From: Christoph Hellwig <hch@lst.de>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] block: Flush image after open
Date: Wed, 9 Mar 2011 18:27:57 +0100 [thread overview]
Message-ID: <20110309172757.GA2884@lst.de> (raw)
In-Reply-To: <1299687353-20424-1-git-send-email-kwolf@redhat.com>
On Wed, Mar 09, 2011 at 05:15:53PM +0100, Kevin Wolf wrote:
> Quoting the bug report:
>
> qemu ensures that guest writes and qemu metadata writes hit the disk
> when necessary to prevent data corruption. However, if an image was
> in host pagecache prior to starting qemu, for example after running
> qemu-img convert, then nothing prevents writes from reaching the
> disk out of order, potentially causing corruption.
>
> I'm not entirely sure if there is a realistic case where we would get
> corruption, but it's probably a case of better safe than sorry.
Except for SCSI with ordered tags (which we don't support) there are not
ordering guarantees in the storage protocols, and as such the above explanation
doesn't make any sense at all.
next prev parent reply other threads:[~2011-03-09 17:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-09 16:15 [Qemu-devel] [PATCH] block: Flush image after open Kevin Wolf
2011-03-09 17:27 ` Christoph Hellwig [this message]
2011-03-09 17:38 ` Anthony Liguori
2011-03-21 12:23 ` Avi Kivity
2011-03-21 13:02 ` Kevin Wolf
2011-03-21 13:21 ` Avi Kivity
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