From: Peter Krempa <pkrempa@redhat.com>
Date: Fri, 20 Dec 2019 08:33:40 +0000 (+0100)
Subject: qemu: backup: Configure backup store image with backing file
X-Git-Tag: v6.0.0-rc1~76
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6b994bafd47aa5ef3d6fc6c063213092b116bb9;p=thirdparty%2Flibvirt.git

qemu: backup: Configure backup store image with backing file

In contrast to snapshots the backup job does not complain when the
backup job's store file has backing pre-configured. It's actually
required so that the NBD server exposes all the data properly.

Remove our fake termination and use the existing disk source as backing.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---

diff --git a/src/qemu/qemu_backup.c b/src/qemu/qemu_backup.c
index a039beaede..24a53fd85f 100644
--- a/src/qemu/qemu_backup.c
+++ b/src/qemu/qemu_backup.c
@@ -302,7 +302,6 @@ qemuBackupDiskPrepareDataOne(virDomainObjPtr vm,
                              bool removeStore)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
-    g_autoptr(virStorageSource) terminator = NULL;
 
     /* set data structure */
     dd->backupdisk = backupdisk;
@@ -331,17 +330,14 @@ qemuBackupDiskPrepareDataOne(virDomainObjPtr vm,
             return -1;
     }
 
-    /* install terminator to prevent qemu form opening backing images */
-    if (!(terminator = virStorageSourceNew()))
-        return -1;
-
     if (!(dd->blockjob = qemuBlockJobDiskNewBackup(vm, dd->domdisk, dd->store,
                                                    removeStore,
                                                    dd->incrementalBitmap)))
         return -1;
 
+    /* use original disk as backing to prevent opening the backing chain */
     if (!(dd->crdata = qemuBuildStorageSourceChainAttachPrepareBlockdevTop(dd->store,
-                                                                           terminator,
+                                                                           dd->domdisk->src,
                                                                            priv->qemuCaps)))
         return -1;