EXT4_EPOCH_MASK 839 fs/ext4/ext4.h u32 extra =((time->tv_sec - (s32)time->tv_sec) >> 32) & EXT4_EPOCH_MASK; EXT4_EPOCH_MASK 846 fs/ext4/ext4.h if (unlikely(extra & cpu_to_le32(EXT4_EPOCH_MASK))) EXT4_EPOCH_MASK 847 fs/ext4/ext4.h time->tv_sec += (u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) << 32;