tree 057708db93a1d45cb79e4ed13b5da4989a4aa7f2
parent e94ef6b04d9ae5f7a32d881cf029abe357354632
author Zim <zezeozue@google.com> 1568021084 +0100
committer Zim <zezeozue@google.com> 1569317953 +0100

Bind mount lower filesystem during FUSE mount

When mounting a FUSE device on /mnt/user/<userid>/<vol>,
bind mount the correspoinding lower filesystem path to
/mnt/pass_through/<userid>/<vol>. At Zygote fork time, an
app with the right privilege will have the pass_through path
bind mounted into /storage instead of the /mnt/user path.

This provides such an app direct access to the lower filesystem
without going through FUSE.

Bug: 140064376
Test: mount(8) shows /mnt/pass_through/0/emulated is a bind
mount of the lower fs

Change-Id: I32c3cad64138910fcec9fb8f66b206706b5fd139