ZFS panic when changing zfs dataset mountpoint

[Niki Denev]

On Fri, May 30, 2008 at 2:54 AM, Pawel Jakub Dawidek <pjd at freebsd.org> wrote:
> On Tue, Feb 12, 2008 at 01:04:38PM +0200, Niki Denev wrote:
>> Hi,
>>
>> I got the following panic when trying to set/change the mountpoint
>> property of a dataset.
>>
>> I did :
>>   # zfs set mountpoint=/usr/ports zfs2/ports
>> and the machine crashed.
>>
>> The datased had one snapshot taken.
>>
>> Here is what i was able to extract from the dump :
> [...]
>> #8  0xffffffff804800d5 in _sx_xlock (sx=0xa0, opts=0,
>>     file=0xffffffff80c697f0
>> "/usr/src/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c",
>> line=1069) at atomic.h:142
>> #9  0xffffffff80c50b2a in zfsctl_umount_snapshots (vfsp=Variable
>> "vfsp" is not available.
>> ) at /usr/src/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c:1069
>> #10 0xffffffff80c57978 in zfs_umount (vfsp=0xffffff00014f5650,
>> fflag=0, td=0xffffff001483b6a0)
>>     at /usr/src/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c:692
> [...]
>
> I tried to reproduce your problem, but I can't. This is clearly related
> to unmounting snapshots. Was your snapshot mounted at the time of
> calling 'zfs set mountpoint='? I tried both scenarious (having mounted
> and unmounted snapshot) and no panic. Is there anything else you did?
>
> --
> Pawel Jakub Dawidek                       http://www.wheel.pl
> pjd at FreeBSD.org                           http://www.FreeBSD.org
> FreeBSD committer                         Am I Evil? Yes, I Am!
>

Hi Pawel,

Sorry for my late reply.

I cannot test right now because the machine suffered multiple disk failures,
and is currently offline, but as far as I remember the machine had
several snapshots mounted at the time of the panic.

Regards,
Niki