Re: [Qemu-devel] [Qemu-block] [PATCH 0/2] qemu-img: Let "info" warn and go ahead without -U

[Nir Soffer]

On Wed, Jan 10, 2018 at 4:04 PM Kashyap Chamarthy <address@hidden>
wrote:

> 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.
>

What abut users running released Nova, upgrading to 2.10?

Nir