Quoting Eric W. Biederman (ebiederm@xxxxxxxxxxxx): > Matt Helsley <matthltc@xxxxxxxxxx> writes: > > > On Tue, Feb 23, 2010 at 12:00:55PM -0800, Eric W. Biederman wrote: > >> jamal <hadi@xxxxxxxxxx> writes: > >> > >> > Added Daniel to the discussion.. > >> > > >> > On Tue, 2010-02-23 at 06:07 -0800, Eric W. Biederman wrote: > >> >> jamal <hadi@xxxxxxxxxx> writes: > >> > > >> >> > Does the point after sys_setns(fd) allow me to do io inside > >> >> > ns <name>? Can i do open() and get a fd from ns <name>? > >> >> > >> >> Yes. My intention is that current->nsproxy->net_ns be changed. > >> >> We can already change it in unshare so this is feasible. > >> > > >> > I like it if it makes it as easy as it sounds;-> With lxc, > >> > i essentially have to create a proxy process inside the > >> > namespace that i use unix domain to open fds inside the ns. > >> > Do i still need that? > >> > >> That point of the mount to hold a persistent reference to the > >> namespace without using a process. > > > > I think technicaly it's still held using processes, only now it's > > much more indirect: > > > > netns <- mount <- mount namespace(s) <- process(es) > > True. The practical difference is that it doesn't require a dedicated > process which is a big improvement operationally. > > > Using a mount requires keeping names for the namespaces themselves > > in the kernel which is a problem we've largely avoided so far. > > The nscgroup is an example of the messes that creates, I think. And it > > further complicates c/r -- we'd need to checkpoint and recreate the > > names of the namespaces too. So we'll need a namespace for the names of > > the namespaces to make restart reliable won't we? Makes my head spin... > > This is strictly different. It may require a bit of extra support from > checkpoint/restart because it introduces some more user visible objects > but the names themselves are nothing special. The name that userspace > sees and deals with is the name of the mount point. No new namespaces > are required. Shouldn't be a big deal - assuming the mount is of a special type for a network ns, we just record the objref for the checkpointed network ns. We don't need a namespace for the namespaces - we just need unique names for the checkpoint image (the objref, which is unique per netns). Guess it really is about time that i work on some clean patches for checkpoint/restart of mounts namespaces and mounts. -serge -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
