From: Phillip Susi <psusi@cfl.rr.com>
To: David Chinner <dgc@sgi.com>
Cc: Neil Brown <neilb@suse.de>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
dm-devel@redhat.com, linux-raid@vger.kernel.org,
Jens Axboe <jens.axboe@oracle.com>,
Stefan Bader <Stefan.Bader@de.ibm.com>,
Andreas Dilger <adilger@clusterfs.com>,
Tejun Heo <htejun@gmail.com>
Subject: Re: [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md.
Date: Tue, 29 May 2007 16:03:43 -0400 [thread overview]
Message-ID: <465C871F.708@cfl.rr.com> (raw)
In-Reply-To: <20070528024559.GA85884050@sgi.com>
David Chinner wrote:
> Sounds good to me, but how do we test to see if the underlying
> device supports barriers? Do we just assume that they do and
> only change behaviour if -o nobarrier is specified in the mount
> options?
The idea is that ALL block devices will support barriers; if the
underlying driver doesn't, then the block layer will work around it.
> The use of barriers in XFS assumes the commit write to be on stable
> storage before it returns. One of the ordering guarantees that we
> need is that the transaction (commit write) is on disk before the
> metadata block containing the change in the transaction is written
> to disk and the current barrier behaviour gives us that.
Barrier != synchronous write, so if XFS relies on that block being on
the media when the request is completed, then it is broken. It should
only care that the ordering of log-data-log is maintained, not exactly
when each specific request completes.
next prev parent reply other threads:[~2007-05-29 20:03 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-25 7:58 [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md Neil Brown
2007-05-25 11:15 ` David Chinner
2007-05-25 11:49 ` Jens Axboe
2007-05-25 14:49 ` Phillip Susi
2007-05-28 18:32 ` [dm-devel] " Jens Axboe
2007-05-25 13:52 ` Stefan Bader
2007-05-28 1:37 ` Neil Brown
2007-05-29 9:12 ` Stefan Bader
2007-05-25 15:11 ` Phillip Susi
2007-05-26 1:03 ` Andreas Dilger
2007-05-26 10:27 ` Tejun Heo
2007-05-28 1:30 ` Neil Brown
2007-05-28 2:45 ` David Chinner
2007-05-28 2:57 ` Neil Brown
2007-05-28 4:29 ` David Chinner
2007-05-31 0:46 ` Neil Brown
2007-05-31 0:57 ` Alasdair G Kergon
2007-05-31 1:07 ` Alasdair G Kergon
2007-05-31 1:11 ` David Chinner
2007-05-28 4:48 ` Timothy Shimmin
2007-05-29 6:45 ` Jeremy Higdon
2007-05-29 20:03 ` Phillip Susi [this message]
2007-05-29 23:48 ` David Chinner
2007-05-30 0:01 ` david
2007-05-30 6:17 ` David Chinner
2007-05-30 8:55 ` Stefan Bader
2007-05-30 16:52 ` david
2007-05-31 0:20 ` David Chinner
2007-05-31 6:26 ` Jens Axboe
2007-05-31 7:03 ` David Chinner
2007-05-31 7:06 ` Jens Axboe
2007-05-31 13:30 ` Bill Davidsen
2007-05-31 13:36 ` Jens Axboe
2007-06-01 16:04 ` Bill Davidsen
2007-06-02 14:51 ` Jens Axboe
2007-06-02 19:55 ` Bill Davidsen
2007-06-01 3:16 ` Tejun Heo
2007-06-01 8:21 ` Jens Axboe
2007-06-02 9:20 ` Tejun Heo
2007-06-02 14:34 ` Jens Axboe
2007-06-02 22:57 ` Guy Watkins
2007-06-04 7:39 ` Tejun Heo
2007-05-31 18:31 ` Phillip Susi
2007-05-31 19:00 ` Jens Axboe
2007-05-31 19:21 ` david
2007-05-31 19:40 ` Jens Axboe
2007-05-31 23:34 ` David Chinner
2007-06-01 5:59 ` Neil Brown
2007-06-01 6:11 ` Jens Axboe
2007-06-01 7:53 ` David Chinner
2007-06-01 23:56 ` Bill Davidsen
2007-05-31 18:24 ` Phillip Susi
2007-05-30 16:45 ` Phillip Susi
2007-05-30 20:27 ` [dm-devel] " Phillip Susi
2007-05-31 6:24 ` Jens Axboe
2007-05-31 18:37 ` [dm-devel] " Phillip Susi
2007-05-31 18:58 ` Jens Axboe
2007-06-02 0:04 ` Bill Davidsen
2007-05-28 9:29 ` Tejun Heo
2007-05-28 9:43 ` Alasdair G Kergon
2007-05-29 9:25 ` [dm-devel] " Stefan Bader
2007-05-29 22:05 ` Alasdair G Kergon
2007-05-30 9:12 ` [dm-devel] " Stefan Bader
2007-05-30 10:41 ` Alasdair G Kergon
2007-05-30 16:55 ` Phillip Susi
2007-05-31 11:14 ` [dm-devel] " Stefan Bader
2007-06-01 3:25 ` Tejun Heo
2007-06-01 5:55 ` david
2007-06-01 7:16 ` [dm-devel] " Tejun Heo
2007-06-01 17:07 ` Valdis.Kletnieks
2007-06-01 18:09 ` Tejun Heo
2007-07-10 18:39 ` Ric Wheeler
2007-07-10 23:40 ` Valdis.Kletnieks
2007-07-11 2:49 ` Tejun Heo
2007-07-11 22:44 ` Ric Wheeler
2007-07-12 17:34 ` Valdis.Kletnieks
2007-07-12 19:43 ` Ric Wheeler
2007-07-12 23:10 ` Guy Watkins
2007-07-13 11:30 ` Ric Wheeler
2007-07-11 2:51 ` Tejun Heo
2007-05-29 19:59 ` Phillip Susi
2007-05-31 0:22 ` Neil Brown
2007-05-30 9:35 ` Jens Axboe
2007-07-05 12:28 ` Tejun Heo
2007-07-09 12:27 ` Jens Axboe
2007-07-18 10:56 ` [PATCH] block: cosmetic changes Tejun Heo
2007-07-18 10:59 ` [PATCH] block: factor out bio_check_eod() Tejun Heo
2007-07-18 11:06 ` Jens Axboe
2007-07-18 11:18 ` Tejun Heo
2007-07-18 11:31 ` Jens Axboe
2007-07-18 11:33 ` Tejun Heo
2007-07-18 11:34 ` Jens Axboe
2007-07-18 11:41 ` Tejun Heo
2007-07-18 11:45 ` Jens Axboe
2007-07-18 11:49 ` Jens Axboe
2007-07-18 12:34 ` Tejun Heo
2007-07-18 12:31 ` Jens Axboe
2007-05-28 11:17 ` [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md Nikita Danilov
2007-05-31 3:31 ` Neil Brown
2007-05-28 14:43 ` Bill Davidsen
2007-05-31 0:37 ` Neil Brown
2007-05-31 12:28 ` Bill Davidsen
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