Re: mlocate/updatedb and btrfs subvolume mounts

["G. Richard Bellamy" <rbellamy@pteradigm.com>]

On Sun, Apr 12, 2015 at 9:12 PM, Duncan <1i5t5.duncan@cox.net> wrote:
>
> Zygo Blaxell posted on Sun, 12 Apr 2015 16:11:07 -0400 as excerpted:
>
> > Since these are simple binds (not rbinds), they don't see any other
> > filesystems, period.  They do see btrfs subvolumes, though.
>
> Tho... for systemd users...
>
> Do note that systemd plays with the kernel's shared-subtree "private"
> default, switching it to shared for /.

I like to think I know a bit about a thing or two. I've read both Zygo
and Duncan's probably cogent responses.

My brain hurts, and I am just not getting it.

If I am to understand correctly, and specific to my OP, the problem
with updatedb et al. on my system is that /, /home, /var, /opt and
/var/lib/libvirt are all subvolume mounts - which appear as bind
mounts. Thus the PRUNE_BIND_MOUNTS prunes ALL mounts, and updatedb
sees nothing.

Everything else is a blur when we start talking about "mount --bind /
/.binds/root"

Oh wait, maybe I get it now...

By running "mount --bind / /.binds/root" and running updatedb in
"/.binds/root" while still allowing it to see binds, I am certain to
get a an mlocate db, and it won't ever see anything outside that
explicit hierarchy.

Something like that?

-rb