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Date: Fri, 1 Jun 2018 21:33:59 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20180601133359.GA24752@lemon.usersys.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] file-posix: Consolidate the locking error
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To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= <berrange@redhat.com>
Cc: qemu-devel@nongnu.org, Kevin Wolf <kwolf@redhat.com>, qemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>

On Fri, 06/01 13:43, Daniel P. Berrang=E9 wrote:
> On Fri, Jun 01, 2018 at 05:18:35PM +0800, Fam Zheng wrote:
> > When hot-plugging a block device fails due to image locking errors,
> > users won't see the helpful 'Is another process using the image?'
> > message in QMP because currently the error hint is not carried over
> > there.
> >=20
> > Even though extending QMP to include hint is a conceivably easy task,
> > Libvirt will need some change to consume that data.
> >=20
> > Before that is fully sorted out, let's just do the easy fix by joinin=
g
> > the two lines.
>=20
> There are many places in QEMU which uses error hints and these are all
> invisible to libvirt. Arbitrarily picking one hint to remove, while
> leaving everything else unfixed is not a very satisfactory approach.
>=20
> If QEMU passes the hint in QMP, it is trivial for libvirt to be changed
> to append the hint when reporting its own error message, so can we just
> focus on fixing the root cause instead of special casing file-posix.c

The plan was to work on the QMP change in parallel, while this simple pat=
ch can
mitigate the confusion caused by the relatively vague message (the text i=
tself
is going a bit on the cryptic side for people who don't know QEMU interna=
ls).

Fam