From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Jin <joe.jin@oracle.com>
Subject: Re: [patch] xen-blkback: sync I/O after backend
	disconnected
Date: Tue, 16 Aug 2011 14:56:30 +0800
Message-ID: <4E4A149E.5080608@oracle.com>
References: <4E48A6A6.4040706@oracle.com> <20110815144610.GA3707@infradead.org>
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To: Christoph Hellwig <hch@infradead.org>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Jens Axboe <jaxboe@fusionio.com>, Greg Marsden <greg.marsden@oracle.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Ian Campbell <Ian.Campbell@eu.citrix.com>, Kurt C Hackel <KURT.HACKEL@oracle.com>
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On 08/15/11 22:46, Christoph Hellwig wrote:
> On Mon, Aug 15, 2011 at 12:55:02PM +0800, Joe Jin wrote:
>> When backend disconnect, sync IO requests to the disk.
> 
> Care to explain why?

When backend disconnect, I think we'd better flush all dirty data 
to the disk ASAP.

> 
> Also you'll just need a sync_blockdev, fsync_bdev does far to many
> things that don't make any sense when you don't have a file system
> mounted on a device.
> 

xen-blkback support physical device and loopback file, so I think
here should be fsync_bdev()? 

Thanks,
Joe