From cda6b5ab7f5935565ed5b9bbc385bd1d0a3feb75 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Tue, 17 Apr 2018 00:33:14 +0200
Subject: dm delay: add flush as a third class of IO

Add a new class for dm-delay that delays flush requests.  Previously,
flushes were delayed as writes, but it caused problems if the user
needed to create a device with one or a few slow sectors for the purpose
of testing - all flushes would be forwarded to this device and delayed,
and that skews the test results.  Fix this by allowing to select 0 delay
for flushes.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 Documentation/device-mapper/delay.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'Documentation/device-mapper')

diff --git a/Documentation/device-mapper/delay.txt b/Documentation/device-mapper/delay.txt
index 4b1d22a44ce4..6426c45273cb 100644
--- a/Documentation/device-mapper/delay.txt
+++ b/Documentation/device-mapper/delay.txt
@@ -5,7 +5,8 @@ Device-Mapper's "delay" target delays reads and/or writes
 and maps them to different devices.
 
 Parameters:
-    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
+    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>
+			       [<flush_device> <flush_offset> <flush_delay>]]
 
 With separate write parameters, the first set is only used for reads.
 Offsets are specified in sectors.
-- 
cgit v1.2.3