Re: [Qemu-devel] [libvirt] [PATCH] qemu: Fix shutdown regression

[Anthony Liguori]

On 09/20/2011 01:01 PM, Eric Blake wrote:
> On 09/20/2011 11:39 AM, Jiri Denemark wrote:
> > The commit that prevents disk corruption on domain shutdown
> > (96fc4784177ecb70357518fa863442455e45ad0e) causes regression with QEMU
> > 0.14.* and 0.15.* because of a regression bug in QEMU that was fixed
> > only recently in QEMU git. With affected QEMU binaries, domains cannot
> > be shutdown properly and stay in a paused state. This patch tries to
> > avoid this by sending SIGKILL to 0.1[45].* QEMU processes. Though we
> > wait a bit more between sending SIGTERM and SIGKILL to reduce the
> > possibility of virtual disk corruption.
> > ---
> > src/qemu/qemu_capabilities.c | 7 +++++++
> > src/qemu/qemu_capabilities.h | 1 +
> > src/qemu/qemu_process.c | 19 +++++++++++++------
> > 3 files changed, 21 insertions(+), 6 deletions(-)
>
> ACK. But it would be nice if upstream qemu could give us a more reliable
> indication of whether the qemu SIGTERM bug is fixed, so that we don't corrupt
> data on a patched 0.14 or 0.15 qemu.

Can you be a lot more specific about what bug you mean?

> That is, as part of fixing the bug in qemu,
> we should also update -help text or something similar, so that libvirt can avoid
> making decisions solely on version numbers.

The version number *is* the right way to make decisions.  We've gone through 
this dozens of times.

The fact that distros backport all sorts of stuff means that you need to 
maintain a matrix of versions with features.  It's not our (upstream QEMU's) 
responsibility to tell you the differences that exist in forks of QEMU.

Regards,

Anthony Liguori