Re: [osstest test] 60719: tolerable FAIL - PUSHED

[Ian Campbell <ian.campbell@citrix.com>]

On Thu, 2015-09-03 at 10:35 -0600, Jim Fehlig wrote:

> I wonder if this has anything to do with migration V2? I noticed a migration 
> regression a few days back, but later realized that the sender was 4.5 and 
> receiver was 4.6. I planned to see if migration worked through libvirt between 
> two 4.6 hosts, but before doing so I had to re-purpose the machines for another 
> task. I think libvirt needs some work to accommodate migration V2...

So after shaving a bunch of yakks wrt getting my test boxes setup I've
finally tracked this one down...

libvirt is passing libxl a restore (and perhaps save) file descriptor which
is set O_NONBLOCK, which libxl/c doesn't expect and therefore doesn't
handle the resulting EAGAIN.

Ian and I think it would be more convenient for most callers if libxl took
care of this by making the fd blocking again and returning it to the
original state when it was done.

I'll cook up a patch.

I think migr v1 probably had the same requirement, although it may not have
manifested itself as a bug.

Ian