Re: [Qemu-devel] [PATCH 2/3] move vm stop/start to migrate_set_state

[Anthony Liguori]

Paolo Bonzini wrote:
> On 07/09/2009 03:53 PM, Anthony Liguori wrote:
> > Paolo Bonzini wrote:
> > > On 07/09/2009 03:45 PM, Anthony Liguori wrote:
> > > > How does the disk become full during the final stage? The guest isn't
> > > > running.
> > >
> > > The host disk can become full and cause a "migrate exec" to fail. Or
> > > for network migration migration, you could have the connection drop
> > > exactly during the final stage. In this case, the VM would be
> > > unconditionally restarted.
> >
> > Because migration failed. Is that not the desired behavior? It seems
> > like it is to me.
>
> By "unconditionally" I meant "even if the VM used to be paused".

Oh, that's definitely a bug.  But that's an easy fix too:

diff --git a/migration.c b/migration.c
index 190b37e..e6c8b16 100644
--- a/migration.c
+++ b/migration.c
@@ -261,12 +261,16 @@ void migrate_fd_put_ready(void *opaque)
    dprintf("iterate\n");
    if (qemu_savevm_state_iterate(s->file) == 1) {
        int state;
+        int old_vm_running = vm_running;
+
        dprintf("done iterating\n");
        vm_stop(0);

        bdrv_flush_all();
        if ((qemu_savevm_state_complete(s->file)) < 0) {
-            vm_start();
+            if (old_vm_running) {
+                vm_start();
+            }
            state = MIG_STATE_ERROR;
        } else {
            state = MIG_STATE_COMPLETED;

Regards,

Anthony Liguori

> Paolo