From a66700e316301f0c894fc009507b831ec3cdcfdc Mon Sep 17 00:00:00 2001
From: Thomas Faber <thomas.faber@reactos.org>
Date: Wed, 5 Nov 2014 19:06:19 +0000
Subject: [PATCH] [FASTFAT] - Assert that we never reference or dereference an
 FCB with RefCount 0 CORE-8733

svn path=/trunk/; revision=65270
---
 reactos/drivers/filesystems/fastfat/fcb.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/reactos/drivers/filesystems/fastfat/fcb.c b/reactos/drivers/filesystems/fastfat/fcb.c
index d443be36aeb..f2a04e7b47b 100644
--- a/reactos/drivers/filesystems/fastfat/fcb.c
+++ b/reactos/drivers/filesystems/fastfat/fcb.c
@@ -295,6 +295,7 @@ vfatGrabFCB(
     ASSERT(ExIsResourceAcquiredExclusive(&pVCB->DirResource));
 
     ASSERT(pFCB != pVCB->VolumeFcb);
+    ASSERT(pFCB->RefCount > 0);
     ++pFCB->RefCount;
 }
 
@@ -313,6 +314,7 @@ vfatReleaseFCB(
     while (pFCB)
     {
         ASSERT(pFCB != pVCB->VolumeFcb);
+        ASSERT(pFCB->RefCount > 0);
         pFCB->RefCount--;
         if (pFCB->RefCount == 0)
         {
@@ -497,7 +499,6 @@ vfatFCBInitializeCacheFromVolume(
     fileObject->FsContext = fcb;
     fileObject->FsContext2 = newCCB;
     fcb->FileObject = fileObject;
-    vfatGrabFCB(vcb, fcb);
 
     _SEH2_TRY
     {
@@ -510,7 +511,6 @@ vfatFCBInitializeCacheFromVolume(
     _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
     {
         status = _SEH2_GetExceptionCode();
-        fcb->RefCount--;
         fcb->FileObject = NULL;
         ExFreeToNPagedLookasideList(&VfatGlobalData->CcbLookasideList, newCCB);
         ObDereferenceObject(fileObject);
@@ -518,6 +518,7 @@ vfatFCBInitializeCacheFromVolume(
     }
     _SEH2_END;
 
+    vfatGrabFCB(vcb, fcb);
     fcb->Flags |= FCB_CACHE_INITIALIZED;
     return STATUS_SUCCESS;
 }
@@ -663,7 +664,7 @@ vfatMakeFCBFromDirEntry(
     rcFCB->RFCB.FileSize.QuadPart = Size;
     rcFCB->RFCB.ValidDataLength.QuadPart = Size;
     rcFCB->RFCB.AllocationSize.QuadPart = ROUND_UP(Size, vcb->FatInfo.BytesPerCluster);
-    vfatGrabFCB(vcb, rcFCB);
+    rcFCB->RefCount = 1;
     if (vfatFCBIsDirectory(rcFCB))
     {
         vfatFCBInitializeCacheFromVolume(vcb, rcFCB);
-- 
2.17.1