Date: Wed, 25 Aug 1999 15:45:41 +0930 From: Greg Lehey <grog@lemis.com> To: hackers@FreeBSD.org Cc: cvs-committers@FreeBSD.org Subject: Re: Locking in Vinum (was: Mandatory locking?) Message-ID: <19990825154541.P83273@freebie.lemis.com> In-Reply-To: <199908250528.WAA16151@kithrup.com>; from Sean Eric Fagan on Tue, Aug 24, 1999 at 10:28:10PM -0700 References: <199908250152.SAA16323@usr01.primenet.com>; <19990825113518.D83273.kithrup.freebsd.cvs-all@freebie.lemis.com> <199908250528.WAA16151@kithrup.com>
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On Tuesday, 24 August 1999 at 22:28:10 -0700, Sean Eric Fagan wrote: > In article <19990825113518.D83273.kithrup.freebsd.cvs-all@freebie.lemis.com> you write: >> Correct. I lock a stripe at a time. > > What people need to realize is that Greg is doing this locking in user mode. > > As such, he has two real options: > > 1. Implement a vinum-specific ioctl that locks a region of a file at the > device level, or > > 2. Implement standard mandatory region locking, which damned near every > OS in existence has, and which OSes which have existed for decades > longer than unix has existed have always had. > > Now, because this _is_ (currently) a vinum-specific requirement, doing (1) is > not all that unpalatable. However, it's at the wrong level (device driver, > instead of file), and it is merely putting off the inevitable. In fact, this confusion with Vinum is more historical than anything. I started thinking "what tools are available for this as yet not clearly defined task that will run in user mode and require locking?". The obvious first question was "do we support read (i.e. mandatory) locking?". > Or does nobody wish to have working Linux and Solaris/x86 > compatibility after all? > > That reason, if nothing else, is reason to design it, so it gets done > correctly. Exactly, and that was why I started this thread. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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