[libvirt] [PATCH v2 5/7] qemu: Kill QEMU process if Prepare phase fails

[Pavel Hrdina]

On Thu, Nov 19, 2015 at 01:09:19PM +0100, Jiri Denemark wrote:
> Some failure paths in qemuMigrationPrepareAny forgot to kill the just
> started QEMU process. This patch fixes this by combining 'stop' and
> 'endjob' label into a new label 'stopjob'. This name was chosen to avoid
> confusion with the most common semantics of 'endjob'. Normally, 'endjob'
> is always called at the end of an API to stop the job we entered at the
> beginning. In qemuMigrationPrepareAny we only want to stop the job in
> failure path; on success we need to carry the job over to the Finish
> phase.
> 
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
> 
> Notes:
>     ACKed in version 1
>     
>     Version 2:
>     - no change
> 
>  src/qemu/qemu_migration.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index 4ab6ab7..9a4f19f 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -3522,7 +3522,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>          (pipe(dataFD) < 0 || virSetCloseExec(dataFD[1]) < 0)) {
>          virReportSystemError(errno, "%s",
>                               _("cannot create pipe for tunnelled migration"));
> -        goto endjob;
> +        goto stopjob;
>      }
>  
>      virObjectUnref(priv->qemuCaps);
> @@ -3530,11 +3530,11 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>                                                  vm->def->emulator,
>                                                  vm->def->os.machine);
>      if (!priv->qemuCaps)
> -        goto endjob;
> +        goto stopjob;
>  
>      if (!(migrateFrom = qemuMigrationPrepareIncoming(vm, tunnel, protocol,
>                                                       listenAddress, port)))
> -        goto endjob;
> +        goto stopjob;
>  
>      /* Start the QEMU daemon, with the same command-line arguments plus
>       * -incoming $migrateFrom
> @@ -3545,14 +3545,14 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>                           VIR_QEMU_PROCESS_START_PAUSED |
>                           VIR_QEMU_PROCESS_START_AUTODESTROY) < 0) {
>          virDomainAuditStart(vm, "migrated", false);
> -        goto endjob;
> +        goto stopjob;
>      }
>  
>      if (tunnel) {
>          if (virFDStreamOpen(st, dataFD[1]) < 0) {
>              virReportSystemError(errno, "%s",
>                                   _("cannot pass pipe for tunnelled migration"));
> -            goto stop;
> +            goto stopjob;
>          }
>          dataFD[1] = -1; /* 'st' owns the FD now & will close it */
>      }
> @@ -3560,17 +3560,17 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>      if (qemuMigrationSetCompression(driver, vm,
>                                      flags & VIR_MIGRATE_COMPRESSED,
>                                      QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
> -        goto stop;
> +        goto stopjob;
>  
>      if (STREQ_NULLABLE(protocol, "rdma") &&
>          virProcessSetMaxMemLock(vm->pid, vm->def->mem.hard_limit << 10) < 0) {
> -        goto stop;
> +        goto stopjob;
>      }
>  
>      if (qemuMigrationSetPinAll(driver, vm,
>                                 flags & VIR_MIGRATE_RDMA_PIN_ALL,
>                                 QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
> -        goto stop;
> +        goto stopjob;
>  
>      if (mig->lockState) {
>          VIR_DEBUG("Received lockstate %s", mig->lockState);
> @@ -3593,7 +3593,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>          if (qemuMigrationStartNBDServer(driver, vm, listenAddress,
>                                          nmigrate_disks, migrate_disks) < 0) {
>              /* error already reported */
> -            goto endjob;
> +            goto stopjob;
>          }
>          cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
>      }
> @@ -3608,7 +3608,7 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>      }
>  
>      if (qemuDomainCleanupAdd(vm, qemuMigrationPrepareCleanup) < 0)
> -        goto endjob;
> +        goto stopjob;
>  
>      if (!(flags & VIR_MIGRATE_OFFLINE)) {
>          virDomainAuditStart(vm, "migrated", true);
> @@ -3647,12 +3647,13 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
>      virNWFilterUnlockFilterUpdates();
>      return ret;
>  
> - stop:
> -    virDomainAuditStart(vm, "migrated", false);
> -    qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED,
> -                    VIR_QEMU_PROCESS_STOP_MIGRATED);
> + stopjob:
> +    if (vm->def->id != -1) {
> +        virDomainAuditStart(vm, "migrated", false);
> +        qemuProcessStop(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED,
> +                        VIR_QEMU_PROCESS_STOP_MIGRATED);
> +    }
>  
> - endjob:
>      qemuMigrationJobFinish(driver, vm);
>      goto cleanup;

I wouldn't join those two labels together regarding the change in 1/7 patch.
Just change all goto after qemuProcessStart to jump to stop.  About the naming
we've discussed, what about endmigjob? It's maybe to long, but tels, that we are
about to stop the qemuMigrationJob.

Pavel

>  }
> -- 
> 2.6.3
> 
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