gfs2_log_header
struct gfs2_log_header *lh;
BUILD_BUG_ON(offsetof(struct gfs2_log_header, lh_crc) != LH_V1_SIZE);
int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
error = __get_log_header(sdp, (const struct gfs2_log_header *)bh->b_data,
const struct gfs2_log_header *lh, unsigned int blkno,
#define LH_V1_SIZE (offsetofend(struct gfs2_log_header, lh_hash))