[Pkg-ltsp-devel] Bug#758090: ltspfs: lbmount use of "mount --move" incompatible with systemd

[Vagrant Cascadian]

Package: ltspfs
Version: 1.3-1
Justification: unusable with default init system
Severity: serious
X-Debbugs-Cc: alkisg at gmail.com

ltspfs doesn't appear to work with systemd, as it relies on mounting the
fuse based ltspfs filesystem in one location, and then using "mount
--move" to relocate it to another section. But using "mount --move" with
a system running systemd results in this:

  sudo mount --move test test2
  mount: wrong fs type, bad option, bad superblock on /media/test,
         missing codepage or helper program, or other error
         In some cases useful info is found in syslog - try
         dmesg | tail  or so

Apparently this has something to do with "MS_REC|MS_SHARED" and can be
disabled on a per-filesystem basis with "mount --make-private /", for
example. This may change behavior for other systems (such as containers)
which assume it is not marked private...

A quick workaround is to use "mount --bind" instead of "mount --move",
but this has the undesired side-effect of leaving two mounts in place,
one in /tmp/.USERNAME-ltspfs/MOUNT and one in /media/USERNAME/MOUNT.
Though some brief experiments show that unmounting the /tmp mount left
the /media mount in place when i tried it... that might make it a viable
workaround.

Honestly, I'd rather figure out a way to safely mount the ltspfs mount
directly without "mount --move". We could have a setuid wrapper that instead
creates the mountpoint directly as /media/USERNAME/MOUNT and ensures it
actually mounts, and some way of ensuring that it unmounts and removes
the /media/USERNAME/MOUNT directory when done... possibly with a
mount.helper and/or umount.helper.


live well,
  vagrant
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