Error while reliniking Oracle 11G binaries on 64Bit Linux - You do not have sufficient permissions to access the inventory

Problem:
While trying to relink the Oracle binaries for Oracle Database 11.2.0.3, we had the below error
For Unix system
set $ORACLE_HOME,
set $ORACLE_SID

$ORACLE_HOME/bin/relink all
writing relink log to: /mnt/TSTapps/DMDEV/11.2.0/dbhome_2/install/relink.log

$ cat /mnt/TSTapps/DMDEV/11.2.0/dbhome_2/install/relink.log
You do not have sufficient permissions to access the inventory '/etc/oracle/oraInventory'. Installation cannot continue. It is required that the primary group of the install user is same as the inventory owner group. Make sure that the install user is part of the inventory owner group and restart the installer.: Permission denied

Cause:
The inventory location is not accessible by the user attempting to perform the installation. The oraInventory being pointed to through the inventory_loc reference in the /var/opt/oracle/oraInst.loc or /etc/oraInst.loc file or inst_loc in registry has permissions that restrict the user running the OUI from writing to the oraInventory.

Solution:

• Verify you have all the right permission given to oracle user.
• Verify the following user belongs to inventory owner group.

                 %cat /etc/group | grep dba
                  dba:x:501:applmgr

• Modified user' primary group and issue is resolved now.

                  # usermod -g dba oracle
                  $ id

                  uid=506(oracle) gid=501(dba) groups=501(dba)

References:
How to Relink Oracle Database Software on UNIX [ID 131321.1]
Oracle 11gR2 Relink New Feature [ID 883299.1]
http://docs.oracle.com/cd/E11882_01/em.112/e12255/e_oui_appendix.htm#OUICG386

http://docs.oracle.com/cd/B19306_01/install.102/b28052/toc.htm