ubifs_get_wbuf
if (ubifs_get_wbuf(c, zbr.lnum)) {
wbuf = ubifs_get_wbuf(c, lnum);
wbuf = ubifs_get_wbuf(c, zbr->lnum);
struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum);