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From: Paolo Bonzini <pbonzini@redhat.com>
To: famz@redhat.com
Cc: kwolf@redhat.com, jcody@redhat.com, qemu-devel@nongnu.org,
	stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH 1/2] block: allow live commit of active image
Date: Mon, 22 Jul 2013 13:07:14 +0200	[thread overview]
Message-ID: <51ED1262.4000000@redhat.com> (raw)
In-Reply-To: <20130722064834.GA1992@T430s.redhat.com>

Il 22/07/2013 08:48, Fam Zheng ha scritto:
>> > I have only skimmed the patch, but I think this is incomplete.
>> > Management needs to know the moment when 'active' is not valid anymore,
>> > thus this job needs to be completed manually with "block-job-complete".
> Does management need access to 'active' image outside of QEMU process?
> Although original 'active' it is "dropped" by bdrv_drop_intermediate,
> the pointers to original 'active' is still valid because 'base' is moved
> to this address (with bdrv_swap). I don't know, what is the problem here
> for management?

Management needs to know, in case of a crash in QEMU or management
itself at exactly the right time, whether any I/O have been issued by
the guest to the 'base'.  The only way to do this is, at this time,
something like

    stop
    block-job-complete ide0-hd0
    cont

Paolo

  reply	other threads:[~2013-07-22 11:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-22  3:46 [Qemu-devel] [PATCH 0/2] block: allow commit active as top Fam Zheng
2013-07-22  3:46 ` [Qemu-devel] [PATCH 1/2] block: allow live commit of active image Fam Zheng
2013-07-22  6:34   ` Paolo Bonzini
2013-07-22  6:48     ` Fam Zheng
2013-07-22 11:07       ` Paolo Bonzini [this message]
2013-07-23  2:03         ` Fam Zheng
2013-07-23 11:13           ` Paolo Bonzini
2013-07-22  3:46 ` [Qemu-devel] [PATCH 2/2] qemu-iotests: update test cases for commit active Fam Zheng
2013-07-22  6:43 ` [Qemu-devel] [PATCH 0/2] block: allow commit active as top Wenchao Xia
2013-07-22  7:05   ` Fam Zheng

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