svn commit: r255568 - stable/9/sys/geom/eli

[Alexander Motin]

Author: mav
Date: Sat Sep 14 10:14:09 2013
New Revision: 255568
URL: http://svnweb.freebsd.org/changeset/base/255568

Log:
  MFC r255144:
  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.

Modified:
  stable/9/sys/geom/eli/g_eli.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/geom/eli/g_eli.c
==============================================================================
--- stable/9/sys/geom/eli/g_eli.c	Sat Sep 14 10:12:28 2013	(r255567)
+++ stable/9/sys/geom/eli/g_eli.c	Sat Sep 14 10:14:09 2013	(r255568)
@@ -620,21 +620,19 @@ 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
@@ -664,7 +662,7 @@ g_eli_access(struct g_provider *pp, int 
 	 */
 	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);
 }
@@ -910,6 +908,10 @@ g_eli_destroy(struct g_eli_softc *sc, bo
 		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,