Re: multimounting cdroms ???

From: Michael T. Gilmore (mgilmore@zk3.dec.com)
Date: Wed Jul 26 2000 - 19:44:11 EST


Alexander Viro wrote:

> On Wed, 26 Jul 2000, Rik van Riel wrote:
>
> > Only one problem though.
> >
> > A user can mount the same filesystem multiple times on the
> > same mountpoint, but will be unable to umount the filesystem
> > again ...
> >
> > umount -f does the trick, but is restricted to root
>
> ... but doing umount the same number of times you've done mount isn't ;-)
>
> Actually, the more I'm looking at it, the more it seems that correct
> solution is to consider mount as
> if (nothing mounted)
> mount
> else if (mounted is not busy)
> replace
> else
> fail
> Makes sense for union-mounts too - normal mount is =, union is += ...

I would really think hard about this.

Mounting (or replacing) on an current mount path, busy or nor, wil really
lead to bizzare and damaging senerios later.

You may not see the "why" now, but when your process mounts a volume, and
takes time between acess (busy), if it is replaced, something will go boom!

RULE: once a path is mounted upon, no mounts are allowed on any of the path
         (directory) components.

If you insist on adding this "feature", please make it a system tunable (config)
option. Some of us really do not want it.

regards,
    mike

>
>
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