[TD-4593]<fix>: fix vnode cannnot close while syncing

src/dnode/src/dnodeVMgmt.c

@@ -169,7 +169,7 @@ static int32_t dnodeProcessCreateVnodeMsg(SRpcMsg *rpcMsg) {
 static int32_t dnodeProcessAlterVnodeMsg(SRpcMsg *rpcMsg) {
   SAlterVnodeMsg *pAlter = dnodeParseVnodeMsg(rpcMsg);
 
-  void *pVnode = vnodeAcquire(pAlter->cfg.vgId);
+  void *pVnode = vnodeAcquireNotClose(pAlter->cfg.vgId);
   if (pVnode != NULL) {
     dDebug("vgId:%d, alter vnode msg is received", pAlter->cfg.vgId);
     int32_t code = vnodeAlter(pVnode, pAlter);

src/dnode/src/dnodeVRead.c

@@ -63,7 +63,7 @@ void dnodeDispatchToVReadQueue(SRpcMsg *pMsg) {
     pHead->contLen = htonl(pHead->contLen);
 
     assert(pHead->contLen > 0);
-    void *pVnode = vnodeAcquire(pHead->vgId);
+    void *pVnode = vnodeAcquireNotClose(pHead->vgId);
     if (pVnode != NULL) {
       code = vnodeWriteToRQueue(pVnode, pCont, pHead->contLen, TAOS_QTYPE_RPC, pMsg);
       if (code == TSDB_CODE_SUCCESS) queuedMsgNum++;

src/dnode/src/dnodeVWrite.c

@@ -85,7 +85,7 @@ void dnodeDispatchToVWriteQueue(SRpcMsg *pRpcMsg) {
   pMsg->vgId = htonl(pMsg->vgId);
   pMsg->contLen = htonl(pMsg->contLen);
 
-  void *pVnode = vnodeAcquire(pMsg->vgId);
+  void *pVnode = vnodeAcquireNotClose(pMsg->vgId);
   if (pVnode == NULL) {
     code = TSDB_CODE_VND_INVALID_VGROUP_ID;
   } else {

src/inc/vnode.h

@@ -68,6 +68,7 @@ int32_t vnodeInitMgmt();
 void    vnodeCleanupMgmt();
 void*   vnodeAcquire(int32_t vgId);
 void    vnodeRelease(void *pVnode);
+void*   vnodeAcquireNotClose(int32_t vgId);
 void*   vnodeGetWal(void *pVnode);
 int32_t vnodeGetVnodeList(int32_t vnodeList[], int32_t *numOfVnodes);
 void    vnodeBuildStatusMsg(void *pStatus);

src/vnode/inc/vnodeInt.h

@@ -41,6 +41,8 @@ typedef struct {
   int32_t  queuedWMsg;
   int32_t  queuedRMsg;
   int32_t  flowctrlLevel;
+  int8_t   preClose;  // drop and close switch
+  int8_t   reserved[3];
   int64_t  sequence;  // for topic
   int8_t   status;
   int8_t   role;