Re: [libvirt] [PATCH 5/5] blockjob: allow for fast-finishing job

On Wed, Apr 11, 2012 at 05:40:38PM -0600, Eric Blake wrote: > In my testing, I was able to provoke an odd block pull failure: > > $ virsh blockpull dom vda --bandwidth 10000 > error: Requested operation is not valid: No active operation on device: drive-virtio-disk0 > > merely by using gdb to artifically wait to do the block job set speed > until after the pull had already finished. But in reality, that should > be a success, since the pull finished before we had a chance to set > speed. Furthermore, using a double job lock is annoying; we can alter > the speed as part of the same job that started the block pull for less > likelihood of hitting the speed failure in the first place. > > * src/qemu/qemu_monitor.h (BLOCK_JOB_CMD): Add new mode. > * src/qemu/qemu_driver.c (qemuDomainBlockRebase): Move secondary > job call... > (qemuDomainBlockJobImpl): ...here, for fewer locks. > * src/qemu/qemu_monitor_json.c (qemuMonitorJSONBlockJob): Change > return value on new internal mode. > ---

ACK, a race we can't really avoid at that level and that's the proper handling. Again I'm wondering how we could automate testing for this ...