Nir Soffer has posted comments on this change.
Change subject: Invalidate filters on HSMs before rescanning extended VG ......................................................................
Patch Set 18:
If the domainMonitor has issued its vgs command when the new lun was not there, it's filter would have lacked the new device. On other threads, getDevVis may now report the device as visible, a vgextend command takes place, and the old domainMonitor would return a dreaded "partial" result.
When domain monitor runs, it invokes some lvm commands; on the first command, the filter is rebuilt using all /dev/mapper devices. Since we invalidate the filter in getDeviceVisibility, the next lvm command after that will cause the filter to be correct.
If domain monitor run before vgextend, the vg is obviously not partial. If domain monitor run after vgextend, the vg contains now the new pv, and the vg is not partial. In both case the filter created by running domain monitor is correct.