bcachefs: bch2_trans_updates_to_text()

This turns bch2_dump_trans_updates() into a to_text() method - this way
it can be used by debug tracing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -1793,30 +1793,44 @@ void bch2_path_put(struct btree_trans *trans, struct btree_path *path, bool inte
 	__bch2_path_free(trans, path);
 }
 
-noinline __cold
-void bch2_dump_trans_updates(struct btree_trans *trans)
+void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)
 {
 	struct btree_insert_entry *i;
-	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
-	bch_err(trans->c, "transaction updates:");
+	pr_buf(buf, "transaction updates for %s journal seq %llu",
+	       trans->fn, trans->journal_res.seq);
+	pr_newline(buf);
+	pr_indent_push(buf, 2);
 
 	trans_for_each_update(trans, i) {
 		struct bkey_s_c old = { &i->old_k, i->old_v };
 
-		printbuf_reset(&buf1);
-		printbuf_reset(&buf2);
-		bch2_bkey_val_to_text(&buf1, trans->c, old);
-		bch2_bkey_val_to_text(&buf2, trans->c, bkey_i_to_s_c(i->k));
-
-		printk(KERN_ERR "update: btree %s %pS\n  old %s\n  new %s",
+		pr_buf(buf, "update: btree=%s cached=%u %pS",
 		       bch2_btree_ids[i->btree_id],
-		       (void *) i->ip_allocated,
-		       buf1.buf, buf2.buf);
+		       i->cached,
+		       (void *) i->ip_allocated);
+		pr_newline(buf);
+
+		pr_buf(buf, "  old ");
+		bch2_bkey_val_to_text(buf, trans->c, old);
+		pr_newline(buf);
+
+		pr_buf(buf, "  new ");
+		bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(i->k));
+		pr_newline(buf);
 	}
 
-	printbuf_exit(&buf2);
-	printbuf_exit(&buf1);
+	pr_indent_pop(buf, 2);
+}
+
+noinline __cold
+void bch2_dump_trans_updates(struct btree_trans *trans)
+{
+	struct printbuf buf = PRINTBUF;
+
+	bch2_trans_updates_to_text(&buf, trans);
+	bch_err(trans->c, "%s", buf.buf);
+	printbuf_exit(&buf);
 }
 
 noinline __cold

fs/bcachefs/btree_iter.h

@@ -425,6 +425,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 
 /* new multiple iterator interface: */
 
+void bch2_trans_updates_to_text(struct printbuf *, struct btree_trans *);
 void bch2_dump_trans_updates(struct btree_trans *);
 void bch2_dump_trans_paths_updates(struct btree_trans *);
 void __bch2_trans_init(struct btree_trans *, struct bch_fs *,