panic: vput: negative ref cnt
Stefan Bethke
stb at lassitu.de
Sun Apr 5 04:34:29 PDT 2009
Am 05.04.2009 um 13:15 schrieb Mark Powell:
> On Sun, 5 Apr 2009, Stefan Bethke wrote:
>
> Stefan,
> Thanks for the input.
>
>> Am 04.04.2009 um 13:55 schrieb Mark Powell:
>>> My script takes a zfs snapshot, mounts the snapshot, backs it up
>>> using star, then umounts the snapshot. The panic seems to occur on
>>> the umount.
>>
>> This is a different panic from the one I was getting, but appears
>> to occur under the same circumstances.
>>
>> I managed to avoid the panic by keeping the snapshot until the next
>> run of my backup script, and not unmounting anything.
>
> Yeah, I got around it by avoiding the unmount.
> My script dates from 7-STABLE days, where a zfs bug caused the
> automounted snapdir e.g. .zfs/snapshot/star_L0_2009-04-04-16:57, to
> be missing a '..' entry. That prevented star from detecting that I
> was performing a true full backup. Thus my script directly mounted
> the snapshot to get a proper fs with a '..' entry and unmounted it
> when finished.
> Now the included version of zfs in 8-CURRENT doesn't have that bug
> any longer. So I've reverted to backing up the automounted snapdir.
> Consequently as I don't perform a mount I don't have to unmount
> either, effectively working around the bug.
>
>> See <http://lists.freebsd.org/pipermail/freebsd-current/2009-February/003513.html
>> >
>
> Do you know if a PR has been submitted for this one?
When I lasted searched for it about six weeks ago, I couldn't find
any. I wanted to reproduce the panic in VMware first to gather more
details, but I've been unsuccessful in triggering it there at all.
Maybe I need to switch my production boxes over to VMware :-)
Stefan
--
Stefan Bethke <stb at lassitu.de> Fon +49 151 14070811
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