6 files changed, 23 insertions, 7 deletions
diff --git a/src/core/lib/iomgr/call_combiner.h b/src/core/lib/iomgr/call_combiner.h
index 641fa18082..6f7ddd4043 100644
--- a/src/core/lib/iomgr/call_combiner.h
+++ b/src/core/lib/iomgr/call_combiner.h
@@ -102,7 +102,10 @@ void grpc_call_combiner_stop(grpc_call_combiner* call_combiner,
 /// If \a closure is NULL, then no closure will be invoked on
 /// cancellation; this effectively unregisters the previously set closure.
 /// However, most filters will not need to explicitly unregister their
-/// callbacks, as this is done automatically when the call is destroyed.
+/// callbacks, as this is done automatically when the call is destroyed. Filters
+/// that schedule the cancellation closure on ExecCtx do not need to take a ref
+/// on the call stack to guarantee closure liveness. This is done by explicitly
+/// flushing ExecCtx after the unregistration during call destruction.
 void grpc_call_combiner_set_notify_on_cancel(grpc_call_combiner* call_combiner,
                                              grpc_closure* closure);
 
diff --git a/src/core/lib/iomgr/iocp_windows.cc b/src/core/lib/iomgr/iocp_windows.cc
index ce77231036..ad325fe215 100644
--- a/src/core/lib/iomgr/iocp_windows.cc
+++ b/src/core/lib/iomgr/iocp_windows.cc
@@ -89,10 +89,15 @@ grpc_iocp_work_status grpc_iocp_work(grpc_millis deadline) {
   } else {
     abort();
   }
-  success = WSAGetOverlappedResult(socket->socket, &info->overlapped, &bytes,
-                                   FALSE, &flags);
-  info->bytes_transfered = bytes;
-  info->wsa_error = success ? 0 : WSAGetLastError();
+  if (socket->shutdown_called) {
+    info->bytes_transfered = 0;
+    info->wsa_error = WSA_OPERATION_ABORTED;
+  } else {
+    success = WSAGetOverlappedResult(socket->socket, &info->overlapped, &bytes,
+                                     FALSE, &flags);
+    info->bytes_transfered = bytes;
+    info->wsa_error = success ? 0 : WSAGetLastError();
+  }
   GPR_ASSERT(overlapped == &info->overlapped);
   grpc_socket_become_ready(socket, info);
   return GRPC_IOCP_WORK_WORK;
diff --git a/src/core/lib/iomgr/socket_windows.cc b/src/core/lib/iomgr/socket_windows.cc
index 4ad31cb35d..999c6646ad 100644
--- a/src/core/lib/iomgr/socket_windows.cc
+++ b/src/core/lib/iomgr/socket_windows.cc
@@ -52,6 +52,10 @@ grpc_winsocket* grpc_winsocket_create(SOCKET socket, const char* name) {
   return r;
 }
 
+SOCKET grpc_winsocket_wrapped_socket(grpc_winsocket* socket) {
+  return socket->socket;
+}
+
 /* Schedule a shutdown of the socket operations. Will call the pending
    operations to abort them. We need to do that this way because of the
    various callsites of that function, which happens to be in various
diff --git a/src/core/lib/iomgr/socket_windows.h b/src/core/lib/iomgr/socket_windows.h
index b09b9da562..46d7d58356 100644
--- a/src/core/lib/iomgr/socket_windows.h
+++ b/src/core/lib/iomgr/socket_windows.h
@@ -92,6 +92,8 @@ typedef struct grpc_winsocket {
    it will be responsible for closing it. */
 grpc_winsocket* grpc_winsocket_create(SOCKET socket, const char* name);
 
+SOCKET grpc_winsocket_wrapped_socket(grpc_winsocket* socket);
+
 /* Initiate an asynchronous shutdown of the socket. Will call off any pending
    operation to cancel them. */
 void grpc_winsocket_shutdown(grpc_winsocket* socket);
diff --git a/src/core/lib/iomgr/tcp_windows.cc b/src/core/lib/iomgr/tcp_windows.cc
index 5d316d477b..b3cb442f18 100644
--- a/src/core/lib/iomgr/tcp_windows.cc
+++ b/src/core/lib/iomgr/tcp_windows.cc
@@ -53,7 +53,7 @@
 
 extern grpc_core::TraceFlag grpc_tcp_trace;
 
-static grpc_error* set_non_block(SOCKET sock) {
+grpc_error* grpc_tcp_set_non_block(SOCKET sock) {
   int status;
   uint32_t param = 1;
   DWORD ret;
@@ -90,7 +90,7 @@ static grpc_error* enable_loopback_fast_path(SOCKET sock) {
 
 grpc_error* grpc_tcp_prepare_socket(SOCKET sock) {
   grpc_error* err;
-  err = set_non_block(sock);
+  err = grpc_tcp_set_non_block(sock);
   if (err != GRPC_ERROR_NONE) return err;
   err = set_dualstack(sock);
   if (err != GRPC_ERROR_NONE) return err;
diff --git a/src/core/lib/iomgr/tcp_windows.h b/src/core/lib/iomgr/tcp_windows.h
index 161a545a2a..04ef8102b6 100644
--- a/src/core/lib/iomgr/tcp_windows.h
+++ b/src/core/lib/iomgr/tcp_windows.h
@@ -46,6 +46,8 @@ grpc_endpoint* grpc_tcp_create(grpc_winsocket* socket,
 
 grpc_error* grpc_tcp_prepare_socket(SOCKET sock);
 
+grpc_error* grpc_tcp_set_non_block(SOCKET sock);
+
 #endif
 
 #endif /* GRPC_CORE_LIB_IOMGR_TCP_WINDOWS_H */