diff --git a/lib/libgeom/geom_ctl.c b/lib/libgeom/geom_ctl.c
index b60c4c297257..b1d738333b3f 100644
--- a/lib/libgeom/geom_ctl.c
+++ b/lib/libgeom/geom_ctl.c
@@ -194,7 +194,7 @@ gctl_rw_param(struct gctl_req *req, const char *name, int len, void *value)
 const char *
 gctl_issue(struct gctl_req *req)
 {
-	int fd, error;
+	int fd;
 
 	if (req == NULL)
 		return ("NULL request pointer");
@@ -212,11 +212,11 @@ gctl_issue(struct gctl_req *req)
 	fd = open(_PATH_DEV PATH_GEOM_CTL, O_RDONLY);
 	if (fd < 0)
 		return(strerror(errno));
-	error = ioctl(fd, GEOM_CTL, req);
+	req->nerror = ioctl(fd, GEOM_CTL, req);
 	close(fd);
 	if (req->error[0] != '\0')
 		return (req->error);
-	if (error != 0)
+	if (req->nerror == -1)
 		return(strerror(errno));
 	return (NULL);
 }
diff --git a/sbin/geom/core/geom.c b/sbin/geom/core/geom.c
index 9b43910b88f9..535d7d9f6f21 100644
--- a/sbin/geom/core/geom.c
+++ b/sbin/geom/core/geom.c
@@ -503,7 +503,10 @@ run_command(int argc, char *argv[])
 	}
 	if (errstr != NULL && errstr[0] != '\0') {
 		warnx("%s", errstr);
-		if (strncmp(errstr, "warning: ", strlen("warning: ")) != 0) {
+		/* Suppress EXIT_FAILURE for warnings */
+		if (strncmp(errstr, "warning: ", strlen("warning: ")) == 0)
+			req->nerror = 0;
+		if (req->nerror != 0) {
 			gctl_free(req);
 			exit(EXIT_FAILURE);
 		}
diff --git a/sys/geom/geom.h b/sys/geom/geom.h
index 70d21e346c9b..a9990f669863 100644
--- a/sys/geom/geom.h
+++ b/sys/geom/geom.h
@@ -436,7 +436,7 @@ char const *gctl_get_asciiparam(struct gctl_req *req, const char *param);
 void *gctl_get_paraml(struct gctl_req *req, const char *param, int len);
 void *gctl_get_paraml_opt(struct gctl_req *req, const char *param, int len);
 int gctl_error(struct gctl_req *req, const char *fmt, ...) __printflike(2, 3);
-void gctl_msg(struct gctl_req *req, const char *fmt, ...) __printflike(2, 3);
+void gctl_msg(struct gctl_req *req, int, const char *fmt, ...) __printflike(3, 4);
 void gctl_post_messages(struct gctl_req *req);
 struct g_class *gctl_get_class(struct gctl_req *req, char const *arg);
 struct g_geom *gctl_get_geom(struct gctl_req *req, struct g_class *mp, char const *arg);
diff --git a/sys/geom/geom_ctl.c b/sys/geom/geom_ctl.c
index 0f1dce934b63..132f30070b3c 100644
--- a/sys/geom/geom_ctl.c
+++ b/sys/geom/geom_ctl.c
@@ -117,9 +117,15 @@ gctl_error(struct gctl_req *req, const char *fmt, ...)
  * the application must either call gctl_post_messages() or
  * call gctl_error() to cause the messages to be reported to
  * the calling process.
+ *
+ * The errno argument should be zero if it is an informational
+ * message or an errno value (EINVAL, EBUSY, etc) if it is an error.
+ * If any of the messages has a non-zero errno, the utility will
+ * EXIT_FAILURE. If only informational messages (with zero errno)
+ * are posted, the utility will EXIT_SUCCESS.
  */
 void
-gctl_msg(struct gctl_req *req, const char *fmt, ...)
+gctl_msg(struct gctl_req *req, int errno, const char *fmt, ...)
