This commit from linux-3.14 breaks our NFS-root clients here:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6e14b46b91fee8a049b0940333ce13a820beaaa5


- *p++ = htonl((u32) stat->mode);
+ *p++ = htonl((u32) (stat->mode & S_IALLUGO));


Reverting the one-liner above (on the server) fixes it for us,
as does reverting back to linux-3.13.8 on the server.

The NFS-root clients are on PowerPC (big-endian) architecture,
running linux-3.12.16. The NFS server is on an Intel PC running linux-3.14.

ACL is completely disabled on server and client,
and we're using NFSv2/v3.  No support for v4.

I instrumented the function to see what other bits were being cleared
by the (stat->mode & S_IALLUGO) masking.  The results are attached.

Cheers
Mark