git: kernel - Do not allow (devfs) devices to be force-unmounted

Matthew Dillon dillon at
Wed Jan 23 14:00:23 PST 2013

commit 0465e1d385953232678697cd5c17964cf45eaf49
Author: Matthew Dillon <dillon at>
Date:   Wed Jan 23 13:56:37 2013 -0800

    kernel - Do not allow (devfs) devices to be force-unmounted
    * Do not force-unmount devfs devices.  Even more importantly, don't
      force-unmount devfs devices and then try to force-vflush them.
      Filesystems have always been responsible for flushing their underlying
      block devices.
      These situations occur during halt/reboot.
    * Fixes at least one issue when hammer's volume-add is used to specify
      a block device in /dev which is then added to the root mount.  This
      created a situation where the /dev vs / unmount order breaks.
    * Should also prevent e.g. the console or other vty hangers-on from being
      destroyed out from under active descriptors during a halt or reboot.

Summary of changes:
 sys/kern/vfs_mount.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

DragonFly BSD source repository

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