from_bh 27 fs/gfs2/meta_io.h struct buffer_head *from_bh, from_bh 31 fs/gfs2/meta_io.h memcpy(to_bh->b_data + to_head, from_bh->b_data + from_head, from_bh 32 fs/gfs2/meta_io.h from_bh->b_size - from_head);