- Fix an issue with access permissions to underlying disks used by a gvinum

  plex. If the plex is a raid5 plex, and is being written to, parity data might
  have to be read from the underlying disks, requiring them to be opened for
  reading as well as writing.

MFC after:	1 week

1 files changed, 10 insertions, 0 deletions

diff --git a/sys/geom/vinum/geom_vinum_plex.c b/sys/geom/vinum/geom_vinum_plex.c
index 424e95a..8281cb2 100644
--- a/sys/geom/vinum/geom_vinum_plex.c
+++ b/sys/geom/vinum/geom_vinum_plex.c
@@ -663,11 +663,21 @@ gv_plex_normal_request(struct gv_plex *p, struct bio *bp)
 static int
 gv_plex_access(struct g_provider *pp, int dr, int dw, int de)
 {
+	struct gv_plex *p;
 	struct g_geom *gp;
 	struct g_consumer *cp, *cp2;
 	int error;
 
 	gp = pp->geom;
+	p = gp->softc;
+	KASSERT(p != NULL, ("NULL p"));
+
+	if (p->org == GV_PLEX_RAID5) {
+		if (dw > 0 && dr == 0)
+			dr = 1;
+		else if (dw < 0 && dr == 0)
+			dr = -1;
+	}
 
 	LIST_FOREACH(cp, &gp->consumer, consumer) {
 		error = g_access(cp, dr, dw, de);