Index: geom_io.c
===================================================================
--- geom_io.c	(wersja 195169)
+++ geom_io.c	(kopia robocza)
@@ -480,14 +481,6 @@
 	KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
 	pp = bp->bio_to;
 	KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
-#ifdef DIAGNOSTIC
-	KASSERT(bp->bio_caller1 == bp->_bio_caller1,
-	    ("bio_caller1 used by the provider %s", pp->name));
-	KASSERT(bp->bio_caller2 == bp->_bio_caller2,
-	    ("bio_caller2 used by the provider %s", pp->name));
-	KASSERT(bp->bio_cflags == bp->_bio_cflags,
-	    ("bio_cflags used by the provider %s", pp->name));
-#endif
 	cp = bp->bio_from;
 	if (cp == NULL) {
 		bp->bio_error = error;
@@ -496,6 +489,20 @@
 	}
 	KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
 	KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
+#ifdef DIAGNOSTIC
+	/*
+	 * GJournal can modify bio's private fields while the bio is in
+	 * transit and provider is not the one to blame.
+	 */
+	if (strcmp(bp->bio_from->geom->class->name, "JOURNAL") != 0) {
+		KASSERT(bp->bio_caller1 == bp->_bio_caller1,
+		    ("bio_caller1 used by the provider %s", pp->name));
+		KASSERT(bp->bio_caller2 == bp->_bio_caller2,
+		    ("bio_caller2 used by the provider %s", pp->name));
+		KASSERT(bp->bio_cflags == bp->_bio_cflags,
+		    ("bio_cflags used by the provider %s", pp->name));
+	}
+#endif
 	KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
 	KASSERT(bp->bio_completed <= bp->bio_length,
 	    ("bio_completed can't be greater than bio_length"));