Re: reiser4 plugins

David Masover
2005-07-01T08:06:49Z

Hubert Chan wrote:
> On Wed, 29 Jun 2005 17:34:41 -0400, Ross Biro <ross.biro@gmail.com> said:
>
>
>>I'm confused. Can someone on one of these lists enlighten me?
>
>
>>How is directories as files logically any different than putting all
>>data into .data files and making all files directories (yes you would
>>need some sort of special handling for files that were really called
>>.data). Then it's just a matter of deciding what happens when you
>>call open and stat on one of these files?
>
>
> Logically, I don't think there is a difference. A filesystem that
> doesn't support file-as-dir could implement the same functionality that
> way. [1] In fact, that's essentially what MacOS X/NeXTSTEP does with its
> bundle format -- it's just a regular directory with regular files
> inside.

I, personally, would hate it if everything in my /bin suddenly became a
directory, mainly because everything would stop working. Is that the
kind of thing you're suggesting?

I'm a little confused about the .data idea, I guess.

>>But we could have a whole new set of system calls that treat things as
>>magic, and if files as directories is as cool as many people think,
>>apps will start using the new api. If not, they won't and the new api
>>can be deprecated.
>
>
> File-as-dir doesn't require new system calls (that I know of), which is
> the whole point of the idea. Existing programs can edit the strange new
> attributes without being modified.

That is indeed the point, but scroll down.

> The main thing blocking file-as-dir is that there are some
> locking(IIRC?) issues. And, of course, some people wouldn't want it to
> be merged into the mainline kernel. (Of course, the latter doesn't
> prevent Namesys from maintaining their own patches for people to play
> around with.)

What's the locking issue? I think that was more about transactions...

[...]
> People like Horst (and probably others, who are less vocal), I think,
> don't think that it's even worth trying it out because they don't see
> any major advantages. Or at least they think that the potential
> negatives outweigh the potential positives. I respect that they have
> different opinions, but I of course disagree and attempt to convince
> them otherwise.

Did the /meta (metafs) idea get killed while I was out? Using that
approach, your potential negatives are that apps which crawl the entire
FS tree, starting at /, with hardcoded apps for /proc and /sys, are now
broken -- but then, /sys already broke them once, so I don't
particularly care if we break them again.

Potential positives? I think even just because we like the idea is
enough, because it doesn't break anything and doesn't really affect
anyone who doesn't use it.

Maybe there are coding standards, but I think others are working that
out now.