Search notes:

/sys/fs

/sys/fs contains subdirectories for mounted(?) filesystems.

Some subdirectories I found under /sys/fs include:

`9p`
`bpf`
`btrfs`
`cgroup`	(and filesystem below) expose the kernel control group hierarchy.
`ext4`
`fuse`
`nfs`
`selinux`
`xfs`

See also