From owner-freebsd-fs Fri Feb 27 21:13:45 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id VAA21355 for freebsd-fs-outgoing; Fri, 27 Feb 1998 21:13:45 -0800 (PST) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from dyson.iquest.net (dyson.iquest.net [198.70.144.127]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id VAA21345 for ; Fri, 27 Feb 1998 21:13:40 -0800 (PST) (envelope-from toor@dyson.iquest.net) Received: (from root@localhost) by dyson.iquest.net (8.8.8/8.8.8) id AAA00289; Sat, 28 Feb 1998 00:13:06 -0500 (EST) (envelope-from toor) From: "John S. Dyson" Message-Id: <199802280513.AAA00289@dyson.iquest.net> Subject: Re: syncer / SMP question In-Reply-To: <199802280454.PAA20951@godzilla.zeta.org.au> from Bruce Evans at "Feb 28, 98 03:54:10 pm" To: bde@zeta.org.au (Bruce Evans) Date: Sat, 28 Feb 1998 00:13:06 -0500 (EST) Cc: eivind@yes.no, jlemon@americantv.com, fs@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL32 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Bruce Evans said: > >> It appears to be released. The vfs_busy() routine makes a call to > >> lockmgr(), which sets a lock on mountpoint and releases the lock on > >> the mountlist. > > > >But... But... What about the fetch of the next-pointer? Looks like > >a potential race-condition to me, but this includes some lock-calls I > >don't really understand what do (interlocks? What are they?). > > Interlocks are for very short-term locks and for locking the aquisition > of full locks. > One rule-of-thumb is never to block (tsleep) when you have an interlock. -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message