linux-kernel - Re: [PATCH 0/17] Make O_SYNC handling use standard syncing path (Version 2)

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Message-ID: <20090822162711.GA7542@shareable.org>
Date:	Sat, 22 Aug 2009 17:27:11 +0100
From:	Jamie Lokier <jamie@...reable.org>
To:	Jan Kara <jack@...e.cz>
Cc:	LKML <linux-kernel@...r.kernel.org>, hch@....de,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 0/17] Make O_SYNC handling use standard syncing path (Version 2)

Jan Kara wrote:
> The patch set unifines O_SYNC handling with standard fsync() path.  After this,
> we have just one place forcing a single file to disk so filesystems like ext3 /
> ext4 don't have to force a transaction commit in ext?_file_write for O_SYNC
> files / IS_SYNC inodes.  The code is also cleaner this way (actually about 150
> lines shorter), we don't sync the inode several times as it happened previously
> etc.

Afaik, O_SYNC requires just the written data to be committed to disk,
but fsync() requires all dirty data for the file (including written by
other processes / descriptors) to be committed to disk.

So doing the equivalent of fsync() after write might be the wrong
thing to do.

-- Jamie
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