From: Jonathan Brassow <jbrassow@redhat.com>
Subject: [PATCH rhel 5.1] bz 241006 incorrect parameter to dm_io causes 	read failures
Date: Wed, 23 May 2007 11:58:43 -0500
Bugzilla: 241006
Message-Id: <1179939523.25041.8.camel@hydrogen.msp.redhat.com>
Changelog: [md] incorrect parameter to dm_io causes read failures


Writes to mirrors go to all devices, but reads only come from one.
However, the dm_io call from read_async_bio specifies m->ms->nr_mirrors
as the number of requests... causing an error to be returned.

This happens when reads are requested from mirror regions which are not
in-sync.

 brassow

Index: linux-rhel5/drivers/md/dm-raid1.c
===================================================================
--- linux-rhel5.orig/drivers/md/dm-raid1.c
+++ linux-rhel5/drivers/md/dm-raid1.c
@@ -964,7 +964,7 @@ static void read_async_bio(struct mirror
 
 	map_region(&io, m, bio);
 	bio_set_m(bio, m);
-	(void) dm_io(&io_req, m->ms->nr_mirrors, &io, NULL);
+	(void) dm_io(&io_req, 1, &io, NULL);
 }
 
 static void do_reads(struct mirror_set *ms, struct bio_list *reads)