NFSv4: Add post-op attributes to nfs4_proc_link()

 Optimise attribute revalidation when hardlinking. Add post-op attributes
 for the directory and the original inode.

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

fs/nfs/nfs4proc.c

@@ -1724,22 +1724,34 @@ static int nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
 
 static int _nfs4_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
 {
+	struct nfs_server *server = NFS_SERVER(inode);
 	struct nfs4_link_arg arg = {
 		.fh     = NFS_FH(inode),
 		.dir_fh = NFS_FH(dir),
 		.name   = name,
+		.bitmask = server->attr_bitmask,
+	};
+	struct nfs_fattr fattr, dir_attr;
+	struct nfs4_link_res res = {
+		.server = server,
+		.fattr = &fattr,
+		.dir_attr = &dir_attr,
 	};
-	struct nfs4_change_info	cinfo = { };
 	struct rpc_message msg = {
 		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LINK],
 		.rpc_argp = &arg,
-		.rpc_resp = &cinfo,
+		.rpc_resp = &res,
 	};
 	int			status;
 
-	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
-	if (!status)
-		update_changeattr(dir, &cinfo);
+	nfs_fattr_init(res.fattr);
+	nfs_fattr_init(res.dir_attr);
+	status = rpc_call_sync(server->client, &msg, 0);
+	if (!status) {
+		update_changeattr(dir, &res.cinfo);
+		nfs_post_op_update_inode(dir, res.dir_attr);
+		nfs_refresh_inode(inode, res.fattr);
+	}
 
 	return status;
 }

fs/nfs/nfs4xdr.c

@@ -324,12 +324,18 @@ static int nfs_stat_to_errno(int);
 				encode_putfh_maxsz + \
 				encode_savefh_maxsz + \
 				encode_putfh_maxsz + \
-				encode_link_maxsz)
+				encode_link_maxsz + \
+				decode_getattr_maxsz + \
+				encode_restorefh_maxsz + \
+				decode_getattr_maxsz)
 #define NFS4_dec_link_sz	(compound_decode_hdr_maxsz + \
 				decode_putfh_maxsz + \
 				decode_savefh_maxsz + \
 				decode_putfh_maxsz + \
-				decode_link_maxsz)
+				decode_link_maxsz + \
+				decode_getattr_maxsz + \
+				decode_restorefh_maxsz + \
+				decode_getattr_maxsz)
 #define NFS4_enc_symlink_sz	(compound_encode_hdr_maxsz + \
 				encode_putfh_maxsz + \
 				encode_symlink_maxsz + \
@@ -1357,7 +1363,7 @@ static int nfs4_xdr_enc_link(struct rpc_rqst *req, uint32_t *p, const struct nfs
 {
 	struct xdr_stream xdr;
 	struct compound_hdr hdr = {
-		.nops = 4,
+		.nops = 7,
 	};
 	int status;
 
@@ -1369,7 +1375,13 @@ static int nfs4_xdr_enc_link(struct rpc_rqst *req, uint32_t *p, const struct nfs
 		goto out;
 	if ((status = encode_putfh(&xdr, args->dir_fh)) != 0)
 		goto out;
-	status = encode_link(&xdr, args->name);
+	if ((status = encode_link(&xdr, args->name)) != 0)
+		goto out;
+	if ((status = encode_getfattr(&xdr, args->bitmask)) != 0)
+		goto out;
+	if ((status = encode_restorefh(&xdr)) != 0)
+		goto out;
+	status = encode_getfattr(&xdr, args->bitmask);
 out:
 	return status;
 }
@@ -3529,7 +3541,7 @@ out:
 /*
  * Decode LINK response
  */
-static int nfs4_xdr_dec_link(struct rpc_rqst *rqstp, uint32_t *p, struct nfs4_change_info *cinfo)
+static int nfs4_xdr_dec_link(struct rpc_rqst *rqstp, uint32_t *p, struct nfs4_link_res *res)
 {
 	struct xdr_stream xdr;
 	struct compound_hdr hdr;
@@ -3544,7 +3556,17 @@ static int nfs4_xdr_dec_link(struct rpc_rqst *rqstp, uint32_t *p, struct nfs4_ch
 		goto out;
 	if ((status = decode_putfh(&xdr)) != 0)
 		goto out;
-	status = decode_link(&xdr, cinfo);
+	if ((status = decode_link(&xdr, &res->cinfo)) != 0)
+		goto out;
+	/*
+	 * Note order: OP_LINK leaves the directory as the current
+	 *             filehandle.
+	 */
+	if (decode_getfattr(&xdr, res->dir_attr, res->server) != 0)
+		goto out;
+	if ((status = decode_restorefh(&xdr)) != 0)
+		goto out;
+	decode_getfattr(&xdr, res->fattr, res->server);
 out:
 	return status;
 }

include/linux/nfs_xdr.h

@@ -566,8 +566,17 @@ struct nfs4_link_arg {
 	const struct nfs_fh *		fh;
 	const struct nfs_fh *		dir_fh;
 	const struct qstr *		name;
+	const u32 *			bitmask;
+};
+
+struct nfs4_link_res {
+	const struct nfs_server *	server;
+	struct nfs_fattr *		fattr;
+	struct nfs4_change_info		cinfo;
+	struct nfs_fattr *		dir_attr;
 };
 
+
 struct nfs4_lookup_arg {
 	const struct nfs_fh *		dir_fh;
 	const struct qstr *		name;