From a275fa42fa872828585e9e6a92f975e87776554b Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 8 May 2012 16:51:43 +0200
Subject: [PATCH] block: do not reuse the backing file across
 bdrv_close/bdrv_open

This is another bug caused by not doing a full cleanup of the BDS
across close/open.  This was found with mirroring by Shaolong Hu,
but it can probably be reproduced also with eject or change.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block.c b/block.c
index 6dc0d4486e..271f109cbe 100644
--- a/block.c
+++ b/block.c
@@ -878,6 +878,8 @@ void bdrv_close(BlockDriverState *bs)
         bs->opaque = NULL;
         bs->drv = NULL;
         bs->copy_on_read = 0;
+        bs->backing_file[0] = '\0';
+        bs->backing_format[0] = '\0';
 
         if (bs->file != NULL) {
             bdrv_close(bs->file);