From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shaya Potter <spotter@cs.columbia.edu>
Subject: Re: [RFC][PATCH  0/15] VFS based Union Mount
Date: Tue, 17 Apr 2007 10:35:50 -0400
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Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Jan Blunck <j.blunck@tu-harburg.de>
To: bharata@linux.vnet.ibm.com
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Bharata B Rao wrote:
> Hi,
> 
> Here is an attempt towards vfs based union mount implementation.
> Union mount provides the filesytem namespace unification feature.
> Unlike the traditional mounts which hide the contents of the mount point,
> the union mount presents the merged view of the mount point and the
> mounted filesytem.

does this approach allow one to add directories to the union and have it 
behave normally.  namely when imagine one has the situation

dir-b
dir-a/ (contains file foo)


if one unions this and deletes foo, that will create a whiteout entry in 
dir-a

now, what happens if one does

dir-c
dir-b (now contains whiteout, from previous union).
dir-a (contains file foo)

will one see foo or not. i.e. are whiteouts only looked for in the 
topmost dir, or in every dir?