Date: Fri, 13 Aug 1999 12:51:48 -0700 (PDT) From: Julian Elischer <julian@whistle.com> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/miscfs/specfs spec_vnops.c src/sys/sys conf.h Message-ID: <Pine.BSF.3.95.990813124653.3531H-100000@current1.whistle.com> In-Reply-To: <4546.934573133@critter.freebsd.dk>
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On Fri, 13 Aug 1999, Poul-Henning Kamp wrote: > > I'm not sure I copy you here, (actually I very sure I don't :-) > > Could you explain what it is that the driver wants to know here ? The driver in one system I was playing with, needed to know when the last writer releasd the device so that the driver could downgrade the device to read-only mode. The reason for this was that when this happenned, the device would complete an internal back-up of the data, and label the backup as 'stable'. Unless you keep track of all closes and mode changes, you can't do this. Also Justin was saying he wnated to do this for some of his own reasons as well. The simplest way to do it would be to add an advisory entrypoint that was called for ALL closes, not just the last one, and also when a fork happenned as you now have more users. I wasn't too fussed about that one, but Justin had some good reasons at the time... julian > > Poul-Henning > > In message <Pine.BSF.3.95.990813111357.3531A-100000@current1.whistle.com>, Julian Elischer writes: > >(yey) > >however I discovered in the SLICE code that it woudl be good if the third > >operation was: > >proc2: close > > devsw->modechenge(R/W, 0, proc2 ) > > > >on fork: > >proc2: close > > devsw->modechenge(0, R/W, proc2 ) > > > > > > > >where the close2() operation is called on all close() operations > > > >On Fri, 13 Aug 1999, Poul-Henning Kamp wrote: > > > >> phk 1999/08/13 09:29:28 PDT > >> > >> Modified files: > >> sys/miscfs/specfs spec_vnops.c > >> sys/sys conf.h > >> Log: > >> Add support for device drivers which want to track all open/close > >> operations. This allows a device driver better insight into > >> what is going on that the current: > >> > >> proc1: open /dev/foo R/O > >> devsw->open( R/O, proc1 ) > >> proc2: open /dev/foo R/W > >> devsw->open( R/W, proc2 ) > >> proc2: close > >> /* nothing, but device is > >> really only R/O open */ > >> proc1: close > >> devsw->close( R/O, proc1 ) > >> > >> Revision Changes Path > >> 1.95 +18 -59 src/sys/miscfs/specfs/spec_vnops.c > >> 1.72 +3 -2 src/sys/sys/conf.h > >> > >> > >> > > > > > > -- > 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 cvs-all" in the body of the message
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