zfs deadlock

[krichy at cflinux.hu]

I've applied r258294 on top of releng/9.2, and using the attached 
scripts parallel, the system got into a deadlock again.

2013-12-06 11:35 időpontban Steven Hartland ezt írta:
> Thats correct it unmounts the mounted snapshot.
> 
>    Regards
>    Steve
> 
> ----- Original Message ----- From: <krichy at cflinux.hu>
> To: "Steven Hartland" <killing at multiplay.co.uk>
> Cc: <freebsd-fs at freebsd.org>
> Sent: Friday, December 06, 2013 8:50 AM
> Subject: Re: zfs deadlock
> 
> 
>> What is strange also, when a zfs send finishes, the paralell running 
>> find command issues errors:
>> 
>> find: ./e/Chuje: No such file or directory
>> find: ./e/singe: No such file or directory
>> find: ./e/joree: No such file or directory
>> find: ./e/fore: No such file or directory
>> find: fts_read: No such file or directory
>> Fri Dec  6 09:46:04 CET 2013 2
>> 
>> Seems if the filesystem got unmounted meanwhile. But the script is 
>> changed its working directory to the snapshot dir.
>> 
>> Regards,
>> 
>> 2013-12-06 09:03 időpontban krichy at cflinux.hu ezt írta:
>>> Dear Steven,
>>> 
>>> While I was playig with zfs, trying to reproduce the previous bug,
>>> accidentaly hit another one, which caused a trace I attached.
>>> 
>>> The snapshot contains directories in 2 depth, which contain files. It
>>> was to simulate a vmail setup, with domain/user hierarchy.
>>> 
>>> I hope it is useful for someone.
>>> 
>>> I used the attached two scripts to reproduce the ZFS bug.
>>> 
>>> It definetly crashes the system, in the last 10 minutes it is the 3rd 
>>> time.
>>> 
>>> Regards,
>>> 2013-12-05 20:26 időpontban krichy at cflinux.hu ezt írta:
>>>> Dear Steven,
>>>> 
>>>> Thanks for your reply. Do you know how to reproduce the bug? Because
>>>> simply sending a snapshot which is mounted does not automatically
>>>> trigger the deadlock. Some special cases needed, or what?
>>>> How to prove that the patch fixes this?
>>>> 
>>>> Regards,
>>>> 2013-12-05 19:39 időpontban Steven Hartland ezt írta:
>>>>> Known issue you want:
>>>>> http://svnweb.freebsd.org/changeset/base/258595
>>>>> 
>>>>>    Regards
>>>>>    Steve
>>>>> 
>>>>> ----- Original Message ----- From: "Richard Kojedzinszky" 
>>>>> <krichy at cflinux.hu>
>>>>> To: <freebsd-fs at freebsd.org>
>>>>> Sent: Thursday, December 05, 2013 2:56 PM
>>>>> Subject: zfs deadlock
>>>>> 
>>>>> 
>>>>>> Dear fs devs,
>>>>>> 
>>>>>> We have a freenas server, which is basicaly a freebsd. I was 
>>>>>> trying to look at snapshots using ls .zfs/snapshot/.
>>>>>> 
>>>>>> When I issued it, the system entered a deadlock. An NFSD was 
>>>>>> running, a zfs send was running when I issued the command.
>>>>>> 
>>>>>> I attached to command outputs while the system was in a deadlock 
>>>>>> state. I tried to issue
>>>>>> # reboot -q
>>>>>> But that did not restart the system. After a while (5-10 minutes) 
>>>>>> the system rebooted, I dont know if the deadman caused that.
>>>>>> 
>>>>>> Now the system is up and running.
>>>>>> 
>>>>>> It is basically a freebsd 9.2 kernel.
>>>>>> 
>>>>>> Do someone has a clue?
>>>>>> 
>>>>>> Kojedzinszky Richard
>>>>> 
>>>>> 
>>>>> --------------------------------------------------------------------------------
>>>>> 
>>>>> 
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>>>>> 
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> 
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