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

diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index a3da80f88886060c8f5b03f8b75d6649c90ef1ec..6faecb0aeb41386719aedac132b444b5dfca3947 100644 (file)
--- 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;
 }