Object to disc address?

I was copying something using FTPs when it crashed and stiffed the machine (hint, it doesn’t like long paths!).

Upon rebooting and trying again, the target directory is giving “Broken directory” errors. This ought to be fairly easily fixable as there was no indication that anything was actually transferred, so it most likely died trying to create the file – leaving the directory either as gibberish or with invalid data, checksums, whatever.

My question is this: is there a SWI call that can return a disc address for an object (file, dir)? Or does one have to walk the structure manually, starting from $?