Hello,

The original Linus' minix zmap blocks calculation was correct, in the
formula of: sbi->s_nzones - sbi->s_firstdatazone + 1. It is (sp->s_zones
- (sp->s_firstdatazone - 1) in the minix3 source code.

But a later patch (fs/minix: Verify bitmap block counts before mounting)
has changed it unfortunately as:
  sbi->s_nzones - (sbi->s_firstdatazone + 1).
This would show free blocks one block less than the real when the total
data blocks are in "full zmap blocks plus one".

commit 016e8d44bc06dd3322f26712bdd3f3a6973592d0
Author: Josh Boyer <jwboyer@redhat.com>
Date:   Fri Aug 19 14:50:26 2011 -0400

This patch corrects that zmap blocks calculation and tidy a printk
message while at it.

Signed-off-by: Qi Yong <qiyong@fc-cn.com>

-- 
Qi Yong