Hi Trond,
Thank you for your answer.
exportfs does not report the individual directories that are mounted
on the exported directory, so I cannot use your script.
on the nfsserver exports file:
/adir 192.168.11.129(rw,sync,no_subtree_check,crossmnt,no_root_squash)
on the same machine:
mount -o loop virtual.iso virtualstuff
so now I have /adir/virtualstuff
(which by the way, I can: umount virtualstuff immediately without
problem and it releases.
however, if I run XEN on the client, then the directory is permanently
locked, ie, umount virtualstuff
DOESN'T work again unless I run exportfs -ua killing all connections
to the server.)
the nfs-client sees /adir/virtualstuff, since parent /adir is mounted.
When I run the virtualmachine within the virtualstuff directory (xm
create /adir/virtualstuff/config.cfg)
and then I destroy the virtualmachine (xm destroy /adir/virtualstuff/config.cfg)
I can never 'umount virtualstuff' from the nfsserver, even though no
one is accessing the directory
any more.
So on the nfsserver I cannot umount virtualstuff. this is the bug.
exportfs -ua kills nfs for everybody, and then I can run 'umount
virtualstuff', but this is not what I want.
exportfs -u nfsclient:/adir doesn't even work. I don't want this
variation because I might be running 2 virtual machines
in two subdirectories.
question: is the fact that ;exportfs -u nfsclient:/adir' doesn't work a bug?
What I want to be able to do is from the nfsserver side, 'umount
virtualstuff', which I can do if I
1) never run XEN, or
2) exportfs -ua. The latter command kills all clients attached to the server
so I cannot use this second command.
3) the command 'exportfs -u nfsclient:/adir' doesn't work and this
might be a bug. I do not
want this variant since if I am running 2 virtual machines on the
nfsclient I would kill the other machine.
In /proc/net/rpc/nfsd.export/content I see my virtualstuff
subdirectory referenced. Perhaps this
tells you something.
Thank you in advance,
Roger Marcus
On Fri, May 8, 2009 at 2:24 PM, Trond Myklebust
<trond.myklebust@xxxxxxxxxx> wrote:
> On Fri, 2009-05-08 at 08:10 +0200, Roger Marcus wrote:
>> Hi,
>>
>> I am having a problem with NFS and I thought that you could help me or
>> you could steer me to
>> someone who might be able to.
>>
>> The problem is this:
>>
>> An NFS Server mounts an image on a local directory, containing a XEN
>> virtual machine configuration file and a XEN image.
>>
>> An NFS Client computer sees the directory that was mounted remotely
>> and starts the XEN Virtual machine on the mounted directory.
>> The NFS Client computer then stops the XEN Virtual machine. So far, so
>> good. The machine ran. It stopped. The NFS Client
>> leaves the directory. No process is accessing that directory from the
>> client side.
>
> It is still exported, so the NFS server still has a reference to it.
>
>> Problem: The NFS Server cannot umount the local directory.
>> fuser returns no usage of the directory.
>> lsof returns no usage of the directory.
>
> correction: lsof and fuser don't show any _user processes_ that
> reference the directory. NFSd runs in the kernel...
>
>> umount -f won't force umount the directory.
>>
>> What does work is exportfs -ua.
>
> or 'exportfs -u client:/directory'. See 'man exportfs'
>
>> This is not a good way to go, since it is planned that many clients
>> will be using the server; indeed many
>> clients will be using multiple subdirectories on the server.
>>
>> 1. Is this a XEN bug or an NFS bug?
>> 2. Is there some other command like exportfs in which you can just
>> disable the one local directory but maintain an
>> active mount on the parent directory?
>
> See above.
>
> Note that if you want to unexport all export entries for a particular
> directory '/mydir', then something like this simple script will do it:
>
> exportfs -u $(exportfs | awk '/^\/mydir/ { print $2 ":" $1; }')
>
> Trond
>
>
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