I have now tested writing and reading files over NFSv4.1 on Precise and Quantal. Looks good!
$ uname -rv 3.2.0-40-generic #63-Ubuntu SMP Wed Mar 20 17:18:21 UTC 2013 3.5.0-27-generic #45-Ubuntu SMP Tue Mar 19 23:38:37 UTC 2013
I have now tested writing and reading files over NFSv4.1 on Precise and Quantal. Looks good!
$ uname -rv
3.2.0-40-generic #63-Ubuntu SMP Wed Mar 20 17:18:21 UTC 2013
3.5.0-27-generic #45-Ubuntu SMP Tue Mar 19 23:38:37 UTC 2013