Re: silent semantic changes with reiser4

From: Hans Reiser
Date: Sun Aug 29 2004 - 15:12:53 EST


viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:

On Sun, Aug 29, 2004 at 07:36:29PM +0100, viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:


he wants without recompiling to do it. This kind of a view requires no coding because you can just mount the root filesystem two ways, one with the -nopseudos mount option, and one without it.


*What*?

OK, now I want detailed explanation of the reasons why that doesn't create
cache coherency problems.

Do you have an analysis of locking in the entire thing?



And I am very, very serious about that - we are talking about very nasty
minefield and design choices in that area have fundamental impact on the
entire layer, wherever it is located.

It's *NOT* something that you can leave until later and hope it somehow
falls into place - it can be merged in steps, but you MUST know the goal
on that level. To rearchitect later might be possible (even though you
will a hell of a time avoiding plugins breakage), but it will be *hard*.




How about if you educate me on the problems you see for a bit before I respond? I think it might help us move into a constructive discussion.

You are more experienced with your code than I am.... but I firmly believe that having different views of the same filesystem in which some files are visible in one view but not in another is technically feasible for some VFS, though I'd like to learn about the problems you see for doing it in the current VFS.
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