diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 109b5a8..ef3952a 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1262,6 +1262,8 @@
 	xdr->iov = head;
 	xdr->p   = head->iov_base + head->iov_len;
 	xdr->end = head->iov_base + PAGE_SIZE - 2 * RPC_MAX_AUTH_SIZE;
+	/* Tail and page_len should be zero at this point: */
+	buf->len = buf->head[0].iov_len;
 }
 
 /*