[tfaber] 73072: [FASTFAT] - Only lock down the user buffer in the non-cached read/write case. CcCopyRead/CcCopyWrite takes care of this in the cached case, and does not impose a size limit like an ...

Author: tfaber
Date: Sat Oct 29 20:30:49 2016
New Revision: 73072

URL: http://svn.reactos.org/svn/reactos?rev=73072&view=rev
Log:
[FASTFAT]
- Only lock down the user buffer in the non-cached read/write case. CcCopyRead/CcCopyWrite
takes care of this in the cached case, and does not impose a size limit like an MDL does.
CORE-12132 #resolve

Modified:
    trunk/reactos/drivers/filesystems/fastfat/rw.c

Modified: trunk/reactos/drivers/filesystems/fastfat/rw.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/filesystems/fastfa…
==============================================================================
--- trunk/reactos/drivers/filesystems/fastfat/rw.c	[iso-8859-1] (original)
+++ trunk/reactos/drivers/filesystems/fastfat/rw.c	[iso-8859-1] Sat Oct 29 20:30:49 2016
@@ -656,11 +656,6 @@
     }
 
     Buffer = VfatGetUserBuffer(IrpContext->Irp,
BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
-    Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoWriteAccess);
-    if (!NT_SUCCESS(Status))
-    {
-        goto ByeBye;
-    }
 
     if (!(IrpContext->Irp->Flags & (IRP_NOCACHE|IRP_PAGING_IO)) &&
         !(Fcb->Flags & (FCB_IS_PAGE_FILE|FCB_IS_VOLUME)))
@@ -711,6 +706,12 @@
     else
     {
         // non cached read
+        Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoWriteAccess);
+        if (!NT_SUCCESS(Status))
+        {
+            goto ByeBye;
+        }
+
         if (ByteOffset.QuadPart + Length > ROUND_UP_64(Fcb->RFCB.FileSize.QuadPart,
BytesPerSector))
         {
             Length = (ULONG)(ROUND_UP_64(Fcb->RFCB.FileSize.QuadPart, BytesPerSector)
- ByteOffset.QuadPart);
@@ -921,12 +922,6 @@
     }
 
     Buffer = VfatGetUserBuffer(IrpContext->Irp,
BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
-    Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
-    if (!NT_SUCCESS(Status))
-    {
-        Status = STATUS_INVALID_USER_BUFFER;
-        goto ByeBye;
-    }
 
     if (!(Fcb->Flags & (FCB_IS_FAT|FCB_IS_VOLUME)) &&
         !(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
@@ -987,6 +982,12 @@
     else
     {
         // non cached write
+        Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
+        if (!NT_SUCCESS(Status))
+        {
+            Status = STATUS_INVALID_USER_BUFFER;
+            goto ByeBye;
+        }
 
         if (ByteOffset.QuadPart > OldFileSize.QuadPart)
         {