FSInfo linux returns (available bytes, byte capacity, error) for the filesystem that path resides upon.

IsReady checks for the existence of a regular file called 'ready' in the given directory and returns true if that file exists.

NewAtomicWriter creates a new AtomicWriter configured to write to the given target directory, or returns an error if the target directory does not exist.

SetReady creates a file called 'ready' in the given directory.

AtomicWriter handles atomically projecting content for a set of files into a target directory.