--- usr.sbin/nfscbd/nfscbd.c.sav	2010-06-08 18:55:56.000000000 -0400
+++ usr.sbin/nfscbd/nfscbd.c	2010-07-23 19:20:46.000000000 -0400
@@ -105,6 +105,7 @@
 	int nfssvc_flag, on, sock, tcpsock, ret, mustfreeai = 0;
 	char *cp, princname[128];
 	char myname[MAXHOSTNAMELEN], *myfqdnname = NULL;
+	char packrat_path[MAXPATHLEN];
 	struct addrinfo *aip, hints;
 	pid_t pid;
 	short myport = NFSV4_CBPORT;
@@ -147,10 +148,24 @@
 	}
 
 	princname[0] = '\0';
-#define	GETOPT	"p:P:"
-#define	USAGE	"[ -p port_num ] [ -P client_principal ]"
+#define	GETOPT	"C:p:P:"
+#define	USAGE	"[ -C packrat_path ] [ -p port_num ] [ -P client_principal ]"
 	while ((ch = getopt(argc, argv, GETOPT)) != -1)
 		switch (ch) {
+		case 'C':
+			if (optarg[0] != '/')
+				errx(1, "bad packrat path %s", optarg);
+			strlcpy(packrat_path, optarg, MAXPATHLEN);
+			len = strlen(packrat_path);
+			if (packrat_path[len - 1] != '/') {
+				/* Append trailing '/', as required. */
+				if (len >= MAXPATHLEN - 1)
+					errx(1, "packrat path too long");
+				packrat_path[len] = '/';
+				packrat_path[len + 1] = '\0';
+			}
+			(void) nfssvc(NFSSVC_PACKRAT, packrat_path);
+			break;
 		case 'p':
 			myport = atoi(optarg);
 			if (myport < 1) {
@@ -170,9 +185,8 @@
 				else
 					strlcpy(princname, cp,
 					    sizeof (princname));
-			} else {
+			} else
 				warnx("client princ invalid. ignored\n");
-			}
 			break;
 		default:
 		case '?':
--- usr.sbin/nfscbd/nfscbd.8.sav	2010-06-27 22:32:37.000000000 -0400
+++ usr.sbin/nfscbd/nfscbd.8	2010-06-27 22:37:15.000000000 -0400
@@ -33,6 +33,7 @@
 client side callback daemon
 .Sh SYNOPSIS
 .Nm nfscbd
+.Op Fl C Ar packrat_dirpath
 .Op Fl p Ar port_number
 .Op Fl P Ar client_principal
 .Sh DESCRIPTION
@@ -50,6 +51,15 @@
 .Pp
 The following options are available:
 .Bl -tag -width Ds
+.It Fl C Ar packrat_dirpath
+If this option is specified, it enables the packrat kernel threads that
+create local cache copies of files for which the client has delegations
+in the directory specified by the absolute pathname
+.Cm packrat_dirpath .
+This directory must be on local non-volatile storage. The packrat kernel
+threads will make local cache copies of delegated files up to the size
+specified by nfscl_packratmaxsize when the NFSv4 server issues a delegation
+to the client for the file.
 .It Fl p Ar port_number
 Specifies what port# the callback server should use.
 .It Fl P Ar client_principal