[libvirt] [PATCH 3/3] qemu: Properly abort migration to a file

[Peter Krempa]

On 05/22/14 16:28, Jiri Denemark wrote:
> On Thu, May 22, 2014 at 16:14:22 +0200, Peter Krempa wrote:
>> On 05/22/14 13:55, Jiri Denemark wrote:
>>> This is similar to the previous commit in that we need to explicitly
>>> send migrate_cancel when libvirt detects an error other than those
>>> reported by query-migrate. However, the possibility to hit such error is
>>> pretty small.
>>>
>>> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
>>> ---
>>>  src/qemu/qemu_migration.c | 21 ++++++++++++++++++++-
>>>  1 file changed, 20 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
>>> index ae18acb..5754f73 100644
>>> --- a/src/qemu/qemu_migration.c
>>> +++ b/src/qemu/qemu_migration.c
>>> @@ -4704,6 +4704,7 @@ qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
>>>      int pipeFD[2] = { -1, -1 };
>>>      unsigned long saveMigBandwidth = priv->migMaxBandwidth;
>>>      char *errbuf = NULL;
>>> +    virErrorPtr orig_err = NULL;
>>>  
>>>      /* Increase migration bandwidth to unlimited since target is a file.
>>>       * Failure to change migration speed is not fatal. */
>>> @@ -4806,8 +4807,17 @@ qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
>>>  
>>>      rc = qemuMigrationWaitForCompletion(driver, vm, asyncJob, NULL, false);
>>>  
>>> -    if (rc < 0)
>>> +    if (rc < 0) {
>>> +        if (rc == -2) {
>>> +            orig_err = virSaveLastError();
>>> +            virCommandAbort(cmd);
>>
>> Shouldn't we abort the migration in qemu before killing the I/O helper?
>> Qemu will get a sigpipe probably after we do that. Not sure wether
>> that's worth dealing with as the migration is still going to fail.
> 
> Hmm, good question. Do we even need to abort I/O helper as I guess
> cancelling the migration will result in EOF on the I/O helper's input?

Well and a counter-example is if qemu get's stuck, then you at least
abort the iohelper and then get stuck a few lines below on the monitor.

> 
>>> +            if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) == 0) {
>>> +                qemuMonitorMigrateCancel(priv->mon);
>>> +                qemuDomainObjExitMonitor(driver, vm);
>>> +            }
>>> +        }
> 
> Jirka
> 


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