diff --git a/btrbk b/btrbk
index 38c47dc..880d1b7 100755
--- a/btrbk
+++ b/btrbk
@@ -80,11 +80,11 @@ my %config_options = (
   incremental                 => { default => "yes",     accept => [ "yes", "no", "strict" ] },
   resume_missing              => { default => "yes",     accept => [ "yes", "no" ] },
   preserve_day_of_week        => { default => "sunday",  accept => [ (keys %day_of_week_map) ] },
-  snapshot_preserve_daily     => { default => "all",     accept => [ "all" ], accept_numeric => 1  },
-  snapshot_preserve_weekly    => { default => 0,         accept => [ "all" ], accept_numeric => 1  },
-  snapshot_preserve_monthly   => { default => "all",     accept => [ "all" ], accept_numeric => 1  },
-  snapshot_preserve_yearly    => { default => "0",       accept => [ "all" ], accept_numeric => 1  },
-  snapshot_preserve           => { shortcut => 1,        accept_preserve_matrix => 1, },
+  snapshot_preserve_daily     => { default => "all",     accept => [ "all" ], accept_numeric => 1, context => [ "root", "volume", "subvolume" ]  },
+  snapshot_preserve_weekly    => { default => 0,         accept => [ "all" ], accept_numeric => 1, context => [ "root", "volume", "subvolume" ]  },
+  snapshot_preserve_monthly   => { default => "all",     accept => [ "all" ], accept_numeric => 1, context => [ "root", "volume", "subvolume" ]  },
+  snapshot_preserve_yearly    => { default => "0",       accept => [ "all" ], accept_numeric => 1, context => [ "root", "volume", "subvolume" ]  },
+  snapshot_preserve           => { shortcut => 1,        accept_preserve_matrix => 1,              context => [ "root", "volume", "subvolume" ], },
   target_preserve_daily       => { default => "all",     accept => [ "all" ], accept_numeric => 1  },
   target_preserve_weekly      => { default => 0,         accept => [ "all" ], accept_numeric => 1  },
   target_preserve_monthly     => { default => "all",     accept => [ "all" ], accept_numeric => 1  },