Added get_open_fd() function which gets the descriptor and also

increments its open count.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25317 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/fs/fd.cpp

@@ -303,6 +303,21 @@ get_fd(struct io_context *context, int fd)
 }
 
 
+struct file_descriptor *
+get_open_fd(struct io_context *context, int fd)
+{
+	MutexLocker(context->io_mutex);
+
+	file_descriptor *descriptor = get_fd_locked(context, fd);
+	if (descriptor == NULL)
+		return NULL;
+
+	atomic_add(&descriptor->open_count, 1);
+
+	return descriptor;
+}
+
+
 /**	Removes the file descriptor from the specified slot.
  */