Re: ufs_wapbl_rename

[David Holland <dholland-tech%netbsd.org@localhost>]

On Fri, Jul 15, 2011 at 10:43:31PM +0000, David Holland wrote:
 > I will commit it later after an anita run if I don't find any more
 > problems.

I did find one more problem... hopefully no more than that.

 > Note that when pounding on rename I am occasionally seeing:
 > 
 >    panic: lockdebug_barrier: holding 1 shared locks
 > 
 > but I don't think this is anything I did, because vnode locks aren't
 > shared except in a few cases pertaining to getdents, which should be
 > entirely uninvolved. Also there appears to be no way whatsoever to
 > debug this; if anyone has suggestions please share.

This seems to be connected to rmdir, not rename. The panic has (so
far) always occurred in a process doing only rmdirs and no renames.

I've spotted two problems in ufs_rmdir but neither of them could be
causing this; as far as I can tell by inspection the locking in both
sys_rmdir and ufs_rmdir is fine... plus those aren't shared locks.

Anyone have any theories or guesses?

-- 
David A. Holland
dholland%netbsd.org@localhost