The option is called --tablespace-mapping, not --tablespace.
Amit Kapila
/*
* Symbolic link
*
- * It's most likely a link in pg_tblspc directory, to
- * the location of a tablespace. Apply any tablespace
- * mapping given on the command line (--tablespace).
+ * It's most likely a link in pg_tblspc directory, to the
+ * location of a tablespace. Apply any tablespace mapping
+ * given on the command line (--tablespace-mapping).
* (We blindly apply the mapping without checking that
* the link really is inside pg_tblspc. We don't expect
* there to be other symlinks in a data directory, but