Re: [RFC] shared subtrees

From: Ram
Date: Tue Jan 25 2005 - 17:14:40 EST


On Tue, 2005-01-25 at 13:47, Mike Waychison wrote:
...snip...
> >
> > Question 2:
> >
> > When a mount gets propogated to a slave, but the slave
> > has mounted something else at the same place, and hence
> > that mount point is masked, what will happen?
> >
> > Concrete example:
> >
> > mount <device1> /tmp/mnt1
> > mkdir -p /tmp/mnt1/a/b
> > mount --rbind /tmp/mnt1 /tmp/mnt2
> > mount --make-slave /tmp/mnt2
>
> EINVAL. You should only be able to demote a mountpoint to a slave if it
> was part of a p-node (shared).

oops. I had the following in mind.

mount <device1> /tmp/mnt1
** mount --make-shared /tmp/mnt1 **
mkdir -p /tmp/mnt1/a/b
mount --rbind /tmp/mnt1 /tmp/mnt2
mount --make-slave /tmp/mnt2

In this case it cannot be EINVAL, because /tmp/mnt1 and /tmp/mnt2 will
both be part of a pnode and hence /tmp/mnt2 can be demoted to be a
slave.
>
> > mount <device2> /tmp/mnt2/a
> > rm -f /tmp/mnt2/a/*
> >
> > what happens when a mount is attempted on /tmp/mnt1/a/b?
> > will that be reflected in /tmp/mnt2/a ?
> >
> > I believe the answer is 'no', because that part of the subtree
> > in /tmp/mnt2 no more mirrors its parent subtree.
> >
> > RP
> >
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>
> - --
> Mike Waychison
> Sun Microsystems, Inc.
> 1 (650) 352-5299 voice
> 1 (416) 202-8336 voice
>
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