To get all processes with open files on a filesystem on OpenBSD, use either:
fuser -c /some/mountpoint
For the same result on Linux:
fuser -c /dev/disk
Does not work on OpenBSD:
Does not work on Linux:
(Never mind that -c is just a Posix compatibility flag on Linux...)
@galaxis the actual posix standard for fuser is terrible and confusing. It's no surprise people implement it differently.