Re: [Qemu-discuss] qemu-img convert stuck

[David Lee]

On Thu, Apr 12, 2018 at 10:23 PM, Fam Zheng <address@hidden> wrote:
> On Thu, 04/12 21:45, David Lee wrote:
>> On Thu, Apr 12, 2018 at 10:16 AM, David Lee <address@hidden> wrote:
>> >> > My team caught this issue too after switching to CentOS 7.4 with 
>> >> > qemu-img
>> >> > 2.9.0
>> >> > gdb shows exactly the same backtrace when the convert stuck, and we are 
>> >> > on
>> >> > NFS.
>> >> >
>> >> > Later we found the following:
>> >> > 1. The stuck can happen on local storage, too.
>> >> > 2. Replace qemu-img 2.9.0 with 2.6.0 and everything works smoothly 
>> >> > again.
>> >> >
>> >> > BTW, we use "qemu-img convert" to convert qcow2 and its backing files 
>> >> > into
>> >> > a single qcow2 image.
>> >>
>> >> Maybe it is RHBZ 1508886?
>> >>
>> >> Fam
>> >
>> >
>> >
>> > Thanks, Fam.  We just tracked down to this BZ too and are about to trying
>> > the commit ef6dada8b44e1e7c4bec5c1115903af9af415b50
>>
>> We tested qemu-kvm-ev-2.9.0-16.el7_4.14.1 - where from the source RPM we
>> verified it does contain ef6dada8b44e1e7c4bec5c1115903af9af415b50
>>
>> But the issue still exists.  The convert got stuck if one of the old
>> active overlay
>> had been 'vol-resize'd  with qemu monitor command to a larger size.  This 
>> looks
>> like a prerequisite but not sufficient condition to trigger this badness.
>
> So it is a separate issue. Did you try upstream master as well?
>
> Fam

Not yet.

-- 
Thanks,
Li Qun