 {
 	va_list ap;
 
@@ -131,6 +137,8 @@ gctl_msg(struct gctl_req *req, const char *fmt, ...)
 #endif
 		return;
 	}
+	if (req->nerror == 0)
+		req->nerror = errno;
 	/* Put second and later messages indented on a new line */
 	if (sbuf_len(req->serror) > 0)
 		sbuf_cat(req->serror, "\n\t");
diff --git a/sys/geom/union/g_union.c b/sys/geom/union/g_union.c
index ddc0acf52b78..dee541064ced 100644
--- a/sys/geom/union/g_union.c
+++ b/sys/geom/union/g_union.c
@@ -341,8 +341,9 @@ g_union_ctl_create(struct gctl_req *req, struct g_class *mp, bool verbose)
 	    (sc->sc_root_size + sc->sc_root_size * sc->sc_leaf_size) *
 	    sizeof(uint64_t) + roundup(sc->sc_root_size, BITS_PER_ENTRY);
 	if (verbose)
-		gctl_error(req, "Device %s created with memory map size %jd.",
+		gctl_msg(req, 0, "Device %s created with memory map size %jd.",
 		    gp->name, (intmax_t)sc->sc_writemap_memory);
+	gctl_post_messages(req);
 	G_UNION_DEBUG(1, "Device %s created with memory map size %jd.",
 	    gp->name, (intmax_t)sc->sc_writemap_memory);
 	return;
@@ -373,7 +374,8 @@ g_union_fetcharg(struct gctl_req *req, const char *name)
 		return (0);
 	if (*val >= 0)
 		return (*val);
-	gctl_error(req, "Invalid '%s': negative value, using default.", name);
+	gctl_msg(req, EINVAL, "Invalid '%s' (%jd): negative value, "
+	    "using default.", name, *val);
 	return (0);
 }
 
@@ -425,20 +427,20 @@ g_union_ctl_destroy(struct gctl_req *req, struct g_class *mp, bool verbose)
 		snprintf(param, sizeof(param), "arg%d", i);
 		name = gctl_get_asciiparam(req, param);
 		if (name == NULL) {
-			gctl_msg(req, "No '%s' argument.", param);
+			gctl_msg(req, EINVAL, "No '%s' argument.", param);
 			continue;
 		}
 		if (strncmp(name, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 			name += strlen(_PATH_DEV);
 		gp = g_union_find_geom(mp, name);
 		if (gp == NULL) {
-			gctl_msg(req, "Device %s is invalid.", name);
+			gctl_msg(req, EINVAL, "Device %s is invalid.", name);
 			continue;
 		}
 		error = g_union_destroy(verbose ? req : NULL, gp, *force);
 		if (error != 0)
-			gctl_msg(req, "Error %d: cannot destroy device %s.",
-			    error, gp->name);
+			gctl_msg(req, error, "Error %d: "
+			    "cannot destroy device %s.", error, gp->name);
 	}
 	gctl_post_messages(req);
 }
@@ -486,12 +488,12 @@ g_union_ctl_reset(struct gctl_req *req, struct g_class *mp, bool verbose)
 		snprintf(param, sizeof(param), "arg%d", i);
 		pp = gctl_get_provider(req, param);
 		if (pp == NULL) {
-			gctl_msg(req, "No '%s' argument.", param);
+			gctl_msg(req, EINVAL, "No '%s' argument.", param);
 			continue;
 		}
 		gp = pp->geom;
 		if (gp->class != mp) {
-			gctl_msg(req, "Provider %s is invalid.",
+			gctl_msg(req, EINVAL, "Provider %s is invalid.",
 			    pp->name);
 			continue;
 		}
@@ -508,7 +510,7 @@ g_union_ctl_reset(struct gctl_req *req, struct g_class *mp, bool verbose)
 		sc->sc_readbytes = 0;
 		sc->sc_wrotebytes = 0;
 		if (verbose)
-			gctl_msg(req, "Device %s has been reset.", pp->name);
+			gctl_msg(req, 0, "Device %s has been reset.", pp->name);
 		G_UNION_DEBUG(1, "Device %s has been reset.", pp->name);
 	}
 	gctl_post_messages(req);
