From 4c433d800c5c5c31e72f69d8192b44dc3382ba02 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 18 Jun 2018 16:12:07 +0200
Subject: [PATCH 040/268] block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes

RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <20180618161212.14444-6-mreitz@redhat.com>
Patchwork-id: 80766
O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 05/10] block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes
Bugzilla: 1518738
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180421132929.21610-5-mreitz@redhat.com
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit 7adcf59fecf3c8ce9330430187350b53f9e50cf7)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/io.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/io.c b/block/io.c
index 134b2a4..fada4ef 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1115,13 +1115,15 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
                 /* FIXME: Should we (perhaps conditionally) be setting
                  * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
                  * that still correctly reads as zero? */
-                ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, pnum, 0);
+                ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, pnum,
+                                               BDRV_REQ_WRITE_UNCHANGED);
             } else {
                 /* This does not change the data on the disk, it is not
                  * necessary to flush even in cache=writethrough mode.
                  */
                 ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
-                                          &local_qiov, 0);
+                                          &local_qiov,
+                                          BDRV_REQ_WRITE_UNCHANGED);
             }
 
             if (ret < 0) {
-- 
1.8.3.1