Re: umount fails with device busy

[Peter Staubach <staubach@redhat.com>]

Zoot wrote:
> On Thu, Aug 23, 2007 at 04:29:46PM -0400, Peter Staubach wrote:
>   
>> Chuck Lever wrote:
>>     
>>> z00t@gmx.net wrote:
>>>       
>>>> Hi guys,
>>>>
>>>> I get the device busy error when I try to umount an NFS file system 
>>>> although there is no process with an open file on it (at least fuser 
>>>> -m /mnt/point and lsof +f -- /mnt/point don't find anything).
>>>>
>>>> To be more precise this only happens, when I run the umount right 
>>>> after stopping an application which has its executables and work 
>>>> directory on this file system. Running umount again some seconds 
>>>> later works fine.
>>>> I do not have any submounts under this mount point. There are no 
>>>> packet transmit or receive errors nor any NFS/RPC errors only a very 
>>>> small number of RPC retransmitts. So it seems that I have a stable 
>>>> environment. Client and server is SLES9 with 2.6.5-7.202.7-smp/X86_64.
>>>> I enabled NFS debug output and the only noticeable thing is, that 
>>>> some NFS operations are still ongoing after the application processes 
>>>> have already terminated:
>>>>
>>>>  Aug 23 08:25:23 marvin kernel: NFS reply getattr
>>>>  Aug 23 08:25:23 marvin kernel: NFS: nfs_update_inode(0:12/149296 
>>>> ct=1 info=0x6)
>>>>  Aug 23 08:25:23 marvin kernel: NFS: (0:12/149296) revalidation 
>>>> complete
>>>>  Aug 23 08:25:23 marvin kernel: nfs: flush(0:12/149296)
>>>>  Aug 23 08:25:23 marvin kernel: NFS: dentry_delete(bin/stop, 0)
>>>>  Aug 23 08:25:23 marvin kernel: NFS: revalidating (0:12/2)
>>>>  Aug 23 08:25:23 marvin kernel: NFS call  getattr
>>>>  Aug 23 08:25:23 marvin kernel: NFS reply getattr
>>>>  Aug 23 08:25:23 marvin kernel: NFS: nfs_update_inode(0:12/2 ct=1 
>>>> info=0x6)
>>>>  Aug 23 08:25:23 marvin kernel: NFS: (0:12/2) revalidation complete
>>>>  Aug 23 08:25:25 marvin kernel: NFS call  fsstat
>>>>  Aug 23 08:25:25 marvin kernel: NFS reply statfs: 0
>>>>  Aug 23 08:25:35 marvin kernel: NFS call  fsstat
>>>>  Aug 23 08:25:35 marvin kernel: NFS reply statfs: 0
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6368 initiated commit call
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6369 initiated commit call
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6370 initiated commit call
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6371 initiated commit call
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6368 nfs_commit_done (status 0)
>>>>  Aug 23 08:25:38 marvin kernel: NFS: commit (0:12/121805 3207@0)NFS: 
>>>> dentry_delete(log/mux_marvin.trc, 0)
>>>>  Aug 23 08:25:38 marvin kernel:  OK
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6369 nfs_commit_done (status 0)
>>>>  Aug 23 08:25:38 marvin kernel: NFS: commit (0:12/149304 2238@0)NFS: 
>>>> dentry_delete(log/pw_marvin_1.trc, 0)
>>>>  Aug 23 08:25:38 marvin kernel:  OK
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6370 nfs_commit_done (status 0)
>>>>  Aug 23 08:25:38 marvin kernel: NFS: commit (0:12/149297 2238@0)NFS: 
>>>> dentry_delete(log/pw_marvin_0.trc, 0)
>>>>  Aug 23 08:25:38 marvin kernel:  OK
>>>>  Aug 23 08:25:38 marvin kernel: NFS: 6371 nfs_commit_done (status 0)
>>>>  Aug 23 08:25:38 marvin kernel: NFS: commit (0:12/149295 965@0)NFS: 
>>>> dentry_delete(net.trc, 0)
>>>>  Aug 23 08:25:38 marvin kernel:  OK
>>>>  Aug 23 08:25:45 marvin kernel: NFS call  fsstat
>>>>  Aug 23 08:25:45 marvin kernel: NFS reply statfs: 0
>>>>  Aug 23 08:25:55 marvin kernel: NFS call  fsstat
>>>>
>>>> When I run umount during these ops I get an device busy. Any help 
>>>> would be very appreciated!
>>>>         
>>> This is normal and expected behavior.  One problem may be that your 
>>> server is slow, and thus there are RPCs left outstanding for a bit on 
>>> your client after your application exits.  The COMMIT calls from that 
>>> trace suggest that there is dirty data the client is writing back to 
>>> the server. 
>>>       
>> It seems to me that this should not be the expected behavior unless
>> the file system is mounted "nocto".  Is it?
>>
>>    Thanx...
>>
>>       ps
>>     
> No, mount options are: nfsvers=3,soft,tcp,rsize=32768,wsize=32768
>   

"soft"?

Dangerous.

       ps

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