diff --git a/modules/lib/fs.lua b/modules/lib/fs.lua
index 385bacf..edc4822 100644
--- a/modules/lib/fs.lua
+++ b/modules/lib/fs.lua
@@ -16,11 +16,19 @@ do
   end
   return tacl
  end
- fs.parseacl = parseacl
- local function getattr(fn,k)
+ local function canread(fn)
   if os.getuid() ~= "superuser" then
    if not parseacl(fsattr[fn].read or "")[os.getuid()] then return false end
   end
+ end
+ local function canwrite(fn)
+  if os.getuid() ~= "superuser" then
+   if not parseacl(getattr(fn,"write"))[os.getuid()] then return false end
+  end
+ end
+ fs.parseacl = parseacl
+ local function getattr(fn,k)
+  if not canread(fn) then return false end
   if fsattr[fn] then
    return fsattr[fn][k]
   else
@@ -28,11 +36,9 @@ do
   end
  end
  local function setattr(fn,k,v)
+  if not canwrite(fn) then return false end
   if k:find("\t") or v:find("\t") then return false end
   log(parseacl(getattr(fn,"write"))[os.getuid()])
-  if os.getuid() ~= "superuser" then
-   if not parseacl(getattr(fn,"write"))[os.getuid()] then return false end
-  end
   if not fsattr[fn] then
    fsattr[fn] = {}
    setmetatable(fsattr[fn],{__index=dfsattr})