pnfs_within_mdsthreshold() is called inside pg_init. We need to set
read_io/write_io before that. Otherwise we fail pnfs_within_mdsthreshold()
and IO goes to MDS.
A simple test case:
dd if=foo of=/mnt/pnfs/bar bs=10M count=1 oflag=direct
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>