Make ELI destruction (including orphanization) less aggressive, making it

always wait for provider close.  Old algorithm was reported to cause NULL
dereference panic on attempt to close provider after softc destruction.
If not global workaroung in GEOM, that could even cause destruction with
requests still in flight.

1 files changed, 12 insertions, 10 deletions

diff --git a/sys/geom/eli/g_eli.c b/sys/geom/eli/g_eli.c
index 6819fcc..18e3cc4 100644
--- a/sys/geom/eli/g_eli.c
+++ b/sys/geom/eli/g_eli.c
@@ -621,21 +621,19 @@ end:
  * to close it when this situation occur.
  */
 static void
-g_eli_last_close(struct g_eli_softc *sc)
+g_eli_last_close(void *arg, int flags __unused)
 {
 	struct g_geom *gp;
-	struct g_provider *pp;
-	char ppname[64];
+	char gpname[64];
 	int error;
 
 	g_topology_assert();
-	gp = sc->sc_geom;
-	pp = LIST_FIRST(&gp->provider);
-	strlcpy(ppname, pp->name, sizeof(ppname));
-	error = g_eli_destroy(sc, TRUE);
+	gp = arg;
+	strlcpy(gpname, gp->name, sizeof(gpname));
+	error = g_eli_destroy(gp->softc, TRUE);
 	KASSERT(error == 0, ("Cannot detach %s on last close (error=%d).",
-	    ppname, error));
-	G_ELI_DEBUG(0, "Detached %s on last close.", ppname);
+	    gpname, error));
+	G_ELI_DEBUG(0, "Detached %s on last close.", gpname);
 }
 
 int
@@ -665,7 +663,7 @@ g_eli_access(struct g_provider *pp, int dr, int dw, int de)
 	 */
 	if ((sc->sc_flags & G_ELI_FLAG_RW_DETACH) ||
 	    (sc->sc_flags & G_ELI_FLAG_WOPEN)) {
-		g_eli_last_close(sc);
+		g_post_event(g_eli_last_close, gp, M_WAITOK, NULL);
 	}
 	return (0);
 }
@@ -916,6 +914,10 @@ g_eli_destroy(struct g_eli_softc *sc, boolean_t force)
 		if (force) {
 			G_ELI_DEBUG(1, "Device %s is still open, so it "
 			    "cannot be definitely removed.", pp->name);
+			sc->sc_flags |= G_ELI_FLAG_RW_DETACH;
+			gp->access = g_eli_access;
+			g_wither_provider(pp, ENXIO);
+			return (EBUSY);
 		} else {
 			G_ELI_DEBUG(1,
 			    "Device %s is still open (r%dw%de%d).", pp->name,