When creating a snapshot with _REUSE_EXTERNAL when the pre-created image does not directly link to the current active layer libvirt would re-detect the backing chain incorrectly and it would not match with qemu's view. Since the configuration is an operator mistake, document that only the top layer image gets inserted. --- src/libvirt-domain-snapshot.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/libvirt-domain-snapshot.c b/src/libvirt-domain-snapshot.c index ac858ba..55826fd 100644 --- a/src/libvirt-domain-snapshot.c +++ b/src/libvirt-domain-snapshot.c @@ -177,8 +177,9 @@ virDomainSnapshotGetConnect(virDomainSnapshotPtr snapshot) * the correct image format and metadata including backing store path * (this allows a management app to pre-create files with relative backing * file names, rather than the default of creating with absolute backing - * file names). Note that setting incorrect metadata in the pre-created - * image may lead to the VM being unable to start. + * file names). Note that only the file specified in the snapshot XML is + * inserted as a snapshot thus setting incorrect metadata in the pre-created + * image may lead to the VM being unable to start or other block jobs may fail. * * Be aware that although libvirt prefers to report errors up front with * no other effect, some hypervisors have certain types of failures where -- 2.3.5