NFS readdirplus on ZFS with > 1 billion files

[Josh Paetzel]

We've been chasing this bug for a very long time and finally managed to
pin it down.  When a ZFS dataset has more than 1 billion files on it and
an NFS client does a readdirplus the file handles for files with high
znode/inode numbers gets truncated due to a 64 -> 32 bit conversion.

https://reviews.freebsd.org/D9009

This isn't a fix so much as a workaround.  From a performance standpoint
it's the same as if the client mounts with noreaddirplus; sometimes it's
a win, sometimes it's a lose.  CPU usage does go up on the server a bit.

-- 

Thanks,

Josh Paetzel