diff --git a/include/crucible/fs.h b/include/crucible/fs.h
index 0cb5275..01bef77 100644
--- a/include/crucible/fs.h
+++ b/include/crucible/fs.h
@@ -192,6 +192,9 @@ namespace crucible {
 		// Copy objectid/type/offset so we move forward
 		void next_min(const BtrfsIoctlSearchHeader& ref);
 
+		// move forward to next object of a single type
+		void next_min(const BtrfsIoctlSearchHeader& ref, const uint8_t type);
+
 		size_t m_buf_size;
 		set<BtrfsIoctlSearchHeader> m_result;
 	};
diff --git a/lib/fs.cc b/lib/fs.cc
index c3ae00f..db10b13 100644
--- a/lib/fs.cc
+++ b/lib/fs.cc
@@ -823,8 +823,46 @@ namespace crucible {
 		min_type = ref.type;
 		min_offset = ref.offset + 1;
 		if (min_offset < ref.offset) {
-			// We wrapped, try the next objectid
-			++min_objectid;
+			// We wrapped, try the next type
+			++min_type;
+			assert(min_offset == 0);
+			if (min_type < ref.type) {
+				assert(min_type == 0);
+				// We wrapped, try the next objectid
+				++min_objectid;
+				// no advancement possible at end
+				THROW_CHECK1(runtime_error, min_type, min_type == 0);
+			}
+		}
+	}
+
+	void
+	BtrfsIoctlSearchKey::next_min(const BtrfsIoctlSearchHeader &ref, const uint8_t type)
+	{
+		if (ref.type < type) {
+			// forward to type in same object with zero offset
+			min_objectid = ref.objectid;
+			min_type = type;
+			min_offset = 0;
+		} else if (ref.type > type) {
+			// skip directly to start of next objectid with target type
+			min_objectid = ref.objectid + 1;
+			// no advancement possible at end
+			THROW_CHECK2(out_of_range, min_objectid, ref.objectid, min_objectid > ref.objectid);
+			min_type = type;
+			min_offset = 0;
+		} else {
+			// advance within this type
+			min_objectid = ref.objectid;
+			min_type = ref.type;
+			min_offset = ref.offset + 1;
+			if (min_offset < ref.offset) {
+				// We wrapped, try the next objectid, same type
+				++min_objectid;
+				THROW_CHECK2(out_of_range, min_objectid, ref.objectid, min_objectid > ref.objectid);
+				min_type = type;
+				assert(min_offset == 0);
+			}
 		}
 	}