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Re: [Qemu-devel] [RFC PATCH 0/3] Point-in-time snapshot exporting with d
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [RFC PATCH 0/3] Point-in-time snapshot exporting with drive-backup |
Date: |
Thu, 27 Jun 2013 15:39:47 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Jun 27, 2013 at 12:06:44PM +0200, Paolo Bonzini wrote:
> Il 27/06/2013 10:17, Stefan Hajnoczi ha scritto:
> >>> > > Il 26/06/2013 05:59, Fam Zheng ha scritto:
> >>> > > This leads to another observation: a sync:'none' block-backup job
> >>> > > probably should never complete, and should instead go on until
> >>> > > explicit
> >>> > > cancellation. This is because the job does no background writes, and
> >>> > > thus completion would only happen after the guest has written the
> >>> > > whole
> >>> > > disk. Writing the whole disk is rare enough that it will likely cause
> >>> > > bugs in the clients. It is easier just to never complete the job.
> >>> > >
> >> >
> >> > Yes, the sync mode none will simply run forever until cancelled.
> > There is a dedicated command to successfully complete a job:
> >
> > block-job-complete
>
> block-job-complete should only be called after a BLOCK_JOB_READY event,
> but when would the backup job raise it? Immediately after starting?
>
> There is no behavioral difference in this case between cancel and
> complete in fact as far as I understand, so I think cancelling the job
> would match existing practice better.
Okay. Ian Main also preferred using block-job-cancel without the
BLOCK_JOB_READY/block-job-complete lifecycle.
Thanks for the input!
Stefan
- Re: [Qemu-devel] [RFC PATCH 1/3] block: add target-id option to drive-backup QMP command, (continued)
[Qemu-devel] [RFC PATCH 2/3] block: assign backing relationship in drive-backup, Fam Zheng, 2013/06/26
[Qemu-devel] [RFC PATCH 3/3] nbd: don't get ref if bs has no drive, Fam Zheng, 2013/06/26
Re: [Qemu-devel] [RFC PATCH 0/3] Point-in-time snapshot exporting with drive-backup, Paolo Bonzini, 2013/06/26