Because we first write metadata into new place and then trash old place we

don't want situation where old size is equal to new size, as we will trash
newly written metadata.

MFC after:	1 week

sbin/geom/class/eli/geom_eli.c

@@ -1302,6 +1302,10 @@ eli_resize(struct gctl_req *req)
 		gctl_error(req, "Invalid oldsize: Out of range.");
 		goto out;
 	}
+	if (oldsize == mediasize) {
+		gctl_error(req, "Size hasn't changed.");
+		goto out;
+	}
 
 	/* Read metadata from the 'oldsize' offset. */
 	if (pread(provfd, sector, secsize, oldsize - secsize) != secsize) {