How to bind root (/) to itself with fuse on linux?

Question

I'm writing a fuse file system that mount one directory to itself. I want to log some calls ( flush for example). I've started to adapt fuse tutorial sample code . If I try to bind any directory it works great:

./bbfs -o nonempty ./test ./test

but if I try to bind particular root directory ("/"):

sudo ./bbfs -o nonempty / / 

no one line is in logfile.

Is it possible?

My mangled version of sample program . I've changed only bbfs.c file.

Answer 1

You can't mount a FUSE filesystem (or any other type of filesystem, for that matter) at / , because your root filesystem is already there.

Doing so would be disastrous anyway, as mounting a filesystem at a path makes any files which previously existed under that path inaccessible. You can't use FUSE as a filter like this -- you will need to find another solution to whatever it is you're trying to do.