RHEL NFS client returns NULL bytes when reading a growing file

Issue

• Since upgrading from Red Hat Enterprise Linux 4 to Red Hat Enterprise Linux 5u3, under high NFS load, the java application reading and writing to the NFS volumes will occasionally read NULL bytes from a file even though none exist.
• This is similar to a previously reported and fixed Bug 429755. But the current issue is reported against a more recent kernel.
• One of our developers noticed that sometimes log files on NFS shares contain NULL bytes when they shouldn't.
• There is a kernel invalidation issue fixed in the kernels newer than 2.6.18-164.4.1 (Bug 511170), but upgrading past this kernel did not resolve the issue.