On 09/16/2011 10:11 PM, Eric Blake wrote:
For external snapshots to be useful on persistent domains, we must alter the persistent definition alongside the running definition. Thanks to the possibility of disk hotplug as well as of edits that only affect the persistent xml, we can't assume that vm->def and vm->newDef have the same disk at the same index, so we can only update the persistent copy if the device destination matches up.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive) (qemuDomainSnapshotCreateSingleDiskActive): Also affect newDef, if present. ---
This is worth including in 0.9.5 - without it, the new feature of disk snapshots on a persistent domain are lost the moment the domain stops running, which is likely to cause data corruption for guests.
I'm squashing this in, so that the persistent changes are preserved over libvirtd restarts. diff --git i/src/qemu/qemu_driver.c w/src/qemu/qemu_driver.c index cbe28d8..2a1e5ea 100644 --- i/src/qemu/qemu_driver.c +++ w/src/qemu/qemu_driver.c @@ -9221,6 +9221,7 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn, bool resume = false; int ret = -1; int i; + bool persist = false; if (qemuDomainObjBeginJobWithDriver(driver, vm, QEMU_JOB_MODIFY) < 0) return -1; @@ -9259,8 +9260,10 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn, int indx = virDomainDiskIndexByName(vm->newDef, vm->def->disks[i]->dst, false); - if (indx >= 0) + if (indx >= 0) { persistDisk = vm->newDef->disks[indx]; + persist = true; + } } ret = qemuDomainSnapshotCreateSingleDiskActive(driver, vm, @@ -9301,7 +9304,9 @@ cleanup: } if (vm) { - if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0) + if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0 || + (persist && + virDomainSaveConfig(driver->configDir, vm->newDef) < 0)) ret = -1; if (qemuDomainObjEndJob(driver, vm) == 0) { /* Only possible if a transient vm quit while our locks were down, -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org