From 93575f345116fe1413f6fe3109227b8be2f416da Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Mon, 25 Sep 2017 11:44:00 +0200
Subject: [PATCH] qemu: block: Use correct alias when extracting disk node
 names

The alias recorded in disk->info.alias is the alias for the frontend
device but we are interested in the backend drive. This messed up the
disk node name extraction code as qemu reports the drive alias in the
block query commands. This was broken in the node name detector
refactoring done in commit 0175dc6ea024d

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1494327
---
 src/qemu/qemu_block.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index a3da80f888..6faecb0aeb 100644
--- a/src/qemu/qemu_block.c
+++ b/src/qemu/qemu_block.c
@@ -20,6 +20,7 @@
 
 #include "qemu_block.h"
 #include "qemu_domain.h"
+#include "qemu_alias.h"
 
 #include "viralloc.h"
 #include "virstring.h"
@@ -271,36 +272,46 @@ qemuBlockDiskDetectNodes(virDomainDiskDefPtr disk,
 {
     qemuBlockNodeNameBackingChainDataPtr entry = NULL;
     virStorageSourcePtr src = disk->src;
+    char *alias = NULL;
+    int ret = -1;
 
     /* don't attempt the detection if the top level already has node names */
     if (src->nodeformat || src->nodestorage)
         return 0;
 
-    if (!(entry = virHashLookup(disktable, disk->info.alias)))
-        return 0;
+    if (!(alias = qemuAliasFromDisk(disk)))
+        goto cleanup;
+
+    if (!(entry = virHashLookup(disktable, alias))) {
+        ret = 0;
+        goto cleanup;
+    }
 
     while (src && entry) {
         if (src->nodeformat || src->nodestorage) {
             if (STRNEQ_NULLABLE(src->nodeformat, entry->nodeformat) ||
                 STRNEQ_NULLABLE(src->nodestorage, entry->nodestorage))
-                goto error;
+                goto cleanup;
 
             break;
         } else {
             if (VIR_STRDUP(src->nodeformat, entry->nodeformat) < 0 ||
                 VIR_STRDUP(src->nodestorage, entry->nodestorage) < 0)
-                goto error;
+                goto cleanup;
         }
 
         entry = entry->backing;
         src = src->backingStore;
     }
 
-    return 0;
+    ret = 0;
 
- error:
-    qemuBlockDiskClearDetectedNodes(disk);
-    return -1;
+ cleanup:
+    VIR_FREE(alias);
+    if (ret < 0)
+        qemuBlockDiskClearDetectedNodes(disk);
+
+    return ret;
 }