qemu: snapshot: Check for block jobs individually

If any disk of a VM was involved in a (copy) block job we refused to do
a snapshot. As not only copy jobs interlock snapshots and the
interlocking is applicable to individual disks only we can make the
check in a more individual fashion and interlock all block job types
supported by libvirt.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1203628

src/qemu/qemu_driver.c

@@ -13926,6 +13926,14 @@ qemuDomainSnapshotPrepare(virConnectPtr conn,
         virDomainSnapshotDiskDefPtr disk = &def->disks[i];
         virDomainDiskDefPtr dom_disk = vm->def->disks[i];
 
+        if (disk->snapshot != VIR_DOMAIN_SNAPSHOT_LOCATION_NONE &&
+            dom_disk->blockjob) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("disk '%s' has an active block job"),
+                           disk->name);
+            goto cleanup;
+        }
+
         switch ((virDomainSnapshotLocation) disk->snapshot) {
         case VIR_DOMAIN_SNAPSHOT_LOCATION_INTERNAL:
             found_internal = true;
@@ -14572,11 +14580,6 @@ qemuDomainSnapshotCreateXML(virDomainPtr domain,
                        "%s", _("domain is marked for auto destroy"));
         goto cleanup;
     }
-    if (virDomainHasDiskMirror(vm)) {
-        virReportError(VIR_ERR_BLOCK_COPY_ACTIVE, "%s",
-                       _("domain has active block job"));
-        goto cleanup;
-    }
 
     if (!vm->persistent && (flags & VIR_DOMAIN_SNAPSHOT_CREATE_HALT)) {
         virReportError(VIR_ERR_OPERATION_INVALID, "%s",