Fix "multisegment RAID1, allocator uses one disk for both legs"

In case of e.g. 3 PVs, creating or extending a RaidLV causes SubLV
collocation thus putting segments of diffent rimage (and potentially
larger rmeta) SubLVs onto the same PV.  For redundant RaidLVs this'll
compromise redundancy.  Fix by detecting such bogus allocation on
lvcreate/lvextend and reject the request.

1 files changed, 41 insertions, 0 deletions

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 298d307f3..9a9e547be 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -4454,6 +4454,38 @@ static int _lv_extend_layered_lv(struct alloc_handle *ah,
 	return 1;
 }
 
+/* Check either RAID images and metas are being allocated redundantly. */
+static int _lv_raid_redundant(struct logical_volume *lv,
+			      struct dm_list *allocatable_pvs, int meta)
+{
+	uint32_t nlvs, s;
+	struct lv_segment *seg = first_seg(lv);
+	struct pv_list *pvl;
+
+	if (meta && !seg->meta_areas)
+		return 1;
+
+	dm_list_iterate_items(pvl, allocatable_pvs) {
+		nlvs = 0;
+
+		for (s = 0; s < seg->area_count; s++) {
+			struct logical_volume *slv = meta ? seg_metalv(seg, s) : seg_lv(seg, s);
+
+			if (slv && lv_is_on_pv(slv, pvl->pv) && nlvs++)
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+/* Check both RAID images and metas are being allocated redundantly. */
+static int _lv_raid_redundant_allocation(struct logical_volume *lv, struct dm_list *allocatable_pvs)
+{
+	return _lv_raid_redundant(lv, allocatable_pvs, 0) &&
+	       _lv_raid_redundant(lv, allocatable_pvs, 1);
+}
+
 /*
  * Entry point for single-step LV allocation + extension.
  * Extents is the number of logical extents to append to the LV unless
@@ -4556,6 +4588,15 @@ int lv_extend(struct logical_volume *lv,
 						mirrors, stripes, stripe_size)))
 			goto_out;
 
+		if (segtype_is_raid(segtype) &&
+		    alloc != ALLOC_ANYWHERE &&
+		    !(r = _lv_raid_redundant_allocation(lv, allocatable_pvs))) {
+			log_error("Insufficient suitable allocatable extents for logical volume %s", display_lvname(lv));
+			if (!lv_remove(lv) || !vg_write(lv->vg) || !vg_commit(lv->vg))
+				return_0;
+			goto out;
+		}
+
 		if (lv_raid_has_integrity(lv)) {
 			if (!lv_extend_integrity_in_raid(lv, allocatable_pvs)) {
 				r = 0;