"panic: snapblkfree: inconsistent block type" on FreeBSD 9.0 RELEASE

[Yamagi Burmeister]

Hello :)

On Tue, 5 Jun 2012 22:37:21 +0200
Jose Garcia Juanino <jjuanino at gmail.com> wrote:

> > > I have three full core dumps:
> > >
> > > http://www.mipaginapersonal.movistar.es/web3/jjuanino/core.txt.1
> > > http://www.mipaginapersonal.movistar.es/web3/jjuanino/core.txt.2
> > > http://www.mipaginapersonal.movistar.es/web3/jjuanino/core.txt.3
> > >
> > > The relevant code is, in the three examples:
> > >
> > > #3  0xffffffff80a40124 in ffs_snapblkfree (fs=0xfffffe0002deb000,
> > > devvp=Variable "devvp" is not available.
> > > )
> > >     at /usr/src/sys/ufs/ffs/ffs_snapshot.c:1799
> > >
> > > Regards
> > 
> > I don't know about the internals of FFS, but I know there were some fixes  
> > to FFS + snapshots ( + journal (SUJ) ??) after 9.0-RELEASE. So maybe you  
> > can test updating to and running with 9-STABLE.
> 
> Thanks for your reply. I cannot upgrade to 9-STABLE; it is a production
> environment and only can run -RELEASE. In the other hand, I removed the
> unclean snapshots (checked with fsck_ffs), but unfortunately did not
> help and I got a new "snapblkfree: inconsistent block type" panic a few
> hours later. At this moment, the overall of filesystems and snapshots
> were clean (checked again with fsck).
>
> When the system started up again, I decided remove all the snapshots,
> but while I am doing this work, the computer again raised a new panic:
> "ffs_blkfree_cg: freeing free block". Related this panic, I found this
> post on freebsd-current:
> 
> http://lists.freebsd.org/pipermail/freebsd-current/2011-October/028860.html
> 
> I am almost sure I have not hardware failures. Indeed, after that panic,
> I definitively removed all the remaining snapshots, and did a new fsck on
> the filesystems. The system now goes smoothly, and the computer does not
> panic anymore.

If you're using SU+J this is a known problem. In 9.0-RELEASE creating
and removing snapshots on filesystems with SU+J has a high chance to
lead to panics, filesystem corruption and several more not so nice
things. While there were some commits in 9-STABLE in that area,
snapshots are still not working with SU+J. They are disabled and
an error messages is printed when you try to create one.



-- 
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