[TD-2594]<fix>: return error and stop taosd startup if too many vnodes

src/dnode/src/dnodeVnodes.c

@@ -73,7 +73,8 @@ static int32_t dnodeGetVnodeList(int32_t vnodeList[], int32_t *numOfVnodes) {
 
       if (*numOfVnodes >= TSDB_MAX_VNODES) {
         dError("vgId:%d, too many vnode directory in disk, exist:%d max:%d", vnode, *numOfVnodes, TSDB_MAX_VNODES);
-        continue;
+        closedir(dir);
+        return TSDB_CODE_DND_TOO_MANY_VNODES;
       } else {
         vnodeList[*numOfVnodes - 1] = vnode;
       }

src/inc/taoserror.h

@@ -194,6 +194,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_DND_OUT_OF_MEMORY,            0, 0x0401, "Dnode out
 TAOS_DEFINE_ERROR(TSDB_CODE_DND_NO_WRITE_ACCESS,          0, 0x0402, "No permission for disk files in dnode")
 TAOS_DEFINE_ERROR(TSDB_CODE_DND_INVALID_MSG_LEN,          0, 0x0403, "Invalid message length")
 TAOS_DEFINE_ERROR(TSDB_CODE_DND_ACTION_IN_PROGRESS,       0, 0x0404, "Action in progress")
+TAOS_DEFINE_ERROR(TSDB_CODE_DND_TOO_MANY_VNODES,          0, 0x0405, "Too many vnode directories")
 
 // vnode 
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_ACTION_IN_PROGRESS,       0, 0x0500, "Action in progress")