[libvirt] Regression in createQemuImg()@storage_backend_fs.c of 0.6.4

Hi, I've found a regression in using a backing store of a volume (qcow2) in a pool (dir). The following code of 0.6.4 hits my system that works with 0.6.3. static int createQemuImg(virConnectPtr conn, virStorageVolDefPtr vol, virStorageVolDefPtr inputvol) { (snip) const char *inputBackingPath = (inputvol ? inputvol->backingStore.path : NULL); (snip) /* XXX: Not strictly required: qemu-img has an option a different * 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)) { virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, "%s", _("a different backing store can not " "be specified.")); return -1; } The inputBackingPath will be always NULL when it is called via virStorageBackendFileSystemVolBuild(). (The third argument is passed to that of createQemuImg as it is.) static int virStorageBackendFileSystemVolBuild(virConnectPtr conn, virStorageVolDefPtr vol) { return _virStorageBackendFileSystemVolBuild(conn, vol, NULL); } I've addressed the regression with the patch - if (!inputBackingPath || + if (inputBackingPath && However, I'm not sure whether this fix satisfies the aim of the original code. Any idea? Thanks in advance, ozaki-r