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>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 2509305..0420b5e 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -224,7 +224,7 @@
 	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 @@
 	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) {
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3e5345e..cbb16e1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -204,7 +204,6 @@
 	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;
diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index 233b60d..346b603 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -74,7 +74,6 @@
 	time_t			dl_time;
 /* For recall: */
 	u32			dl_ident;
-	int			dl_trunc;
 	stateid_t		dl_stateid;
 	struct knfsd_fh		dl_fh;
 };