diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 22020729cb..67e3713cd3 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -48,8 +48,13 @@ static const char *tag_resolve_undo = "";
 
 static void write_name(const char* name, size_t len)
 {
-	write_name_quoted_relative(name, len, prefix, prefix_len, stdout,
-			line_terminator);
+	/*
+	 * With "--full-name", prefix_len=0; write_name_quoted_relative()
+	 * ignores prefix_len, so this caller needs to pass empty string
+	 * in that case (a NULL is good for "").
+	 */
+	write_name_quoted_relative(name, len, prefix_len ? prefix : NULL,
+			prefix_len, stdout, line_terminator);
 }
 
 static void show_dir_entry(const char *tag, struct dir_entry *ent)
diff --git a/quote.c b/quote.c
index 911229fdf3..64ff344158 100644
--- a/quote.c
+++ b/quote.c
@@ -312,75 +312,24 @@ void write_name_quotedpfx(const char *pfx, size_t pfxlen,
 	fputc(terminator, fp);
 }
 
-static const char *path_relative(const char *in, int len,
-				 struct strbuf *sb, const char *prefix,
-				 int prefix_len);
-
 void write_name_quoted_relative(const char *name, size_t len,
 				const char *prefix, size_t prefix_len,
 				FILE *fp, int terminator)
 {
 	struct strbuf sb = STRBUF_INIT;
 
-	name = path_relative(name, len, &sb, prefix, prefix_len);
+	name = relative_path(name, prefix, &sb);
 	write_name_quoted(name, fp, terminator);
 
 	strbuf_release(&sb);
 }
 
-/*
- * Give path as relative to prefix.
- *
- * The strbuf may or may not be used, so do not assume it contains the
- * returned path.
- */
-static const char *path_relative(const char *in, int len,
-				 struct strbuf *sb, const char *prefix,
-				 int prefix_len)
-{
-	int off, i;
-
-	if (len < 0)
-		len = strlen(in);
-	if (prefix_len < 0) {
-		if (prefix)
-			prefix_len = strlen(prefix);
-		else
-			prefix_len = 0;
-	}
-
-	off = 0;
-	i = 0;
-	while (i < prefix_len && i < len && prefix[i] == in[i]) {
-		if (prefix[i] == '/')
-			off = i + 1;
-		i++;
-	}
-	in += off;
-	len -= off;
-
-	if (i >= prefix_len)
-		return in;
-
-	strbuf_reset(sb);
-	strbuf_grow(sb, len);
-
-	while (i < prefix_len) {
-		if (prefix[i] == '/')
-			strbuf_addstr(sb, "../");
-		i++;
-	}
-	strbuf_add(sb, in, len);
-
-	return sb->buf;
-}
-
 /* quote path as relative to the given prefix */
 char *quote_path_relative(const char *in, int len,
 			  struct strbuf *out, const char *prefix)
 {
 	struct strbuf sb = STRBUF_INIT;
-	const char *rel = path_relative(in, len, &sb, prefix, -1);
+	const char *rel = relative_path(in, prefix, &sb);
 	strbuf_reset(out);
 	quote_c_style_counted(rel, strlen(rel), out, NULL, 0);
 	strbuf_release(&sb);