Re: how to show propagation state for mounts

[Ram Pai <linuxram@us.ibm.com>]

On Wed, 2008-02-20 at 09:31 -0700, Matthew Wilcox wrote:
> On Wed, Feb 20, 2008 at 04:04:22PM +0000, Al Viro wrote:
> > It's less about the form of representation (after all, we generate poll
> > events when contents of that sucker changes, so one *can* get a consistent
> > snapshot of the entire thing) and more about having it self-contained
> > when we have namespaces in the play.
> > 
> > IOW, the data in there should give answers to questions that make sense.
> > "Do events get propagated from this vfsmount I have to that vfsmount I have?"
> > is a meaningful one; ditto for "are events here propagated to somewhere I
> > don't see?" or "are events getting propagated here from somewhere I don't
> > see?".
> 
> Why do those last two questions deserve an answer?  How will a person's
> or application's behaviour be affected by whether a change will
> propagate to something they don't know about and can't see?

Well, I do not want to be surprised to see a mount suddenly show up in
my namespace because of some action by some other user in some other
namespace. Its going to happen anyway if the namespace is forked of 
a namespace that had shared mounts in them. However I would rather
prefer to know in advance the spots (mounts) where such surprises can
happen. Also I would prefer to know how my actions will effect mounts in
other namespaces.

RP


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