Return error when opening read-only volumes (like RAID4/5/...) for writing.

Previously opens succeeded, but actual write operations returned errors.

Requested by:	peter
MFC after:	2 weeks

3 files changed, 8 insertions, 1 deletions

diff --git a/sys/geom/raid/g_raid.c b/sys/geom/raid/g_raid.c
index fd6d69c..41a1f96 100644
--- a/sys/geom/raid/g_raid.c
+++ b/sys/geom/raid/g_raid.c
@@ -1863,6 +1863,11 @@ g_raid_access(struct g_provider *pp, int acr, int acw, int ace)
 		error = ENXIO;
 		goto out;
 	}
+	/* Deny write opens for read-only volumes. */
+	if (vol->v_read_only && acw > 0) {
+		error = EROFS;
+		goto out;
+	}
 	if (dcw == 0)
 		g_raid_clean(vol, dcw);
 	vol->v_provider_open += acr + acw + ace;
diff --git a/sys/geom/raid/g_raid.h b/sys/geom/raid/g_raid.h
index 183edff6..993b100 100644
--- a/sys/geom/raid/g_raid.h
+++ b/sys/geom/raid/g_raid.h
@@ -306,6 +306,7 @@ struct g_raid_volume {
 	int			 v_stopping;	/* Volume is stopping */
 	int			 v_provider_open; /* Number of opens. */
 	int			 v_global_id;	/* Global volume ID (rX). */
+	int			 v_read_only;	/* Volume is read-only. */
 	TAILQ_ENTRY(g_raid_volume)	 v_next; /* List of volumes entry. */
 	LIST_ENTRY(g_raid_volume)	 v_global_next; /* Global list entry. */
 };
diff --git a/sys/geom/raid/tr_raid5.c b/sys/geom/raid/tr_raid5.c
index 989343b..6e54d16 100644
--- a/sys/geom/raid/tr_raid5.c
+++ b/sys/geom/raid/tr_raid5.c
@@ -185,8 +185,9 @@ g_raid_tr_start_raid5(struct g_raid_tr_object *tr)
 	struct g_raid_volume *vol;
 
 	trs = (struct g_raid_tr_raid5_object *)tr;
-	vol = tr->tro_volume;
 	trs->trso_starting = 0;
+	vol = tr->tro_volume;
+	vol->v_read_only = 1;
 	g_raid_tr_update_state_raid5(vol, NULL);
 	return (0);
 }