btrfs: Add qgroup tracing

This patch adds tracepoints to the qgroup code on both the reporting side
(insert_dirty_extents) and the accounting side. Taken together it allows us
to see what qgroup operations have happened, and what their result was.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/qgroup.c

@@ -1463,6 +1463,7 @@ struct btrfs_qgroup_extent_record
 	u64 bytenr = record->bytenr;
 
 	assert_spin_locked(&delayed_refs->lock);
+	trace_btrfs_qgroup_insert_dirty_extent(record);
 
 	while (*p) {
 		parent_node = *p;
@@ -1594,6 +1595,9 @@ static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
 		cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
 		cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
 
+		trace_qgroup_update_counters(qg->qgroupid, cur_old_count,
+					     cur_new_count);
+
 		/* Rfer update part */
 		if (cur_old_count == 0 && cur_new_count > 0) {
 			qg->rfer += num_bytes;
@@ -1683,6 +1687,9 @@ btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
 		goto out_free;
 	BUG_ON(!fs_info->quota_root);
 
+	trace_btrfs_qgroup_account_extent(bytenr, num_bytes, nr_old_roots,
+					  nr_new_roots);
+
 	qgroups = ulist_alloc(GFP_NOFS);
 	if (!qgroups) {
 		ret = -ENOMEM;
@@ -1752,6 +1759,8 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
 		record = rb_entry(node, struct btrfs_qgroup_extent_record,
 				  node);
 
+		trace_btrfs_qgroup_account_extents(record);
+
 		if (!ret) {
 			/*
 			 * Use (u64)-1 as time_seq to do special search, which

include/trace/events/btrfs.h

@@ -23,7 +23,7 @@ struct map_lookup;
 struct extent_buffer;
 struct btrfs_work;
 struct __btrfs_workqueue;
-struct btrfs_qgroup_operation;
+struct btrfs_qgroup_extent_record;
 
 #define show_ref_type(type)						\
 	__print_symbolic(type,						\
@@ -1231,6 +1231,93 @@ DEFINE_EVENT(btrfs__qgroup_delayed_ref, btrfs_qgroup_free_delayed_ref,
 
 	TP_ARGS(ref_root, reserved)
 );
+
+DECLARE_EVENT_CLASS(btrfs_qgroup_extent,
+	TP_PROTO(struct btrfs_qgroup_extent_record *rec),
+
+	TP_ARGS(rec),
+
+	TP_STRUCT__entry(
+		__field(	u64,  bytenr		)
+		__field(	u64,  num_bytes		)
+	),
+
+	TP_fast_assign(
+		__entry->bytenr		= rec->bytenr,
+		__entry->num_bytes	= rec->num_bytes;
+	),
+
+	TP_printk("bytenr = %llu, num_bytes = %llu",
+		  (unsigned long long)__entry->bytenr,
+		  (unsigned long long)__entry->num_bytes)
+);
+
+DEFINE_EVENT(btrfs_qgroup_extent, btrfs_qgroup_account_extents,
+
+	TP_PROTO(struct btrfs_qgroup_extent_record *rec),
+
+	TP_ARGS(rec)
+);
+
+DEFINE_EVENT(btrfs_qgroup_extent, btrfs_qgroup_insert_dirty_extent,
+
+	TP_PROTO(struct btrfs_qgroup_extent_record *rec),
+
+	TP_ARGS(rec)
+);
+
+TRACE_EVENT(btrfs_qgroup_account_extent,
+
+	TP_PROTO(u64 bytenr, u64 num_bytes, u64 nr_old_roots, u64 nr_new_roots),
+
+	TP_ARGS(bytenr, num_bytes, nr_old_roots, nr_new_roots),
+
+	TP_STRUCT__entry(
+		__field(	u64,  bytenr			)
+		__field(	u64,  num_bytes			)
+		__field(	u64,  nr_old_roots		)
+		__field(	u64,  nr_new_roots		)
+	),
+
+	TP_fast_assign(
+		__entry->bytenr		= bytenr;
+		__entry->num_bytes	= num_bytes;
+		__entry->nr_old_roots	= nr_old_roots;
+		__entry->nr_new_roots	= nr_new_roots;
+	),
+
+	TP_printk("bytenr = %llu, num_bytes = %llu, nr_old_roots = %llu, "
+		  "nr_new_roots = %llu",
+		  __entry->bytenr,
+		  __entry->num_bytes,
+		  __entry->nr_old_roots,
+		  __entry->nr_new_roots)
+);
+
+TRACE_EVENT(qgroup_update_counters,
+
+	TP_PROTO(u64 qgid, u64 cur_old_count, u64 cur_new_count),
+
+	TP_ARGS(qgid, cur_old_count, cur_new_count),
+
+	TP_STRUCT__entry(
+		__field(	u64,  qgid			)
+		__field(	u64,  cur_old_count		)
+		__field(	u64,  cur_new_count		)
+	),
+
+	TP_fast_assign(
+		__entry->qgid		= qgid;
+		__entry->cur_old_count	= cur_old_count;
+		__entry->cur_new_count	= cur_new_count;
+	),
+
+	TP_printk("qgid = %llu, cur_old_count = %llu, cur_new_count = %llu",
+		  __entry->qgid,
+		  __entry->cur_old_count,
+		  __entry->cur_new_count)
+);
+
 #endif /* _TRACE_BTRFS_H */
 
 /* This part must be outside protection */