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Date: Tue, 13 Jan 2009 09:03:47 -0500
From: Theodore Tso <tytso@mit.edu>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pavel Machek <pavel@suse.cz>, kernel list <linux-kernel@vger.kernel.org>,
       jack@suse.cz, Jens Axboe <jens.axboe@oracle.com>
Subject: Re: ext2 + -osync: not as easy as it seems
Message-ID: <20090113140347.GD17664@mit.edu>
Mail-Followup-To: Theodore Tso <tytso@mit.edu>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>, Pavel Machek <pavel@suse.cz>,
	kernel list <linux-kernel@vger.kernel.org>, jack@suse.cz,
	Jens Axboe <jens.axboe@oracle.com>
References: <20090113131418.GD30352@atrey.karlin.mff.cuni.cz> <20090113134503.41318144@lxorguk.ukuu.org.uk>
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Adding a barrier shouldn't be that hard; just a matter adding a call
to blkdev_issue_flush() to ext2_sync_file() before it returns.

BTW, I think there's a stale documentation bug in in
block/blk-barrier.c, around line 305:

  * Description:
  *    Issue a flush for the block device in question. Caller can supply
  *    room for storing the error offset in case of a flush error, if they
- *    wish to.  Caller must run wait_for_completion() on its own.
+ *    wish to.
  */
 int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 {

Jens, is that right?

						- Ted