qemu: Stop recursive detection of image chains when an image is missing

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.

diff --git a/src/util/storage_file.c b/src/util/storage_file.c
index 224921277ceb58c5d40004671fdedf6004fcea8d..44174047013bb885d5bd368ed8b3cc9e3b84ac91 100644 (file)
--- 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);