There is in struct statfs, which can be obtained for an open file descriptor using the fstatfs(2) system call, if you (a) want to make this autodetection OS-spe

There is in struct statfs, which can be obtained for an open file descriptor using the fstatfs(2) system call, if you (a) want to make this autodetection OS-specific (statfs is Linux-specific, but I'm sure there's equivalents on other OSs) and (b) maintain your own list of compatible file system types.