Add packet-drop to fix the new flaky failover test (#2196)

The new test was added in #2178, obviously there may be
pending reads in the connection, so there may be a race
in the DROP-CLUSTER-PACKET-FILTER part causing the test
to fail. Add CLOSE-CLUSTER-LINK-ON-PACKET-DROP to ensure
that the replica does not process the packet.

Signed-off-by: Binbin <[email protected]>
(cherry picked from commit 2019337)

Author: enjoy-binbin

src/blocked.c

@@ -230,14 +230,12 @@ void unblockClient(client *c, int queue_for_reprocessing) {
 /* Check if the specified client can be safely timed out using
  * unblockClientOnTimeout(). */
 int blockedClientMayTimeout(client *c) {
-    if (c->bstate->btype == BLOCKED_MODULE) {
+    if (c->bstate.btype == BLOCKED_MODULE) {
         return moduleBlockedClientMayTimeout(c);
     }
 
-    if (c->bstate->btype == BLOCKED_LIST ||
-        c->bstate->btype == BLOCKED_ZSET ||
-        c->bstate->btype == BLOCKED_STREAM ||
-        c->bstate->btype == BLOCKED_WAIT) {
+    if (c->bstate.btype == BLOCKED_LIST || c->bstate.btype == BLOCKED_ZSET || c->bstate.btype == BLOCKED_STREAM ||
+        c->bstate.btype == BLOCKED_WAIT) {
         return 1;
     }
     return 0;

tests/unit/cluster/failover2.tcl

@@ -148,6 +148,7 @@ proc test_replica_config_epoch_failover {type} {
             R 3 CONFIG SET cluster-replica-no-failover yes
         }
         R 3 DEBUG DROP-CLUSTER-PACKET-FILTER $CLUSTER_PACKET_TYPE_ALL
+        R 3 DEBUG CLOSE-CLUSTER-LINK-ON-PACKET-DROP 1
 
         set R0_nodeid [R 0 cluster myid]
 
@@ -170,6 +171,7 @@ proc test_replica_config_epoch_failover {type} {
         # Pause the R 0 and wait for the cluster to be down.
         pause_process [srv 0 pid]
         R 3 DEBUG DROP-CLUSTER-PACKET-FILTER $CLUSTER_PACKET_TYPE_NONE
+        R 3 DEBUG CLOSE-CLUSTER-LINK-ON-PACKET-DROP 0
         wait_for_condition 1000 50 {
             [CI 1 cluster_state] == "fail" &&
             [CI 2 cluster_state] == "fail" &&