Messages in this thread |  | | From | "Thorsten Glaser Geuer" <> | | Subject | Re: OK to mount multiple FS in one dir? | | Date | Tue, 6 Feb 2001 19:47:11 -0000 |
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----- Original Message ----- From: "Peter Samuelson" <peter@cadcamlab.org> To: "Michael D. Crawford" <crawford@goingware.com> Cc: <linux-kernel@vger.kernel.org> Sent: Tuesday, 6. February 2001 00:06 Subject: Re: OK to mount multiple FS in one dir?
> > [Michael D. Crawford] > > I found I could mount three partitions on /mnt > > Yes. New feature, appeared in the 2.4.0test series, or shortly before. > > > and they'd all show up as mounted at /mnt in the "mount" command, but > > if I unmounted one of them (only tried with the currently visible > > one), then it appeared that there were no filesystems mounted there, > > but I could continue umounting until the other two were gone. > > util-linux gets rather confused by this feature. They say newer > versions fix this. > > > But I had the 2.10r util-linux sources on my machine and installed > > mount and umount from it, and I find that it gets it right mostly > > when I mount and unmount multiple things, with the exception that if > > /dev/sda5 was mounted before /dev/sda1, then if I give the command > > "umount /dev/sda5", sda1 is the one that gets unmounted rather than > > sda5, so it takes the most recently mounted filesystem rather than > > the one you specify. > > I think this is a kernel limitation. 'umount' takes '/dev/sda5' and > turns it into '/mnt/test' and calls umount("/mnt/test"). The kernel > then unmounts whatever is on "top" of /mnt/test. > > I don't think there's anything umount can do about this behavior.
What about userland umount checking which device is umounted and refusing to umount it or at least issuing a printf warning?
> > Peter
-mirabilos
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