Index: share/man/man9/disk.9
===================================================================
--- share/man/man9/disk.9
+++ share/man/man9/disk.9
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 30, 2012
+.Dd August 3, 2017
 .Dt DISK 9
 .Os
 .Sh NAME
@@ -45,6 +45,8 @@
 .Fn disk_destroy "struct disk *disk"
 .Ft int
 .Fn disk_resize "struct disk *disk" "int flags"
+.Ft void
+.Fn disk_add_alias "struct disk *disk" "const char *alias"
 .Sh DESCRIPTION
 The disk storage API permits kernel device drivers providing access to
 disk-like storage devices to advertise the device to other kernel
@@ -69,6 +71,20 @@
 fill in the fields and call
 .Fn disk_create
 when the device is ready to service requests.
+.Fn disk_add_alias
+adds an alias for the disk and must be called before
+.Fn disk_create ,
+but may be called multiple times.
+For each alias added, a device node will be created with
+.Xr make_dev_alias 9
+in the same way primary device nodes are created with
+.Xr make_dev 9
+for
+.Va d_name
+and
+.Va d_unit .
+Care should be taken to ensure that only one driver creates aliases
+for any given name.
 .Fn disk_resize
 can be called by the driver after modifying
 .Va d_mediasize
@@ -227,7 +243,13 @@
 .El
 .Sh SEE ALSO
 .Xr GEOM 4 ,
-.Xr devfs 5
+.Xr devfs 5 ,
+.Xr MAKE_DEV 9
 .Sh AUTHORS
 This manual page was written by
 .An Robert Watson .
+.Sh BUGS
+Disk aliases are not a general purpose aliasing mechanism, but are
+intended only to ease the transition from one name to another.
+They can be used to ensure that nvd0 and nda0 are the same thing.
+They cannot be used to implement the diskX concept from macOS.
Index: sys/cam/nvme/nvme_da.c
===================================================================
--- sys/cam/nvme/nvme_da.c
+++ sys/cam/nvme/nvme_da.c
@@ -808,6 +808,10 @@
 	    DEVSTAT_ALL_SUPPORTED,
 	    DEVSTAT_TYPE_DIRECT | XPORT_DEVSTAT_TYPE(cpi.transport),
 	    DEVSTAT_PRIORITY_DISK);
+	/*
+	 * Add alias for older nvd drives to ease transition.
+	 */
+	disk_add_alias(disk, "nvd");
 
 	/*
 	 * Acquire a reference to the periph before we register with GEOM.
Index: sys/geom/geom.h
===================================================================
--- sys/geom/geom.h
+++ sys/geom/geom.h
@@ -120,6 +120,15 @@
 	LIST_HEAD(,g_geom)	geom;
 };
 
+/*
+ * The g_geom_alias is a list node for aliases for the geom name
+ * for device node creation.
+ */
+struct g_geom_alias {
+	LIST_ENTRY(g_geom_alias) ga_next;
+	const char		*ga_alias;
+};
+
 #define G_VERSION_00	0x19950323
 #define G_VERSION_01	0x20041207	/* add fflag to g_ioctl_t */
 #define G_VERSION	G_VERSION_01
@@ -150,6 +159,7 @@
 	unsigned		flags;
 #define	G_GEOM_WITHER		1
 #define	G_GEOM_VOLATILE_BIO	2
+	LIST_HEAD(,g_geom_alias) aliases;
 };
 
 /*
@@ -269,6 +279,7 @@
 void g_detach(struct g_consumer *cp);
 void g_error_provider(struct g_provider *pp, int error);
 struct g_provider *g_provider_by_name(char const *arg);
+void g_geom_add_alias(struct g_geom *gp, const char *alias);
 int g_getattr__(const char *attr, struct g_consumer *cp, void *var, int len);
 #define g_getattr(a, c, v) g_getattr__((a), (c), (v), sizeof *(v))
 int g_handleattr(struct bio *bp, const char *attribute, const void *val,
Index: sys/geom/geom_dev.c
===================================================================
--- sys/geom/geom_dev.c
+++ sys/geom/geom_dev.c
@@ -315,10 +315,11 @@
 g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
 {
 	struct g_geom *gp;
+	struct g_geom_alias *gap;
 	struct g_consumer *cp;
 	struct g_dev_softc *sc;
 	int error;
-	struct cdev *dev;
+	struct cdev *dev, *adev;
 	char buf[SPECNAMELEN + 6];
 
