Date: Wed, 18 Aug 1999 19:36:22 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Bill Studenmund <wrstuden@nas.nasa.gov> Cc: Terry Lambert <tlambert@primenet.com>, Alton Matthew <Matthew.Alton@anheuser-busch.com>, Hackers@FreeBSD.ORG, fs@FreeBSD.ORG Subject: Re: BSD XFS Port & BSD VFS Rewrite Message-ID: <1240.934997782@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 18 Aug 1999 10:30:39 PDT." <Pine.SOL.3.96.990818101005.14430B-100000@marcy.nas.nasa.gov>
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In message <Pine.SOL.3.96.990818101005.14430B-100000@marcy.nas.nasa.gov>, Bill Studenmund writes: >Whew! That's reasuring. I agree there are things which need fixing. It'd >be nice if both NetBSD and FreeBSD could fix things in the same way. Well, >that< still remains to be seen... >> >> The use of the "vfs_default" to make unimplemented VOP's >> >> fall through to code which implements function, while well >> >> intentioned, is misguided. >> >> I beg to differ. The only difference is that we pass through >> multiple layers before we hit the bottom of the stack. There is >> no loss of functionality but significant gain of clarity and >> modularity. > >If I understood the issue, it is that the leaf fs's (the bottom ones) >would use a default routine for non-error functionality. I think Terry's >point (which I agree with) was that a leaf fs's default routine should >only return errors. I beg to differ. It is far more likely, in my mind, that you will want to handle a currently existing, unimplemented VOP than add a new one. Using the default for >all< unimplemented VOPs makes this possible, using the same logic which makes adding a VOP possible. Go back and review the diffs from when I did this, and my other argument why this is a good idea should be obvious. >I doubt we need more than 64 bit times. 2^63 seconds works out to >292,279,025,208 years, or 292 (american) billion years. Current theories >put the age of the universe at I think 12 to 16 billion years. So 64-bit >signed times in seconds will cover from before the big bang to way past >any time we'll be caring about. :-) But we cannot do time in seconds resolution, we need to resolve at least the cpu clock frequency, which right now is approaching 1GHz (30bit!) -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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