gnop(8): add the ability to set a nop provider's physical path

While I'm here, expand the existing tests a bit.

MFC after:	3 weeks
Differential Revision:	https://reviews.freebsd.org/D13579

sbin/geom/class/nop/geom_nop.c

@@ -51,10 +51,12 @@ struct g_command class_commands[] = {
 		{ 's', "size", "0", G_TYPE_NUMBER },
 		{ 'S', "secsize", "0", G_TYPE_NUMBER },
 		{ 'w', "wfailprob", "-1", G_TYPE_NUMBER },
+		{ 'z', "physpath", G_NOP_PHYSPATH_PASSTHROUGH, G_TYPE_STRING },
 		G_OPT_SENTINEL
 	    },
 	    "[-v] [-e error] [-o offset] [-p stripesize] [-P stripeoffset] "
-	    "[-r rfailprob] [-s size] [-S secsize] [-w wfailprob] dev ..."
+	    "[-r rfailprob] [-s size] [-S secsize] [-w wfailprob] "
+	    "[-z physpath] dev ..."
 	},
 	{ "configure", G_FLAG_VERBOSE, NULL,
 	    {

sbin/geom/class/nop/gnop.8

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 10, 2015
+.Dd January 17, 2018
 .Dt GNOP 8
 .Os
 .Sh NAME
@@ -42,6 +42,7 @@
 .Op Fl s Ar size
 .Op Fl S Ar secsize
 .Op Fl w Ar wfailprob
+.Op Fl z Ar physpath
 .Ar dev ...
 .Nm
 .Cm configure
@@ -132,6 +133,8 @@ Sector size of the transparent provider.
 Specifies write failure probability in percent.
 .It Fl v
 Be more verbose.
+.It Fl z Ar physpath
+Physical path of the transparent provider.
 .El
 .Sh SYSCTL VARIABLES
 The following

sys/geom/nop/g_nop.c

@@ -126,6 +126,11 @@ g_nop_start(struct bio *bp)
 		break;
 	case BIO_GETATTR:
 		sc->sc_getattrs++;
+		if (sc->sc_physpath && 
+		    g_handleattr_str(bp, "GEOM::physpath", sc->sc_physpath)) {
+			mtx_unlock(&sc->sc_lock);
+			return;
+		}
 		break;
 	case BIO_FLUSH:
 		sc->sc_flushes++;
@@ -182,7 +187,7 @@ g_nop_access(struct g_provider *pp, int dr, int dw, int de)
 static int
 g_nop_create(struct gctl_req *req, struct g_class *mp, struct g_provider *pp,
     int ioerror, u_int rfailprob, u_int wfailprob, off_t offset, off_t size,
-    u_int secsize, u_int stripesize, u_int stripeoffset)
+    u_int secsize, u_int stripesize, u_int stripeoffset, const char *physpath)
 {
 	struct g_nop_softc *sc;
 	struct g_geom *gp;
@@ -253,6 +258,10 @@ g_nop_create(struct gctl_req *req, struct g_class *mp, struct g_provider *pp,
 	sc->sc_explicitsize = explicitsize;
 	sc->sc_stripesize = stripesize;
 	sc->sc_stripeoffset = stripeoffset;
+	if (physpath && strcmp(physpath, G_NOP_PHYSPATH_PASSTHROUGH)) {
+		sc->sc_physpath = strndup(physpath, MAXPATHLEN, M_GEOM);
+	} else
+		sc->sc_physpath = NULL;
 	sc->sc_error = ioerror;
 	sc->sc_rfailprob = rfailprob;
 	sc->sc_wfailprob = wfailprob;
@@ -299,6 +308,7 @@ g_nop_create(struct gctl_req *req, struct g_class *mp, struct g_provider *pp,
 	g_destroy_consumer(cp);
 	g_destroy_provider(newpp);
 	mtx_destroy(&sc->sc_lock);
+	free(sc->sc_physpath, M_GEOM);
 	g_free(gp->softc);
 	g_destroy_geom(gp);
 	return (error);
@@ -314,6 +324,7 @@ g_nop_destroy(struct g_geom *gp, boolean_t force)
 	sc = gp->softc;
 	if (sc == NULL)
 		return (ENXIO);
+	free(sc->sc_physpath, M_GEOM);
 	pp = LIST_FIRST(&gp->provider);
 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 		if (force) {
@@ -348,7 +359,7 @@ g_nop_ctl_create(struct gctl_req *req, struct g_class *mp)
 	struct g_provider *pp;
 	intmax_t *error, *rfailprob, *wfailprob, *offset, *secsize, *size,
 	    *stripesize, *stripeoffset;
-	const char *name;
+	const char *name, *physpath;
 	char param[16];
 	int i, *nargs;
 
