The documentation states that for shallow block copy the image has to have the same guest visible content as backing file of the current image if the file is being reused. This condition can be achieved also with a raw file (or a qcow without a backing file) so remove the condition that would disallow it. (This patch additionally fixes crash described in https://bugzilla.redhat.com/show_bug.cgi?id=1215569 ) --- V2: - different approach to fix Eric's comment src/qemu/qemu_driver.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 80463f2..581211a 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -17122,11 +17122,17 @@ qemuDomainBlockCopyCommon(virDomainObjPtr vm, if (qemuDomainDetermineDiskChain(driver, vm, disk, false, true) < 0) goto endjob; + /* clear the _SHALLOW flag if there is only one layer */ + if (!disk->src->backingStore) + flags &= ~VIR_DOMAIN_BLOCK_COPY_SHALLOW; + + /* unless the user provides a pre-created file, shallow copy into a raw + * file is not possible */ if ((flags & VIR_DOMAIN_BLOCK_COPY_SHALLOW) && - mirror->format == VIR_STORAGE_FILE_RAW && - disk->src->backingStore->path) { + !(flags & VIR_DOMAIN_BLOCK_COPY_REUSE_EXT) && + mirror->format == VIR_STORAGE_FILE_RAW) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, - _("disk '%s' has backing file, so raw shallow copy " + _("shallow copy of disk '%s' into a raw file " "is not possible"), disk->dst); goto endjob; -- 2.3.5