From: Jamie Lokier <jamie@shareable.org>
To: Theodore Tso <tytso@mit.edu>,
Andrew Morton <akpm@linux-foundation.org>,
Eric Sandeen <sandeen@redhat.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vge
Subject: Re: [PATCH 0/4] (RESEND) ext3[34] barrier changes
Date: Tue, 20 May 2008 15:45:50 +0100 [thread overview]
Message-ID: <20080520144550.GB16676@shareable.org> (raw)
In-Reply-To: <20080517204437.GB16496@mit.edu>
Theodore Tso wrote:
> Also, looking more closely on the jbd2 implementation, it looks like
> using the async_commit option, which relies on the checksum for more
> efficient commit, completely disables any barrier support. That's
> because the only place we go into ordered more is if we are writing a
> synchronous journal commit. If async journal commit is enabled, then
> we don't write a barrier at all, which leaves us in potential trouble
> with if data blocks end up getting reordered with respect to the
> journal commit in data=ordered more.
That is a great optimisation to make the filesystem safe against power
fails without barriers. Upon replay, the filesystem is consistent.
But does it break fsync()? Consistency isn't enough for fsync().
Returning from fsync() means "this data is committed now".
-- Jamie
next prev parent reply other threads:[~2008-05-20 14:46 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-16 19:02 [PATCH 0/4] (RESEND) ext3[34] barrier changes Eric Sandeen
2008-05-16 19:05 ` [PATCH 1/4] ext3: enable barriers by default Eric Sandeen
2008-05-19 8:58 ` Pavel Machek
2008-05-16 19:07 ` [PATCH 2/4] ext3: call blkdev_issue_flush on fsync Eric Sandeen
2008-05-16 22:15 ` Jamie Lokier
2008-05-16 19:08 ` [PATCH 3/4] ext4: enable barriers by default Eric Sandeen
2008-05-16 19:09 ` [PATCH 4/4] ext4: call blkdev_issue_flush on fsync Eric Sandeen
2008-05-20 2:34 ` Theodore Tso
2008-05-20 15:43 ` Jamie Lokier
2008-05-20 15:52 ` Eric Sandeen
2008-05-20 19:54 ` Jens Axboe
2008-05-20 22:02 ` Jamie Lokier
2008-05-21 7:30 ` Jens Axboe
[not found] ` <4832F3C6.1050601@redhat.com>
2008-05-20 20:14 ` Jens Axboe
2008-05-16 20:05 ` [PATCH 0/4] (RESEND) ext3[34] barrier changes Andrew Morton
2008-05-16 20:53 ` Eric Sandeen
2008-05-16 20:58 ` Andrew Morton
2008-05-16 21:45 ` Jamie Lokier
2008-05-16 22:03 ` Eric Sandeen
2008-05-16 22:09 ` Jamie Lokier
2008-05-16 22:03 ` Jamie Lokier
2008-05-16 22:21 ` Eric Sandeen
2008-05-16 22:53 ` Jamie Lokier
2008-05-17 0:20 ` Theodore Tso
2008-05-17 0:35 ` Andrew Morton
2008-05-17 13:43 ` Theodore Tso
2008-05-17 17:59 ` Andreas Dilger
2008-05-17 20:44 ` Theodore Tso
2008-05-20 14:45 ` Jamie Lokier [this message]
2008-05-18 0:48 ` Chris Mason
2008-05-18 1:36 ` Theodore Tso
2008-05-18 14:49 ` Ric Wheeler
[not found] ` <4830420D.4080608@gmail.com>
2008-05-20 14:42 ` Jamie Lokier
2008-05-20 23:48 ` Jamie Lokier
2008-05-20 23:44 ` Jamie Lokier
2008-05-18 20:03 ` Andi Kleen
2008-05-19 0:43 ` Theodore Tso
2008-05-19 2:29 ` Eric Sandeen
[not found] ` <4830E60A.2010809@redhat.com>
2008-05-19 4:11 ` Andrew Morton
2008-05-19 17:16 ` Chris Mason
2008-05-19 18:39 ` Chris Mason
2008-05-19 22:39 ` Jan Kara
2008-05-20 0:29 ` Chris Mason
2008-05-20 3:29 ` Timothy Shimmin
2008-05-20 12:04 ` Chris Mason
2008-05-20 8:25 ` Jens Axboe
2008-05-20 12:17 ` Chris Mason
2008-05-21 11:22 ` Pavel Machek
2008-05-21 12:32 ` Theodore Tso
2008-05-21 18:03 ` Andrew Morton
2008-05-21 18:15 ` Eric Sandeen
2008-05-21 19:43 ` Jamie Lokier
2008-05-21 18:29 ` Theodore Tso
2008-05-21 18:49 ` Andrew Morton
2008-05-21 19:42 ` Jamie Lokier
2008-05-21 19:36 ` Jamie Lokier
[not found] ` <20080521193633.GA26780@shareable.org>
2008-05-21 19:40 ` Chris Mason
2008-05-21 19:54 ` Jamie Lokier
2008-05-20 14:58 ` Jamie Lokier
2008-05-21 22:30 ` Daniel Phillips
2008-05-20 23:35 ` Jamie Lokier
2008-05-19 0:28 ` Theodore Tso
2008-05-20 15:13 ` Jamie Lokier
[not found] ` <20080520151306.GF16676@shareable.org>
2008-05-21 20:25 ` Greg Smith
2008-05-16 22:30 ` Jamie Lokier
2008-05-18 19:54 ` Andi Kleen
2008-05-19 13:26 ` Chris Mason
2008-05-19 14:46 ` Theodore Tso
2008-05-20 2:51 ` [PATCH, RFC] ext4: Fix use of write barrier in commit logic Theodore Tso
[not found] ` <20080520025112.GN15035@mit.edu>
2008-05-20 15:23 ` Jamie Lokier
2008-05-23 18:33 ` [PATCH 0/4] (RESEND) ext3[34] barrier changes Ric Wheeler
2008-05-20 15:36 ` Jamie Lokier
2008-05-20 16:02 ` Chris Mason
2008-05-20 16:27 ` Jamie Lokier
2008-05-20 17:08 ` Chris Mason
2008-05-20 22:26 ` Jamie Lokier
2008-05-19 9:04 ` Pavel Machek
2008-05-29 13:36 ` Eric Sandeen
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