qemuDomainBlockCommit: Don't track top_canon path separately

virStorageFileChainLookup is able to give use virStorageSourcePtr which
contains the pointer to its canonical path. There's no need for the
caller to store both of them.

Former top_meta maps to topSource and top_canon maps to topSource->path.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_driver.c

@@ -15285,8 +15285,7 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
     int ret = -1;
     int idx;
     virDomainDiskDefPtr disk = NULL;
-    const char *top_canon = NULL;
-    virStorageSourcePtr top_meta = NULL;
+    virStorageSourcePtr topSource;
     const char *top_parent = NULL;
     const char *base_canon = NULL;
     bool clean_access = false;
@@ -15329,22 +15328,22 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
         goto endjob;
 
     if (!top) {
-        top_canon = disk->src.path;
-        top_meta = &disk->src;
-    } else if (!(top_canon = virStorageFileChainLookup(&disk->src,
-                                                       top, &top_meta,
+        topSource = &disk->src;
+    } else if (!(virStorageFileChainLookup(&disk->src,
+                                           top, &topSource,
                                            &top_parent))) {
         goto endjob;
     }
-    if (!top_meta || !top_meta->backingStore) {
+    if (!topSource->backingStore) {
         virReportError(VIR_ERR_INVALID_ARG,
                        _("top '%s' in chain for '%s' has no backing file"),
-                       top_canon, path);
+                       topSource->path, path);
         goto endjob;
     }
+
     if (!base && (flags & VIR_DOMAIN_BLOCK_COMMIT_SHALLOW))
-        base_canon = top_meta->backingStore->path;
-    else if (!(base_canon = virStorageFileChainLookup(top_meta,
+        base_canon = topSource->backingStore->path;
+    else if (!(base_canon = virStorageFileChainLookup(topSource,
                                                       base, NULL, NULL)))
         goto endjob;
 
@@ -15352,11 +15351,11 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
      * virStorageFileChainLookup guarantees a simple pointer
      * comparison will work, rather than needing full-blown STREQ.  */
     if ((flags & VIR_DOMAIN_BLOCK_COMMIT_SHALLOW) &&
-        base_canon != top_meta->backingStore->path) {
+        base_canon != topSource->backingStore->path) {
         virReportError(VIR_ERR_INVALID_ARG,
                        _("base '%s' is not immediately below '%s' in chain "
                          "for '%s'"),
-                       base, top_canon, path);
+                       base, topSource->path, path);
         goto endjob;
     }
 
@@ -15383,7 +15382,7 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base,
      * thing if the user specified a relative name). */
     qemuDomainObjEnterMonitor(driver, vm);
     ret = qemuMonitorBlockCommit(priv->mon, device,
-                                 top ? top : top_canon,
+                                 top ? top : topSource->path,
                                  base ? base : base_canon, bandwidth);
     qemuDomainObjExitMonitor(driver, vm);