Thanks, Graham! Sorry for not noticing this earlier, but there’s something else:
Actually, this tells whether the mount can be persistent or not. One thing that we should make clear is that this interface by itself does not create any mounts: it only lists what is allowed. The application itself is responsible for creating the mount points it needs, either via using the /bin/mount command, the mount() system call, or the new snapctl mount command. In particular, in order to create a persistent mount point, the only option currently available is using the latter command, and passing the --persistent option. You can see an example of that in our tests. The snapctl mount command works similarly to the command-line mount command (that is: “snapctl mount -o <options> -t <fstype> </path/to/device> </target/mount/puint>”). Also, there is a corresponding “snapctl umount </path/to/mount/point>” command.