nfsd41: implement NFS4_SHARE_WANT_NO_DELEG, NFS4_OPEN_DELEGATE_NONE_EXT, why_no_deleg

Respect client request for not getting a delegation in NFSv4.1
Appropriately return delegation "type" NFS4_OPEN_DELEGATE_NONE_EXT
and WND4_NOT_WANTED reason.

[nfsd41: add missing break when encoding op_why_no_deleg]
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 7110a08..b89781f 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -223,6 +223,7 @@
 	struct xdr_netobj op_fname;	    /* request - everything but CLAIM_PREV */
 	u32		op_delegate_type;   /* request - CLAIM_PREV only */
 	stateid_t       op_delegate_stateid; /* request - response */
+	u32		op_why_no_deleg;    /* response - DELEG_NONE_EXT only */
 	u32		op_create;     	    /* request */
 	u32		op_createmode;      /* request */
 	u32		op_bmval[3];        /* request */