[lxc-devel] loop mounts and #195

[Serge Hallyn]

Quoting Wolfgang Bumiller (w.bumiller at proxmox.com):
> We came across lxc's #195 while working on our frontend to support
> mount entries via lxc.mount.entry.
> 
> The issue there (despite the change of the title) seems to be just the
> `loop' option (which ends up passed to mount(2) as part of the
> `data').
> 
> There's already code for loop devices, and a loop 'bdev' type for a
> `loop:` prefixed rootfs, so adding support for loop mounts shouldn't
> be all too hard (I'm willing to work on that.)
> 
> I'm also wondering, however, if the use of libmount has been considered
> before? Admittedly I haven't looked too deeply into it yet, but it's
> what the mount command uses and so I'd assume it supports all the
> various options. (Though maybe more than desired due to security
> concerns?) Let me know if this has already come up (the big search
> machine hasn't found much ;-P).

Don't think it's been discussed before.  I wouldn't be opposed.  We
have a few lxc.mount.entry options like 'create=file' which we'd need
to filter out, but that's ok.  I've not looked at the api enough to
know whether it would simplify or complicate our code.  The mount
calls themselves are pretty simple.  Does libmount automatically handle
things like readonly bind mounts?