Index: dirwr.c
===================================================================
--- drivers/filesystems/fastfat/dirwr.c	(revision 74351)
+++ drivers/filesystems/fastfat/dirwr.c	(working copy)
@@ -132,7 +132,7 @@
         Status = vfatUpdateFCB(DeviceExt, pFcb, &DirContext, pFcb->parentFcb);
         if (NT_SUCCESS(Status))
         {
-            CcPurgeCacheSection(&pFcb->parentFcb->SectionObjectPointers, NULL, 0, FALSE);
+            CcFlushCache(&pFcb->parentFcb->SectionObjectPointers, NULL, 0, NULL);
         }
 
         return Status;
@@ -987,7 +987,7 @@
     }
 
     OldParent = pFcb->parentFcb;
-    CcPurgeCacheSection(&OldParent->SectionObjectPointers, NULL, 0, FALSE);
+    CcFlushCache(&OldParent->SectionObjectPointers, NULL, 0, NULL);
     MoveContext.InPlace = (OldParent == ParentFcb);
 
     /* Add our new entry with our cluster */
@@ -999,7 +999,7 @@
                           *pFcb->Attributes,
                           &MoveContext);
 
-    CcPurgeCacheSection(&pFcb->parentFcb->SectionObjectPointers, NULL, 0, FALSE);
+    CcFlushCache(&pFcb->parentFcb->SectionObjectPointers, NULL, 0, NULL);
 
     return Status;
 }
Index: cc/fs.c
===================================================================
--- ntoskrnl/cc/fs.c	(revision 74317)
+++ ntoskrnl/cc/fs.c	(working copy)
@@ -269,7 +269,7 @@
     CCTRACE(CC_API_DEBUG, "FileObject=%p TruncateSize=%p UninitializeCompleteEvent=%p\n",
         FileObject, TruncateSize, UninitializeCompleteEvent);
 
-    Status = CcRosReleaseFileCache(FileObject);
+    Status = CcRosReleaseFileCache(FileObject, TruncateSize);
     if (UninitializeCompleteEvent)
         KeSetEvent(&UninitializeCompleteEvent->Event, IO_NO_INCREMENT, FALSE);
     return NT_SUCCESS(Status);
Index: cc/view.c
===================================================================
--- ntoskrnl/cc/view.c	(revision 74317)
+++ ntoskrnl/cc/view.c	(working copy)
@@ -129,6 +129,25 @@
 #endif
 }
 
+static
+VOID
+CcRosPurgeVacb (
+    _Inout_ PROS_VACB Vacb)
+{
+    KIRQL oldIrql;
+
+    KeAcquireGuardedMutex(&ViewLock);
+    KeAcquireSpinLock(&Vacb->SharedCacheMap->CacheMapLock, &oldIrql);
+
+    Vacb->Dirty = FALSE;
+    RemoveEntryList(&Vacb->DirtyVacbListEntry);
+    DirtyPageCount -= VACB_MAPPING_GRANULARITY / PAGE_SIZE;
+    CcRosVacbDecRefCount(Vacb);
+
+    KeReleaseSpinLock(&Vacb->SharedCacheMap->CacheMapLock, oldIrql);
+    KeReleaseGuardedMutex(&ViewLock);
+}
+
 NTSTATUS
 NTAPI
 CcRosFlushVacb (
@@ -885,6 +904,70 @@
     return STATUS_SUCCESS;
 }
 
+static
+NTSTATUS
+CcRosFlushOrPurge(
+    _Inout_ PROS_SHARED_CACHE_MAP SharedCacheMap,
+    _In_opt_ PLARGE_INTEGER FileOffset,
+    _In_ ULONG Length,
+    _In_ LONGLONG TruncateSize)
+{
+    NTSTATUS Status;
+    NTSTATUS FlushStatus;
+    LARGE_INTEGER Offset;
+    LONGLONG RemainingLength;
+    PROS_VACB current;
+    KIRQL oldIrql;
+
+    if (FileOffset)
+    {
+        Offset = *FileOffset;
+        RemainingLength = Length;
+    }
+    else
+    {
+        Offset.QuadPart = 0;
+        RemainingLength = SharedCacheMap->FileSize.QuadPart;
+    }
+
+    Status = STATUS_SUCCESS;
+    while (RemainingLength > 0)
+    {
+        current = CcRosLookupVacb(SharedCacheMap, Offset.QuadPart);
+        if (current != NULL)
+        {
+            if (current->Dirty)
+            {
+                if (current->FileOffset.QuadPart < TruncateSize)
+                {
+                    FlushStatus = CcRosFlushVacb(current);
+                    if (!NT_SUCCESS(FlushStatus))
+                    {
+                        Status = FlushStatus;
+                    }
+                }
+                else
+                {
+                    CcRosPurgeVacb(current);
+                }
+            }
+
+            CcRosReleaseVacbLock(current);
+
+            KeAcquireGuardedMutex(&ViewLock);
+            KeAcquireSpinLock(&SharedCacheMap->CacheMapLock, &oldIrql);
+            CcRosVacbDecRefCount(current);
+            KeReleaseSpinLock(&SharedCacheMap->CacheMapLock, oldIrql);
+            KeReleaseGuardedMutex(&ViewLock);
+        }
+
+        Offset.QuadPart += VACB_MAPPING_GRANULARITY;
+        RemainingLength -= min(RemainingLength, VACB_MAPPING_GRANULARITY);
+    }
+
+    return Status;
+}
+
 /*
  * @implemented
  */
@@ -896,12 +979,7 @@
     IN ULONG Length,
     OUT PIO_STATUS_BLOCK IoStatus)
 {
-    PROS_SHARED_CACHE_MAP SharedCacheMap;
-    LARGE_INTEGER Offset;
-    LONGLONG RemainingLength;
-    PROS_VACB current;
     NTSTATUS Status;
-    KIRQL oldIrql;
 
