* across filesystems, -2 if copy_file() failed, and -1 on other errors.
* If partialptr is not NULL and we need to do a copy, copy the file into
* the active partial-dir instead of over the destination file. */
* across filesystems, -2 if copy_file() failed, and -1 on other errors.
* If partialptr is not NULL and we need to do a copy, copy the file into
* the active partial-dir instead of over the destination file. */