Add "resize" verb to gmirror(8) and such functionality to geom_mirror(4).

Now it is easy to expand the size of the mirror when all its components
are replaced. Also add g_resize method to geom_mirror class. It will write
updated metadata to new last sector, when parent provider is resized.

Silence from:	geom@
MFC after:	1 month

2 files changed, 106 insertions, 5 deletions

diff --git a/sys/geom/mirror/g_mirror.c b/sys/geom/mirror/g_mirror.c
index b4be912a2732..37d52c52f94e 100644
--- a/sys/geom/mirror/g_mirror.c
+++ b/sys/geom/mirror/g_mirror.c
@@ -87,6 +87,7 @@ static int g_mirror_shutdown = 0;
 static int g_mirror_destroy_geom(struct gctl_req *req, struct g_class *mp,
     struct g_geom *gp);
 static g_taste_t g_mirror_taste;
+static g_resize_t g_mirror_resize;
 static void g_mirror_init(struct g_class *mp);
 static void g_mirror_fini(struct g_class *mp);
 
@@ -97,7 +98,8 @@ struct g_class g_mirror_class = {
 	.taste = g_mirror_taste,
 	.destroy_geom = g_mirror_destroy_geom,
 	.init = g_mirror_init,
-	.fini = g_mirror_fini
+	.fini = g_mirror_fini,
+	.resize = g_mirror_resize
 };
 
 
@@ -640,9 +642,17 @@ g_mirror_write_metadata(struct g_mirror_disk *disk,
 	length = cp->provider->sectorsize;
 	offset = cp->provider->mediasize - length;
 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
-	if (md != NULL)
-		mirror_metadata_encode(md, sector);
-	error = g_write_data(cp, offset, sector, length);
+	if (md != NULL) {
+		/*
+		 * Handle the case, when the size of parent provider reduced.
+		 */
+		if (offset < md->md_mediasize)
+			error = ENOSPC;
+		else
+			mirror_metadata_encode(md, sector);
+	}
+	if (error == 0)
+		error = g_write_data(cp, offset, sector, length);
 	free(sector, M_MIRROR);
 	if (error != 0) {
 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
@@ -1323,7 +1333,7 @@ g_mirror_sync_request(struct bio *bp)
 		}
 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
 		sync = &disk->d_sync;
-		if (sync->ds_offset == sc->sc_mediasize ||
+		if (sync->ds_offset >= sc->sc_mediasize ||
 		    sync->ds_consumer == NULL ||
 		    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
 			/* Don't send more synchronization requests. */
@@ -2717,12 +2727,14 @@ g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
 		    "md_balance", pp->name, sc->sc_name);
 		return (EINVAL);
 	}
+#if 0
 	if (md->md_mediasize != sc->sc_mediasize) {
 		G_MIRROR_DEBUG(1,
 		    "Invalid '%s' field on disk %s (device %s), skipping.",
 		    "md_mediasize", pp->name, sc->sc_name);
 		return (EINVAL);
 	}
+#endif
 	if (sc->sc_mediasize > pp->mediasize) {
 		G_MIRROR_DEBUG(1,
 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
@@ -3115,6 +3127,22 @@ g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
 	return (gp);
 }
 
+static void
+g_mirror_resize(struct g_consumer *cp)
+{
+	struct g_mirror_disk *disk;
+
+	g_topology_assert();
+	g_trace(G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name);
+
+	disk = cp->private;
+	if (disk == NULL)
+		return;
+	g_topology_unlock();
+	g_mirror_update_metadata(disk);
+	g_topology_lock();
+}
+
 static int
 g_mirror_destroy_geom(struct gctl_req *req __unused,
     struct g_class *mp __unused, struct g_geom *gp)
diff --git a/sys/geom/mirror/g_mirror_ctl.c b/sys/geom/mirror/g_mirror_ctl.c
index c024bd9d3181..1748d7b9d6b1 100644
--- a/sys/geom/mirror/g_mirror_ctl.c
+++ b/sys/geom/mirror/g_mirror_ctl.c
@@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
+#include <sys/limits.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/bio.h>
@@ -40,6 +41,7 @@ __FBSDID("$FreeBSD$");
 #include <vm/uma.h>
 #include <machine/atomic.h>
 #include <geom/geom.h>
+#include <geom/geom_int.h>
 #include <sys/proc.h>
 #include <sys/kthread.h>
 #include <geom/mirror/g_mirror.h>
@@ -617,6 +619,75 @@ g_mirror_ctl_remove(struct gctl_req *req, struct g_class *mp)
 }
 
 static void
+g_mirror_ctl_resize(struct gctl_req *req, struct g_class *mp)
+{
+	struct g_mirror_softc *sc;
+	struct g_mirror_disk *disk;
+	uint64_t mediasize;
+	const char *name, *s;
+	char *x;
+	int *nargs;
+
+	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
+	if (nargs == NULL) {
+		gctl_error(req, "No '%s' argument.", "nargs");
+		return;
+	}
+	if (*nargs != 1) {
+		gctl_error(req, "Missing device.");
+		return;
+	}
+	name = gctl_get_asciiparam(req, "arg0");
+	if (name == NULL) {
+		gctl_error(req, "No 'arg%u' argument.", 0);
+		return;
+	}
+	s = gctl_get_asciiparam(req, "size");
+	if (s == NULL) {
+		gctl_error(req, "No '%s' argument.", "size");
+		return;
+	}
+	mediasize = strtouq(s, &x, 0);
+	if (*x != '\0' || mediasize == 0) {
+		gctl_error(req, "Invalid '%s' argument.", "size");
+		return;
+	}
+	sc = g_mirror_find_device(mp, name);
+	if (sc == NULL) {
+		gctl_error(req, "No such device: %s.", name);
+		return;
+	}
+	/* Deny shrinking of an opened provider */
+	if ((g_debugflags & 16) == 0 && (sc->sc_provider->acr > 0 ||
+	    sc->sc_provider->acw > 0 || sc->sc_provider->ace > 0)) {
+		if (sc->sc_mediasize > mediasize) {
+			gctl_error(req, "Device %s is busy.",
+			    sc->sc_provider->name);
+			sx_xunlock(&sc->sc_lock);
+			return;
+		}
+	}
+	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
+		if (mediasize > disk->d_consumer->provider->mediasize -
+		    disk->d_consumer->provider->sectorsize) {
+			gctl_error(req, "Provider %s is too small.",
+			    disk->d_name);
+			sx_xunlock(&sc->sc_lock);
+			return;
+		}
+	}
+	/* Update the size. */
+	sc->sc_mediasize = mediasize;
+	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
+		g_mirror_update_metadata(disk);
+	}
+	g_topology_lock();
+	g_resize_provider(sc->sc_provider, mediasize);
+	g_topology_unlock();
+	sx_xunlock(&sc->sc_lock);
+}
+
+static void
 g_mirror_ctl_deactivate(struct gctl_req *req, struct g_class *mp)
 {
 	struct g_mirror_softc *sc;
@@ -793,6 +864,8 @@ g_mirror_config(struct gctl_req *req, struct g_class *mp, const char *verb)
 		g_mirror_ctl_insert(req, mp);
 	else if (strcmp(verb, "remove") == 0)
 		g_mirror_ctl_remove(req, mp);
+	else if (strcmp(verb, "resize") == 0)
+		g_mirror_ctl_resize(req, mp);
 	else if (strcmp(verb, "deactivate") == 0)
 		g_mirror_ctl_deactivate(req, mp);
 	else if (strcmp(verb, "forget") == 0)