Index: geom_part.c
===================================================================
--- geom_part.c	(revision 246183)
+++ geom_part.c	(working copy)
@@ -90,6 +90,7 @@
 static void gpart_print_error(const char *);
 static void gpart_backup(struct gctl_req *, unsigned int);
 static void gpart_restore(struct gctl_req *, unsigned int);
+static void gpart_trim(struct gctl_req *, unsigned int);
 
 struct g_command PUBSYM(class_commands)[] = {
 	{ "add", 0, gpart_issue, {
@@ -159,6 +160,9 @@
 		G_OPT_SENTINEL },
 	    "[-l | -r] [-p] [geom ...]"
 	},
+	{ "trim", 0, gpart_trim, G_NULL_OPTS,
+	    "provider"
+	},
 	{ "undo", 0, gpart_issue, G_NULL_OPTS,
 	    "geom"
 	},
@@ -1279,3 +1283,22 @@
 	gctl_free(req);
 	exit(status);
 }
+
+static void
+gpart_trim(struct gctl_req *req, unsigned int fl __unused)
+{
+	const char *s;
+	int fd;
+
+	if (gctl_get_int(req, "nargs") != 1)
+		errx(EXIT_FAILURE, "Invalid number of arguments.");
+	s = gctl_get_ascii(req, "arg0");
+	if (s == NULL)
+		abort();
+	fd = g_open(s, 1);
+	if (fd == -1)
+		err(EXIT_FAILURE, "Cannot open %s", s);
+	if (g_delete(fd, 0, g_mediasize(fd)) == -1)
+		err(EXIT_FAILURE, "g_delete call failed");
+	g_close(fd);
+}
Index: gpart.8
===================================================================
--- gpart.8	(revision 246183)
+++ gpart.8	(working copy)
@@ -144,6 +144,10 @@
 .Op Fl l | r
 .Op Fl p
 .Op Ar geom ...
+.\" ==== TRIM ====
+.Nm
+.Cm trim
+.Ar provider
 .\" ==== UNDO ====
 .Nm
 .Cm undo
@@ -471,6 +475,15 @@
 .It Fl r
 Show raw partition type instead of symbolic name.
 .El
+.\" ==== TRIM ====
+.It Cm trim
+Sends a BIO_DELETE request for the contents of the provider 
+.Ar provider .
+Depending on the underlying storage device, this may may fill its blocks
+with a constant value (0x00 or 0xFF), or may do nothing.  Running this
+command on a partition on an SSD device before deleting it may improve
+performance, since the SSD can immediately reuse the blocks for subsequent
+write requests.
 .\" ==== UNDO ====
 .It Cm undo
 Revert any pending changes for geom