On 07/21/2014 11:38 PM, chen.fan.fnst@cn.fujitsu.com wrote:
On Mon, 2014-07-21 at 22:34 -0600, Eric Blake wrote:
We were not directly saving the domain XML to file after starting or finishing a blockcopy. Without the startup write, a libvirtd restart in the middle of a copy job would forget that the job was underway. Then at pivot, we were indirectly writing new XML in reaction to events that occur as we stop and restart the guest CPUs. But there was a race: since pivot is an async action, it is possible that the guest is restarted before the pivot completes, so if XML changes during the event, that change was not written. The original blockcopy code cleared out the <mirror> element prior to restarting the CPUs, but this is also a race, observed if a user does an async pivot and a dumpxml before the event occurs. Furthermore, this race will interfere with active commit, because that code relies on the <mirror> element at the time of the qemu event to determine whether to inform the user of a normal commit or an active commit.
+++ b/src/qemu/qemu_process.c @@ -1016,6 +1016,7 @@ qemuProcessHandleBlockJob(qemuMonitorPtr mon ATTRIBUTE_UNUSED, virObjectEventPtr event2 = NULL; const char *path; virDomainDiskDefPtr disk; + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
Hello Eric, The cfg should be unref by virObjectUnref(cfg) at the end.
You're right. I also discovered I need to write state after a normal abort. I'll post an updated version, along with a rebase of my patches to enable active commit. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org