On Thu, Apr 30, 2020 at 09:58:12AM +0100, Dr. David Alan Gilbert wrote: [..] > > > Even without this patch, the SLAVE stuff worked so if you start the > > > daemon and *then* mount under the shared directory, the guest sees it > > > with or without this patch. > > > > Hm, I don’t. Do you really? > > Yes! With your patch reverted: > > Start virtiofsd, mount in the guest: > > host: > # ./virtiofsd --socket-path=/tmp/vhostqemu -o > source=/home/dgilbert/virtio-fs/fs -o log_level=warn -o no_writeback > > guest: > # mount -t virtiofs myfs /sysroot > > host: > # findmnt -o +PROPAGATION -N 6100 > TARGET SOURCE > FSTYPE OPTIONS > PROPAGATION > / /dev/mapper/fedora_dgilbert--t580-root[/home/dgilbert/virtio-fs/fs] > xfs rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,no > private,slave > # mount -t tmpfs /dev/null /home/dgilbert/virtio-fs/fs/tmp > # findmnt -o +PROPAGATION -N 6100 > TARGET SOURCE > FSTYPE OPTIONS > PROPAGATION > / /dev/mapper/fedora_dgilbert--t580-root[/home/dgilbert/virtio-fs/fs] > xfs rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,no > private,slave > └─/tmp /dev/null > tmpfs rw,relatime,seclabel > private,slave
Why is it showing a mount point at "/tmp". If mount point propagated, then inside guest we should see a mount point at /sysroot/tmp? So there are two things. A. Propagation of mount from host to virtiofsd. B. Visibility of that mount inside guest over fuse protocol (submount functionality). I think A works for me without any patches. But don't think B is working for me. I don't see the submount inside guest. > # touch /home/dgilbert/virtio-fs/fs/tmp/hello > > guest: > # ls -l /sysroot/tmp > total 0 > -rw-r--r-- 1 root root 0 Apr 30 08:50 hello Do a "findmnt /sysroot/tmp" inside guest and see what do you see. You will be able to see "hello" as long as virtiofsd sees the new mount point, I think. And guest does not have to see that mount point for this simple test to work. Vivek
