XFS_MIN_BLOCKSIZE_LOG
#define FSBLOCK_SHIFT(fsBlockLog) (fsBlockLog - XFS_MIN_BLOCKSIZE_LOG);
|| sb_blocklog < XFS_MIN_BLOCKSIZE_LOG
#define XFS_MIN_BLOCKSIZE (1 << XFS_MIN_BLOCKSIZE_LOG)
#define XFS_MIN_CRC_BLOCKSIZE (1 << (XFS_MIN_BLOCKSIZE_LOG + 1))