- Fixed theoretical memory leak in g_modevent() function.
- Fix deadlock. When requests were canceled, the g_pending_events counter wasn't
  decresed. Because of that g_waitidle() will wait forever.
- Detect deadlock situations when g_waitfor_event() function is called
  recursively.
- Improve taste mechanism by adding flags for taste event:
	+ G_TA_TASTE - this is a taste event,
	+ G_TA_RETASTE - this is a retaste event (called after spoiled event),
	+ G_TA_FIRST - this is first disk introduced for tasting,
	+ G_TA_LAST - this is last disk introduced for tasting,
	+ G_TA_ALLMASK - mask for all available flags.
- Detect registration of class without a name.
- Detect new provider creation when its geom has no 'start' field defined.
- Don't allow creating new consumer when its geom is being withered.
- Don't allow creating new provider when its geom is being withered.
- Don't allow provider's error changes when its geom is being withered.
- Return EPERM when someone is trying to attach to a provider and
  provider's geom is being withered.
- Added missing '\n' in printf(9).

diff -rup geom.orig/geom.h geom/geom.h
--- geom.orig/geom.h	Fri Jan 23 16:54:52 2004
+++ geom/geom.h	Fri Jan 23 16:58:53 2004
@@ -64,6 +64,11 @@ typedef int g_ctl_destroy_geom_t (struct
 typedef int g_ctl_config_geom_t (struct gctl_req *, struct g_geom *gp, const char *verb);
 typedef void g_init_t (struct g_class *mp);
 typedef void g_fini_t (struct g_class *mp);
+#define	G_TA_TASTE	0x0001
+#define	G_TA_RETASTE	0x0002
+#define	G_TA_FIRST	0x0004
+#define	G_TA_LAST	0x0008
+#define	G_TA_ALLMASK	0x000f
 typedef struct g_geom * g_taste_t (struct g_class *, struct g_provider *, int flags);
 typedef int g_ioctl_t(struct g_provider *pp, u_long cmd, void *data, struct thread *td);
 #define G_TF_NORMAL		0
diff -rup geom.orig/geom_dev.c geom/geom_dev.c
--- geom.orig/geom_dev.c	Fri Jan 23 16:54:52 2004
+++ geom/geom_dev.c	Fri Jan 23 17:01:39 2004
@@ -255,7 +255,7 @@ g_dev_close(dev_t dev, int flags, int fm
 		i += hz / 10;
 	}
 	if (cp->acr == 0 && cp->acw == 0 && cp->nstart != cp->nend) {
-		printf("WARNING: Final close of geom_dev(%s) %s %s",
+		printf("WARNING: Final close of geom_dev(%s) %s %s\n",
 		    gp->name,
 		    "still has outstanding I/O after 10 seconds.",
 		    "Completing close anyway, panic may happen later.");
diff -rup geom.orig/geom_event.c geom/geom_event.c
--- geom.orig/geom_event.c	Fri Jan 23 16:54:52 2004
+++ geom/geom_event.c	Fri Jan 23 18:51:51 2004
@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD: src/sys/geom/geom_ev
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <machine/stdarg.h>
+#include <machine/atomic.h>
 #include <sys/errno.h>
 #include <sys/time.h>
 #include <geom/geom.h>
@@ -242,6 +243,9 @@ g_cancel_event(void *ref)
 				} else {
 					g_free(ep);
 				}
+				g_pending_events--;
+				if (g_pending_events == 0)
+					wakeup(&g_pending_events);
 				break;
 			}
 		}
@@ -309,6 +313,13 @@ g_waitfor_event(g_event_t *func, void *a
 	va_list ap;
 	struct g_event *ep;
 	int error;
+#ifdef INVARIANTS
+	/*
+	 * This variable is used for deadlock prevention when we're waiting here
+	 * for function which is calling g_waitfor_event() function.
+	 */
+	static int waiting_for_function = 0;
+#endif
 
