From: Martin Josefsson (gandalf_at_wlug.westbo.se)
Date: Sun 26 Jan 2003 - 22:11:58 GMT
On Sun, 2003-01-26 at 22:28, Timm Essigke wrote:
> Hi,
>
> I installed vserver on debian without any problems - Great!
>
> Now I want to mount e.g. my local debian mirror into my vserver, but I
> want to do it read-only for the vserver, while having it rw in context 0.
>
> mount --bind -o ro mounts it rw, which is a known bug I found as
> debian-bug #116017 of mount, but seems to be rather a bug in 2.4.x
> kernels, that options are ignored, when --bind is used.
It might be a bug that it doesn't complain about the ro flag but the ro
flag is meaningless anyway since it's not supported on a --bind mount.
2.4 just doesn't have that feature.
Doesn't appear to work in 2.5 either, Al Viro might have patches for 2.5
but I'm not sure.
> I tried to remount ro, which works, but sets not only the mount in the
> vserver ro, but also the original mount.
The thing is that the permissioncheck isn't based on the vfsmnt but on
the superblock and a filesystem only has one superblock independant of
how many times it's mounted (there's one vfsmnt per mountpoint).
So you can either have all mounts of this filesystem rw _or_ ro, not a
combination.
I made some hacks a while ago but I never finished them, and they won't
be released. (ugly as hell and they don't work (only partially))
> Next idea:
> I exported the directory via nfs and mounted it with
> mount -t nfs -o ro,addr=192.168.0.100 (which is the IP of my vserver)
>
> This gives me what I want, when I test is from context 0, but even a cd
> gives "Permission denied" in the vserver! Why?
This I've never tried so I can't help you there.
> I guess, somebody found a solution for this "standard" problem in
> vservers already!?
Maybe someone has, would be great to know.
-- /MartinNever argue with an idiot. They drag you down to their level, then beat you with experience.