Re: [PULL 22/33] migration: remove the QEMUFileOps 'get_buffer' callback

[Daniel P . Berrangé]

On Wed, Jun 22, 2022 at 04:13:39PM -0400, Peter Xu wrote:
> On Wed, Jun 22, 2022 at 03:34:52PM -0400, Peter Xu wrote:
> > On Wed, Jun 22, 2022 at 07:39:06PM +0100, Dr. David Alan Gilbert (git) 
> > wrote:
> > > diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> > > index 74f919de67..e206b05550 100644
> > > --- a/migration/qemu-file.c
> > > +++ b/migration/qemu-file.c
> > > @@ -377,8 +377,22 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
> > >          return 0;
> > >      }
> > >  
> > > -    len = f->ops->get_buffer(f->ioc, f->buf + pending, 
> > > f->total_transferred,
> > > -                             IO_BUF_SIZE - pending, &local_error);
> > > +    do {
> > > +        len = qio_channel_read(f->ioc,
> > > +                               (char *)f->buf + pending,
> > > +                               IO_BUF_SIZE - pending,
> > > +                               &local_error);
> > > +        if (len == QIO_CHANNEL_ERR_BLOCK) {
> > > +            if (qemu_in_coroutine()) {
> > > +                qio_channel_yield(f->ioc, G_IO_IN);
> > > +            } else {
> > > +                qio_channel_wait(f->ioc, G_IO_IN);
> > > +            }
> > > +        } else if (len < 0) {
> > > +            len = EIO;
> > 
> > This should be -EIO.
> > 
> > > +        }
> > > +    } while (len == QIO_CHANNEL_ERR_BLOCK);
> > 
> > It's failing only with the new TLS test I added for postcopy somehow (at
> > least /x86_64/migration/postcopy/recovery/tls).. I also verified after the
> > change it'll work again.
> 
> Hmm, when I wanted to run the whole bunch of the migration-test again I
> found that precopy tls test hangs (/x86_64/migration/precopy/unix/tls/psk).
> Though for this time it also hangs for me even with the master branch, so
> maybe not anything wrong with this specific pull req but still something
> needs fixing..

That pre-existing test has been runnnig by default in CI for a while
now, under different OS builds, so I'm surprised. Is there anything
especially unusual / different about your setup that could explain
why you see hang that we don't get anywhere else ?


With regards,
Daniel
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