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Date: Wed, 28 Feb 2001 12:17:13 -0800 (PST)
From: Ion Badulescu <ionut@cs.columbia.edu>
To: Alexander Viro <viro@math.psu.edu>
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Subject: Re: [PATCH][CFT] per-process namespaces for Linux
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On Wed, 28 Feb 2001, Alexander Viro wrote:

> > And disadvantages: you can't have broken symlinks.
> > 
> > This actually turns out to be quite a bit of a problem when one tries
> > to use bind mounts with autofs. For one thing, it's perfectly legal
> > to have /autofs/foo as a symlink to /autofs/bar/foo, where /autofs/bar
> > is not yet mounted -- but a bind mount can't handle that...
> 
> First of all, you still have symlinks. 

Oh yeah, of course. :-)

> What's more, the right solution is to use local objects at the
> mountpoints. And forget about having a small tree full of links to
> real mountpoints. Think of autofs-with-one-node.

That's what Sun's autofs and am-utils call 'direct mounts', which are not 
yet supported by our autofs (unless I missed something recently). Direct 
mounts are good for some things, but not for everything. In particular, 
they are useless for cascading auto-triggered mounts (think 
/usr/local/src, /usr/local, and /usr, all automounted).

[and, btw, Linux _still_ doesn't properly support am-utils' direct mounts, 
although all that's needed is to remove LOOKUP_FOLLOW from path_init in 
sys_umount...]

As for bind mounts, I'll probably revisit them after I'm done with the 
Solaris autofs support in am-utils -- which will probably be a while. If I 
can get the thing to chain-trigger all the necessary mounts, we might be 
able to do something useful with it..

Thanks,
Ion

-- 
  It is better to keep your mouth shut and be thought a fool,
            than to open it and remove all doubt.

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