Miklos Szeredi <miklos@xxxxxxxxxx> writes: > On Sat, Nov 24, 2012 at 1:07 PM, Eric W. Biederman > <ebiederm@xxxxxxxxxxxx> wrote: >> Ian Kent <raven@xxxxxxxxxx> writes: >> >>> On Sat, 2012-11-24 at 10:23 +0800, Ian Kent wrote: >>>> On Fri, 2012-11-23 at 15:30 +0100, Miklos Szeredi wrote: > >>>> AFAICS autofs mounts mounted with MS_PRIVATE in the initial namespace do >>>> propagate to the clone when it's created so I'm assuming subsequent >>>> mounts would also. If these mounts are busy in some way they can't be >>>> umounted in the clone unless "/" is marked private before attempting the >>>> umount. Subsequent mounts after the clone do not have a mechanism to propogate with MS_PRIVATE. As creating a new mount namespaces is essentially an instance of mount --bind. Those semantics are a little unintuitive I have to admit. >>> This may sound stupid but if there something like, say, MS_NOPROPAGATE >>> then the problem I see would pretty much just go away. No more need to >>> umount existing mounts and container instances would be isolated. But, I >>> guess, I'm not considering the possibility of cloned of processes as >>> well .... if that makes sense, ;) >> >> Something is very weird is going on. MS_PRIVATE should be the >> MS_NOPROPOGATE you are looking for. There is also MS_UNBINDABLE. >> which is a stronger form of MS_PRIVATE and probably worth play with. >> > > MS_UNBINDABLE says: skip this mount when copying a mount tree, such > as when the mount namespace is cloned. > > If you set MS_UNBINDABLE on autofs mounts then they will simply not > appear in a cloned namespace. Which sounds like a good idea, no? Good point. If the desire is for a mount to be managed by autofs setting MS_UNBINDABLE seems required. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
