Date: Wed, 18 Aug 1999 21:01:53 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: phk@critter.freebsd.dk (Poul-Henning Kamp) Cc: tlambert@primenet.com, michaelh@cet.co.jp, wrstuden@nas.nasa.gov, Matthew.Alton@anheuser-busch.com, Hackers@FreeBSD.ORG, fs@FreeBSD.ORG Subject: Re: BSD XFS Port & BSD VFS Rewrite Message-ID: <199908182101.OAA29646@usr06.primenet.com> In-Reply-To: <1774.935002618@critter.freebsd.dk> from "Poul-Henning Kamp" at Aug 18, 99 08:56:58 pm
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> >> >You would have to de-collapse several VOP lists that have been > >> >pre-collapsed. > >> > >> You are talking gibberish here. Please show code where this is > >> a problem. > > > >When you write a proxy stacking layer, such as John Heidemann's > >network proxy stacking layer (an NFS alternative), VOP's which > >would normally be handled by vfs_default have to be handled on > >the other end of the proxy, instead, in the same way that they > >would be handled by the vfs_default stuff. > > And what prevents you from taking over the default op ? It needs to be NULL, not taken over. machine 1 machine2 machine 3 vfs consumer upper proxy <---------> lower proxy vfs stacking layer upper proxy <---------> lower proxy vfs producer How do I get a VOP, unknown to machine 2, from the vfs consumer on machine 1 that does know about it, to the vfs producer on machine 3 that also knows about it? My understanding is that it is very hard, given vfs_default: On machine 1, since the upper proxy doesn't know from VOP's, it wants to locally satisfy it from vfs_default on machine 1. Taking over the default op doesn't really help me; I have to do surgery to the in core dispatch vector instance to do the job properly (e.g. zapping it out, not taking it over). On machine 2, it is out of range, but still needs to be passed through the stacking layer, from the lower porxy to the upper proxy (and the response, back). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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