1 files changed, 3 insertions, 1 deletions

diff --git a/src/System/Torrent/Storage.hs b/src/System/Torrent/Storage.hs
index 6dda07e1..5315d9dc 100644
--- a/src/System/Torrent/Storage.hs
+++ b/src/System/Torrent/Storage.hs
@@ -90,7 +90,9 @@ data Storage = Storage
 --   * when seeding, validation 'ReadOnly' mode.
 --
 open :: Mode -> PieceSize -> FileLayout FileSize -> IO Storage
-open mode s l = Storage mode s <$> mmapFiles mode l
+open mode s l
+  |   s <= 0  = throwIO (InvalidSize s)
+  | otherwise = Storage mode s <$> mmapFiles mode l
 
 -- | Unmaps all files forcefully. It is recommended but not required.
 close :: Storage -> IO ()