bcachefs: Add a tracepoint for when we block on journal reclaim

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

fs/bcachefs/btree_update_leaf.c

@@ -725,6 +725,8 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 	case BTREE_INSERT_NEED_JOURNAL_RECLAIM:
 		bch2_trans_unlock(trans);
 
+		trace_trans_blocked_journal_reclaim(trans->ip);
+
 		wait_event_freezable(c->journal.reclaim_wait,
 				     (ret = journal_reclaim_wait_done(c)));
 		if (ret < 0)

fs/bcachefs/trace.h

@@ -621,6 +621,11 @@ DEFINE_EVENT(transaction_restart,	trans_restart_btree_node_reused,
 	TP_ARGS(ip)
 );
 
+DEFINE_EVENT(transaction_restart,	trans_blocked_journal_reclaim,
+	TP_PROTO(unsigned long ip),
+	TP_ARGS(ip)
+);
+
 TRACE_EVENT(trans_restart_would_deadlock,
 	TP_PROTO(unsigned long	trans_ip,
 		 unsigned long	caller_ip,