> No, the plan is only one namespace at a time. Looking at this a bit more I am frustrated and relieved. I was looking at what it would take to join an arbitrary mount namespace and I realized it is completely non-obvious what fs->root and fs->pwd should be set to. If I leave them untouched the new mount namespace is useless, as all path lookups will give results in a different mount namespace, so not even mount or umount can be used. I can not change fs->root to mnt_ns->root as that is rootfs and there is always something mounted on top so I can not use that. In comparison an unshare of the mount namespace doesn't have to move fs->root or fs->pwd at all and only has to update their mounts to the corresponding mounts in the new mount namespace. I might be able to find the topmost root filesystem and put at least root there, but I'm not particularly fond of that option. Eric -- 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