A library for direct mergerfs file access.
Experimental - use at your own risk.
When injected into a process (using LD_PRELOAD), it intercepts calls to open(2) and redirects them to the underlying filesystem.
For example, if you want to open /mnt/pool/foo.txt, it will open /mnt/disk1/foo.txt instead.
The path mapping is obtained using the IOCTL_FILE_INFO request provided by mergerfs.
In practice, this means you can mount your pool with cache.files=off (better performance) and still use mmap.
This is particularly useful for rtorrent which may otherwise be unstable when accessing mergerfs files (I experienced random crashes during hash checking).
A wrapper script rtorrent-mfs for launching rtorrent is included.
make
sudo make install