diff --git a/tests/shared/011 b/tests/shared/011
index a0ac375d..b4cdc5ed 100755
--- a/tests/shared/011
+++ b/tests/shared/011
@@ -39,11 +39,14 @@ rm -f $seqres.full
 # real QA test starts here
 
 # Modify as appropriate.
-_supported_fs ext4 btrfs
+_supported_fs generic
 _supported_os Linux
 _require_scratch
 _require_cgroup2 io
 
+# cgroup v2 writeback is only support on block devices so far
+_require_block_device $SCRATCH_DEV
+
 smajor=$((0x`stat -L -c %t $SCRATCH_DEV`))
 sminor=$((0x`stat -L -c %T $SCRATCH_DEV`))
 cgdir=$CGROUP2_PATH