[PATCH 3/4] xfs: exact busy extent tracking

[Christoph Hellwig]

> In xfs_alloc_busy_trim():
> > @@ -2894,6 +2959,11 @@ fail:
> >  	 * re-check if the trimmed extent satisfies the minlen requirement.
> >  	 */
> >  	spin_unlock(&args->pag->pagb_lock);
> > +	if (fbno != bno || flen != len) {
> > +		trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len,
> > +					  fbno, flen);
> > +	}
> > +	trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len, fbno, 0);
> >  	*rbno = fbno;
> >  	*rlen = 0;
> >  }
> 
> I don't see why you do two trace calls here, the second
> with 0 for the value of flen.

It's a merge error.  The first trace should be for the regular exit,
but managed to sneak down into the fail case, too.