Fix FS volume creation with backing stores.

This regressed when CreateXMLFrom was added: we should only perform the
backing store comparison if an input volume was passed.

ChangeLog

+Tue Jun 16 11:43:17 EDT 2009 Cole Robinson <crobinso@redhat.com>
+
+	* src/storage_backend_fs.c: Fix FS volume creation with backing stores.
+
 Tue Jun 16 11:33:54 EDT 2009 Cole Robinson <crobinso@redhat.com>
 
 	* src/domain_conf.c src/domain_conf.h src/libvirt_private.syms

src/storage_backend_fs.c

@@ -1251,8 +1251,9 @@ static int createQemuImg(virConnectPtr conn,
          * backing store, not really sure what use it serves though, and it
          * may cause issues with lvm. Untested essentially.
          */
-        if (!inputBackingPath ||
-            !STREQ(inputBackingPath, vol->backingStore.path)) {
+        if (inputvol &&
+            (!inputBackingPath ||
+             STRNEQ(inputBackingPath, vol->backingStore.path))) {
             virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
                                   "%s", _("a different backing store can not "
                                           "be specified."));