From: Jens Axboe <axboe@fb.com>
Date: Tue, 28 Apr 2015 21:30:02 +0000 (-0600)
Subject: blktrace: only set O_DIRECT if the min bs is a multiple of 4k
X-Git-Tag: fio-2.2.8~23
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=76a00ec6684317902e536365b89531431e7f8867

blktrace: only set O_DIRECT if the min bs is a multiple of 4k

Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/blktrace.c b/blktrace.c
index 8ffa9b0e..bb0bcbe6 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -503,9 +503,10 @@ int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 
 	/*
 	 * We need to do direct/raw ios to the device, to avoid getting
-	 * read-ahead in our way.
+	 * read-ahead in our way. But only do so if the minimum block size
+	 * is a multiple of 4k, otherwise we don't know if it's safe to do so.
 	 */
-	if (!fio_option_is_set(&td->o, odirect))
+	if (!fio_option_is_set(&td->o, odirect) && !(td_min_bs(td) & 4095))
 		td->o.odirect = 1;
 
 	/*