Re: patent on O_ATOMICLOOKUP [Re: [PATCH] loopable tmpfs (2.4.17)]

Larry McVoy (lm@bitmover.com)
Sun, 26 May 2002 13:33:35 -0700


On Sun, May 26, 2002 at 04:17:07PM -0400, Alexander Viro wrote:
> > Sniffle, whimper. It is clearly different in that it calls out to the
> > BSD allocation policy, which is completely different.
>
> Um... In 4.2 - more or less so. In 4.4 - way more than that:
> * ffs_bmap() is not doing any allocations now
> * ffs_balloc() does (and is an analog of old bmap()) and it contains

I think I was looking at 4.3Tahoe, but it doesn't matter, what I was
thinking about was your comment about frags, that makes things quite
different. And I know, err, am pretty sure, that by this point Kirk
had worked over the allocation policy to keep things in the same
cylinder group when possible and I don't think that the original
file system was quite as careful.

> WTF? 4BSD code is out there, in SCCS, no less. Goes back
> to 1982 or so. It's not that checking it would be a problem - grab
> the 4th CD from Kirk's 4-parter (CSRG archives) and see yourself.

Yup, got it. I've had some fun in there.

> BTW, having _that_ converted to BK might be an interesting thing.
> To do that one would need to take file moves into account, but they'd
> got enough snapshots of the tree to reconstruct that...

Yes, I know, it's on my list of things to do. There are some compat issues,
it isn't a trivial thing, but we can and will do it. Another thing I plan
to do is to build up BK repositories of all the BSD docs as well as all the
troff docs. I really like troff, I'm not a fan of latex or word, troff
still works better for me but I think many people abandoned it out of a
lack of documentation. And when that's done, I'll make man page versions
of all the stupid info stuff so I can say "man whatever" and get what
I need.

Wandering well into the weeds....

-- 
---
Larry McVoy            	 lm at bitmover.com           http://www.bitmover.com/lm 
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