Hi,
Can anyone please justify me the logic of fs/bufferc.c:buffer_busy()
How can we perform bit-wise operation for ->b_count and ->b_state?
 static inline int buffer_busy(struct buffer_head *bh)
 {
       return atomic_read(&bh->b_count) |
                (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock)));
 }

I try to digg inside git/cvs history and it is appeared that 2.4 was
also implemented like this. At least it was so in 2000'th
http://lkml.indiana.edu/hypermail/linux/kernel/0006.0/0412.html
Also I've found similar complain
http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg24377.html
But seems nobody care about it. What's the point?
The only guess I have is that this is a miss typo  because buffer
is busy if some one hold an reference (bh->b_count !=0 )  ||
it is (dirty | locked). So following patch should fix