From a1401a75772f489bb59c895b33e1f192ebde5fc8 Mon Sep 17 00:00:00 2001
From: Pierre Schweitzer <pierre@reactos.org>
Date: Wed, 3 Oct 2018 10:21:39 +0200
Subject: [PATCH] [NTOSKRNL] Use faster internal helper to query name

This only applies if we're called from kernel mode
with a synchronous file.
---
 ntoskrnl/include/internal/io.h | 10 ++++++++++
 ntoskrnl/io/iomgr/file.c       | 22 +++++++++++++++++-----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/ntoskrnl/include/internal/io.h b/ntoskrnl/include/internal/io.h
index 29ecb808f91..95e3607bb56 100644
--- a/ntoskrnl/include/internal/io.h
+++ b/ntoskrnl/include/internal/io.h
@@ -1276,6 +1276,16 @@ IoComputeDesiredAccessFileObject(
     IN PACCESS_MASK DesiredAccess
 );
 
+NTSTATUS
+NTAPI
+IopGetFileInformation(
+    IN PFILE_OBJECT FileObject,
+    IN ULONG Length,
+    IN FILE_INFORMATION_CLASS FileInfoClass,
+    OUT PVOID Buffer,
+    OUT PULONG ReturnedLength
+);
+
 //
 // I/O Timer Routines
 //
diff --git a/ntoskrnl/io/iomgr/file.c b/ntoskrnl/io/iomgr/file.c
index 4cbdb640a1a..e877888c74d 100644
--- a/ntoskrnl/io/iomgr/file.c
+++ b/ntoskrnl/io/iomgr/file.c
@@ -1941,11 +1941,23 @@ IopQueryNameInternal(IN PVOID ObjectBody,
                  FIELD_OFFSET(FILE_NAME_INFORMATION, FileName);
 
     /* Query the File name */
-    Status = IoQueryFileInformation(FileObject,
-                                    FileNameInformation,
-                                    LengthMismatch ? Length : FileLength,
-                                    LocalFileInfo,
-                                    &LocalReturnLength);
+    if (PreviousMode == KernelMode &&
+        BooleanFlagOn(FileObject->Flags, FO_SYNCHRONOUS_IO))
+    {
+        Status = IopGetFileInformation(FileObject,
+                                       LengthMismatch ? Length : FileLength,
+                                       FileNameInformation,
+                                       LocalFileInfo,
+                                       &LocalReturnLength);
+    }
+    else
+    {
+        Status = IoQueryFileInformation(FileObject,
+                                        FileNameInformation,
+                                        LengthMismatch ? Length : FileLength,
+                                        LocalFileInfo,
+                                        &LocalReturnLength);
+    }
     if (NT_ERROR(Status))
     {
         /* Fail on errors only, allow warnings */