Re: [PATCH] private mounts

From: Jamie Lokier
Date: Sat Apr 30 2005 - 19:01:17 EST

Olivier Galibert wrote:
> > > "mount --bind /proc/self/fd/N mount_point" works, try it.
> >
> > What do people think about that?
> To me it looks like an atrocious hack that works only because of the
> way the implementation is done and not really by design.

>From fs/namespace.c:do_loopback, the function which does bind mounts:

if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {

check_mnt() verifies that a mountpoint is in the same namespace as the
current process. recurse is set for --rbind mounts, but not --bind mounts.

Notice how old_nd.mnt is explicitly _not_ checked for being in the current
namespace when doing --bind?

That says to me that Al thought about this case, and coded for it...

(I'm still not clear why the check_mnt() calls are needed at all, though).

-- Jamie
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at