Index: section.c
===================================================================
--- ntoskrnl/mm/ARM3/section.c	(revision 72853)
+++ ntoskrnl/mm/ARM3/section.c	(working copy)
@@ -1956,7 +1956,7 @@
                     IN PMMPTE PointerPte,
                     IN ULONG ProtectionMask,
                     IN PMMPFN Pfn1,
-                    IN BOOLEAN CaptureDirtyBit)
+                    IN BOOLEAN CheckForDirty)
 {
     MMPTE TempPte, PreviousPte;
     KIRQL OldIrql;
@@ -2030,9 +2030,24 @@
     ASSERT(PreviousPte.u.Hard.Valid == 1);
 
     //
-    // Windows updates the relevant PFN1 information, we currently don't.
+    // Mark the page as modified if dirty, and release page file space if appropriate
     //
-    if (CaptureDirtyBit) DPRINT1("Warning, not handling dirty bit\n");
+    if (CheckForDirty)
+    {
+        ASSERT(Pfn1 != NULL);
+        ASSERT(KeGetCurrentIrql() > APC_LEVEL);
+        if (!Pfn1->u3.e1.Modified && PreviousPte.u.Hard.Dirty)
+        {
+            ASSERT(Pfn1->u3.e1.Rom == 0);
+            Pfn1->u3.e1.Modified = 1;
+            if (!Pfn1->OriginalPte.u.Soft.Prototype &&
+                !Pfn1->u3.e1.WriteInProgress)
+            {
+                DPRINT1("Should call MiReleasePageFileSpace(Pfn1->OriginalPte)\n");
+                Pfn1->OriginalPte.u.Soft.PageFileHigh = 0;
+            }
+        }
+    }
 
     //
     // Not supported in ARM3