 	g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
@@ -357,6 +358,23 @@
 	g_dev_attrchanged(cp, "GEOM::physpath");
 	snprintf(buf, sizeof(buf), "cdev=%s", gp->name);
 	devctl_notify_f("GEOM", "DEV", "CREATE", buf, M_WAITOK);
+	/*
+	 * Now add all the aliases for this drive
+	 */
+	LIST_FOREACH(gap, &pp->geom->aliases, ga_next) {
+		error = make_dev_alias_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &adev, dev,
+		    "%s", gap->ga_alias);
+		if (error) {
+			printf("%s: make_dev_alias_p() failed (name=%s, error=%d)\n",
+			    __func__, gap->ga_alias, error);
+			continue;
+		}
+		adev->si_flags |= SI_UNMAPPED;
+		adev->si_iosize_max = dev->si_iosize_max;
+		adev->si_drv2 = dev->si_drv2;
+		snprintf(buf, sizeof(buf), "cdev=%s", gap->ga_alias);
+		devctl_notify_f("GEOM", "DEV", "CREATE", buf, M_WAITOK);
+	}
 
 	return (gp);
 }
Index: sys/geom/geom_disk.h
===================================================================
--- sys/geom/geom_disk.h
+++ sys/geom/geom_disk.h
@@ -66,6 +66,11 @@
 	DISK_INIT_DONE
 } disk_init_level;
 
+struct disk_alias {
+	LIST_ENTRY(disk_alias)	da_next;
+	const char		*da_alias;
+};
+
 struct disk {
 	/* Fields which are private to geom_disk */
 	struct g_geom		*d_geom;
@@ -109,6 +114,9 @@
 
 	/* Fields private to the driver */
 	void			*d_drv1;
+
+	/* Fields private to geom_disk, to be moved on next version bump */
+	LIST_HEAD(,disk_alias)	d_aliases;
 };
 
 #define DISKFLAG_RESERVED	0x1	/* Was NEEDSGIANT */
@@ -132,6 +140,7 @@
 void disk_media_changed(struct disk *dp, int flag);
 void disk_media_gone(struct disk *dp, int flag);
 int disk_resize(struct disk *dp, int flag);
+void disk_add_alias(struct disk *disk, const char *);
 
 #define DISK_VERSION_00		0x58561059
 #define DISK_VERSION_01		0x5856105a
Index: sys/geom/geom_disk.c
===================================================================
--- sys/geom/geom_disk.c
+++ sys/geom/geom_disk.c
@@ -676,6 +676,7 @@
 	struct g_provider *pp;
 	struct disk *dp;
 	struct g_disk_softc *sc;
+	struct disk_alias *dap;
 	char tmpstr[80];
 
 	if (flag == EV_CANCEL)
@@ -704,6 +705,10 @@
 	sc->dp = dp;
 	gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
 	gp->softc = sc;
+	LIST_FOREACH(dap, &dp->d_aliases, da_next) {
+		snprintf(tmpstr, sizeof(tmpstr), "%s%d", dap->da_alias, dp->d_unit);
+		g_geom_add_alias(gp, tmpstr);
+	}
 	pp = g_new_providerf(gp, "%s", gp->name);
 	devstat_remove_entry(pp->stat);
 	pp->stat = NULL;
@@ -791,6 +796,7 @@
 	struct disk *dp;
 	struct g_geom *gp;
 	struct g_disk_softc *sc;
+	struct disk_alias *dap, *daptmp;
 
 	g_topology_assert();
 	dp = ptr;
@@ -802,6 +808,8 @@
 		dp->d_geom = NULL;
 		g_wither_geom(gp, ENXIO);
 	}
+	LIST_FOREACH_SAFE(dap, &dp->d_aliases, da_next, daptmp)
+		g_free(dap);
 
 	g_free(dp);
 }
@@ -834,8 +842,11 @@
 struct disk *
 disk_alloc(void)
 {
+	struct disk *dp;
 
-	return (g_malloc(sizeof(struct disk), M_WAITOK | M_ZERO));
+	dp = g_malloc(sizeof(struct disk), M_WAITOK | M_ZERO);
+	LIST_INIT(&dp->d_aliases);
+	return (dp);
 }
 
 void
@@ -885,6 +896,18 @@
 }
 
 void
+disk_add_alias(struct disk *dp, const char *name)
+{
+	struct disk_alias *dap;
+
+	dap = (struct disk_alias *)g_malloc(
+		sizeof(struct disk_alias) + strlen(name) + 1, M_WAITOK);
+	strcpy((char *)(dap + 1), name);
+	dap->da_alias = (const char *)(dap + 1);
+	LIST_INSERT_HEAD(&dp->d_aliases, dap, da_next);
+}
+
+void
 disk_gone(struct disk *dp)
 {
 	struct g_geom *gp;
Index: sys/geom/geom_dump.c
===================================================================
--- sys/geom/geom_dump.c
+++ sys/geom/geom_dump.c
@@ -234,6 +234,7 @@
 {
 	struct g_consumer *cp2;
 	struct g_provider *pp2;
+	struct g_geom_alias *gap;
 
