ext4: Add new tracepoint for jbd2_cleanup_journal_tail

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/checkpoint.c

@@ -507,6 +507,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
 	if (blocknr < journal->j_tail)
 		freed = freed + journal->j_last - journal->j_first;
 
+	trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed);
 	jbd_debug(1,
 		  "Cleaning journal tail from %d to %d (offset %lu), "
 		  "freeing %lu\n",

include/trace/events/jbd2.h

@@ -199,6 +199,34 @@ TRACE_EVENT(jbd2_checkpoint_stats,
 		  __entry->forced_to_close, __entry->written, __entry->dropped)
 );
 
+TRACE_EVENT(jbd2_cleanup_journal_tail,
+
+	TP_PROTO(journal_t *journal, tid_t first_tid,
+		 unsigned long block_nr, unsigned long freed),
+
+	TP_ARGS(journal, first_tid, block_nr, freed),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	tid_t,	tail_sequence		)
+		__field(	tid_t,	first_tid		)
+		__field(unsigned long,	block_nr		)
+		__field(unsigned long,	freed			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->tail_sequence	= journal->j_tail_sequence;
+		__entry->first_tid	= first_tid;
+		__entry->block_nr	= block_nr;
+		__entry->freed		= freed;
+	),
+
+	TP_printk("dev %s from %u to %u offset %lu freed %lu",
+		  jbd2_dev_to_name(__entry->dev), __entry->tail_sequence,
+		  __entry->first_tid, __entry->block_nr, __entry->freed)
+);
+
 #endif /* _TRACE_JBD2_H */
 
 /* This part must be outside protection */