[linux-lvm] [lvmlockd] "VGLK res_unlock lm error -250" and lvm command hung forever

[Damon Wang]

Thank you for your reply!

I'll try to sanlock-3.6.0 first (currently I'm using 3.5.0) and try
whether it happen again

Damon

2018-05-24 23:46 GMT+08:00 David Teigland <teigland at redhat.com>:
> On Thu, May 24, 2018 at 10:44:05PM +0800, Damon Wang wrote:
>> Hi all,
>>
>> I'm using lvmlockd + sanlock on iSCSI, and sometimes (usually
>> intensive operations), it shows vglock is failed:
>
> Hi, thanks for this report.
>
>> /var/log/messages:
>>
>>     May 24 21:14:29 dev1 sanlock[1108]: 2018-05-24 21:14:29 605471
>> [1112]: r627 paxos_release 8255 other lver 8258
>
> I believe this is the sanlock bug that was fixed here:
> https://pagure.io/sanlock/c/735781d683e99cccb3be7ffe8b4fff1392a2a4c8?branch=master
>
> By itself, the bug isn't a big problem, the lock was released but sanlock
> returns an error.  The bigger problem is that lvmlockd then believes that
> the lock was not released:
>
>>     1527167669 S lvm_ff35ecc8217543e0a5be9cbe935ffc84 R VGLK
>> unlock_san release error -1
>
> so subsequent requests for the lock get backed up in lvmlockd:
>
>>     [root at dev1 ~]# lvmlockctl -i
>>     LW VG sh ver 0 pid 34216 (lvchange)
>>     LW VG sh ver 0 pid 75685 (lvs)
>>     LW VG sh ver 0 pid 83741 (lvdisplay)
>>     LW VG sh ver 0 pid 90569 (lvchange)
>>     LW VG sh ver 0 pid 92735 (lvchange)
>>     LW VG sh ver 0 pid 99982 (lvs)
>>     LW VG sh ver 0 pid 14069 (lvchange)
>
>> My questions are:
>>
>> 1. why VGLK failed, is it because network failure(cause iSCSI fail and
>> sanlock could not find VGLK volume), can I find a direct proof?
>
> I believe the bug.  Failures of the storage network can also cause similar
> issues, but you would see error messages related to i/o timeouts.
>
>> 2. Is it recoverable? I have tried kill all hung commands but new
>> command still hung forever.
>
> There are recently added options for this kind of situation, but I don't
> believe there is an lvm release with those yet.
>
> If you are prepared to build your own version of lvm, build lvm release
> 2.02.178 (which should be ready shortly, if it's not, take git master
> branch).  Be sure to configure with --enable-lvmlockd-sanlock.  Then try:
>
>   lvchange -an --lockopt skipvg <vgname>
>   lvmlockctl --drop <vgname>
>   stop lvmlockd, stop sanlock
>   restart everything as usual
>
> If that doesn't work, or if you don't want to build lvm, then unmount file
> systems, kill lvmlockd, kill sanlock, you might need to do some dm cleanup
> if LVs were active (or perhaps just reboot the machine.) Restart
> everything as usual.
>
> Dave