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

[Jiri Denemark]

On Fri, May 04, 2012 at 09:52:44 -0600, Eric Blake wrote:
> 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(-)

ACK

Jirka