[libvirt] [PATCH] [3/4] Implement managed save operations for qemu driver

[Daniel Veillard]

On Fri, Apr 02, 2010 at 11:54:59AM -0400, Laine Stump wrote:
> On 04/01/2010 12:22 PM, Daniel Veillard wrote:
> >@@ -5928,6 +6096,29 @@ static int qemudDomainStart(virDomainPtr dom) {
> >          goto endjob;
> >      }
> >
> >+    /*
> >+     * If there is a managed saved state restore it instead of starting
> >+     * from scratch. In any case the old state is removed.
> >+     */
> >+    managed_save = qemuDomainManagedSavePath(driver, vm);
> >+    if ((managed_save)&&  (virFileExists(managed_save))) {
> >+        virDomainObjUnlock(vm);
> >+        qemuDriverUnlock(driver);
> >+        ret = qemudDomainRestore(dom->conn, managed_save);
> 
> There is problem here.
> 
> qemudDomainRestore will call qemuDomainObjBeginJobWithDriver, which
> was already called just above this bit of code in qemudDomainStart.
> The result will be a temporary deadlock, while the semaphore wait
> times out, followed by failure.
> 
> Either qemudDomainStart needs to call that function later, or else
> it needs to call qemuDomainObjEndJob before calling
> qemudDomainRestore.
> 
> (Unfortunately, I haven't yet had the time to do any more of a
> review other than build and try running the code.)

  Right, spot on !
With the fix and the restore patch from Chris the cycle seems to work
just fine for me now :-)
I will integrate the feedback and update the patches,

  thanks !

Daniel

-- 
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