Fix a problem and slightly improve the ENOMEM handling:

Give up the entire bio as soon as we detect a problem.

When we detect a problem, give up the bio by contributing the
remainder with ENOMEM, rather than kicking the bio back right
away.

If we failed on a non-first iteration we previously could end up
modifying fields in the bio after we delivered it.  This could
account for memory corruption (none directly reported) on machines
with GBDE.

1 files changed, 12 insertions, 11 deletions

diff --git a/sys/geom/bde/g_bde_work.c b/sys/geom/bde/g_bde_work.c
index d8186ce..9375051 100644
--- a/sys/geom/bde/g_bde_work.c
+++ b/sys/geom/bde/g_bde_work.c
@@ -720,18 +720,19 @@ g_bde_start1(struct bio *bp)
 	mtx_lock(&sc->worklist_mutex);
 	for(done = 0; done < bp->bio_length; ) {
 		wp = g_bde_new_work(sc);
-		if (wp == NULL) {
-			g_io_deliver(bp, ENOMEM);
-			mtx_unlock(&sc->worklist_mutex);
-			return;
+		if (wp != NULL) {
+			wp->bp = bp;
+			wp->offset = bp->bio_offset + done;
+			wp->data = bp->bio_data + done;
+			wp->length = bp->bio_length - done;
+			g_bde_map_sector(wp);
+			done += wp->length;
+			g_bde_start2(wp);
+		}
+		if (wp == NULL || bp->bio_error != 0) {
+			g_bde_contribute(bp, bp->bio_length - done, ENOMEM);
+			break;
 		}
-		wp->bp = bp;
-		wp->offset = bp->bio_offset + done;
-		wp->data = bp->bio_data + done;
-		wp->length = bp->bio_length - done;
-		g_bde_map_sector(wp);
-		done += wp->length;
-		g_bde_start2(wp);
 	}
 	mtx_unlock(&sc->worklist_mutex);
 	return;