 	/* g_topology_assert_not(); */
 	KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
@@ -318,9 +329,14 @@ g_waitfor_event(g_event_t *func, void *a
 	va_end(ap);
 	if (error)
 		return (error);
+	KASSERT(atomic_cmpset_int(&waiting_for_function, 0, 1) == 1,
+	    ("wait-for-event request called recursively"));
 	do 
 		tsleep(ep, PRIBIO, "g_waitfor_event", hz);
 	while (!(ep->flag & EV_DONE));
+#ifdef INVARIANTS
+	atomic_store_rel_int(&waiting_for_function, 0);
+#endif
 	if (ep->flag & EV_CANCELED)
 		error = EAGAIN;
 	g_free(ep);
diff -rup geom.orig/geom_subr.c geom/geom_subr.c
--- geom.orig/geom_subr.c	Fri Jan 23 16:54:52 2004
+++ geom/geom_subr.c	Fri Jan 23 18:52:06 2004
@@ -59,10 +59,14 @@ char *g_wait_event, *g_wait_up, *g_wait_
 
 static int g_valid_obj(void const *ptr);
 
-struct g_hh00 {
+struct g_hh00_class {
 	struct g_class	*mp;
 	int		error;
 };
+struct g_hh00_provider {
+	struct g_provider	*provider;
+	int			flags;
+};
 
 /*
  * This event offers a new class a chance to taste all preexisting providers.
@@ -70,10 +74,11 @@ struct g_hh00 {
 static void
 g_load_class(void *arg, int flag)
 {
-	struct g_hh00 *hh;
+	struct g_hh00_class *hh;
 	struct g_class *mp2, *mp;
 	struct g_geom *gp;
-	struct g_provider *pp;
+	struct g_provider *pp, *pp2;
+	int tflags;
 
 	g_topology_assert();
 	if (flag == EV_CANCEL)	/* XXX: can't happen ? */
@@ -84,6 +89,7 @@ g_load_class(void *arg, int flag)
 	hh = arg;
 	mp = hh->mp;
 	g_free(hh);
+	KASSERT(mp->name != NULL, ("Cannot load class without a name"));
 	g_trace(G_T_TOPOLOGY, "g_load_class(%s)", mp->name);
 	LIST_FOREACH(mp2, &g_classes, class) {
 		KASSERT(mp2 != mp,
@@ -98,22 +104,34 @@ g_load_class(void *arg, int flag)
 		mp->init(mp);
 	if (mp->taste == NULL)
 		return;
+	pp = NULL;
+	tflags = G_TA_TASTE | G_TA_FIRST;
 	LIST_FOREACH(mp2, &g_classes, class) {
 		if (mp == mp2)
 			continue;
 		LIST_FOREACH(gp, &mp2->geom, geom) {
-			LIST_FOREACH(pp, &gp->provider, provider) {
-				mp->taste(mp, pp, 0);
-				g_topology_assert();
+			LIST_FOREACH(pp2, &gp->provider, provider) {
+				if (pp != NULL) {
+					mp->taste(mp, pp, tflags);
+					g_topology_assert();
+					if ((tflags & G_TA_FIRST) != 0)
+						tflags &= ~G_TA_FIRST;
+				}
+				pp = pp2;
 			}
 		}
 	}
+	if (pp != NULL) {
+		tflags |= G_TA_LAST;
+		mp->taste(mp, pp, tflags);
+		g_topology_assert();
+	}
 }
 
 static void
 g_unload_class(void *arg, int flag)
 {
-	struct g_hh00 *hh;
+	struct g_hh00_class *hh;
 	struct g_class *mp;
 	struct g_geom *gp;
 	struct g_provider *pp;
@@ -165,7 +183,7 @@ g_unload_class(void *arg, int flag)
 int
 g_modevent(module_t mod, int type, void *data)
 {
-	struct g_hh00 *hh;
+	struct g_hh00_class *hh;
 	int error;
 	static int g_ignition;
 
@@ -194,6 +212,8 @@ g_modevent(module_t mod, int type, void 
 		}
 		g_free(hh);
 		break;
+	default:
+		g_free(hh);
 	}
 	return (error);
 }
@@ -288,6 +308,9 @@ g_new_consumer(struct g_geom *gp)
 	struct g_consumer *cp;
 
 	g_topology_assert();
+	KASSERT(!(gp->flags & G_GEOM_WITHER),
+	    ("g_new_consumer called on geom(%s) with WITHER flag set (class %s)",
+	    gp->name, gp->class->name));
 	KASSERT(gp->orphan != NULL,
 	    ("g_new_consumer on geom(%s) (class %s) without orphan",
 	    gp->name, gp->class->name));
@@ -323,17 +346,28 @@ g_destroy_consumer(struct g_consumer *cp
 static void
 g_new_provider_event(void *arg, int flag)
 {
+	struct g_hh00_provider *hh;
 	struct g_class *mp;
 	struct g_provider *pp;
 	struct g_consumer *cp;
-	int i;
+	int i, tflags;
 
