Re: silent semantic changes with reiser4

From: Hans Reiser
Date: Wed Aug 25 2004 - 14:58:22 EST


I had not intended to respond to this because I have nothing positive to say, but Andrew said I needed to respond and suggested I should copy Linus. Sigh.

Dear Christoph,

Let me see if I can summarize what you and your contingent are saying, and if I misconstrue anything, let me know.;-)

You ignored everything I said during the discussion of xattrs about how there is no need to have attributes when you can just have files and directories, and that xattrs reflected a complete ignorance of name space design principles. When I said we should just add some nice optional features to files and directories so that they can do everything that attributes can do if they are used that way, you just didn't get it. You instead went for the quick ugly hack called xattrs. You then got that ugly hack done first, because quick hacks are, well, quick. I then went about doing it the right way for Reiser4, and got DARPA to fund doing it. I was never silent about it.

Making files into directories caused only two applications out of the entire OS to notice the change, and that was because of a bug in what error code we returned that we are going to fix. You think that was a disaster; I think it was a triumph.

Now a cleanly architected filesystem with no attributes and just files and directories that can do everything attributes are used for exists. You don't want it to have the competitive advantage. Instead, you want it to have its clean design excised until you have something that duplicates it ready to go, and only then should it be allowed that users will use the features of your competitor's filesystem which you disdained implementing for so long.

Since you never studied or understood namespace design principles (or you would not have created and supported xattrs), you want to rename it to be called VFS, rewrite what we have done, and take over as the maintainer, mangling its design in a committee clusterfuck as you go.

We have just implemented very trivial semantic enhancements of the FS namespace, nothing like as ambitious as www.namesys.com/whitepaper.html or WinFS, and you are already pissing your pants.

Is that a fair summary?

Eat my dust.

Hans

PS

I should of course qualify what I have said. The use of files and directories in place of attributes is not a finished work. It has bugs, sys_reiser4() does not yet work, and there are little features still missing like having files readdir ignores.

Still, except for the bugs, what we have is usable, and there are a lot of happy reiser4 users right now even with the bugs. It will need a little bit more time, and then all the pieces will be in place.

PPS

If you implement your filesystems as reiser4 plugins, and rename reiser4's plugin code to be called "vfs", your filesystems will go faster. Not as fast as reiser4 though, because it has a better layout and that affects performance a lot, but faster is faster.... See www.namesys.com/benchmarks.html for details.

PPPS

Since we have such a performance lead, Namesys is about to change its focus from the storage layer to semantics, look at www.namesys.com/whitepaper.html for details. Semantic enhancements are the important stuff, and finally Namesys is where we have all the storage layer prerequisites done right, and the real work can begin. The gap between us is about to widen further.



Christoph Hellwig wrote:

After looking trough the code and mailinglists I'm quite unhappy with
a bunch of user-visible changes that Hans sneaked in and make reiser4
incompatible with other filesystems

if we leave you in the dust, run faster.... not my problem....


Given these problems I request that these interfaces are removed from
reiser4 for the kernel merge, and if added later at the proper VFS level
after discussion on linux-kernel and linux-fsdevel, like we did for
xattrs.




If you can't help fight WinFS, then get out of the way. Namesys is on the march. Read www.namesys.com/whitepaper.html.

Or, be smart, recognize that reiser4 is faster and more flexible than your storage layers because we are older and wiser and worked harder at it, join the team, and start contributing plugins that tap into the higher performance it offers.

Microsoft tried to build a storage layer that could handle small objects without losing performance, failed, and gave up at considerable cost to their architecture and pocketbook.

We just broke a hole in the enemy line. You could come swarming through it with us, but it sounds like you prefer complaining to HQ that we are getting too far in front of you.

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