zfs panic during find(1) on zfs snapshot directory

[Andreas Longwitz]

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.

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.

-- 
Andreas Longwitz