@@ -542,17 +544,18 @@ g_union_ctl_revert(struct gctl_req *req, struct g_class *mp, bool verbose)
 		snprintf(param, sizeof(param), "arg%d", i);
 		pp = gctl_get_provider(req, param);
 		if (pp == NULL) {
-			gctl_msg(req, "No '%s' argument.", param);
+			gctl_msg(req, EINVAL, "No '%s' argument.", param);
 			continue;
 		}
 		gp = pp->geom;
 		if (gp->class != mp) {
-			gctl_msg(req, "Provider %s is invalid.", pp->name);
+			gctl_msg(req, EINVAL, "Provider %s is invalid.",
+			    pp->name);
 			continue;
 		}
 		sc = gp->softc;
 		if (g_union_get_writelock(sc) != 0) {
-			gctl_msg(req, "Revert already in progress for "
+			gctl_msg(req, EINVAL, "Revert already in progress for "
 			    "provider %s.", pp->name);
 			continue;
 		}
@@ -560,8 +563,8 @@ g_union_ctl_revert(struct gctl_req *req, struct g_class *mp, bool verbose)
 		 * No mount or other use of union is allowed.
 		 */
 		if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) {
-			gctl_msg(req, "Unable to get exclusive access for "
-			    "reverting of %s;\n\t%s cannot be mounted or "
+			gctl_msg(req, EPERM, "Unable to get exclusive access "
+			    "for reverting of %s;\n\t%s cannot be mounted or "
 			    "otherwise open during a revert.",
 			     pp->name, pp->name);
 			g_union_rel_writelock(sc);
@@ -570,7 +573,8 @@ g_union_ctl_revert(struct gctl_req *req, struct g_class *mp, bool verbose)
 		g_union_revert(sc);
 		g_union_rel_writelock(sc);
 		if (verbose)
-			gctl_msg(req, "Device %s has been reverted.", pp->name);
+			gctl_msg(req, 0, "Device %s has been reverted.",
+			    pp->name);
 		G_UNION_DEBUG(1, "Device %s has been reverted.", pp->name);
 	}
 	gctl_post_messages(req);
@@ -637,17 +641,18 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 		snprintf(param, sizeof(param), "arg%d", i);
 		pp = gctl_get_provider(req, param);
 		if (pp == NULL) {
-			gctl_msg(req, "No '%s' argument.", param);
+			gctl_msg(req, EINVAL, "No '%s' argument.", param);
 			continue;
 		}
 		gp = pp->geom;
 		if (gp->class != mp) {
-			gctl_msg(req, "Provider %s is invalid.", pp->name);
+			gctl_msg(req, EINVAL, "Provider %s is invalid.",
+			    pp->name);
 			continue;
 		}
 		sc = gp->softc;
 		if (g_union_get_writelock(sc) != 0) {
-			gctl_msg(req, "Commit already in progress for "
+			gctl_msg(req, EINVAL, "Commit already in progress for "
 			    "provider %s.", pp->name);
 			continue;
 		}
@@ -661,10 +666,10 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 		 */
 		if ((*force == false && pp->acr > 0) || pp->acw > 0 ||
 		     pp->ace > 0) {
-			gctl_msg(req, "Unable to get exclusive access for "
-			    "writing of %s.\n\tNote that %s cannot be mounted "
-			    "or otherwise\n\topen during a commit unless the "
-			    "-f flag is used.", pp->name, pp->name);
+			gctl_msg(req, EPERM, "Unable to get exclusive access "
+			    "for writing of %s.\n\tNote that %s cannot be "
+			    "mounted or otherwise\n\topen during a commit "
+			    "unless the -f flag is used.", pp->name, pp->name);
 			g_union_rel_writelock(sc);
 			continue;
 		}
@@ -675,7 +680,7 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 		if ((*force == false && lowerpp->acr > lowercp->acr) ||
