file system deadlock in RELENG_11

[Mike Tancsa]

On 8/24/2017 9:33 PM, Shane Ambler wrote:
> On 25/08/2017 05:40, Mike Tancsa wrote:
>> On 8/24/2017 4:01 PM, Mike Tancsa wrote:
>>> OK, this is fairly easy to repeat. If I start a sync of a snapshot via
>>> zrep, it hangs the box.  CTRL+T shows
>>>
>>>
>>> DEBUG: overiding stale lock on zroot/chyves from pid 19378
>>> sending zroot/chyves at zrep_000010 to 10.151.9.2:zroot/chyves
>>> cannot receive new filesystem stream: destination
>>> 'zroot/chyves/guests/resi/disk1' exists
>>> must specify -F to overwrite it
> 
> Are you sending a snapshot from the host to the guest?
> or is the guest sending to the host?

sending a snapshot from an active host, to a guest.

>> root     29683   0.0  0.0    7752   3824  5  DE+  15:53      0:00.32 zfs
>> send -R -I zroot/chyves at zrep_00000d zroot/chyves at zrep_000010
>> root     29690   0.0  0.0    7752   3492  5  D+   15:53      0:00.00 zfs
>> rename zroot/chyves at zrep_000010 zroot/chyves at zrep_000010_unsent
>>
> 
> Should be unrelated but several years ago there was a deadlock issue
> when renaming a zvol, unless the fix got undone recently this may just
> be a distraction or a hint of a solution...
> 
> https://svnweb.freebsd.org/base?view=revision&revision=272474

Hmmm, that does sound familiar.  I will try and recreate this next week
on a non production box.

	---Mike



-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
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