[Ocfs2-users] umount hang + high CPU

[Sunil Mushran]

Well, that means the hung node exited the dlm domain successfully.
This is not a dlm issue.

Run alt-sysrq-t on the hung node. If you have netconsole setup you
should see a log.

sylarrrrrrr at aim.com wrote:
> Aha, ok, I don't see the oops, or anything about the hang in the logs. 
> The hanged machine still reply to pings.
>
> The story now is , that I thought that I can use the :
>
>  tunefs.ocfs2  --cloned-volume /dev/mylvmsnapshot
>
> in order to mount the snapshot... (big mistake)...well I did manage to 
> mount the snapshot, but as soon as
> I umounted it, the umount process hanged, and then the whole machine 
> hanged, except that it responds to pings.
>
>
> Now, I have downloaded the ocfs2-1.4-userguide.pdf , and went to 
> section 'f) DLM Debuging', and tried the commands
> there on the still working node, but only 'cat 
> /sys/kernel/debug/o2dlm/*/dlm_state' worked and produced the following 
> output:
>
> Domain: 1ACAFCEE7ACA47C089069117560F5C91  Key: 0xb9d649ba
> Thread Pid: 5664  Node: 0  State: JOINED
> Number of Joins: 1  Joining Node: 255
> Domain Map: 0
> Live Map: 0
> Lock Resources: 51168 (180512)
> MLEs: 0 (291689)
>   Blocking: 0 (139713)
>   Mastery: 0 (151976)
>   Migration: 0 (0)
> Lists: Dirty=Empty  Purge=InUse  PendingASTs=Empty  PendingBASTs=Empty
> Purge Count: 8  Refs: 51169
> Dead Node: 255
> Recovery Pid: 5665  Master: 255  State: INACTIVE
> Recovery Map:
> Recovery Node State:
>
> the other commands:
> debugfs.ocfs2 –R “fs_locks –B” /dev/drbd0
> debugfs.ocfs2 –R “fs_locks –B” /dev/vg/lv
> debugfs.ocfs2 –R “dlm_locks M000000000000000022d63c00000000” /dev/drbd0
>
> produced the error:
> open: Device name specified was not found while opening context for 
> device –R
> debugfs.ocfs2 1.4.2
> debugfs:
>
> and:
>
> ps -e -o pid,stat,comm,wchan=WIDE-WCHAN-COLUMN
>
> procuded no D state process.
>
>
> I am sorry I write it in the mailing list, but I am a noob, so I don't 
> even know if it is a bug, or a misconfiguration, or a misunderstanding.
>
> PS. Is nodiratime option supported for mounts? I used it, but I don't 
> see it in the user-guide.
>
> -----Original Message-----
> From: Sunil Mushran <sunil.mushran at oracle.com>
> To: sylarrrrrrr at aim.com
> Cc: tao.ma at oracle.com; ocfs2-users at oss.oracle.com
> Sent: Tue, Jul 7, 2009 8:46 pm
> Subject: Re: [Ocfs2-users] umount hang + high CPU
>
> The fix was for the oops you saw. 
>  
> The hang is a different issue. We have no info on that. 
>  
> For that, if you would like to diagnose the problem, read up the dlm 
> notes 
> in the 1.4 user's guide. It explains a debugging process vis-a-vis hangs. 
>  
> If the issue is dlm related, then we would like to have the tcpdumps. 
>  
> Lastly, emails are no t an efficient vehicle for handling such issues. 
> Use 
> the bugzilla as it allows us to collect information in one place. 
>  
> Sunil 
>  
> sylarrrrrrr at aim.com <mailto:sylarrrrrrr at aim.com> wrote: 
> > So this bug is not over yet :( 
> > 
> > I have checked my kernel source and indeed it have this patch but I 
> > still get the hang. 
> > 
> > PS. my linux-2.6-2.6.30/fs/ocfs2/dcache.c kernel source has: 
> > 
> > 290 else 
> > 291 mlog_errno(ret); 
> > 292 
> > 293 /* 
> > 294 * In case of error, manually free the allocation and > do the 
> iput(). 
> > 295 * We need to do this because error here means no > d_instantiate(), 
> > 296 * which means iput() will not be called during > dput(dentry). 
> > 297 */ 
> > 298 if (ret < 0 && !alias) { 
> > 299 ocfs2_lock_res_free(&dl->dl_lockres); 
> > 300 BUG_ON(dl->dl_count != 1); 
> > 301 spin_lock(&dentry_attach_lock); 
> > =2 0302 dentry->d_fsdata = NULL; 
> > 303 spin_unlock(&dentry_attach_lock); 
> > 304 kfree(dl); 
> > 305 iput(inode); 
> > 306 } 
> > 307 
> > 308 dput(alias); 
> > 309 
> > 310 return ret; 
> > 311 } 
> > 
> > 
>  
>
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