     CCTRACE(CC_API_DEBUG, "SectionObjectPointers=%p FileOffset=%p Length=%lu\n",
         SectionObjectPointers, FileOffset, Length);
@@ -911,51 +989,15 @@
 
     if (SectionObjectPointers && SectionObjectPointers->SharedCacheMap)
     {
-        SharedCacheMap = SectionObjectPointers->SharedCacheMap;
-        ASSERT(SharedCacheMap);
-        if (FileOffset)
-        {
-            Offset = *FileOffset;
-            RemainingLength = Length;
-        }
-        else
-        {
-            Offset.QuadPart = 0;
-            RemainingLength = SharedCacheMap->FileSize.QuadPart;
-        }
-
+        Status = CcRosFlushOrPurge(SectionObjectPointers->SharedCacheMap,
+                                   FileOffset,
+                                   Length,
+                                   MAXLONGLONG);
         if (IoStatus)
         {
-            IoStatus->Status = STATUS_SUCCESS;
+            IoStatus->Status = Status;
             IoStatus->Information = 0;
         }
-
-        while (RemainingLength > 0)
-        {
-            current = CcRosLookupVacb(SharedCacheMap, Offset.QuadPart);
-            if (current != NULL)
-            {
-                if (current->Dirty)
-                {
-                    Status = CcRosFlushVacb(current);
-                    if (!NT_SUCCESS(Status) && IoStatus != NULL)
-                    {
-                        IoStatus->Status = Status;
-                    }
-                }
-
-                CcRosReleaseVacbLock(current);
-
-                KeAcquireGuardedMutex(&ViewLock);
-                KeAcquireSpinLock(&SharedCacheMap->CacheMapLock, &oldIrql);
-                CcRosVacbDecRefCount(current);
-                KeReleaseSpinLock(&SharedCacheMap->CacheMapLock, oldIrql);
-                KeReleaseGuardedMutex(&ViewLock);
-            }
-
-            Offset.QuadPart += VACB_MAPPING_GRANULARITY;
-            RemainingLength -= min(RemainingLength, VACB_MAPPING_GRANULARITY);
-        }
     }
     else
     {
@@ -969,8 +1011,9 @@
 NTSTATUS
 NTAPI
 CcRosDeleteFileCache (
-    PFILE_OBJECT FileObject,
-    PROS_SHARED_CACHE_MAP SharedCacheMap)
+    _Inout_ PFILE_OBJECT FileObject,
+    _Inout_ PROS_SHARED_CACHE_MAP SharedCacheMap,
+    _In_opt_ PLARGE_INTEGER TruncateSize)
 /*
  * FUNCTION: Releases the shared cache map associated with a file object
  */
@@ -985,7 +1028,10 @@
     SharedCacheMap->RefCount++;
     KeReleaseGuardedMutex(&ViewLock);
 
-    CcFlushCache(FileObject->SectionObjectPointer, NULL, 0, NULL);
+    (VOID)CcRosFlushOrPurge(SharedCacheMap,
+                            NULL,
+                            0,
+                            TruncateSize ? TruncateSize->QuadPart : MAXLONGLONG);
 
     KeAcquireGuardedMutex(&ViewLock);
     SharedCacheMap->RefCount--;
@@ -1056,7 +1102,7 @@
     SharedCacheMap = SectionObjectPointer->SharedCacheMap;
     if (SharedCacheMap && SharedCacheMap->RefCount == 0)
     {
-        CcRosDeleteFileCache(SharedCacheMap->FileObject, SharedCacheMap);
+        CcRosDeleteFileCache(SharedCacheMap->FileObject, SharedCacheMap, NULL);
     }
     KeReleaseGuardedMutex(&ViewLock);
 }
@@ -1077,7 +1123,7 @@
         if (SharedCacheMap->RefCount == 0)
         {
             MmFreeSectionSegments(SharedCacheMap->FileObject);
-            CcRosDeleteFileCache(FileObject, SharedCacheMap);
+            CcRosDeleteFileCache(FileObject, SharedCacheMap, NULL);
         }
     }
     KeReleaseGuardedMutex(&ViewLock);
@@ -1086,7 +1132,8 @@
 NTSTATUS
 NTAPI
 CcRosReleaseFileCache (
-    PFILE_OBJECT FileObject)
+    _Inout_ PFILE_OBJECT FileObject,
+    _In_opt_ PLARGE_INTEGER TruncateSize)
 /*
  * FUNCTION: Called by the file system when a handle to a file object
  * has been closed.
@@ -1108,7 +1155,7 @@
                 if (SharedCacheMap->RefCount == 0)
                 {
                     MmFreeSectionSegments(SharedCacheMap->FileObject);
-                    CcRosDeleteFileCache(FileObject, SharedCacheMap);
+                    CcRosDeleteFileCache(FileObject, SharedCacheMap, TruncateSize);
                 }
             }
         }
Index: include/internal/cc.h
===================================================================
--- ntoskrnl/include/internal/cc.h	(revision 74317)
+++ ntoskrnl/include/internal/cc.h	(working copy)
@@ -334,7 +334,8 @@
 NTSTATUS
 NTAPI
 CcRosReleaseFileCache(
-    PFILE_OBJECT FileObject
+    _Inout_ PFILE_OBJECT FileObject,
+    _In_opt_ PLARGE_INTEGER TruncateSize
 );
 
 NTSTATUS