 	sbuf_printf(sb, "    <geom id=\"%p\">\n", gp);
 	sbuf_printf(sb, "      <class ref=\"%p\"/>\n", gp->class);
@@ -259,6 +260,11 @@
 			continue;
 		g_conf_provider(sb, pp2);
 	}
+	LIST_FOREACH(gap, &gp->aliases, ga_next) {
+		sbuf_printf(sb, "      <alias>\n");
+		g_conf_printf_escaped(sb, "%s", gap->ga_alias);
+		sbuf_printf(sb, "      </alias>\n");
+	}
 	sbuf_printf(sb, "    </geom>\n");
 }
 
Index: sys/geom/geom_subr.c
===================================================================
--- sys/geom/geom_subr.c
+++ sys/geom/geom_subr.c
@@ -347,6 +347,7 @@
 	gp->rank = 1;
 	LIST_INIT(&gp->consumer);
 	LIST_INIT(&gp->provider);
+	LIST_INIT(&gp->aliases);
 	LIST_INSERT_HEAD(&mp->geom, gp, geom);
 	TAILQ_INSERT_HEAD(&geoms, gp, geoms);
 	strcpy(gp->name, sbuf_data(sb));
@@ -367,6 +368,7 @@
 void
 g_destroy_geom(struct g_geom *gp)
 {
+	struct g_geom_alias *gap, *gaptmp;
 
 	g_topology_assert();
 	G_VALID_GEOM(gp);
@@ -380,6 +382,8 @@
 	g_cancel_event(gp);
 	LIST_REMOVE(gp, geom);
 	TAILQ_REMOVE(&geoms, gp, geoms);
+	LIST_FOREACH_SAFE(gap, &gp->aliases, ga_next, gaptmp)
+		g_free(gap);
 	g_free(gp->name);
 	g_free(gp);
 }
@@ -1212,6 +1216,18 @@
 	return (0);
 }
 
+void
+g_geom_add_alias(struct g_geom *gp, const char *alias)
+{
+	struct g_geom_alias *gap;
+
+	gap = (struct g_geom_alias *)g_malloc(
+		sizeof(struct g_geom_alias) + strlen(alias) + 1, M_WAITOK);
+	strcpy((char *)(gap + 1), alias);
+	gap->ga_alias = (const char *)(gap + 1);
+	LIST_INSERT_HEAD(&gp->aliases, gap, ga_next);
+}
+
 #if defined(DIAGNOSTIC) || defined(DDB)
 /*
  * This function walks the mesh and returns a non-zero integer if it
Index: sys/geom/part/g_part.c
===================================================================
--- sys/geom/part/g_part.c
+++ sys/geom/part/g_part.c
@@ -429,6 +429,7 @@
 	struct g_consumer *cp;
 	struct g_provider *pp;
 	struct sbuf *sb;
+	struct g_geom_alias *gap;
 	off_t offset;
 
 	cp = LIST_FIRST(&gp->consumer);
@@ -439,6 +440,19 @@
 		entry->gpe_offset = offset;
 
 	if (entry->gpe_pp == NULL) {
+		/*
+		 * Add aliases to the geom before we create the provider so that
+		 * geom_dev can taste it with all the aliases in place so all
+		 * the aliased dev_t instances get created for each partition
+		 * (eg foo5p7 gets created for bar5p7 when foo is an alias of bar).
+		 */
+		LIST_FOREACH(gap, &table->gpt_gp->aliases, ga_next) {
+			sb = sbuf_new_auto();
+			G_PART_FULLNAME(table, entry, sb, gap->ga_alias);
+			sbuf_finish(sb);
+			g_geom_add_alias(gp, sbuf_data(sb));
+			sbuf_delete(sb);
+		}
 		sb = sbuf_new_auto();
 		G_PART_FULLNAME(table, entry, sb, gp->name);
 		sbuf_finish(sb);
@@ -1901,6 +1915,7 @@
 	struct g_part_entry *entry;
 	struct g_part_table *table;
 	struct root_hold_token *rht;
+	struct g_geom_alias *gap;
 	int attr, depth;
 	int error;
 
@@ -1913,10 +1928,12 @@
 
 	/*
 	 * Create a GEOM with consumer and hook it up to the provider.
-	 * With that we become part of the topology. Optain read access
+	 * With that we become part of the topology. Obtain read access
 	 * to the provider.
 	 */
 	gp = g_new_geomf(mp, "%s", pp->name);
+	LIST_FOREACH(gap, &pp->geom->aliases, ga_next)
+		g_geom_add_alias(gp, gap->ga_alias);
 	cp = g_new_consumer(gp);
 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
 	error = g_attach(cp, pp);