From 4f7be2806e672fa232e406ac5eec26789b9d5f85 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Sat, 24 Feb 2018 16:40:33 +0100
Subject: block: Deprecate "backing": ""

We have a clear replacement, so let's deprecate it.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20180224154033.29559-8-mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'block.c')

diff --git a/block.c b/block.c
index ab77ba0233..a2caadf0a0 100644
--- a/block.c
+++ b/block.c
@@ -2649,6 +2649,10 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
     if (qobject_to(QNull, qdict_get(options, "backing")) != NULL ||
         (backing && *backing == '\0'))
     {
+        if (backing) {
+            warn_report("Use of \"backing\": \"\" is deprecated; "
+                        "use \"backing\": null instead");
+        }
         flags |= BDRV_O_NO_BACKING;
         qdict_del(options, "backing");
     }
-- 
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