[PATCH] Change O_DIRECT vs buffered setup

Change the default from O_DIRECT IO to normal buffered IO. That makes
more sense, as O_DIRECT is a special case and should be manually
enabled as such.

Do this by adding a option negate switch, so we don't need two sets
of parameters to control these options.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/parse.h b/parse.h
index 4ddb76a..7374c25 100644
--- a/parse.h
+++ b/parse.h
@@ -29,6 +29,7 @@
 	unsigned int off4;
 	unsigned int maxval;		/* max and min value */
 	int minval;
+	int neg;			/* negate value stored */
 	void *cb;			/* callback */
 	const char *help;		/* help text for option */
 	const char *def;		/* default setting */