XFS_SB_VERSION_NUMBITS
#define XFS_SB_VERSION_NUM(sbp) ((sbp)->sb_versionnum & XFS_SB_VERSION_NUMBITS)
((XFS_SB_VERSION_NUMBITS | XFS_SB_VERSION_ALLFBITS) & \
(((be16_to_cpu(dsb->sb_versionnum) & XFS_SB_VERSION_NUMBITS) ==
vernum_mask = cpu_to_be16(XFS_SB_VERSION_NUMBITS |