[NTOSKRNL:CC] Implemented CcCanIWrite and CcDeferWrite

NTOSKRNL/CC/ccutil.cpp

@@ -130,12 +130,120 @@ CcCanIWrite(
     _In_ PFILE_OBJECT FileObject,
     _In_ ULONG BytesToWrite,
     _In_ BOOLEAN Wait,
-    _In_ BOOLEAN IsRetrying)
+    _In_ UCHAR Retrying)
 {
-     NT_DBGBREAK("UNIMPLEMENTED\n");
+    PFSRTL_COMMON_FCB_HEADER FsContext;
-}
+    PSHARED_CACHE_MAP SharedCacheMap;
+    DEFERRED_WRITE DeferredWrite;
+    KEVENT Event;
+    ULONG WriteSize;
+    ULONG Pages;
+    KIRQL OldIrql;
+    BOOLEAN IsSmallThreshold = FALSE;
 
 
+    /* Quick checks for immediate return */
+    if (FileObject->Flags & FO_WRITE_THROUGH)
+        return TRUE;
+
+    if (IoIsFileOriginRemote(FileObject) && Retrying < 0xFD)
+        return TRUE;
+
+    /* Calculate size and pages */
+    WriteSize = min(BytesToWrite, 0x40000);
+    Pages = ROUND_UP(WriteSize, PAGE_SIZE) / PAGE_SIZE;
+
+    FsContext = FileObject->FsContext;
+
+    /* Check threshold conditions */
+    if (Retrying >= 0xFE || (FsContext->Flags & FSRTL_FLAG_LIMIT_MODIFIED_PAGES))
+    {
+        if (Retrying != 0xFF)
+        {
+            OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
+        }
+
+        if (FileObject->SectionObjectPointer)
+        {
+            SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
+            if (SharedCacheMap && 
+                SharedCacheMap->DirtyPageThreshold && 
+                SharedCacheMap->DirtyPages)
+            {
+                if (SharedCacheMap->DirtyPageThreshold < (SharedCacheMap->DirtyPages + Pages))
+                {
+                    IsSmallThreshold = TRUE;
+                }
+            }
+        }
+
+        if (Retrying != 0xFF)
+        {
+            KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
+        }
+    }
+
+    /* Check if we can write immediately */
+    if ((Retrying || IsListEmpty(&CcDeferredWrites)) &&
+        (CcDirtyPageThreshold > (CcTotalDirtyPages + Pages)))
+    {
+        if ((MmAvailablePages > MmThrottleTop && !IsSmallThreshold) ||
+            (MmModifiedPageListHead.Total < 1000 &&
+             MmAvailablePages > MmThrottleBottom &&
+             !IsSmallThreshold))
+        {
+            return TRUE;
+        }
+    }
+
+    if (!Wait)
+        return FALSE;
+
+    /* Initialize deferred write */
+    if (IsListEmpty(&CcDeferredWrites))
+    {
+        OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
+        CcScheduleLazyWriteScan(TRUE);
+        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
+    }
+
+    KeInitializeEvent(&Event, NotificationEvent, FALSE);
+
+    DeferredWrite.NodeTypeCode = NODE_TYPE_DEFERRED_WRITE;
+    DeferredWrite.NodeByteSize = sizeof(DEFERRED_WRITE);
+    DeferredWrite.FileObject = FileObject;
+    DeferredWrite.BytesToWrite = BytesToWrite;
+    DeferredWrite.Event = &Event;
+    DeferredWrite.LimitModifiedPages = (FsContext->Flags & FSRTL_FLAG_LIMIT_MODIFIED_PAGES) != 0;
+
+    /* Insert into deferred writes list */
+    /* Insert into deferred writes list */
+    if (Retrying)
+    {
+        ExInterlockedInsertHeadList(&CcDeferredWrites,
+                                  &DeferredWrite.DeferredWriteLinks,
+                                  &CcDeferredWriteSpinLock);
+    }
+    else
+    {
+        ExInterlockedInsertTailList(&CcDeferredWrites,
+                                  &DeferredWrite.DeferredWriteLinks,
+                                  &CcDeferredWriteSpinLock);
+    }
+
+    /* Wait for the write to complete */
+    do
+    {
+        CcPostDeferredWrites();
+    } while (KeWaitForSingleObject(&Event,
+                                 Executive,
+                                 KernelMode,
+                                 FALSE,
+                                 &CcIdleDelay) != STATUS_SUCCESS);
+
+    return TRUE;
+}
+
 
 BOOLEAN
 NTAPI
@@ -165,18 +273,53 @@ CcCopyWrite(
 
 
 VOID
-NTAPI
+CcDeferWrite(
-CcDeferWrite(IN PFILE_OBJECT FileObject,
+    _In_ PFILE_OBJECT FileObject,
-             IN PCC_POST_DEFERRED_WRITE PostRoutine,
+    _In_ PCC_POST_DEFERRED_WRITE PostRoutine,
-             IN PVOID Context1,
+    _In_ PVOID Context1,
-             IN PVOID Context2,
+    _In_ PVOID Context2,
-             IN ULONG BytesToWrite,
+    _In_ ULONG BytesToWrite,
-             IN BOOLEAN Retrying)
+    _In_ BOOLEAN Retrying
+    )
 {
-    NT_DBGBREAK("UNIMPLEMENTED\n");
+    
-}
+    KIRQL OldIrql;
 
 
+    PDEFERRED_WRITE  DeferredWrite = ExAllocatePoolWithTag(NonPagedPoolNx, sizeof(DEFERRED_WRITE), 'wDcC');
+    if (DeferredWrite != nullptr)
+    {
+        RtlZeroMemory(DeferredWrite, sizeof(DEFERRED_WRITE));
+
+        DeferredWrite->NodeTypeCode = NODE_TYPE_DEFERRED_WRITE;
+        DeferredWrite->NodeByteSize = sizeof(DEFERRED_WRITE);
+        DeferredWrite->FileObject = FileObject;
+        DeferredWrite->BytesToWrite = BytesToWrite;
+        DeferredWrite->PostRoutine = PostRoutine;
+        DeferredWrite->Context1 = Context1;
+        DeferredWrite->Context2 = Context2;
+
+        if (Retrying)
+            ExInterlockedInsertHeadList(&CcDeferredWrites, 
+                                        &DeferredWrite->DeferredWriteLinks, 
+                                        &CcDeferredWriteSpinLock);
+        else
+            ExInterlockedInsertTailList(&CcDeferredWrites, 
+                                        &DeferredWrite->DeferredWriteLinks, 
+                                        &CcDeferredWriteSpinLock);
+
+        CcPostDeferredWrites();
+
+        OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
+        CcScheduleLazyWriteScan(TRUE);
+        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
+    }
+    else
+    {
+        PostRoutine(Context1, Context2);
+    }
+}
+
 VOID
 NTAPI
 CcFastCopyRead(