手机内置存储 1<->n 挂载到了很多个路径上， why? 求科普

[lxk11153]

Filesystem                    Size
/mnt/runtime/default/emulated 26.0G
/mnt/runtime/read/emulated    26.0G
/mnt/runtime/write/emulated   26.0G
/storage/emulated             26.0G

/data/media:
total 12K
drwxrwx---  143 media_rw media_rw    8.0K Oct 24 16:24 0/
drwxrwx---    4 media_rw media_rw    4.0K Oct  8 08:22 obb/

/mnt/runtime/default/emulated:
total 12K
drwxrwx--x  143 root     sdcard_r    8.0K Oct 24 16:24 0/
drwxrwx--x    4 root     sdcard_r    4.0K Oct  8 08:22 obb/

/mnt/runtime/read/emulated:
total 12K
drwxr-x---  143 root     everybod    8.0K Oct 24 16:24 0/
drwxr-x---    4 root     everybod    4.0K Oct  8 08:22 obb/

/mnt/runtime/write/emulated:
total 12K
drwxrwx---  143 root     everybod    8.0K Oct 24 16:24 0/
drwxrwx---    4 root     everybod    4.0K Oct  8 08:22 obb/

/storage/emulated:
total 12K
drwxrwx--x  143 root     sdcard_r    8.0K Oct 24 16:24 0/
drwxrwx--x    4 root     sdcard_r    4.0K Oct  8 08:22 obb/

mount 信息太多了，有需要再贴

Q: 我可以 umount 吗？

[RikkaW]

/mnt/runtime/ 用于实现存储权限控制，当应用进程出现时没有存储权限挂载 default ；有读 read ；有写 write
/data/media -> /storage/emulated 是变成 sdcardfs，最容易感知的是 /storage/emulated 里不分大小写而 /data/media 里分