replication: interrupt failover if the main device is closed

Without this change, there is a race condition in tests/test-replication.
Depending on how fast the failover job (active commit) runs, there is a
chance of two bad things happening:

1) replication_done can be called after the secondary has been closed
and hence when the BDRVReplicationState is not valid anymore.

2) two copies of the active disk are present during the
/replication/secondary/stop test (that test runs immediately after
/replication/secondary/start, which tests failover).  This causes the
corruption detector to fire.

Reviewed-by: Wen Congyang <[email protected]>
Reviewed-by: Changlong Xie <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Reviewed-by: Fam Zheng <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Fam Zheng <[email protected]>

block/replication.c

@@ -138,6 +138,9 @@ static void replication_close(BlockDriverState *bs)
     if (s->replication_state == BLOCK_REPLICATION_RUNNING) {
         replication_stop(s->rs, false, NULL);
     }
+    if (s->replication_state == BLOCK_REPLICATION_FAILOVER) {
+        block_job_cancel_sync(s->active_disk->bs->job);
+    }
 
     if (s->mode == REPLICATION_MODE_SECONDARY) {
         g_free(s->top_id);