@@ -431,6 +442,7 @@ g_nop_ctl_create(struct gctl_req *req, struct g_class *mp)
 		gctl_error(req, "Invalid '%s' argument", "stripeoffset");
 		return;
 	}
+	physpath = gctl_get_asciiparam(req, "physpath");
 
 	for (i = 0; i < *nargs; i++) {
 		snprintf(param, sizeof(param), "arg%d", i);
@@ -452,7 +464,8 @@ g_nop_ctl_create(struct gctl_req *req, struct g_class *mp)
 		    *rfailprob == -1 ? 0 : (u_int)*rfailprob,
 		    *wfailprob == -1 ? 0 : (u_int)*wfailprob,
 		    (off_t)*offset, (off_t)*size, (u_int)*secsize,
-		    (u_int)*stripesize, (u_int)*stripeoffset) != 0) {
+		    (u_int)*stripesize, (u_int)*stripeoffset,
+		    physpath) != 0) {
 			return;
 		}
 	}

sys/geom/nop/g_nop.h

@@ -34,6 +34,11 @@
 #define	G_NOP_CLASS_NAME	"NOP"
 #define	G_NOP_VERSION		4
 #define	G_NOP_SUFFIX		".nop"
+/*
+ * Special flag to instruct gnop to passthrough the underlying provider's
+ * physical path
+ */
+#define G_NOP_PHYSPATH_PASSTHROUGH "\255"
 
 #ifdef _KERNEL
 #define	G_NOP_DEBUG(lvl, ...)	do {					\
@@ -75,6 +80,7 @@ struct g_nop_softc {
 	uintmax_t	sc_cmd2s;
 	uintmax_t	sc_readbytes;
 	uintmax_t	sc_wrotebytes;
+	char*		sc_physpath;
 	struct mtx	sc_lock;
 };
 #endif	/* _KERNEL */

tests/sys/geom/class/nop/nop_test.sh

@@ -27,14 +27,14 @@
 MD_DEVS="md.devs"
 PLAINFILES=plainfiles
 
-atf_test_case diskinfo cleanup
-diskinfo_head()
+atf_test_case preserve_props cleanup
+preserve_props_head()
 {
-	atf_set "descr" "gnop should preserve diskinfo's basic properties"
+	atf_set "descr" "gnop should preserve basic GEOM properties"
 	atf_set "require.user" "root"
 	atf_set "timeout" 15
 }
-diskinfo_body()
+preserve_props_body()
 {
 	load_gnop
 	us=$(alloc_md)
@@ -49,11 +49,54 @@ diskinfo_body()
 	atf_check_equal "$md_mediasize" "$nop_mediasize"
 	atf_check_equal "$md_stripesize" "$nop_stripesize"
 }
-diskinfo_cleanup()
+preserve_props_cleanup()
 {
 	common_cleanup
 }
 
