There are two possible root causes for 515, both of which are only problems in the non-udev hotplug case because udev uses udevsend which already implements the required serialisation.
1) Script concurrency.
2) Kernel reordering hotplug events.
This changeset fixes (1) but not (2). Since (1) is the problem that seems to be happening this is probably OK.
A fix for (2) for the hotplug case might be to add extra serialisation using state changes in the store but this would impact all the drivers and the code and extra complexity would be redundant once everyone had moved to udev. This doesn't seem worthwhile unless we actually start to see (2) happening.
script's lock before doing the cleanup, to avoid a race that causes the message
"xenstore-list: could not list path backend/vbd/40" in /var/log/hotplug.log,
with a subsequent refusal to create the domain, after a domain reboot.
Signed-off-by: Ewan Mellor <ewan@xensource.com>
and udev. Pass all commands through from xen-backend.agent or
xen-backend.rules rather than second-guessing the individual scripts. This
should make it easier to tear down devices cleanly, especially the dangling
vifs we are seeing at the moment.
Cope with a missing type node inside the block script, as we don't want to
resurrect a removed node by writing a hotplug error message.
Log failure of iptables command.
Signed-off-by: Ewan Mellor <ewan@xensource.com>
/local/domain/0/backend/<devclass>/<dom>/<devid>/error, write them instead to
/local/domain/0/error/backend/<yada>. This is not the best place for them
perhaps, but it moves them out of the backend directory, on which the drivers
have a watch. This fixes the problem whereby writing an error will trigger a
watch, causing the error message to be written again, and repeat. Fixes bug
#286.
Signed-off-by: Ewan Mellor <ewan@xensource.com>
Fixes file: devices since unbind now runs after the backend driver
closes the loopback device.
Also moves name -> node translation into the backend domain.
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Move the hotplug script from /etc/hotplug.d/xen-backend/backend.hotplug
to /etc/hotplug/xen-backend.agent, which seems to be a more common place
for the script.
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
--HG--
rename : tools/examples/backend.hotplug => tools/examples/xen-backend.agent
