[Qemu-devel] [PULL 1/6] migration: Only change state after migration has finished

[Juan Quintela]

On previous change, we changed state at post load time if it was not
running, special casing the "running" change.  Now, we change any states
at the end of the migration.

Signed-off-by: Juan Quintela <quint...@redhat.com>
Tested-by: Christian Borntraeger <borntrae...@de.ibm.com>
---
 migration/migration.c | 48 +++++++++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 45719a0..ede432e 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -104,6 +104,8 @@ typedef struct {
     bool optional;
     uint32_t size;
     uint8_t runstate[100];
+    RunState state;
+    bool received;
 } GlobalState;

 static GlobalState global_state;
@@ -119,9 +121,14 @@ static int global_state_store(void)
     return 0;
 }

-static char *global_state_get_runstate(void)
+static bool global_state_received(void)
 {
-    return (char *)global_state.runstate;
+    return global_state.received;
+}
+
+static RunState global_state_get_runstate(void)
+{
+    return global_state.state;
 }

 void global_state_set_optional(void)
@@ -154,26 +161,25 @@ static bool global_state_needed(void *opaque)
 static int global_state_post_load(void *opaque, int version_id)
 {
     GlobalState *s = opaque;
-    int ret = 0;
+    Error *local_err = NULL;
+    int r;
     char *runstate = (char *)s->runstate;

+    s->received = true;
     trace_migrate_global_state_post_load(runstate);

-    if (strcmp(runstate, "running") != 0) {
-        Error *local_err = NULL;
-        int r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE_MAX,
+    r = qapi_enum_parse(RunState_lookup, runstate, RUN_STATE_MAX,
                                 -1, &local_err);

-        if (r == -1) {
-            if (local_err) {
-                error_report_err(local_err);
-            }
-            return -EINVAL;
+    if (r == -1) {
+        if (local_err) {
+            error_report_err(local_err);
         }
-        ret = vm_stop_force_state(r);
+        return -EINVAL;
     }
+    s->state = r;

-   return ret;
+    return 0;
 }

 static void global_state_pre_save(void *opaque)
@@ -202,6 +208,7 @@ void register_global_state(void)
 {
     /* We would use it independently that we receive it */
     strcpy((char *)&global_state.runstate, "");
+    global_state.received = false;
     vmstate_register(NULL, 0, &vmstate_globalstate, &global_state);
 }

@@ -283,20 +290,19 @@ static void process_incoming_migration_co(void *opaque)
         exit(EXIT_FAILURE);
     }

-    /* runstate == "" means that we haven't received it through the
-     * wire, so we obey autostart.  runstate == runing means that we
-     * need to run it, we need to make sure that we do it after
-     * everything else has finished.  Every other state change is done
-     * at the post_load function */
+    /* If global state section was not received or we are in running
+       state, we need to obey autostart. Any other state is set with
+       runstate_set. */

-    if (strcmp(global_state_get_runstate(), "running") == 0) {
-        vm_start();
-    } else if (strcmp(global_state_get_runstate(), "") == 0) {
+    if (!global_state_received() ||
+        global_state_get_runstate() == RUN_STATE_RUNNING) {
         if (autostart) {
             vm_start();
         } else {
             runstate_set(RUN_STATE_PAUSED);
         }
+    } else {
+        runstate_set(global_state_get_runstate());
     }
     migrate_decompress_threads_join();
 }
-- 
2.4.3