nfsd4: remove unused dl_trunc

There's no point in keeping this field around--it's always zero.

(Background: the protocol allows you to tell the client that the file is
about to be truncated, as an optimization to save the client from
writing back dirty pages that will just be discarded.  We don't
implement this hint.  If we do some day, adding this field back in will
be the least of the work involved.)
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/nfs4callback.c

@@ -224,7 +224,7 @@ encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp)
 	WRITE32(OP_CB_RECALL);
 	WRITE32(dp->dl_stateid.si_generation);
 	WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
-	WRITE32(dp->dl_trunc);
+	WRITE32(0); /* truncate optimization not implemented */
 	WRITE32(len);
 	WRITEMEM(&dp->dl_fh.fh_base, len);
 	return 0;
@@ -510,8 +510,6 @@ nfsd4_cb_recall(struct nfs4_delegation *dp)
 	int retries = 1;
 	int status = 0;
 
-	dp->dl_trunc = 0; /* XXX need to implement truncate optimization */
-
 	status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT);
 	while (retries--) {
 		switch (status) {

fs/nfsd/nfs4state.c

@@ -204,7 +204,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
 	dp->dl_vfs_file = stp->st_vfs_file;
 	dp->dl_type = type;
 	dp->dl_ident = cb->cb_ident;
-	dp->dl_trunc = 0;
 	dp->dl_stateid.si_boot = get_seconds();
 	dp->dl_stateid.si_stateownerid = current_delegid++;
 	dp->dl_stateid.si_fileid = 0;

include/linux/nfsd/state.h

@@ -74,7 +74,6 @@ struct nfs4_delegation {
 	time_t			dl_time;
 /* For recall: */
 	u32			dl_ident;
-	int			dl_trunc;
 	stateid_t		dl_stateid;
 	struct knfsd_fh		dl_fh;
 };