Re: [PATCH] Minor sys_umount fix (changes semantics slightly)

Rogier Wolff (R.E.Wolff@bitwizard.nl)
Wed, 15 Dec 1999 21:51:17 +0100 (MET)

Guest section DW wrote:
> > > Also, think of the very common case where people mount a CDROM
> > > on /dev/cdrom which is a symlink to /dev/sr0 or /dev/hdc or so.
> >
> > Huh? That's not the issue. The issue is:
> >
> > I use:
> > mount /cdrom
> > ls /cdrom
> > umount /cdrom
> > while:
> > ls -l /cdrom
> > lrwxrwxrwx 1 root root 9 Oct 18 20:46 cdrom -> mnt/cdrom
> >
>
> I am not sure what you are saying here.
> The issue is, "should the umount system call follow symlinks?".

Ehmm. I think I have to agree with Andre here: "Listen to Andries. He's
right."

Sorry to have interrupted.

> Now if in this example the umount system call is executed for the
> path "/cdrom" (which it isnt for the mount/umount that I maintain,
> but that is beside the point, the question is what the kernel should
> do) then it should follow symlinks in order to reach the mount
> point. But that makes Malcolm unhappy, because his filesystem has a
> symlink at the root, and umount would happily continue following
> symlinks past the mount point.

> As it is, umount can be called with both a mount point and a special
> device. But it would be unworkable to have the behaviour depend on
> the type of argument; that type is known first after following the
> symlinks. So, really, we want to follow symlinks in all cases, I
> think.

Ehm. May I ask: What would a filesystem with a symlink at its root be
doing when mounted?

Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
 "I didn't say it was your fault. I said I was going to blame it on you."


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