bcachefs: fix error message in device remove path

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/super.c

@@ -1258,7 +1258,7 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 	if (data) {
 		char data_has_str[100];
 
-		bch2_string_opt_to_text(&PBUF(data_has_str),
+		bch2_flags_to_text(&PBUF(data_has_str),
 				   bch2_data_types, data);
 		bch_err(ca, "Remove failed, still has data (%s)", data_has_str);
 		ret = -EBUSY;

fs/bcachefs/util.c

@@ -134,6 +134,7 @@ void bch2_flags_to_text(struct printbuf *out,
 			const char * const list[], u64 flags)
 {
 	unsigned bit, nr = 0;
+	bool first = true;
 
 	if (out->pos != out->end)
 		*out->pos = '\0';
@@ -142,7 +143,10 @@ void bch2_flags_to_text(struct printbuf *out,
 		nr++;
 
 	while (flags && (bit = __ffs(flags)) < nr) {
-		pr_buf(out, "%s,", list[bit]);
+		pr_buf(out, "%s", list[bit]);
+		if (!first)
+			pr_buf(out, ",");
+		first = false;
 		flags ^= 1 << bit;
 	}
 }