EXT4_EPOCH_BITS   401 fs/ext4/ext4.h #define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
EXT4_EPOCH_BITS   402 fs/ext4/ext4.h #define EXT4_NSEC_MASK  (~0UL << EXT4_EPOCH_BITS)
EXT4_EPOCH_BITS  2152 fs/ext4/super.c 			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);