Re: [RFC][PATCH] rbind across namespaces

Miklos Szeredi
2005-05-24T06:38:43Z

> FWIW, all this stuff has already been done and posted here.
>
> Detachable chunks of vfsmounts:
> http://marc.theaimsgroup.com/?l=linux-fsdevel&m=109872862003192&w=2
>
> 'Soft' reference counts for manipulating vfsmounts without pinning them
> down:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109872797030644&w=2

I think this might just interest Jamie Lokier. He had a very similar
poposal recently, but without reference to this patch, so I guess he
wasn't aware of it.

> Referencing vfsmounts in userspace using a file descriptor:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109871948812782&w=2

Why not just use /proc/PID/fd/FD?

> walking mountpoints in userspace:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109875012510262&w=2

Is this needed? Userspace can find out mountpoints from /proc/mounts
(or something similar for detached trees).

> attaching mountpoints in userspace:
> http://marc.theaimsgroup.com/?l=linux-fsdevel&m=109875063100111&w=2

Again, bind from/to /proc/PID/fd/FD should work without any new
interfaces.

> detaching mountpoints in userspace:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109880051800963&w=2

What's wrong with sys_umount()?

> getting info from a vfsmount:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109875135030473&w=2

/proc or /sys should do fine for this purpose I think.

I agree, that having "floating trees" could be useful, but I don't see
the point of adding new interfaces to support it.

Miklos