On Fri, 4 Mar 2016, Gustau Pérez wrote: > El 4/03/16 a les 11:00, Roger Pau Monné ha escrit: > > > > What other parameters do you want to pass to your script that cannot be > > fetched from xenstore? IMHO I was planning to only pass the xenstore > > backend node and the action. > > The action (if I understand it correctly) is already there.
Yes, the xenstore backend path is $1 and the action $2. > > OTOH, I'd like to check if the disks are already in use, and so I'd > need to walk the /local/domain/0/backend/vbd/$domin/$devid/ looking if > the disks are already there. This arises two questions: > > * can I assume the domain0 store would always be /local/domain/0/? Hm, I wouldn't be on it. This is true in the most common scenario, where Dom0 (domain with id 0) runs all the backends. But if you are using a driver domain or a radically disagregated system (where control domain != hardware domain) this is no longer true. So in general you shouldn't make this assumption. > * would I need to walk for each $domid checking for each $devid and > getting the physical device? Linux already has some code to do this checking, but this also involves taking a lock in order to make sure there's only one hotplug script performing this check at the same time. The Linux function that performs this checking is in: http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=tools/hotplug/Linux/block;h=2691b56951c9b82094471a141b9e0bed04abb929;hb=HEAD#l40 And the caller is: http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=tools/hotplug/Linux/block;h=2691b56951c9b82094471a141b9e0bed04abb929;hb=HEAD#l275 If you take a look, the call to check_device_sharing is protected with the "block" lock. Roger. _______________________________________________ freebsd-xen@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"