[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and
From: |
Kashyap Chamarthy |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U |
Date: |
Wed, 10 Jan 2018 15:03:49 +0100 |
User-agent: |
NeoMutt/20171215 |
On Mon, Jan 08, 2018 at 03:41:36PM +0100, Kevin Wolf wrote:
> Am 05.01.2018 um 07:55 hat Fam Zheng geschrieben:
> > Management and users are accustomed to "qemu-img info" to query status of
> > images even when they are used by guests. Since image locking was added,
> > the -U
> > (--force-share) option is needed for that to work. The reason has been that
> > due
> > to possible race with image header update, the output can be misleading.
> >
> > But what are likely to happen after we emit the error are that, for
> > interactive
> > users, '-U' will be used and the command retried; for management (nova, RHV,
> > etc.), the operation is broken with no knob to workaround this.
> >
> > This series changes that error to a warning so that it doesn't get in the
> > way.
>
> Are management tools actually doing this? There is no good reason to
> call 'qemu-img info' for an image that is in use by a VM.
Yes, Nova does use 'qemu-img info' in a few places (haven't audited them
all) for a running guest. From a quick look at the code, at-least
during Nova's live snaphot (as part of libvirt's "shallow rebase") it is
used.
> If no, NACK. Automatically disabling locking because it can be
> inconvenient defeats the purpose of locking.
>
> If yes, clearly indicate that this usage is deprecated and we'll turn
> this into an error again with 2.13. Then management tools can be fixed
> in time.
Yes, for completness' sake, Nova upstream is already patched to use the
`qemu-img` '--force-share' flag that comes with QEMU >= 2.10.
--
/kashyap
- Re: [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, (continued)
- Re: [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Kevin Wolf, 2018/01/08
- Re: [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Fam Zheng, 2018/01/09
- Re: [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Kevin Wolf, 2018/01/09
- Re: [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Ala Hino, 2018/01/09
- Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Eric Blake, 2018/01/09
- Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Ala Hino, 2018/01/09
- Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Daniel P. Berrange, 2018/01/10
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U, Daniel P. Berrange, 2018/01/10
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U,
Kashyap Chamarthy <=