diff --git a/inc/winfsp/winfsp.h b/inc/winfsp/winfsp.h
index 7f77b64a..0ca965d9 100644
--- a/inc/winfsp/winfsp.h
+++ b/inc/winfsp/winfsp.h
@@ -105,7 +105,8 @@ typedef NTSTATUS FSP_FILE_SYSTEM_OPERATION(FSP_FILE_SYSTEM *,
  * The fine-grained concurrency model applies the exclusive-shared lock as
  * follows:
  * <ul>
- * <li>EXCL: SetVolumeLabel, Create, Cleanup(Delete), SetInformation(Rename)</li>
+ * <li>EXCL: SetVolumeLabel, Flush(Volume),
+ * Create, Cleanup(Delete), SetInformation(Rename)</li>
  * <li>SHRD: GetVolumeInfo, Open, SetInformation(Disposition), ReadDirectory</li>
  * <li>NONE: all other operations</li>
  * </ul>
diff --git a/src/dll/fsop.c b/src/dll/fsop.c
index 0fcd7d86..4805cb3f 100644
--- a/src/dll/fsop.c
+++ b/src/dll/fsop.c
@@ -29,7 +29,9 @@ FSP_API NTSTATUS FspFileSystemOpEnter(FSP_FILE_SYSTEM *FileSystem,
                 Request->Req.Cleanup.Delete) ||
             (FspFsctlTransactSetInformationKind == Request->Kind &&
                 10/*FileRenameInformation*/ == Request->Req.SetInformation.FileInformationClass) ||
-            FspFsctlTransactSetVolumeInformationKind == Request->Kind)
+            FspFsctlTransactSetVolumeInformationKind == Request->Kind ||
+            (FspFsctlTransactFlushBuffersKind == Request->Kind &&
+                0 == Request->Req.FlushBuffers.UserContext))
         {
             AcquireSRWLockExclusive(&FileSystem->OpGuardLock);
         }