[libvirt PATCH 42/80] qemu: Improve post-copy migration handling on reconnect

[Peter Krempa]

On Tue, May 10, 2022 at 17:21:03 +0200, Jiri Denemark wrote:
> When libvirt daemon is restarted during an active post-copy migration,
> we do not always mark the migration as broken. In this phase libvirt is
> not really needed for migration to finish successfully. In fact the
> migration could have even finished while libvirt was not running or it
> may still be happily running.
> 
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
>  src/qemu/qemu_migration.c | 27 +++++++++++++++++++++++++++
>  src/qemu/qemu_migration.h |  6 ++++++
>  src/qemu/qemu_process.c   | 39 +++++++++++++++++++++++++++++----------
>  3 files changed, 62 insertions(+), 10 deletions(-)
> 
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index dacea63610..854dfd43c1 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -2460,6 +2460,33 @@ qemuMigrationSrcBeginPhaseBlockDirtyBitmaps(qemuMigrationCookie *mig,
>  }
>  
>  
> +int
> +qemuMigrationAnyRefreshStatus(virQEMUDriver *driver,
> +                              virDomainObj *vm,
> +                              virDomainAsyncJob asyncJob,
> +                              virDomainJobStatus *status)
> +{
> +    g_autoptr(virDomainJobData) jobData = NULL;
> +    qemuDomainJobDataPrivate *priv;
> +
> +    jobData = virDomainJobDataInit(&qemuJobDataPrivateDataCallbacks);
> +    priv = jobData->privateData;
> +
> +    if (qemuMigrationAnyFetchStats(driver, vm, asyncJob, jobData, NULL) < 0)
> +        return -1;
> +
> +    qemuMigrationUpdateJobType(jobData);
> +    VIR_DEBUG("QEMU reports domain '%s' is in '%s' migration state, "
> +              "translated as %d",

Diagnostics on a single line please

> +              vm->def->name,
> +              qemuMonitorMigrationStatusTypeToString(priv->stats.mig.status),
> +              jobData->status);
> +
> +    *status = jobData->status;
> +    return 0;
> +}
> +

[...]

> @@ -3731,7 +3728,29 @@ qemuProcessRecoverMigration(virQEMUDriver *driver,
>          return -1;
>  
>      if (rc > 0) {
> -        qemuProcessRestoreMigrationJob(vm, job);
> +        if (migStatus == VIR_DOMAIN_JOB_STATUS_POSTCOPY) {
> +            VIR_DEBUG("Post-copy migration of domain %s still running, it "
> +                      "will be handled as unattended", vm->def->name);

This one too.

Reviewed-by: Peter Krempa <pkrempa at redhat.com>