diff --git a/common/xfs b/common/xfs
index ce49057c..5cd7b35c 100644
--- a/common/xfs
+++ b/common/xfs
@@ -1144,6 +1144,18 @@ _check_scratch_xfs_features()
 	test "${found}" -eq "$#"
 }
 
+# Skip a test if any of the given fs features aren't present on the scratch
+# filesystem.  The scratch fs must have been formatted already.
+_require_scratch_xfs_features()
+{
+	local features="$(_scratch_xfs_db -c 'version' 2>/dev/null)"
+
+	for feature in "$@"; do
+		echo "${features}" | grep -q -w "${feature}" ||
+			_notrun "Missing scratch feature: ${feature}"
+	done
+}
+
 # Decide if xfs_repair knows how to set (or clear) a filesystem feature.
 _require_xfs_repair_upgrade()
 {
diff --git a/tests/xfs/491 b/tests/xfs/491
index 6420202b..7d447ccf 100755
--- a/tests/xfs/491
+++ b/tests/xfs/491
@@ -36,6 +36,10 @@ _require_scratch
 
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
+
+# pre-lazysbcount filesystems blindly trust the primary sb fdblocks
+_require_scratch_xfs_features LAZYSBCOUNT
+
 _scratch_mount >> $seqres.full 2>&1
 echo "test file" > $SCRATCH_MNT/testfile
 
diff --git a/tests/xfs/492 b/tests/xfs/492
index 522def47..21c6872f 100755
--- a/tests/xfs/492
+++ b/tests/xfs/492
@@ -36,6 +36,10 @@ _require_scratch
 
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
+
+# pre-lazysbcount filesystems blindly trust the primary sb fdblocks
+_require_scratch_xfs_features LAZYSBCOUNT
+
 _scratch_mount >> $seqres.full 2>&1
 echo "test file" > $SCRATCH_MNT/testfile