Retrying a patch apply after a failed attempted resulted in following error.
$ /opt/app/11.2.0/grid4/OPatch/opatch apply -local
Oracle Interim Patch Installer version 11.2.0.3.6
Copyright (c) 2013, Oracle Corporation. All rights reserved.
Oracle Home : /opt/app/11.2.0/grid4
Central Inventory : /opt/app/oraInventory
from : /opt/app/11.2.0/grid4/oraInst.loc
OPatch version : 11.2.0.3.6
OUI version : 11.2.0.4.0
Log file location : /opt/app/11.2.0/grid4/cfgtoollogs/opatch/19852360_Sep_24_2015_13_35_27/apply2015-09-24_13-35-27PM_1.log
Applying interim patch '19852360' to OH '/opt/app/11.2.0/grid4'
Verifying environment and performing prerequisite checks...
[ Error during Oracle Home discovery Phase]. Detail: OPatchSession cannot load inventory for the given Oracle Home /opt/app/11.2.0/grid4. Possible causes are:
No read or write permission to ORACLE_HOME/.patch_storage
Central Inventory is locked by another OUI instance
No read permission to Central Inventory
The lock file exists in ORACLE_HOME/.patch_storage
The Oracle Home does not exist in Central Inventory
[ Error during Oracle Home discovery Phase]. Detail: OPatch failed: ApplySession failed to prepare the system. Lock file left by a different patch, OPatch will not try re-using the lock file.
Log file location: /opt/app/11.2.0/grid4/cfgtoollogs/opatch/19852360_Sep_24_2015_13_35_27/apply2015-09-24_13-35-27PM_1.log
Recommended actions: Please make sure no other OPatch or OUI processes is running. Try running $ORACLE_HOME/oui/bin/runInstsaller.
OPatch failed with error code 22
Looking in the oraInventory showed a lock directory which was empty. Removing it didn't resolve the issue
[grid@rhel6m1 oraInventory]$ ls
backup ContentsXML locks logs oraInst.loc orainstRoot.sh oui
[grid@rhel6m1 oraInventory]$ cd locks/
[grid@rhel6m1 oraInventory]$ rmdir locks
Inside the .patch_storage there was another file
patch_locked which had the information for which patch the lock is taken for
cat $ORACLE_HOME/.patch_storage/patch_locked
Locked for patch : 21068539
Locked by class : rollback
Removing this file resolved the issue
rm $ORACLE_HOME/.patch_storage/patch_locked