File libvirt-qemu-Stop-recursive-detection-of-image-chains-when-an-image-is-missing.patch of Package libvirt

From 54eb1126f0c4f4fc05edb3926a7a60d3a01892bc Mon Sep 17 00:00:00 2001
Message-Id: <54eb1126f0c4f4fc05edb3926a7a60d3a01892bc.1353944810.git.jdenemar@redhat.com>
From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 22 Nov 2012 17:42:10 +0100
Subject: [PATCH] qemu: Stop recursive detection of image chains when an image
 is missing

https://bugzilla.redhat.com/show_bug.cgi?id=878862

Commit e0c469e58b93f852a72265919703cb6abd3779f8 that fixes the detection
of image chain wasn't complete. Iteration through the backing image
chain has to stop at the last existing image if some of the images are
missing otherwise the backing chain that is cached contains entries with
paths being set to NULL resulting to:

error: Unable to allow access for disk path (null): Bad address

Fortunately stat() is kind enough not to crash when it's presented with
a NULL argument. At least on Linux.
(cherry picked from commit 58a54dc37340113f83da587387a297d05d5342cf)
---
 src/util/storage_file.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/util/storage_file.c b/src/util/storage_file.c
index 54b9ea0..50f64ae 100644
--- a/src/util/storage_file.c
+++ b/src/util/storage_file.c
@@ -728,8 +728,13 @@ virStorageFileGetMetadataFromBuf(int format,
                 meta->backingStore = absolutePathFromBaseFile(path, backing);
                 if (meta->backingStore == NULL) {
                     /* the backing file is (currently) unavailable, treat this
-                     * file as standalone */
+                     * file as standalone:
+                     * backingStoreRaw is kept to mark broken image chains */
+                    meta->backingStoreIsFile = false;
                     backingFormat = VIR_STORAGE_FILE_NONE;
+                    VIR_WARN("Backing file '%s' of image '%s' is missing.",
+                             meta->backingStoreRaw, path);
+
                 }
             }
             VIR_FREE(backing);
-- 
1.8.0