Fix a self build regression.  Now the time is as follows:
Fix a self build regression.  Now the time is as follows:

real	3m50.095s
user	6m56.387s
sys	2m8.369s

I don't know why missing a bmap write actually make performance crawl.

pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable