Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263653AbUAITlw (ORCPT ); Fri, 9 Jan 2004 14:41:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263823AbUAITlw (ORCPT ); Fri, 9 Jan 2004 14:41:52 -0500 Received: from nwkea-mail-1.sun.com ([192.18.42.13]:16822 "EHLO nwkea-mail-1.sun.com") by vger.kernel.org with ESMTP id S263653AbUAITls (ORCPT ); Fri, 9 Jan 2004 14:41:48 -0500 Date: Fri, 09 Jan 2004 14:41:30 -0500 From: Mike Waychison Subject: Re: [autofs] [RFC] Towards a Modern Autofs In-reply-to: <20040108183135.GE30321@parcelfarce.linux.theplanet.co.uk> To: viro@parcelfarce.linux.theplanet.co.uk Cc: Ian Kent , autofs mailing list , "H. Peter Anvin" , "Ogden, Aaron A." , Kernel Mailing List Message-id: <3FFF03EA.4060603@sun.com> MIME-version: 1.0 Content-type: multipart/signed; boundary=------------enigDF8BFFCC985004A828D633B9; protocol="application/pgp-signature"; micalg=pgp-sha1 X-Accept-Language: en User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20031107 Debian/1.5-3 X-Enigmail-Version: 0.82.2.0 X-Enigmail-Supports: pgp-inline, pgp-mime References: <3FFC96FE.9050002@zytor.com> <20040108183135.GE30321@parcelfarce.linux.theplanet.co.uk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2600 Lines: 80 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigDF8BFFCC985004A828D633B9 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit viro@parcelfarce.linux.theplanet.co.uk wrote: >On Thu, Jan 08, 2004 at 08:52:31PM +0800, Ian Kent wrote: > > >>On Wed, 7 Jan 2004, H. Peter Anvin wrote: >> >> >> >>>These are the mount traps Al Viro has been architecting. >>> >>> >>> >>Please tell me about these. >> >>I have`nt seen any discussion on the implementation. >> >>Just a few sentences .... >> >> > >Special vfsmount mounted somewhere; has no superblock associated with it; >attempt to step on it triggers event; normal result of that event is to >get a normal mount on top of it, at which point usual chaining logics >will make sure that we don't see the trap until it's uncovered by removal >of covering filesystem. Trap (and everything mounted on it, etc.) can >be removed by normal lazy umount. > >Basically, it's a single-point analog of autofs done entirely in VFS. >The job of automounter is to maintain the traps and react to events. > > > Is there any clear advantage to doing this in the VFS other than saving a superblock and a dentry/inode pair or two? I remember talking to you about this, and I seem to recall that these mount traps would probably communicate using a struct file, so a trap-user would somehow receive events about when the trap was set off. Will this communication model continue to work within a cloned namespace? What happens if the trap-client closes the file? -- Mike Waychison Sun Microsystems, Inc. 1 (650) 352-5299 voice 1 (416) 202-8336 voice mailto: Michael.Waychison@Sun.COM http://www.sun.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NOTICE: The opinions expressed in this email are held by me, and may not represent the views of Sun Microsystems, Inc. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ --------------enigDF8BFFCC985004A828D633B9 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) Comment: Using GnuPG with Debian - http://enigmail.mozdev.org iD8DBQE//wPtdQs4kOxk3/MRAiUvAJ9AdoamY4cnkTfTF4eRq00Ue+6/ygCfcauv aeslSGMIzLiEiGNx/3Pb0FY= =Hp/r -----END PGP SIGNATURE----- --------------enigDF8BFFCC985004A828D633B9-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/