[NaCl SDK] Upate atomic ops in nacl_io

native_client_sdk/src/libraries/nacl_io/kernel_handle.h

Index: native_client_sdk/src/libraries/nacl_io/kernel_handle.h
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
index 64ef8abd15f3254ef72655b43eda35b9d041d6f4..0a374c4078bb8d05e0ea4a155573cf037355b43e 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
@@ -15,6 +15,7 @@
 #include "sdk_util/macros.h"
 #include "sdk_util/ref_object.h"
 #include "sdk_util/scoped_ref.h"
+#include "sdk_util/simple_lock.h"
 
 // KernelHandle provides a reference counted container for the open
 // file information, such as it's mount, node, access type and offset.
@@ -29,11 +30,20 @@ class KernelHandle : public RefObject {
   // Assumes |out_offset| is non-NULL.
   Error Seek(off_t offset, int whence, off_t* out_offset);
 
-  ScopedRef<Mount> mount_;
+  // Dispatches Read, Write, GetDents to atomically update offs_.
+  Error Read(void* buf, size_t nbytes, int* bytes_read);
+  Error Write(const void* buf, size_t nbytes, int* bytes_written);
+  Error GetDents(struct dirent* pdir, size_t count, int* bytes_written);
+
+  const ScopedRef<MountNode>& node();
+  const ScopedRef<Mount>& mount();
+
+private:
   ScopedRef<MountNode> node_;
+  ScopedRef<Mount> mount_;
+  SimpleLock offs_lock_;
   size_t offs_;
 
- private:
   friend class KernelProxy;
   DISALLOW_COPY_AND_ASSIGN(KernelHandle);
 };