UBIFS: Question about calc_dd_growth()

[Dongsheng Yang]

Hi Atem and Richard and all:

	I am doing some work about adding support of quota
in ubifs. But I found there is a question in  calc_dd_growth
I am confused about.

  417         if (req->dirtied_ino)
  418                 dd_growth += c->bi.inode_budget << 
(req->dirtied_ino - 1);

Why it's a '<<'?? I mean, to myself, it's clear to be that:

   dd_growth += c->bi.inode_budget * req->dirtied_ino;


Could you help to explain it to me?

Thanx
Yang