On Fri, Jun 16, 2017 at 10:01:26AM +0200, Michal Privoznik wrote: > Dear list, > > while trying to fix a bug of mine, I've realized the mounts are not > being propagated into qemu namespaces once domains are running. That is, > imagine you have a domain running and then you plug in a flash disk, > mount it into host, because you have a file there that you want to > hotplug as a disk to your domain. You're not hotplugging the whole flash > disk, but a file on it. Problem is, that the mount event of the flash > disk is not propagated to qemu namespace even though the root is > remounted as MS_SLAVE|MS_REC right after the namespace is created. > > After some digging. I am able to reproduce this even without libvirt at all: > > # mount --make-rshared / > # mount | grep floppy > <empty/> > # unshare -m /bin/bash > # mount --make-rslave / The problem here is your 'unshare' command, which mounts '/' as private, and it appears the later '--make-rslave' is unable to undo this. If you use unshare -m --propagation slave /bin/sh then the example works correctly. Also, you shouldn't need the initial '--make-rshare /' as (at least on systemd host, this is already the case). You can look in /proc/self/mountinfo to view current propagation status Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
