qemu: hotplug: Prepare disk source for media changing

The disk storage source needs to be prepared if we want to use -blockdev
or secrets for the new media image. It does not hurt to do the same for
the legacy hotplug code as well.

Unfortunately helpers like qemuDomainPrepareDiskSource take
virDomainDiskDef as an argument and it would be hard to fix them to take
an explicit source, so the function also temporarily replaces disk->src
for the new source in this function.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

src/qemu/qemu_hotplug.c

@@ -730,10 +730,17 @@ qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
                                virStorageSourcePtr newsrc,
                                bool force)
 {
+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     qemuDomainObjPrivatePtr priv = vm->privateData;
+    virStorageSourcePtr oldsrc = disk->src;
     int ret = -1;
     int rc;
 
+    disk->src = newsrc;
+
+    if (qemuDomainPrepareDiskSource(disk, priv, cfg) < 0)
+        goto cleanup;
+
     if (qemuHotplugPrepareDiskAccess(driver, vm, disk, newsrc, false) < 0)
         goto cleanup;
 
@@ -741,11 +748,11 @@ qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
         goto cleanup;
 
     if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV))
-        rc = qemuDomainChangeMediaBlockdev(driver, vm, disk, disk->src, newsrc, force);
+        rc = qemuDomainChangeMediaBlockdev(driver, vm, disk, oldsrc, newsrc, force);
     else
         rc = qemuDomainChangeMediaLegacy(driver, vm, disk, newsrc, force);
 
-    virDomainAuditDisk(vm, disk->src, newsrc, "update", rc >= 0);
+    virDomainAuditDisk(vm, oldsrc, newsrc, "update", rc >= 0);
 
     if (rc < 0) {
         ignore_value(qemuHotplugPrepareDiskAccess(driver, vm, disk, newsrc, true));
@@ -753,17 +760,24 @@ qemuDomainChangeEjectableMedia(virQEMUDriverPtr driver,
     }
 
     /* remove the old source from shared device list */
+    disk->src = oldsrc;
     ignore_value(qemuRemoveSharedDisk(driver, disk, vm->def->name));
-    ignore_value(qemuHotplugPrepareDiskAccess(driver, vm, disk, NULL, true));
+    ignore_value(qemuHotplugPrepareDiskAccess(driver, vm, disk, oldsrc, true));
 
-    virStorageSourceFree(disk->src);
-    VIR_STEAL_PTR(disk->src, newsrc);
+    /* media was changed, so we can remove the old media definition now */
+    virStorageSourceFree(oldsrc);
+    oldsrc = NULL;
+    disk->src = newsrc;
 
     ignore_value(qemuHotplugRemoveManagedPR(driver, vm, QEMU_ASYNC_JOB_NONE));
 
     ret = 0;
 
  cleanup:
+    if (oldsrc)
+        disk->src = oldsrc;
+
+    virObjectUnref(cfg);
     return ret;
 }