 	g_topology_assert();
 	if (flag == EV_CANCEL)
 		return;
 	if (g_shutdown)
 		return;
-	pp = arg;
+	hh = arg;
+	pp = hh->provider;
+	tflags = hh->flags;
+	g_free(hh);
+	KASSERT((tflags & ~G_TA_ALLMASK) == 0, ("Wrong flags for taste event"));
+	KASSERT(tflags != 0, ("Wrong flags for taste event"));
+/* We need logical XOR operation for a moment. */
+#define	LXOR(a, b)	(!(a) != !(b))
+	KASSERT(LXOR((tflags & G_TA_TASTE) != 0, (tflags & G_TA_RETASTE) != 0),
+	    ("Wrong flags for taste event"));
+#undef	LXOR
 	LIST_FOREACH(mp, &g_classes, class) {
 		if (mp->taste == NULL)
 			continue;
@@ -343,7 +377,7 @@ g_new_provider_event(void *arg, int flag
 				i = 0;
 		if (!i)
 			continue;
-		mp->taste(mp, pp, 0);
+		mp->taste(mp, pp, tflags);
 		g_topology_assert();
 		/*
 		 * XXX: Bandaid for 5.2-RELEASE
@@ -360,11 +394,19 @@ g_new_provider_event(void *arg, int flag
 struct g_provider *
 g_new_providerf(struct g_geom *gp, const char *fmt, ...)
 {
+	struct g_hh00_provider *hh;
 	struct g_provider *pp;
 	struct sbuf *sb;
 	va_list ap;
 
 	g_topology_assert();
+	KASSERT(gp->start != NULL,
+	    ("g_new_providerf on geom(%s) (class %s) without start",
+	    gp->name, gp->class->name));
+	KASSERT(!(gp->flags & G_GEOM_WITHER),
+	    ("g_new_providerf called on geom(%s) with WITHER flag set (class %s)",
+	    gp->name, gp->class->name));
+
 	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
 	va_start(ap, fmt);
 	sbuf_vprintf(sb, fmt, ap);
@@ -380,7 +422,10 @@ g_new_providerf(struct g_geom *gp, const
 	pp->stat = devstat_new_entry(pp, -1, 0, DEVSTAT_ALL_SUPPORTED,
 	    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
 	LIST_INSERT_HEAD(&gp->provider, pp, provider);
-	g_post_event(g_new_provider_event, pp, M_WAITOK, pp, NULL);
+	hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
+	hh->provider = pp;
+	hh->flags = G_TA_TASTE | G_TA_FIRST | G_TA_LAST;
+	g_post_event(g_new_provider_event, hh, M_WAITOK, hh, NULL);
 	return (pp);
 }
 
@@ -388,6 +433,9 @@ void
 g_error_provider(struct g_provider *pp, int error)
 {
 
+	KASSERT(!(pp->geom->flags & G_GEOM_WITHER),
+	    ("error change for provider(%s) on geom(%s) with WITHER flag set (class %s)",
+	    pp->name, pp->geom->name, pp->geom->class->name));
 	pp->error = error;
 }
 
@@ -504,6 +552,8 @@ g_attach(struct g_consumer *cp, struct g
 
 	g_topology_assert();
 	KASSERT(cp->provider == NULL, ("attach but attached"));
+	if (pp->geom->flags & G_GEOM_WITHER)
+		return (EPERM);	/* XXX: ENXIO? pp->error? */
 	cp->provider = pp;
 	LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
 	error = redo_rank(cp->geom);
@@ -634,9 +684,15 @@ g_access_rel(struct g_consumer *cp, int 
 		if (pp->acw == 0 && dcw != 0)
 			g_spoil(pp, cp);
 		else if (pp->acw != 0 && pp->acw == -dcw && 
-		    !(pp->geom->flags & G_GEOM_WITHER))
-			g_post_event(g_new_provider_event, pp, M_WAITOK, 
-			    pp, NULL);
+		    !(pp->geom->flags & G_GEOM_WITHER)) {
+			struct g_hh00_provider *hh;
+
+			hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
+			hh->provider = pp;
+			hh->flags = G_TA_RETASTE | G_TA_FIRST | G_TA_LAST;
+			g_post_event(g_new_provider_event, hh, M_WAITOK,
+			    hh, NULL);
+		}
 
 		pp->acr += dcr;
 		pp->acw += dcw;