[edk2-platforms][PATCH v3 10/11] Ext4Pkg: Fixes build on MSVC

["Savva Mitrofanov" <savvamtr@gmail.com>]

Accessing array using index of uint64 type makes MSVC compiler to
include `__allmul` function in NOOPT which is not referenced in IA32.
So we null-terminates string using ReadSize, which should be equal to
SymlinkSizeTmp after correct reading. Also adds missing MultU64x32
in Ext4Read.

Cc: Marvin Häuser <mhaeuser@posteo.de>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vitaly Cheptsov <vit9696@protonmail.com>
Fixes: 7c46116b0e18 ("Ext4Pkg: Add ext2/3 support")
Fixes: e81432fbacb7 ("Ext4Pkg: Add symbolic links support")
Signed-off-by: Savva Mitrofanov <savvamtr@gmail.com>
---
 Features/Ext4Pkg/Ext4Dxe/Inode.c   |  4 ++--
 Features/Ext4Pkg/Ext4Dxe/Symlink.c | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Features/Ext4Pkg/Ext4Dxe/Inode.c b/Features/Ext4Pkg/Ext4Dxe/Inode.c
index 90e3eb88f523..8db051d3c444 100644
--- a/Features/Ext4Pkg/Ext4Dxe/Inode.c
+++ b/Features/Ext4Pkg/Ext4Dxe/Inode.c
@@ -152,7 +152,7 @@ Ext4Read (
       } else {
         // Uninitialized extents behave exactly the same as file holes, except they have
         // blocks already allocated to them.
-        HoleLen = (Ext4GetExtentLength (&Extent) * Partition->BlockSize) - HoleOff;
+        HoleLen = MultU64x32 (Ext4GetExtentLength (&Extent), Partition->BlockSize) - HoleOff;
       }
 
       WasRead = HoleLen > RemainingRead ? RemainingRead : (UINTN)HoleLen;
@@ -166,7 +166,7 @@ Ext4Read (
                            Partition->BlockSize
                            );
       ExtentLengthBytes  = Extent.ee_len * Partition->BlockSize;
-      ExtentLogicalBytes = (UINT64)Extent.ee_block * Partition->BlockSize;
+      ExtentLogicalBytes = MultU64x32 ((UINT64)Extent.ee_block, Partition->BlockSize);
       ExtentOffset       = CurrentSeek - ExtentLogicalBytes;
       ExtentMayRead      = (UINTN)(ExtentLengthBytes - ExtentOffset);
 
diff --git a/Features/Ext4Pkg/Ext4Dxe/Symlink.c b/Features/Ext4Pkg/Ext4Dxe/Symlink.c
index 19b357ac6ba0..8b1511a38b55 100644
--- a/Features/Ext4Pkg/Ext4Dxe/Symlink.c
+++ b/Features/Ext4Pkg/Ext4Dxe/Symlink.c
@@ -1,7 +1,7 @@
 /** @file
   Symbolic links routines
 
-  Copyright (c) 2022 Savva Mitrofanov All rights reserved.
+  Copyright (c) 2022-2023 Savva Mitrofanov All rights reserved.
   SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
 
@@ -155,11 +155,6 @@ Ext4ReadSlowSymlink (
     return Status;
   }
 
-  //
-  // Add null-terminator
-  //
-  SymlinkTmp[SymlinkSizeTmp] = '\0';
-
   if (SymlinkSizeTmp != ReadSize) {
     DEBUG ((
       DEBUG_FS,
@@ -168,6 +163,11 @@ Ext4ReadSlowSymlink (
     return EFI_VOLUME_CORRUPTED;
   }
 
+  //
+  // Add null-terminator
+  //
+  SymlinkTmp[ReadSize] = '\0';
+
   *AsciiSymlinkSize = SymlinkAllocateSize;
   *AsciiSymlink     = SymlinkTmp;
 
-- 
2.39.0