svn commit: r294329 - in head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs: . sys

[Steven Hartland]

On 21/01/2016 15:10, Slawa Olhovchenkov wrote:
> On Thu, Jan 21, 2016 at 08:03:25AM -0700, alan somers wrote:
>
>> On Thu, Jan 21, 2016 at 4:38 AM, Slawa Olhovchenkov <slw at zxy.spb.ru> wrote:
>>> On Thu, Jan 21, 2016 at 01:34:57AM +0200, Andriy Gapon wrote:
>>>
>>>> On 20/01/2016 22:03, Alan Somers wrote:
>>>>> On Wed, Jan 20, 2016 at 2:20 AM, Andriy Gapon <avg at freebsd.org> wrote:
>>>>>> On 19/01/2016 19:20, Alan Somers wrote:
>>>>>>> The thing is, it never really worked in the first place.  Panics and
>>>>>>> deadlocks are so frequent that I don't think the feature was usable
>>>>>>> for anybody.
>>>>>> The feature is perfectly usable for me.  I have never run into the problems that
>>>>>> you describe.  Why not fix the real bugs that you've run into?
>>>>> Spectra Logic and iXSystems both experienced many problems with this.
>>>>> The worst is a deadlock that can be triggered simply by pulling a
>>>>> drive from a redundant pool when there exists a zvol anywhere in the
>>>>> system (see https://reviews.freebsd.org/D4998 for a quick way to
>>>>> reproduce).  Fixing it correctly would likely require far more time
>>>>> than I have available.  I just want the bugs to go away.  See that
>>>>> same code review for a change to make the feature optional.
>>>> I think that we all want all the bugs to go way.  One way to remove bugs is to
>>>> remove (disable) code that contains bugs.  That way the perfect bug-free
>>>> software is clearly achievable :-)  Unfortunately, that technique is not always
>>>> welcomed.
>>>>
>>>> P.S.
>>>> I think that the real problem here is that a method of a geom must never drop
>>>> topology_lock.  In other words, the GEOM management code (like g_xxx() stuff in
>>>> geom_subr.c) expects that a topology can not change underneath it.  But
>>>> zvol_geom_access() clearly breaks that contract.
>>> May be same cause problem with swap on zvol (don't test on latest
>>> -stable)?
>> I'm not familiar with that problem.  Is there a PR?
> I am find PR 199189.
> My expirense slightly different: VirtualBox VM with test install (384M
> RAM) hang, not crashed, just infinite wait somewhere. Tested on 10.1.
>
Had the same on 10.2 last night.