Andriy Gapon wrote: > on 14/02/2014 21:18 Jeremie Le Hen said the following: > > I've just got another occurence of the exact same panic. Any clue > > how > > to debug this? > > Could you please obtain *vp from frame 12 ? > > The problem seems to be happening in this piece of ZFS code: > if (cnp->cn_flags & ISDOTDOT) { > ltype = VOP_ISLOCKED(dvp); > VOP_UNLOCK(dvp, 0); > } > ZFS_EXIT(zfsvfs); > error = vn_lock(*vpp, cnp->cn_lkflags); > if (cnp->cn_flags & ISDOTDOT) > vn_lock(dvp, ltype | LK_RETRY); > > ltype is apparently LK_SHARED and the assertion is apparently > triggered by > EDEADLK error. The error can occur only if a thread tries to obtain > a lock in a > shared mode when it already has the lock exclusively. > My only explanation of how this could happen is that dvp == *vpp and > cn_lkflags > is LK_EXCLUSIVE. In other words, this is a dot-dot lookup that > results in the > same vnode. I think that this is only possible if dvp is the root > vnode. > I am not sure if my theory is correct though. > Also, I am not sure if zfs_lookup() should be prepared to handle such > a lookup > or if this kind of lookup should be handled by upper/other layers. > In this case > these would be VFS lookup code and nullfs code. > I don't know if it ever occurs, but the NFS client has a check for if (vp != dvp) vn_lock(dvp...); /* roughly what the code looks like. */ in the ISDOTDOT section of nfs_lookup(). I don't think this check would be harmful? rick > -- > Andriy Gapon > _______________________________________________ > freebsd-current_at_freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to > "freebsd-current-unsubscribe_at_freebsd.org" >Received on Sat Feb 15 2014 - 22:48:55 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:40:46 UTC