[libvirt] XenStore fix

Hi, I have been examining a bug where libvirtd (and virsh) does not show all virtual machines on a xen host. This proved to be because of this program flow: 1. virConnectNumOfDomains -> .. -> xenUnifiedNumOfDomains -> xenHypervisorNumOfDomains => 3 2. virConnectListDomains(max=3) -> .. -> xenUnifiedListDomains(max=3) -> xenStoreNumOfDomains(max=3) => { 0, 2, 7 } The domain with ID 2 is then removed when it is discovered that it is not a running domain, which leads to this: xenhost# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 14970 2 r----- 2544.7 vm1 7 512 1 -b---- 2191.7 vm4 512 1 28.0 vm5 12 512 1 -b---- 467.1 vm6 512 1 0.0 vm7 512 1 482.4 xenhost# virsh list Id Name State ---------------------------------- 0 Domain-0 running 7 vm1 idle xenhost# But where does "2" come from? If we check all "directories" in /local/domain which is queried by the xenstore driver, it is apparent that xenstore is not properly cleaned. We find the sequence {0, 2, 7} as the first entries: xenhost# xenstore ls /local/domain |grep '^[^ ]' 0 = "" 2 = "" 7 = "" 9 = "" 10 = "" 11 = "" 12 = "" xenhost# This patch checks that the path found in /local/domain/<domid>/vm exists in xenstore before adding the domid to the return list. The same thing is done for xenStoreNumOfDomains. I use SLES11 with Xen 3.3.1_18546_12-3.1. /Jonas