diff --git a/src/filo-fs-ext2.adb b/src/filo-fs-ext2.adb
index 46cd4cc..d0f91cb 100644
--- a/src/filo-fs-ext2.adb
+++ b/src/filo-fs-ext2.adb
@@ -148,6 +148,38 @@
       Blockdev.Read (Buf, Blockdev_Length (FSBlock) * Block_Size, Success);
    end Read_FSBlock;
 
+   procedure Cache_FSBlock
+     (State       : in out T;
+      Phys        : in     FSBlock_Offset;
+      Level       : in     Block_Cache_Index;
+      Logical_Off : in     FSBlock_Logical;
+      Cache_Start :    out Max_Block_Index;
+      Cache_End   :    out Max_Block_Index;
+      Success     :    out Boolean)
+   with
+      Post => Cache_End = Cache_Start + 2 ** State.Block_Size_Bits
+   is
+      Block_Size : constant Natural := 2 ** State.Block_Size_Bits;
+      -- Limit cache usage depending on block size:
+      Max_Level   : constant Block_Cache_Index :=
+         2 ** (Log_Block_Size'Last - State.Block_Size_Bits) - 1;
+      Cache_Level : constant Block_Cache_Index :=
+         Block_Cache_Index'Min (Level, Max_Level);
+   begin
+      Cache_Start := Cache_Level * Block_Size;
+      Cache_End   := Cache_Start + Block_Size - 1;
+      if State.Block_Cache_Index (Cache_Level) = Logical_Off then
+         Success := True;
+      else
+         Read_FSBlock
+           (State    => State,
+            Buf      => State.Block_Cache (Cache_Start .. Cache_End),
+            FSBlock  => Phys,
+            Success  => Success);
+         State.Block_Cache_Index (Cache_Level) := Logical_Off;
+      end if;
+   end Cache_FSBlock;
+
    procedure Ext2_Block_Map
      (State       : in out T;
       Logical     : in     FSBlock_Logical;
@@ -169,30 +201,19 @@
       with
          Pre => FSBlock_Logical (Addr_In_Block) < Addr_Per_Block
       is
-         -- Limit cache usage depending on block size:
-         Max_Level   : constant Block_Cache_Index :=
-            2 ** (Log_Block_Size'Last - State.Block_Size_Bits) - 1;
-         Cache_Level : constant Block_Cache_Index :=
-            Block_Cache_Index'Min (Level, Max_Level);
-         Cache_Start : constant Index_Type := Cache_Level * Block_Size;
-         Cache_End   : constant Index_Type := Cache_Start + Block_Size - 1;
+         Cache_Start, Cache_End : Max_Block_Index;
       begin
-         if State.Block_Cache_Index (Cache_Level) /= Logical_Off then
-            Read_FSBlock
-              (State    => State,
-               Buf      => State.Block_Cache (Cache_Start .. Cache_End),
-               FSBlock  => Indirect_Block_Phys,
-               Success  => Success);
-            State.Block_Cache_Index (Cache_Level) := Logical_Off;
-            if not Success then
-               return;
-            end if;
-         end if;
-
+         Cache_FSBlock
+           (State       => State,
+            Phys        => Indirect_Block_Phys,
+            Level       => Level,
+            Logical_Off => Logical_Off,
+            Cache_Start => Cache_Start,
+            Cache_End   => Cache_End,
+            Success     => Success);
          Next_Physical := FSBlock_Offset (Read_LE32
            (Buf => State.Block_Cache (Cache_Start .. Cache_End),
             Off => Natural (Addr_In_Block) * 4));
-         Success := True;
       end Indirect_Block_Lookup;
 
       Logical_Rest : FSBlock_Logical := Logical;