+/*
+ Controls ongoing disk read-ahead operations during boot-up. The argument
+ must be a string, and either "cancel", "done" or "noreplay".
+
+ cancel = terminate read-ahead data collection, drop collected information
+ done = terminate read-ahead data collection, keep collected information
+ noreplay = terminate read-ahead replay
+*/
+int sd_readahead(const char *action);
+