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From: Andrew Morton <akpm@linux-foundation.org>
To: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] ext3,4:fdatasync should skip metadata writeout
Date: Thu, 15 Nov 2007 18:59:19 -0800	[thread overview]
Message-ID: <20071115185919.7df4cda9.akpm@linux-foundation.org> (raw)
In-Reply-To: <6.0.0.20.2.20071116114652.03b9e4e8@172.19.0.2>

On Fri, 16 Nov 2007 11:47:27 +0900 Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> wrote:

> Currently fdatasync is identical to fsync in ext3,4.
> I think fdatasync should skip journal flush in data=ordered and data=writeback mode
> because this syscall is not required to synchronize the metadata.

I suppose so.  Although one wonders what earthly point there is in syncing
a file's data if we haven't yet written out the metadata which is required
for locating that data.

IOW, fdatasync() is only useful if the application knows that it is overwriting
already-instantiated blocks.

In which case it might as well have used fsync().  For ext2-style filesystems,
anyway.

hm.  It needs some thought.

  reply	other threads:[~2007-11-16  2:59 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-16  2:47 [PATCH] ext3,4:fdatasync should skip metadata writeout Hisashi Hifumi
2007-11-16  2:59 ` Andrew Morton [this message]
2007-11-16  3:17   ` Jörn Engel
2007-11-16 18:12     ` Bryan Henderson
2007-11-16  3:47   ` Wendy Cheng
2007-11-16  3:53     ` Andrew Morton
2007-11-20  7:20   ` Hisashi Hifumi
2008-02-04 10:15   ` [RESEND] [PATCH] ext3,4:fdatasync should skip metadata writeout when overwriting Hisashi Hifumi
2008-02-06 16:22     ` Jan Kara
2008-02-07  6:45       ` Hisashi Hifumi
2007-11-16  3:43 ` [PATCH] ext3,4:fdatasync should skip metadata writeout Jörn Engel

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