Google’s flagship phones Pixel 3 and 3 XL have just been announcedusedSamsung's F2FS file system. Most Android phones today use the ext4 file system.
Samsung's F2FS is a storage system developed specifically for NAND flash chips. It is faster than ext4, but it is considered to have reliability problems. Therefore, the number of smartphones using F2FS is small, and Google seems to have confidence in F2FS. Mobile phones currently using the F2FS file systemincludingOneplus 3T, Huawei Mate 9, Huawei P9/Honor 8/V8, Google Nexus 9 and Motorola's multiple collections.