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Date: Thu, 14 Apr 2016 14:23:13 +0800
From: Fam Zheng <famz@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH for-2.7 00/15] block: Lock images when
 opening
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To: "Denis V. Lunev" <den@openvz.org>
Cc: qemu-devel@nongnu.org, Kevin Wolf <kwolf@redhat.com>, Max Reitz <mreitz@redhat.com>, Jeff Cody <jcody@redhat.com>, Markus Armbruster <armbru@redhat.com>, Eric Blake <eblake@redhat.com>, John Snow <jsnow@redhat.com>, qemu-block@nongnu.org, berrange@redhat.com, pbonzini@redhat.com

On Thu, 04/14 09:14, Denis V. Lunev wrote:
> On 04/14/2016 08:46 AM, Fam Zheng wrote:
> >On Thu, 04/14 08:04, Denis V. Lunev wrote:
> >>unfortunately no. If the lock will be on the image file,
> >>we will have get it on the target node on QEMU start
> >>and re-acquire it in bdrv_invalidate_cache.
> >>
> >> From my POW you should not get the lock if
> >>BDRV_O_INACTIVE is set.
> >That is what I meant. :)
> >
> >At source: Images are unlocked in bdrv_inactivate().
> >
> >At destinition: Images are not locked if opened with BDRV_O_INACTIVE, and
> >are locked in bdrv_invalidate_cache() (at the INMIGRATE -> RUNNING switch).
> >
> >Fam
> it looks I have missed something. The above will work, but
> I do not see clause where you set BDRV_O_NOLOCK when BDRV_O_INACTIVE
> is set.
> 
> Do you mean that we will not reach bdrv_open_common with this flag
> set?

I'm updating the patch to also check BDRV_O_INACTIVE in bdrv_open_common in v2.

Fam