[PATCH 0/1] MR9431: ole32: implement proper file flushing in FileLockBytes

[Jiajin Cui (＠jin-king1)]

Previously the Flush method was a no-op that always returned S_OK
Now it properly calls FlushFileBuffers on the underlying file handle
This ensures that all buffered data is written to disk
Added error handling to return STG_E_WRITEFAULT on flush failures
This fixes potential data loss issues when using file-based lock bytes

Log: Fixed file flushing to prevent data loss in file operations

Signed-off-by: Jiajin Cui <cuijiajin(a)uniontech.com>

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9431

[PATCH 1/1] ole32: implement proper file flushing in FileLockBytes

[Jiajin Cui]

From: Jiajin Cui <cuijiajin(a)uniontech.com>

Previously the Flush method was a no-op that always returned S_OK
Now it properly calls FlushFileBuffers on the underlying file handle
This ensures that all buffered data is written to disk
Added error handling to return STG_E_WRITEFAULT on flush failures
This fixes potential data loss issues when using file-based lock bytes

Log: Fixed file flushing to prevent data loss in file operations

Signed-off-by: Jiajin Cui <cuijiajin(a)uniontech.com>
---
 dlls/ole32/filelockbytes.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/dlls/ole32/filelockbytes.c b/dlls/ole32/filelockbytes.c
index d806916f1d5..05de0a77f4b 100644
--- a/dlls/ole32/filelockbytes.c
+++ b/dlls/ole32/filelockbytes.c
@@ -279,6 +279,19 @@ static HRESULT WINAPI FileLockBytesImpl_WriteAt(
 
 static HRESULT WINAPI FileLockBytesImpl_Flush(ILockBytes* iface)
 {
+    FileLockBytesImpl *This = impl_from_ILockBytes(iface);
+
+    TRACE("(%p)\n", iface);
+
+    /* verify a sane environment */
+    if (!This) return E_FAIL;
+
+    if (This->flProtect != PAGE_READWRITE)
+        return STG_E_ACCESSDENIED;
+
+    if (!FlushFileBuffers(This->hfile))
+        return STG_E_WRITEFAULT;
+
     return S_OK;
 }
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/9431

[Esme Povirk (＠madewokherd)]

Esme Povirk (@madewokherd) commented about dlls/ole32/filelockbytes.c:
> static HRESULT WINAPI FileLockBytesImpl_Flush(ILockBytes* iface)
>  {
> +    FileLockBytesImpl *This = impl_from_ILockBytes(iface);
> +
> +    TRACE("(%p)\n", iface);
> +
> +    /* verify a sane environment */
> +    if (!This) return E_FAIL;
> +
> +    if (This->flProtect != PAGE_READWRITE)
> +        return STG_E_ACCESSDENIED;

I think we should have a test for this.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9431#note_121712