NFSD: Add nfsd4_encode_open_read_delegation4()

Refactor nfsd4_encode_open() so the open_read_delegation4 type is
encoded in a separate function. This makes it more straightforward
to later add support for returning an nfsace4 in OPEN responses that
offer a delegation.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4state.c

@@ -5688,11 +5688,11 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	struct path path;
 
 	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
-	open->op_recall = 0;
+	open->op_recall = false;
 	switch (open->op_claim_type) {
 		case NFS4_OPEN_CLAIM_PREVIOUS:
 			if (!cb_up)
-				open->op_recall = 1;
+				open->op_recall = true;
 			break;
 		case NFS4_OPEN_CLAIM_NULL:
 			parent = currentfh;
@@ -5746,7 +5746,7 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
 	    open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE) {
 		dprintk("NFSD: WARNING: refusing delegation reclaim\n");
-		open->op_recall = 1;
+		open->op_recall = true;
 	}
 
 	/* 4.1 client asking for a delegation? */

fs/nfsd/nfs4xdr.c

@@ -4078,6 +4078,49 @@ nfsd4_encode_link(struct nfsd4_compoundres *resp, __be32 nfserr,
 	return nfsd4_encode_change_info4(xdr, &link->li_cinfo);
 }
 
+/*
+ * This implementation does not yet support returning an ACE in an
+ * OPEN that offers a delegation.
+ */
+static __be32
+nfsd4_encode_open_nfsace4(struct xdr_stream *xdr)
+{
+	__be32 status;
+
+	/* type */
+	status = nfsd4_encode_acetype4(xdr, NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
+	if (status != nfs_ok)
+		return nfserr_resource;
+	/* flag */
+	status = nfsd4_encode_aceflag4(xdr, 0);
+	if (status != nfs_ok)
+		return nfserr_resource;
+	/* access mask */
+	status = nfsd4_encode_acemask4(xdr, 0);
+	if (status != nfs_ok)
+		return nfserr_resource;
+	/* who - empty for now */
+	if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
+		return nfserr_resource;
+	return nfs_ok;
+}
+
+static __be32
+nfsd4_encode_open_read_delegation4(struct xdr_stream *xdr, struct nfsd4_open *open)
+{
+	__be32 status;
+
+	/* stateid */
+	status = nfsd4_encode_stateid4(xdr, &open->op_delegate_stateid);
+	if (status != nfs_ok)
+		return status;
+	/* recall */
+	status = nfsd4_encode_bool(xdr, open->op_recall);
+	if (status != nfs_ok)
+		return status;
+	/* permissions */
+	return nfsd4_encode_open_nfsace4(xdr);
+}
 
 static __be32
 nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr,
@@ -4110,22 +4153,8 @@ nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr,
 	case NFS4_OPEN_DELEGATE_NONE:
 		break;
 	case NFS4_OPEN_DELEGATE_READ:
-		nfserr = nfsd4_encode_stateid4(xdr, &open->op_delegate_stateid);
-		if (nfserr)
-			return nfserr;
-		p = xdr_reserve_space(xdr, 20);
-		if (!p)
-			return nfserr_resource;
-		*p++ = cpu_to_be32(open->op_recall);
-
-		/*
-		 * TODO: ACE's in delegations
-		 */
-		*p++ = cpu_to_be32(NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE);
-		*p++ = cpu_to_be32(0);
-		*p++ = cpu_to_be32(0);
-		*p++ = cpu_to_be32(0);   /* XXX: is NULL principal ok? */
-		break;
+		/* read */
+		return nfsd4_encode_open_read_delegation4(xdr, open);
 	case NFS4_OPEN_DELEGATE_WRITE:
 		nfserr = nfsd4_encode_stateid4(xdr, &open->op_delegate_stateid);
 		if (nfserr)

fs/nfsd/xdr4.h

@@ -380,9 +380,9 @@ struct nfsd4_open {
 	u32		op_deleg_want;      /* request */
 	stateid_t	op_stateid;         /* response */
 	__be32		op_xdr_error;       /* see nfsd4_open_omfg() */
-	u32		op_recall;          /* recall */
 	struct nfsd4_change_info  op_cinfo; /* response */
 	u32		op_rflags;          /* response */
+	bool		op_recall;          /* response */
 	bool		op_truncate;        /* used during processing */
 	bool		op_created;         /* used during processing */
 	struct nfs4_openowner *op_openowner; /* used during processing */