Comment 5 for bug 1327563

That is strange that upstream 3.13.9 also has the bug, since that is what 3.13.0-24-generic is based on. I don't see any specific SAUCE patches that would fix this. I do see a number of nfs changes that went into upstream 3.13.11.1 and 3.13.11.2:

  * nfsd4: buffer-length check for SUPPATTR_EXCLCREAT
  * nfsd4: session needs room for following op to error out
  * nfsd4: leave reply buffer space for failed setattr
  * nfsd4: fix test_stateid error reply encoding
  * nfsd: notify_change needs elevated write count
  * nfsd4: fix setclientid encode size
  * nfsd: check passed socket's net matches NFSd superblock's one

Can you confirm that v3.11.9 does in fact exhibit the bug:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13.9-trusty/

If it does, then we may need to perform a kernel bisect between the 3.13.0-24-generic and 3.13.0-27-generic Ubuntu kernels.