[INS-40406] The installer detects no existing Oracle Grid Infrastructure software on the system.

由于之前升级GI过程没成功，手动介绍了，本以为删除升级过程创建的新目录就OK了，没想到再次升级执行到第一步就报错

[INS-40406] The installer detects no existing Oracle Grid Infrastructure software on the system.

Cause - The installer was unable to detect any existing Oracle Clusterware or Oracle ASM installation to upgrade.  Action - You can choose either to install a new Oracle Grid Infrastructure installation (Oracle Clusterware and Oracle ASM) on this node,
and add the node to an existing cluster, or you can install a new Oracle Grid Infrastructure installation and make the node part of a new cluster. If you want to add the node to an existing cluster, then review Oracle Clusterware Administration and Deployment
Guide and follow the add node procedure. If you want to create a new cluster, then select the option for a new installation.  

安装程序未检测到任何要升级的现有 Oracle Clusterware 或 Oracle ASM 安装。这就奇怪了，如是检查配置文件

$ cat /etc/oraInst.loc 
inventory_loc=/app/grid/oraInventory
inst_group=oinstall

如是进入该目录
$ cd /app/grid/oraInventory/ContentsXML/

查看 inventory.xml  文件，发现之前升级过程已修改了这个文件

# cat inventory.xml 
<?xml version="1.0" standalone="yes" ?>
<!-- Copyright (c) 1999, 2011, Oracle. All rights reserved. -->
<!-- Do not modify the contents of this file by hand. -->
<INVENTORY>
<VERSION_INFO>
   <SAVED_WITH>11.2.0.3.0</SAVED_WITH>
   <MINIMUM_VER>2.1.0.6.0</MINIMUM_VER>
</VERSION_INFO>
<HOME_LIST>
<HOME NAME="Ora11g_gridinfrahome1" LOC="/app/grid/11.2.0" TYPE="O" IDX="1">
   <NODE_LIST>
      <NODE NAME="rac01"/>
      <NODE NAME="rac02"/>
   </NODE_LIST>
</HOME>
<HOME NAME="OraDb11g_home1" LOC="/app/oracle/product/oracle/11.2.0/db_1" TYPE="O" IDX="2">
   <NODE_LIST>
      <NODE NAME="rac01"/>
      <NODE NAME="rac02"/>
   </NODE_LIST>
</HOME>
<HOME NAME="Ora11g_gridinfrahome2" LOC="/app/grid/11.2.3" TYPE="O" IDX="3" CRS="true">
   <NODE_LIST>
      <NODE NAME="rac01"/>
      <NODE NAME="rac02"/>
   </NODE_LIST>
</HOME>
</HOME_LIST>
<COMPOSITEHOME_LIST>
</COMPOSITEHOME_LIST>
</INVENTORY>

如是删除后面那段多余的，并把上面grid1 后面加上CRS="true"，还有上面的<SAVED_WITH>改回11.2.0.1.0 保存退出（RAC的几个节点都要修改该配置文件）。
退出升级后再次运行，这一步成功通过