Fix a bug that caused da(4) peripheral drivers to not fully go away

after the underlying device went away.

The problem was that callers who queue the GEOM resize provider
event didn't check to make sure that the provider had not been
withered.  For the other equivalent case, g_new_provider_event(),
the code checks to see whether the provider has been withered
before queueing a g_new_provider_event() to the event thread.

In some cases, a resize provider event would come through after
the provider had been withered and all of the existing consumers
had been orphaned.  When the resize event triggered a taste of
the provider, that would attach a new consumer to the now
withered provider.  The wither washer (g_wither_washer() would
never be able to completely tear down the GEOM because of the
consumers that were hanging around.

The solution was to check the G_PF_WITHER provider flag before
queueing the g_resize_provider_event(), and add an assert to
g_resize_provider_event() to insure that it isn't called on a
withered provider.

sys/geom/geom_subr.c:
	In g_resize_provider(), don't try to continue if the
	G_PF_WITHER flag is set.

	In g_resize_provider_event(), add an assert that the
	G_PF_WITHER flag is not set.

	In g_access(), if a provider has an error, print out the
	name of the provider with the error.

Sponsored by:	Spectra Logic
Approved by:	re (marius)
MFC after:	3 days

1 files changed, 8 insertions, 1 deletions

diff --git a/sys/geom/geom_subr.c b/sys/geom/geom_subr.c
index d9128380866f..f67b74413c82 100644
--- a/sys/geom/geom_subr.c
+++ b/sys/geom/geom_subr.c
@@ -620,6 +620,8 @@ g_resize_provider_event(void *arg, int flag)
 	g_free(hh);
 
 	G_VALID_PROVIDER(pp);
+	KASSERT(!(pp->flags & G_PF_WITHER),
+	    ("g_resize_provider_event but withered"));
 	g_trace(G_T_TOPOLOGY, "g_resize_provider_event(%p)", pp);
 
 	LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) {
@@ -662,6 +664,8 @@ g_resize_provider(struct g_provider *pp, off_t size)
 	struct g_hh00 *hh;
 
 	G_VALID_PROVIDER(pp);
+	if (pp->flags & G_PF_WITHER)
+		return;
 
 	if (size == pp->mediasize)
 		return;
@@ -909,8 +913,11 @@ g_access(struct g_consumer *cp, int dcr, int dcw, int dce)
 	else if (dcw > 0 && pe > 0)
 		return (EPERM);
 	/* If we try to open more but provider is error'ed: fail */
-	else if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0)
+	else if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0) {
+		printf("%s(%d): provider %s has error\n",
+		       __func__, __LINE__, pp->name);
 		return (pp->error);
+	}
 
 	/* Ok then... */