Download your favorite Linux distribution at LQ ISO.
Go Back > Forums > Linux Forums > Linux - Distributions > Slackware
User Name
Slackware This Forum is for the discussion of Slackware Linux.


  Search this Thread
Old 03-05-2006, 05:36 PM   #1
Registered: Jun 2002
Location: Southeast PA
Distribution: Slackware
Posts: 40

Rep: Reputation: 15
Strange NFS mount / umount problem .. ..or Bug?

On one of my systems, running Slackware 10.1 with a Kernel, I
have been noticing the following problem with using NFS.

I mount a Linux ext2 partition on a USB drive

BOX1> mount /dev/sdb1 /usb1

I have the /usb1 directory listed in my /etc/exports file so it
so other systems on my network can access the USB drive.

So.. then.. from another system I will do ..

BOX2> mount BOX1:/usb1 /usb1

OK.. Fine. Then from BOX2 I access the USB drive just fine as you would
expect. When I am done with it I do :

BOX2> umount /usb1

And as expected, the NFS filesystem is unmounted just fine .. on BOX2

Now from BOX1 I do:

BOX1> umount /usb1

and I get..

umount: /usb1: device is busy
umount: /usb1: device is busy

.. yet nothing appears to be using it. There is no way to umount /usb1
unless I shutdown NFS by doing :

BOX1> /etc/rc.d/rc.nfsd stop
BOX1> /umount /usb1 ( it un mounts just fine now)
BOX1> /etc/rc.d/rc.nfsd start

This does not seem right to me. I can't imagine this being by design.
Anyone else see it? Is it a [known] bug or limitation?

If I mount the USB partition on BOX1 and *do not* access
it via NFS from another system, then I can unmount it later.
But it seems like once NFS gets ahold of it it does not
want to let it go.

Last edited by PeteRossi; 03-05-2006 at 05:41 PM.
Old 03-05-2006, 08:57 PM   #2
Registered: Apr 2005
Location: Ohio
Distribution: Slackware && freeBSD
Posts: 676

Rep: Reputation: 30
Make sure you have no open files from box1 or box2, ie: still not in the usb directory on either box and/or other files are not open.
Hope it helps some.
Old 03-06-2006, 08:52 PM   #3
Registered: Jun 2002
Location: Southeast PA
Distribution: Slackware
Posts: 40

Original Poster
Rep: Reputation: 15
That is why I am asking this question. No files on the
USB filesystem *are* open. To repeat the question in
another way...

If I do the mount and then do the umount it will unmount
just fine.

If I do the mount and then do an NFS mount from another
system.. then unmount NFS from the other system, then I
can't do an umount unless I shutdown all NFS services,
do the umount, and then restart NFS.

USB has anything to do with it. Same thing happens
with any file system.
Old 03-07-2006, 09:25 PM   #4
Senior Member
Registered: Mar 2003
Location: Burke, VA
Distribution: RHEL, Slackware, Ubuntu, Fedora
Posts: 1,418
Blog Entries: 1

Rep: Reputation: 46
Try running
lsof /usb1
For what it's worth, this sounds like normal behavior. Once the nfsd daemon
fires up and begins sharing that directory, it caches certain things in memory
and treats the share as being 'open'. No matter if the remote box closed the

If 'lsof' doesn't reveal any open files in the mount point, try using the
'sync' command, which writes any changes to file systems, and then umount.

NFS wasn't meant traditionally to share removable devices, so I would call
this more of an 'oversight' than a bug.

-- Shade


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to mount a nfs mount from linux client to AIX nfs server dennyqian AIX 13 04-11-2016 11:30 PM
NFS mount of smb mount of windows share: permission denied problem :( Bagatur Linux - Networking 4 07-07-2009 11:34 AM
mount and umount problem salahuddin_66 Debian 3 05-03-2005 07:49 AM
Strange problem or bug bato Slackware 3 02-18-2005 01:56 PM
Mount/Umount Floppy problem - Urgent! moisvon Linux - Newbie 1 07-10-2003 03:10 PM > Forums > Linux Forums > Linux - Distributions > Slackware

All times are GMT -5. The time now is 11:40 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration