[libvirt] [PATCH] qemu: don't modify domain on failed blockiotune

If you have a qemu build that lacks the blockio tune monitor command, then this command: $ virsh blkdeviotune rhel6u2 hda --total_bytes_sec 1000 error: Unable to change block I/O throttle error: internal error Unexpected error fails as expected (well, the error message is lousy), but the next dumpxml shows that the domain was modified anyway. Worse, that means if you save the domain then restore it, the restore will likely fail due to throttling being unsupported, even though no throttling should even be active because the monitor command failed in the first place. * src/qemu/qemu_driver.c (qemuDomainSetBlockIoTune): Check for error before making modification permanent. --- src/qemu/qemu_driver.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index a36c348..2fde15b 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -12011,9 +12011,9 @@ qemuDomainSetBlockIoTune(virDomainPtr dom, qemuDomainObjEnterMonitorWithDriver(driver, vm); ret = qemuMonitorSetBlockIoThrottle(priv->mon, device, &info); qemuDomainObjExitMonitorWithDriver(driver, vm); - vm->def->disks[idx]->blkdeviotune = info; if (ret < 0) goto endjob; + vm->def->disks[idx]->blkdeviotune = info; } if (flags & VIR_DOMAIN_AFFECT_CONFIG) { -- 1.7.7.6