https://kernelnewbies.org/LinuxChanges
例如
1.2. Ext4 fast commit support, for faster metadata performance
Many applications use fsync(2) to ensure that data is reliably placed on disk. Such operation attempts to synchronize to the disk a few more metadata than expected. In this release, Ext4 will use a novel journaling technique, consisting in optimistically only journal the minimum required information through which a crash recovery operation can recover the metadata modified through an fsync operation. This speeds up fsync() and metadata heavy operations. This feature needs to be enabled at mkfs time.
Recommended LWN article: Fast commits for ext4