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From: "Charles P. Wright" <cwright@cs.sunysb.edu>
To: Lou Kamenov <loukamenov@gmail.com>
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Date: Thu, 10 Mar 2005 12:45:53 -0500
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Subject: Re: the current status of nullfs, unionfs
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On Thu, 2005-03-10 at 12:24 -0500, Lou Kamenov wrote:
> Erez's unionfs has the same problem, the case there is that you wont be able to
> unmount it at all. (At least last time I tried with 1.0.3)
The code has improved quite a bit since then.  We've ironed out most of
of the big bugs (there are still other smaller ones to go, but we are
making reasonable progress).  A recent version has been included in
Knoppix 3.8.

> Problem or not it could be easily solved with simple heuristics.
> Building a filespace
> with unioning shouldnt really  be that hard.
That isn't quite true.  In theory, all you have to do is repeat some
operations over many branches.  In practice, building a Unioning file
system is not an easy task.  There are very many corner cases to deal
with, and what were previously atomic VFS ops can require many
operations.  

Charles