RHEL6.2: NFSv4 client hangs and lot of process in D state, constant stream of NFS4ERR_EXPIRED (-10011) errors in tcpdump

Issue

• rhel6 nfs client hangs and lot of process in D state.
• tcpdump of hung nfs client shows constant stream of NFS4ERR_EXPIRED (-10011) errors.
• System while responsive would hang when access a file from a remote NFS share. We have several other hosts that access the same area remotely with no issues.
• A reboot is required to recover.