WK_JNEWBLK
jnewblk = WK_JNEWBLK(wk);
free_jnewblk(WK_JNEWBLK(wk));
jnewblk_write(WK_JNEWBLK(wk), jseg, data);
handle_written_jnewblk(WK_JNEWBLK(wk));
if (WK_JNEWBLK(old)->jn_blkno != WK_JFREEFRAG(new)->fr_blkno)
jnewblk = WK_JNEWBLK(old);
njnewblk = WK_JNEWBLK(new);
cancel_jnewblk(WK_JNEWBLK(freefrag->ff_jdep), &wkhd);