From 282bd9dc619f7514363b59073a1af32f5e0e7dee Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 4 May 2012 09:43:23 -0600 Subject: [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. (cherry picked from commit 98cec052882c9acb5e3b8bc3f8e8a37a2cdb2982) --- src/qemu/qemu_driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 2582dadf2e..4b23ee061b 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -11923,9 +11923,9 @@ 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) {