zfs panic during find(1) on zfs snapshot directory

[Andriy Gapon]

on 10/09/2013 16:59 Andreas Longwitz said the following:
> Thanks for quick answer !
> 
>> My personal recommendation is to keep .zfs directory hidden and/or perform only
>> basic operations on entries under it while ensuring that there is only one
>> process at a time that peeks there.
>>
>> The gfs stuff that handles .zfs operations is really very broken on FreeBSD[*].
>> If you are interested, I have a patch that should some of the mess, but not all.
>>
>> [*] To see what I mean run several of the following shell loops in parallel:
>> while true; do ls -l /pool/fs/.zfs/ >/dev/null; done
> 
> Ok, I was not aware of the problematic caused by visible snapdir
> property. I think your recommendation to use the default snapdir
> property hidden is fine for me and the panic I have described will not
> happen again.
> 
> On the other side a panic should not happen when a user configures
> something else than the default. Therefore I am interested in helping to
> test the broken gfs stuff on some of my test servers, so your offered
> patch is welcome.

Please try this patch:
http://people.freebsd.org/~avg/zfs-gfs-8.diff
Thank you!

> I run zfs on production for a half year now, and I like to note that
> this panic was the first problem on all of my (eight) production servers
> running zfs. The only open zfs problem I have is described in kern/180060.
> 

I will try to look into this issue.

-- 
Andriy Gapon