Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
probe::nfs.proc.open - NFS client allocates file read/write context information
SYNOPSIS
nfs.proc.open
VALUES
prot
transfer protocol
server_ip
IP address of server
flag
file flag
version
NFS version (the function is used for all NFS version)
mode
file mode
filename
file name
DESCRIPTION
Allocate file read/write context information
SystemTap Tapset Reference March 2016 PROBE::NFS.PROC.(3stap)