Re: [libvirt] [PATCH] qemu: Fix all callers of qemuMonitorGetBlockJobInfo()

On Mon, 2016-01-04 at 15:46 +0100, Michal Privoznik wrote: > On 04.01.2016 15:20, Andrea Bolognani wrote: > > Commit 1b43885 modified one of the callers of this function to take > > into account the possible return value of 0 when the block job can't be > > found. > >  > > This commit finishes the job by updating the remaining caller. > > --- > >  src/qemu/qemu_driver.c | 13 ++++++------- > >  1 file changed, 6 insertions(+), 7 deletions(-) > >  > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > > index 304165c..c4573d9 100644 > > --- a/src/qemu/qemu_driver.c > > +++ b/src/qemu/qemu_driver.c > > @@ -16150,14 +16150,13 @@ qemuDomainBlockPivot(virQEMUDriverPtr driver, > >          rc = qemuMonitorGetBlockJobInfo(priv->mon, disk->info.alias, &info); > >          if (qemuDomainObjExitMonitor(driver, vm) < 0) > >              goto cleanup; > > -        if (rc < 0) > > +        if (rc <= 0) > >              goto cleanup; > > -        if (rc == 1 && > > -            (info.ready == 1 || > > -             (info.ready == -1 && > > -              info.end == info.cur && > > -              (info.type == VIR_DOMAIN_BLOCK_JOB_TYPE_COPY || > > -               info.type == VIR_DOMAIN_BLOCK_JOB_TYPE_COMMIT)))) > > +        if (info.ready == 1 || > > +            (info.ready == -1 && > > +             info.end == info.cur && > > +             (info.type == VIR_DOMAIN_BLOCK_JOB_TYPE_COPY || > > +              info.type == VIR_DOMAIN_BLOCK_JOB_TYPE_COMMIT))) > >              disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_READY; > >      } >  > Interesting. So previously this code worked just right with no block > operation running on @disk. Now it will fail. I guess that's correct > approach since this function's job is to abort a block job. >  > ACK I'm actually having second thoughts about this. We only call qemuMonitorGetBlockJobInfo() if !disk->mirrorState. However, having it return 0 before would skip reading from info (my main concern, as it would not have been filled in) and cause the check for   disk->mirrorState != VIR_DOMAIN_DISK_MIRROR_STATE_READY immediately afterwards to fail and an error to be raised before jumping to cleanup. After my patch, the function will jump to cleanup earlier, still returning a negative error code, but not raising any error in the process. I guess what I'm trying to say is that, unless you can convince otherwise, I'm going to have to SNACK this one :)