EXT4_EPOCH_BITS
#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
#define EXT4_NSEC_MASK (~0UL << EXT4_EPOCH_BITS)
return cpu_to_le32(extra | (ts.tv_nsec << EXT4_EPOCH_BITS));
ts.tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS;