Re: [Problem]NFS Server – Umount results in Device Busy.

[Boaz Harrosh <bharrosh@panasas.com>]

On 06/07/2012 12:43 PM, Namjae Jeon wrote:

> 2012/6/7, Boaz Harrosh <bharrosh@panasas.com>:
>> On 06/07/2012 10:47 AM, Namjae Jeon wrote:
>>
>>> Hi Bruce, Trond.
>>>
>>> As you know, Currently umount results in busy on NFS server although
>>> user tried to succeed to umount on NFS client.
>>> I suggest to add umount procedure to avoid umount busy issue.
>>> When calling umount on NFS client, The resources(exportfs entries
>>> cache) of mount point will be flushed on NFS server. and umount will
>>> be succeed without busy issue.
>>>
>>> how do you think about this suggestion ?
>>>
>>
>>
>> I second this request, what is needed so when all clients unmounted,
>> the system comes back to the sate it was before any clients have
>> mounted. i.e filesystems is not referenced and may unmount cleanly.
>> (This also happens with >= 4.0 clients only, so no excuses)
>>
>> This is a real problem for me, on Fedora machines. Because I export
>> iscsi devices which are network devices, and in the shutdown procedure
>> for some reason the "service nfs stop" of the server is much much to
>> late. the original umount of exofs (-o _netdev) fails because it's
>> held by NFSD, the iscsi devices go away regardless, and when nfsd
>> finally releases exofs, it gets deadlocked on some error handling.
>> OK I know I must fix the stuck-ness, but the problem will remain.
>> The FS will not unmount cleanly because it will only attempt
>> an unmount after its devices are gone. This will be solved if
>> nfsd would release its hold on the FS when all clients are gone.
>>
>> It was on my TODO to fix this for a long time, but I seem to be
>> too busy with more urgent matters. (What's the point of fixing the
>> shutdown if the steady state doesn't work yet)
>>
>> If someone has investigated the matter and knows what to do I would
>> appreciate any insights, and/or patches would be wonderful ;-)
> Hi Boaz.
> Oh.. You also are facing same problem.
> Actually I almost finish to imprement the patch about umount busy
> issue on NFS server. But I want to know Maintainer's opinion before
> posting.
> Thanks.


Please post it (maybe as RFC) I want to see it

Thanks
Boaz

>>
>>> Thanks.
>>>
>>
>> <>
>>
>> Thanks
>> Boaz
>>
>>