Re: [libvirt] [PATCHv2 2/4] network: change location of network state xml files

On 04/17/2014 07:43 AM, Laine Stump wrote: > For some reason these have been stored in /var/lib, although other > drivers (e.g. qemu and lxc) store their state files in /var/run. > > It's much nicer to store state files in /var/run because it is > automatically cleared out when the system reboots. We can then use > existence of the state file as a convenient indicator of whether or > not a particular network is active. > > Since changing the location of the state files by itself will cause > problems in the case of a *live* upgrade from an older libvirt that > uses /var/lib (because current status of active networks will be > lost), the network driver initialization has been modified to migrate > any network state files from /var/lib to /var/run. > > This will not help those trying to *downgrade*, but in practice this > will only be problematic in two cases > > 1) If there are networks with network-wide bandwidth limits configured > *and in use* by a guest during a downgrade to "old" libvirt. In this > case, the class ID's used for that network's tc rules, as well as > the currently in-use bandwidth "floor" will be forgotten. > > 2) If someone does this: 1) upgrade libvirt, 2) downgrade libvirt, 3) > modify running state of network (e.g. add a static dhcp host, etc), > 4) upgrade. In this case, the modifications to the running network > will be lost (but not any persistent changes to the network's > config). > --- > change from V1: > > * merged previous 2/5 & 3/5 into a single patch that changes the > location and migrates old state files, to avoid potential problems > by people trying to use git bisect. > > * move the files with a direct copy, rather than reading/parsing the > XML then formatting/writing it. Note (hopefully) correct use of > readdir! > > * put the migration into a separate static function > > * don't put oldStateDir in driverState, as we only use it once during > initialization. > > * only attempt migration when running privileged, since the > unprivileged state location hasn't changed. > > src/network/bridge_driver.c | 97 ++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 91 insertions(+), 6 deletions(-) > ACK; however... Your call if you want to wait for virDirRead() from: http://www.redhat.com/archives/libvir-list/2014-April/msg00745.html Then refactor your for (;;) loop to use it...

I'm "assuming" the files cannot be adjusted during the period when libvirt is "migrating" by any other "legal" :-) means.

Just typing "out loud" since your v1 would lock the network object and save the status in the new location.