iolog: don't serialize the writing of all logs
Serialize based on filename, so that independent logs can be
written at the same time. If the logs are big, this can take
a while to flush to disk. It's silly to have all jobs waiting
on each other, when they could write their own logs independently.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/filelock.h b/filelock.h
new file mode 100644
index 0000000..97d13b7
--- /dev/null
+++ b/filelock.h
@@ -0,0 +1,11 @@
+#ifndef FIO_LOCK_FILE_H
+#define FIO_LOCK_FILE_H
+
+extern void fio_lock_file(const char *);
+extern int fio_trylock_file(const char *);
+extern void fio_unlock_file(const char *);
+
+extern int fio_filelock_init(void);
+extern void fio_filelock_exit(void);
+
+#endif