fix(sync): release SyncNode ref

source/dnode/mnode/impl/src/mndMain.c

@@ -519,6 +519,8 @@ int32_t mndProcessSyncMsg(SRpcMsg *pMsg) {
     }
   }
 
+  syncNodeRelease(pSyncNode);
+
   if (code != 0) {
     terrno = TSDB_CODE_SYN_INTERNAL_ERROR;
   }

source/libs/sync/src/syncMain.c

@@ -136,10 +136,9 @@ void syncStartStandBy(int64_t rid) {
 
 void syncStop(int64_t rid) {
   SSyncNode* pSyncNode = (SSyncNode*)taosAcquireRef(tsNodeRefId, rid);
-  if (pSyncNode == NULL) {
-    return;
+  if (pSyncNode != NULL) {
+    syncNodeClose(pSyncNode);
   }
-  syncNodeClose(pSyncNode);
 
   taosReleaseRef(tsNodeRefId, pSyncNode->rid);
   taosRemoveRef(tsNodeRefId, rid);
@@ -154,13 +153,13 @@ int32_t syncSetStandby(int64_t rid) {
   }
 
   if (pSyncNode->state != TAOS_SYNC_STATE_FOLLOWER) {
-    taosReleaseRef(tsNodeRefId, pSyncNode->rid);
     if (pSyncNode->state == TAOS_SYNC_STATE_LEADER) {
       terrno = TSDB_CODE_SYN_IS_LEADER;
     } else {
       terrno = TSDB_CODE_SYN_STANDBY_NOT_READY;
     }
     sError("failed to set standby since it is not follower, state:%s rid:%" PRId64, syncStr(pSyncNode->state), rid);
+    taosReleaseRef(tsNodeRefId, pSyncNode->rid);
     return -1;
   }
 
@@ -616,6 +615,7 @@ int32_t syncPropose(int64_t rid, SRpcMsg* pMsg, bool isWeak) {
 
   SSyncNode* pSyncNode = taosAcquireRef(tsNodeRefId, rid);
   if (pSyncNode == NULL) {
+    taosReleaseRef(tsNodeRefId, rid);
     terrno = TSDB_CODE_SYN_INTERNAL_ERROR;
     return -1;
   }

source/libs/sync/src/syncSnapshot.c

@@ -707,6 +707,7 @@ char *snapshotReceiver2SimpleStr(SSyncSnapshotReceiver *pReceiver, char *event)
 // condition 2, recv SYNC_SNAPSHOT_SEQ_END, finish receiver(apply snapshot data, update commit index, maybe reconfig)
 // condition 3, recv SYNC_SNAPSHOT_SEQ_FORCE_CLOSE, force close
 // condition 4, got data, update ack
+//
 int32_t syncNodeOnSnapshotSendCb(SSyncNode *pSyncNode, SyncSnapshotSend *pMsg) {
   // get receiver
   SSyncSnapshotReceiver *pReceiver = pSyncNode->pNewNodeReceiver;