From owner-cvs-src@FreeBSD.ORG Tue Jan 4 07:52:27 2005 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7AAD516A4CE; Tue, 4 Jan 2005 07:52:27 +0000 (GMT) Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115]) by mx1.FreeBSD.org (Postfix) with ESMTP id 64A1B43D45; Tue, 4 Jan 2005 07:52:27 +0000 (GMT) (envelope-from phk@FreeBSD.org) Received: from repoman.freebsd.org (localhost [127.0.0.1]) by repoman.freebsd.org (8.13.1/8.13.1) with ESMTP id j047qRYX092691; Tue, 4 Jan 2005 07:52:27 GMT (envelope-from phk@repoman.freebsd.org) Received: (from phk@localhost) by repoman.freebsd.org (8.13.1/8.13.1/Submit) id j047qRDD092690; Tue, 4 Jan 2005 07:52:27 GMT (envelope-from phk) Message-Id: <200501040752.j047qRDD092690@repoman.freebsd.org> From: Poul-Henning Kamp Date: Tue, 4 Jan 2005 07:52:26 +0000 (UTC) To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org X-FreeBSD-CVS-Branch: HEAD Subject: cvs commit: src/sys/fs/devfs devfs_vfsops.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Jan 2005 07:52:27 -0000 phk 2005-01-04 07:52:26 UTC FreeBSD src repository Modified files: sys/fs/devfs devfs_vfsops.c Log: Unsupport forceful unmounts of DEVFS. After disscussing things I have decided to take the easy and consistent 90% solution instead of aiming for the very involved 99% solution. If we allow forceful unmounts of DEVFS we need to decide how to handle the devices which are in use through this filesystem at the time. We cannot just readopt the open devices in the main /dev instance since that would open us to security issues. For the majority of the devices, this is relatively straightforward as we can just pretend they got revoke(2)'ed. Some devices get tricky: /dev/console and /dev/tty for instance does a sort of recursive open of the real console device. Other devices may be mmap'ed (kill the processes ?). And then there are disk devices which are mounted. The correct thing here would be to recursively unmount the filesystems mounte from devices from our DEVFS instance (forcefully) and if this succeeds, complete the forcefully unmount of DEVFS. But if one of the forceful unmounts fail we cannot complete the forceful unmount of DEVFS, but we are likely to already have severed a lot of stuff in the process of trying. Event attempting this would be a lot of code for a very far out corner-case which most people would never see or get in touch with. It's just not worth it. Revision Changes Path 1.39 +1 -1 src/sys/fs/devfs/devfs_vfsops.c