From d72fe2ee331e003551ea7ed70e0ca689118744d6 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Fri, 19 Nov 2021 17:16:36 +0000
Subject: [PATCH] sys: FspFsvolSetDispositionInformation: ignore
 FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK flag

---
 src/sys/fileinfo.c              | 26 ++++++++++++++++++--------
 tst/winfsp-tests/exec-test.c    | 21 +++++++++++++++++++++
 tst/winfsp-tests/winfsp-tests.h |  4 ++++
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/src/sys/fileinfo.c b/src/sys/fileinfo.c
index 3072cd17..34512f9d 100644
--- a/src/sys/fileinfo.c
+++ b/src/sys/fileinfo.c
@@ -1513,15 +1513,25 @@ retry:
         if (!NT_SUCCESS(Result))
             goto unlock_exit;
 
-        if (FlagOn(DispositionFlags, FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK))
+        /*
+         * Make sure no process is mapping the file as an image.
+         *
+         * NOTE:
+         *     Turns out that NTFS always does this test, even when
+         *     FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK has been specified.
+         *     If MmFlushImageSection fails (e.g. an actively running EXE) then
+         *     it only allows the deletion to go through when a secondary hard
+         *     link is being deleted.
+         *
+         *     Since WinFsp does not support hard links, we will go ahead and
+         *     ignore the FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK flag and
+         *     always respect the result of MmFlushImageSection.
+         */
+        Success = MmFlushImageSection(FileObject->SectionObjectPointer, MmFlushForDelete);
+        if (!Success)
         {
-            /* make sure no process is mapping the file as an image */
-            Success = MmFlushImageSection(FileObject->SectionObjectPointer, MmFlushForDelete);
-            if (!Success)
-            {
-                Result = STATUS_CANNOT_DELETE;
-                goto unlock_exit;
-            }
+            Result = STATUS_CANNOT_DELETE;
+            goto unlock_exit;
         }
 
         if (FlagOn(DispositionFlags, FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE))
diff --git a/tst/winfsp-tests/exec-test.c b/tst/winfsp-tests/exec-test.c
index c336bae2..b19bd1d1 100644
--- a/tst/winfsp-tests/exec-test.c
+++ b/tst/winfsp-tests/exec-test.c
@@ -200,6 +200,27 @@ static void exec_delete_dotest(ULONG Flags, PWSTR Prefix, ULONG FileInfoTimeout)
     ASSERT(!DeleteFileW(FilePath));
     ASSERT(ERROR_ACCESS_DENIED == GetLastError());
 
+    {
+        MY_FILE_DISPOSITION_INFO_EX DispositionInfo;
+        HANDLE Handle;
+        BOOLEAN Success;
+        Handle = CreateFileW(FilePath,
+            DELETE, FILE_SHARE_DELETE, 0,
+            OPEN_EXISTING, 0, 0);
+        if (INVALID_HANDLE_VALUE != Handle)
+        {
+            DispositionInfo.Disposition = FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS;
+            Success = SetFileInformationByHandle(Handle,
+                21/*FileDispositionInfoEx*/, &DispositionInfo, sizeof DispositionInfo);
+            ASSERT(!Success);
+            ASSERT(
+                ERROR_INVALID_PARAMETER == GetLastError() ||
+                ERROR_ACCESS_DENIED == GetLastError());
+            Success = CloseHandle(Handle);
+            ASSERT(Success);
+        }
+    }
+
     WaitHelper(Process, 1000);
 
     ASSERT(DeleteFileW(FilePath));
diff --git a/tst/winfsp-tests/winfsp-tests.h b/tst/winfsp-tests/winfsp-tests.h
index 63b603d0..a87fc463 100644
--- a/tst/winfsp-tests/winfsp-tests.h
+++ b/tst/winfsp-tests/winfsp-tests.h
@@ -154,6 +154,10 @@ typedef struct
 {
     BOOLEAN Disposition;
 } MY_FILE_DISPOSITION_INFO;
+typedef struct
+{
+    UINT32 Disposition;
+} MY_FILE_DISPOSITION_INFO_EX;
 
 void *memfs_start_ex(ULONG Flags, ULONG FileInfoTimeout);
 void *memfs_start(ULONG Flags);