Date: Mon, 23 Aug 1999 09:47:40 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Greg Lehey <grog@lemis.com> Cc: Matthew Dillon <dillon@apollo.backplane.com>, FreeBSD Hackers <hackers@FreeBSD.ORG>, FreeBSD Committers <cvs-committers@FreeBSD.ORG>, Garrett Wollman <wollman@khavrinen.lcs.mit.edu> Subject: Re: Mandatory locking? Message-ID: <7569.935394460@critter.freebsd.dk> In-Reply-To: Your message of "Mon, 23 Aug 1999 16:28:13 %2B0930." <19990823162813.I83273@freebie.lemis.com>
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In message <19990823162813.I83273@freebie.lemis.com>, Greg Lehey writes: >>>> Why should it be made unavailable ? >>> >>> So that certain multiple accesses can be done atomically. >> >> You don't need that. You initialize a index to 0, and whenever the >> sector with that index is written, you increment it. >> >> At any one time you know that all parityblocks <= your index >> are valid. > >Sure, that's pretty much what I do in the situation you're thinking >about. But it won't work without locking. Take a look at >vinumrevive.c and vinumrequest.c. I still don't see the need for mandatory locking, or locking out user access in general... >>> I'm a little surprised that there's any objection to the concept of >>> mandatory locking. >> >> Too many of us have had wedged systems because of it I guess... > >Strange, I've probably used it more than anybody here, and I've never >had a wedged system. Of course, you need to use it appropriately. >'rm' can be a lethal tool :-) Well, maybe you were more lucky, I've had my share of troubles, and I think the very concept stinks... -- 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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