From 568062cf9d60d52ab3a43ffcd2f7cc43d35bfbb8 Mon Sep 17 00:00:00 2001
From: "Herman S." <429230+has207@users.noreply.github.com>
Date: Tue, 7 Oct 2025 10:33:17 +0900
Subject: [PATCH] [Kernel] Implement XFileAllocationInformation

---
 src/xenia/kernel/info/file.h                  |  6 ++++++
 src/xenia/kernel/xboxkrnl/xboxkrnl_io_info.cc | 14 ++++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/xenia/kernel/info/file.h b/src/xenia/kernel/info/file.h
index 813e4bd2d..06eb791c5 100644
--- a/src/xenia/kernel/info/file.h
+++ b/src/xenia/kernel/info/file.h
@@ -101,6 +101,12 @@ struct X_FILE_END_OF_FILE_INFORMATION {
 };
 static_assert_size(X_FILE_END_OF_FILE_INFORMATION, 8);
 
+// https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/ntifs/ns-ntifs-_file_allocation_information
+struct X_FILE_ALLOCATION_INFORMATION {
+  be<uint64_t> allocation_size;
+};
+static_assert_size(X_FILE_ALLOCATION_INFORMATION, 8);
+
 struct X_FILE_XCTD_COMPRESSION_INFORMATION {
   be<uint32_t> unknown;
 };
diff --git a/src/xenia/kernel/xboxkrnl/xboxkrnl_io_info.cc b/src/xenia/kernel/xboxkrnl/xboxkrnl_io_info.cc
index cb651489e..f3bf9eabd 100644
--- a/src/xenia/kernel/xboxkrnl/xboxkrnl_io_info.cc
+++ b/src/xenia/kernel/xboxkrnl/xboxkrnl_io_info.cc
@@ -158,12 +158,14 @@ uint32_t GetSetFileInfoMinimumLength(uint32_t info_class) {
       return sizeof(X_FILE_POSITION_INFORMATION);
     case XFileCompletionInformation:
       return sizeof(X_FILE_COMPLETION_INFORMATION);
+    case XFileAllocationInformation:
+      return sizeof(X_FILE_ALLOCATION_INFORMATION);
+    case XFileEndOfFileInformation:
+      return sizeof(X_FILE_END_OF_FILE_INFORMATION);
     // TODO(gibbed): structures to get the size of.
     case XFileModeInformation:
     case XFileIoPriorityInformation:
       return 4;
-    case XFileAllocationInformation:
-    case XFileEndOfFileInformation:
     case XFileMountPartitionInformation:
       return 8;
     case XFileLinkInformation:
@@ -258,8 +260,12 @@ dword_result_t NtSetInformationFile_entry(
       break;
     }
     case XFileAllocationInformation: {
-      XELOGW("NtSetInformationFile ignoring alloc");
-      out_length = 8;
+      auto info = info_ptr.as<X_FILE_ALLOCATION_INFORMATION*>();
+      result = file->SetLength(info->allocation_size);
+      out_length = sizeof(*info);
+
+      // Update the files vfs::Entry information
+      file->entry()->update();
       break;
     }
     case XFileEndOfFileInformation: {