Unable to mount NFS or access in linux

Unable to mount NFS or access in linux

Problem: Mountpoint /nfsdemo/nfs2 is mounted but not able to access its directories.

df -Ph
Filesystem                                   Size  Used Avail Use% Mounted on
demooracle:/root_vrdm_1/nfsdemo               18G  4.3G   13G  26% /nfsdemo/nfs2

cd /nfsdemo/nfs2/testdir1/tdir2 -- Failed

Troubleshooting:
1. /proc/mounts does not have the mountpoint entry.
cat /proc/mounts -- It does not have the entry
2. /etc/fstab has the entry
3. Try to umount
umount /nfsdemo/nfs2 -- fails with timeout
4. Try to do force mount
mount -f /nfsdemo/nfs2  -- Completes but does not resolve the issue
5. Reboot the OS to clean the memory and it resolves the issue