Re: kern/38990: Unmounting a disk fails the first time

[Andrew Doran <ad%netbsd.org@localhost>]

The following reply was made to PR kern/38990; it has been noted by GNATS.

From: Andrew Doran <ad%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/38990: Unmounting a disk fails the first time
Date: Fri, 20 Jun 2008 09:28:30 +0000

 On Thu, Jun 19, 2008 at 05:35:00PM +0000, apb%cequrux.com@localhost wrote:
 
 > >Description:
 >         Attempting to unmount a file system that has recently been busy
 >         may fail.  Unmounting again after a short delay and/or sync is
 >         successful.
 >
 > >How-To-Repeat:
 >      $ sudo mount -t ffs /dev/sd0e /mnt
 >      $ rsync /something/ /mnt/something/ # a large directory tree
 >      $ sudo umount /mnt
 >      umount: /mnt: Device busy
 >      $ sync ; sleep 1 ; sync ; sleep 1 ; sync
 >      $ sudo umount /mnt
 >      [ no error ]
 
 It's due to the kernel's 'vrele' thread. Sometimes we have to defer
 VOP_INACTIVE because of the horrible locking requirements. It always
 gets done for layered file systems. The delay is about one second.
 
 Andrew