 		     lowerpp->acw > lowercp->acw ||
 		     lowerpp->ace > lowercp->ace) {
-			gctl_msg(req, "provider %s is unable to get "
+			gctl_msg(req, EPERM, "provider %s is unable to get "
 			    "exclusive access to %s\n\tfor writing. Note that "
 			    "%s cannot be mounted or otherwise open\n\tduring "
 			    "a commit unless the -f flag is used.", pp->name,
@@ -684,8 +689,8 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 			continue;
 		}
 		if ((error = g_access(lowercp, 0, 1, 0)) != 0) {
-			gctl_msg(req, "Error %d: provider %s is unable to "
-			    "access %s for writing.", error, pp->name,
+			gctl_msg(req, error, "Error %d: provider %s is unable "
+			    "to access %s for writing.", error, pp->name,
 			    lowerpp->name);
 			g_union_rel_writelock(sc);
 			continue;
@@ -715,18 +720,18 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 				bp->bio_cmd = BIO_READ;
 				g_io_request(bp, sc->sc_uppercp);
 				if ((error = biowait(bp, "rdunion")) != 0) {
-					gctl_msg(req, "Commit read error %d "
-					    "in provider %s, commit aborted.",
-					    error, pp->name);
+					gctl_msg(req, error, "Commit read "
+					    "error %d in provider %s, commit "
+					    "aborted.", error, pp->name);
 					goto cleanup;
 				}
 				bp->bio_flags &= ~BIO_DONE;
 				bp->bio_cmd = BIO_WRITE;
 				g_io_request(bp, lowercp);
 				if ((error = biowait(bp, "wtunion")) != 0) {
-					gctl_msg(req, "Commit write error %d "
-					    "in provider %s, commit aborted.",
-					    error, pp->name);
+					gctl_msg(req, error, "Commit write "
+					    "error %d in provider %s, commit "
+					    "aborted.", error, pp->name);
 					goto cleanup;
 				}
 				bp->bio_flags &= ~BIO_DONE;
@@ -748,7 +753,7 @@ g_union_ctl_commit(struct gctl_req *req, struct g_class *mp, bool verbose)
 		}
 		g_union_rel_writelock(sc);
 		if (error == 0 && verbose)
-			gctl_msg(req, "Device %s has been committed.",
+			gctl_msg(req, 0, "Device %s has been committed.",
 			    pp->name);
 		G_UNION_DEBUG(1, "Device %s has been committed.", pp->name);
 	}
@@ -1315,13 +1320,13 @@ g_union_destroy(struct gctl_req *req, struct g_geom *gp, bool force)
 	    (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0))) {
 		if (force) {
 			if (req != NULL)
-				gctl_msg(req, "Device %s is still in use, "
+				gctl_msg(req, 0, "Device %s is still in use, "
 				    "so is being forcibly removed.", gp->name);
 			G_UNION_DEBUG(1, "Device %s is still in use, so "
 			    "is being forcibly removed.", gp->name);
 		} else {
 			if (req != NULL)
-				gctl_msg(req, "Device %s is still open "
+				gctl_msg(req, EBUSY, "Device %s is still open "
 				    "(r=%d w=%d e=%d).", gp->name, pp->acr,
 				    pp->acw, pp->ace);
 			G_UNION_DEBUG(1, "Device %s is still open "
@@ -1331,7 +1336,7 @@ g_union_destroy(struct gctl_req *req, struct g_geom *gp, bool force)
 		}
 	} else {
 		if (req != NULL)
-			gctl_msg(req, "Device %s removed.", gp->name);
+			gctl_msg(req, 0, "Device %s removed.", gp->name);
 		G_UNION_DEBUG(1, "Device %s removed.", gp->name);
 	}
 	/* Close consumers */