Re: repeatable ZFS panic: share->excl

On Tuesday 17 March 2009 3:04:40 am Pawel Jakub Dawidek wrote:
> On Fri, Mar 13, 2009 at 02:08:03PM -0400, John Baldwin wrote:
> > John Baldwin wrote:
> > >Yes, I think that is the real bug.  Looking at this further I think
> > >zfs_get_xattrdir() will return the vnode locked if it has to create a
> > >new node via zfs_make_attrdir() but only returns it held and unlocked if
> > >it finds an existing one.  So my new patch is to just fix
> > >zfs_get_xattrdir() to unlock the vnode if it creates a new one like so:
> > >
> > >(Sorry, TBird is probably going to butcher all the whitespace):
> > >
> > >---
> > 
>//depot/user/jhb/lock/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c
> > >+++
> > 
>/Users/jhb/work/p4/lock/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c 
> > >
> > >_at__at_ -940,6 +940,7 _at__at_
> > >         /* NB: we already did dmu_tx_wait() if necessary */
> > >         goto top;
> > >     }
> > >+    VOP_UNLOCK(*xvpp, 0);
> > >
> > >     return (error);
> > > }
> > >
> > >A non-butchered version is at www.FreeBSD.org/~jhb/patches/zfs_ea.patch.
> > 
> > So lulf_at_ reports success with this patch.  Pawel, can you review it?
> 
> Yes, it works for me too and looks good. The only thing we need to
> change is to check for error beeing 0 before unlocking the vnode.
> The zfs_make_xattrdir() function can still return with EIO, so I'd add
> something like this:
> 
> 	if (error == 0)
> 		VOP_UNLOCK(*xvpp, 0);

Yes, I realized this about 30 minutes after I sent this e-mail. :-P  I will 
commit a version with the error check today.

> Thank you John for spending time on tracking this one down.

Sure, was good to read a bit of the ZFS code.

-- 
John Baldwin