 ` Eric Sandeen
2018-09-18 14:09 ` Mikulas Patocka
2018-09-18 14:16 ` Eric Sandeen
2018-09-18 14:19 ` Eric Sandeen
2018-09-18 14:29 ` Mikulas Patocka
2018-09-18 14:36 ` Eric Sandeen
2018-09-18 14:42 ` Mikulas Patocka
2018-09-18 15:04 ` Eric Sandeen
2018-09-18 15:27 ` Eric Sandeen [this message]
2018-09-18 15:29 ` Christoph Hellwig
2018-09-18 17:15 ` Mikulas Patocka
2018-09-18 14:20 ` David Teigland
2018-09-18 14:23 ` Eric Sandeen
2018-09-18 14:22 ` Mikulas Patocka
2018-09-18 15:33 ` Christoph Hellwig
2018-09-18 17:39 ` Mikulas Patocka
2018-09-18 22:52 ` Dave Chinner
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