nfs_sndlock
error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
error = nfs_sndlock(&nmp->nm_flag, rep);
nfs_sndlock(&slp->ns_solock, NULL);
nfs_sndlock(solockp, NULL);
int nfs_sndlock(int *, struct nfsreq *);