Re: kern/45305: umount says device busy without any process having current directory in the mount or file open

[Matthias Kretschmer <kretschm%cs.uni-bonn.de@localhost>]

Hello,

it got it again ...

On Mon, Aug 29, 2011 at 10:25:02AM +0000, matthew green wrote:
>  what does "fstat" say in this case?  it should report any thing that
>  is showing an open filesystem.  also, for the killed everything case,
>  what processes are running?

# fstat
USER     CMD          PID   FD MOUNT       INUM MODE         SZ|DV R/W
root     fstat      18085   wd /          31885 drwxr-xr-x     512 r 
root     fstat      18085    0 /          53128 crw-------   ttyE0 rw
root     fstat      18085    1 /          31999 -rw-r--r--       0 w 
root     fstat      18085    2 /          53128 crw-------   ttyE0 rw
root     fstat      18085    3 /          53828 crw-r-----     mem r 
root     fstat      18085    4 /          53827 crw-r-----    kmem r 
root     fstat      18085    5 /          53826 crw-r-----    drum r 
root     fstat      18085    6 /            377 -rw-------   40960 r 
root     sh          4953   wd /          31885 drwxr-xr-x     512 r 
root     sh          4953    0 /          53128 crw-------   ttyE0 rw
root     sh          4953    1 /          53128 crw-------   ttyE0 rw
root     sh          4953    2 /          53128 crw-------   ttyE0 rw
root     sh          4953  127 /          53833 crw-rw-rw-     tty rw
root     login      23308   wd /          31885 drwxr-xr-x     512 r 
root     login      23308    0 /          53128 crw-------   ttyE0 rw
root     login      23308    1 /          53128 crw-------   ttyE0 rw
root     login      23308    2 /          53128 crw-------   ttyE0 rw
root     init           1   wd /              2 drwxr-xr-x     512 r 
root     system         0   wd /              2 drwxr-xr-x     512 r 

# ps ax
  PID TTY   STAT     TIME COMMAND
    0 ?     DKl  10:46.21 [system]
    1 ?     Is    0:00.71 init 
 4953 ttyE0 S     0:02.82 -sh 
23308 ttyE0 Is    0:00.54 login 
25680 ttyE0 O+    0:00.01 ps -ax 

# umount /netboot
umount: /netboot: Device busy


So as you can see, there is no process running which has any access
to /netboot, even though it cannot be unmounted.
The corresponding /netboot entry from fstab:
<host>:/home/macppc/root  /netboot  nfs  rw,noauto


--
Matthias Kretschmer