nfs41: add support for the exclusive create flags

In v4.1 the client MUST/SHOULD use the EXCLUSIVE4_1 flag instead of
EXCLUSIVE4, and GUARDED when the server supports persistent sessions.
For now (and until we support suppattr_exclcreat), we don't send any
attributes with EXCLUSIVE4_1 relying in the subsequent SETATTR as in v4.0

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -726,9 +726,15 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct path *path,
 	p->o_arg.bitmask = server->attr_bitmask;
 	p->o_arg.claim = NFS4_OPEN_CLAIM_NULL;
 	if (flags & O_EXCL) {
-		u32 *s = (u32 *) p->o_arg.u.verifier.data;
-		s[0] = jiffies;
-		s[1] = current->pid;
+		if (nfs4_has_persistent_session(server->nfs_client)) {
+			/* GUARDED */
+			p->o_arg.u.attrs = &p->attrs;
+			memcpy(&p->attrs, attrs, sizeof(p->attrs));
+		} else { /* EXCLUSIVE4_1 */
+			u32 *s = (u32 *) p->o_arg.u.verifier.data;
+			s[0] = jiffies;
+			s[1] = current->pid;
+		}
 	} else if (flags & O_CREAT) {
 		p->o_arg.u.attrs = &p->attrs;
 		memcpy(&p->attrs, attrs, sizeof(p->attrs));

fs/nfs/nfs4xdr.c

@@ -51,6 +51,7 @@
 #include <linux/nfs_fs.h>
 #include <linux/nfs_idmap.h>
 #include "nfs4_fs.h"
+#include "internal.h"
 
 #define NFSDBG_FACILITY		NFSDBG_XDR
 
@@ -134,7 +135,7 @@ static int nfs4_stat_to_errno(int);
 #define decode_lookup_maxsz	(op_decode_hdr_maxsz)
 #define encode_share_access_maxsz \
 				(2)
-#define encode_createmode_maxsz	(1 + encode_attrs_maxsz)
+#define encode_createmode_maxsz	(1 + encode_attrs_maxsz + encode_verifier_maxsz)
 #define encode_opentype_maxsz	(1 + encode_createmode_maxsz)
 #define encode_claim_null_maxsz	(1 + nfs4_name_maxsz)
 #define encode_open_maxsz	(op_encode_hdr_maxsz + \
@@ -1140,6 +1141,7 @@ static inline void encode_openhdr(struct xdr_stream *xdr, const struct nfs_opena
 static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_openargs *arg)
 {
 	__be32 *p;
+	struct nfs_client *clp;
 
 	p = reserve_space(xdr, 4);
 	switch(arg->open_flags & O_EXCL) {
@@ -1148,8 +1150,23 @@ static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_op
 		encode_attrs(xdr, arg->u.attrs, arg->server);
 		break;
 	default:
-		*p = cpu_to_be32(NFS4_CREATE_EXCLUSIVE);
-		encode_nfs4_verifier(xdr, &arg->u.verifier);
+		clp = arg->server->nfs_client;
+		if (clp->cl_minorversion > 0) {
+			if (nfs4_has_persistent_session(clp)) {
+				*p = cpu_to_be32(NFS4_CREATE_GUARDED);
+				encode_attrs(xdr, arg->u.attrs, arg->server);
+			} else {
+				struct iattr dummy;
+
+				*p = cpu_to_be32(NFS4_CREATE_EXCLUSIVE4_1);
+				encode_nfs4_verifier(xdr, &arg->u.verifier);
+				dummy.ia_valid = 0;
+				encode_attrs(xdr, &dummy, arg->server);
+			}
+		} else {
+			*p = cpu_to_be32(NFS4_CREATE_EXCLUSIVE);
+			encode_nfs4_verifier(xdr, &arg->u.verifier);
+		}
 	}
 }