Date: Mon, 24 Mar 1997 19:24:58 -0800 (PST) From: richw@webcom.com To: freebsd-gnats-submit@freebsd.org Subject: kern/3091: Can't umount MFS file system Message-ID: <199703250324.TAA06593@freefall.freebsd.org> Resent-Message-ID: <199703250330.TAA07002@freefall.freebsd.org>
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>Number: 3091 >Category: kern >Synopsis: Can't umount MFS file system >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Mar 24 19:30:01 PST 1997 >Last-Modified: >Originator: Rich Wales >Organization: >Release: 2.2-RELEASE >Environment: FreeBSD yank.kitchener.on.ca 2.2-RELEASE FreeBSD 2.2-RELEASE #0: Mon Mar 24 19:20:29 EST 1997 richw@yank.kitchener.on.ca:/home/src/sys/compile/YANK i386 >Description: I built a kernel with "options MFS" and mounted a MFS file system as /tmp. I am unable to unmount this file system. "umount /tmp" fails with "umount: /tmp: Device busy". Even when going to single user mode, /tmp cannot be unmounted. If I try to force the issue via "umount -f /tmp" or "reboot", or by killing the "mfs" process supporting /tmp, the kernel crashes with a page fault (code 12). The problem doesn't depend on the MFS file system being /tmp. I tried mounting an MFS file system as /mnt, with the same results. I also mounted /mnt while in single-user mode, and immediately tried to unmount it, but the unmount still failed. >How-To-Repeat: Build a kernel with "options MFS". Add a line like the following to /etc/fstab: /dev/wd0s2b /tmp mfs rw,-s=50000 0 0 (substituting your swap partition as appropriate). After the system is up multi-user, log in as root and "shutdown now". Note how "some processes wouldn't die". If you do "ps ax", you'll see the "mfs" process for the /tmp file system is still around. Forcibly unmount /tmp in any of the following ways: 1. reboot 2. umount -f /tmp 3. kill the "mfs" process The kernel will die with a page-fault panic. >Fix: >Audit-Trail: >Unformatted:
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