+atf_test_case preserve_disk_props cleanup
+preserve_disk_props_head()
+{
+	atf_set "descr" "gnop should preserve properties for disks"
+	atf_set "require.user" "root"
+	atf_set "require.config" "disks"
+	atf_set "timeout" 15
+}
+preserve_disk_props_body()
+{
+	load_gnop
+	disks=`atf_config_get disks`
+	disk=${disks%% *}
+	if [ -z "$disk" ]; then
+		atf_skip "Must define disks (see tests(7))"
+	fi
+	atf_check gnop create ${disk}
+
+	disk_ident=$(diskinfo -s ${disk})
+	disk_physpath=$(diskinfo -p ${disk})
+	disk_descr=$(diskinfo -v ${disk} | awk '/Disk descr/ {print $1}')
+	disk_trim=$(diskinfo -v ${disk} | awk '/TRIM.UNMAP/ {print $1}')
+	disk_rotrate=$(diskinfo -v ${disk} | awk '/Rotation rate/ {print $1}')
+	disk_zonemode=$(diskinfo -v ${disk} | awk '/Zone Mode/ {print $1}')
+	nop_ident=$(diskinfo -s ${disk}.nop)
+	nop_physpath=$(diskinfo -p ${disk}.nop)
+	nop_descr=$(diskinfo -v ${disk}.nop | awk '/Disk descr/ {print $1}')
+	nop_trim=$(diskinfo -v ${disk}.nop | awk '/TRIM.UNMAP/ {print $1}')
+	nop_rotrate=$(diskinfo -v ${disk}.nop | awk '/Rotation/ {print $1}')
+	nop_zonemode=$(diskinfo -v ${disk}.nop | awk '/Zone Mode/ {print $1}')
+	atf_check_equal "$disk_ident" "$nop_ident"
+	atf_check_equal "$disk_physpath" "$nop_physpath"
+	atf_check_equal "$disk_descr" "$nop_descr"
+	atf_check_equal "$disk_trim" "$nop_trim"
+	atf_check_equal "$disk_rotrate" "$nop_rotrate"
+	atf_check_equal "$disk_zonemode" "$nop_zonemode"
+}
+preserve_disk_props_cleanup()
+{
+	disk_cleanup
+	common_cleanup
+}
+
 atf_test_case io cleanup
 io_head()
 {
@@ -80,6 +123,54 @@ io_cleanup()
 	common_cleanup
 }
 
+atf_test_case physpath cleanup
+physpath_head()
+{
+	atf_set "descr" "Test gnop's -z option"
+	atf_set "require.user" "root"
+	atf_set "timeout" 15
+}
+physpath_body()
+{
+	load_gnop
+	us=$(alloc_md)
+	physpath="some/physical/path"
+	atf_check gnop create -z $physpath /dev/${us}
+	gnop_physpath=$(diskinfo -p ${us}.nop)
+	atf_check_equal "$physpath" "$gnop_physpath"
+}
+physpath_cleanup()
+{
+	common_cleanup
+}
+
+atf_test_case physpath_blank cleanup
+physpath_blank_head()
+{
+	atf_set "descr" "gnop can set physical path to the empty string"
+	atf_set "require.user" "root"
+	atf_set "require.config" "disks"
+	atf_set "timeout" 15
+}
+physpath_blank_body()
+{
+	load_gnop
+	disks=`atf_config_get disks`
+	disk=${disks%% *}
+	if [ -z "$disk" ]; then
+		atf_skip "Must define disks (see tests(7))"
+	fi
+
+	atf_check gnop create -z "" ${disk}
+	gnop_physpath=$(diskinfo -p ${disk}.nop)
+	atf_check_equal "" "$gnop_physpath"
+}
+physpath_blank_cleanup()
+{
+	disk_cleanup
+	common_cleanup
+}
+
 atf_test_case size cleanup
 size_head()
 {
@@ -136,7 +227,10 @@ stripesize_cleanup()
 atf_init_test_cases()
 {
 	atf_add_test_case io
-	atf_add_test_case diskinfo
+	atf_add_test_case physpath
+	atf_add_test_case physpath_blank
+	atf_add_test_case preserve_props
+	atf_add_test_case preserve_disk_props
 	atf_add_test_case stripesize
 	atf_add_test_case size
 }
@@ -169,6 +263,15 @@ common_cleanup()
 	true
 }
 
+disk_cleanup()
+{
+	disks=`atf_config_get disks`
+	disk=${disks%% *}
+	if [ -n "$disk" ]; then
+		gnop destroy -f ${disk}.nop 2>/dev/null
+	fi
+}
+
 load_gnop()
 {
 	if ! kldstat -q -m g_nop; then