Nfs server reading data from a file for client
nfsd.read
client_ip
the ip address of client
size
read bytes
file
argument file, indicates if the file has been opened.
vlen
read blocks
fh
file handle (the first part is the length of the file handle)
offset
the offset of file
vec
struct kvec, includes buf address in kernel address and length of each buffer
count
read bytes