[PATCH v3 2/9] btrfs: include delalloc related info in dump space info tracepoint

[Josef Bacik <josef@toxicpanda.com>]

In order to debug delalloc flushing issues I added delalloc_bytes and
ordered_bytes to this tracepoint to see if they were non-zero when we
were ENOSPC'ing.  This was valuable for me and showed me cases where we
weren't waiting on ordered extents properly. In order to add this to the
tracepoint we need to take away the const modifier for fs_info, as
percpu_sum_counter_positive() will change the counter when it adds up
the percpu buckets.  This is needed to make sure we're getting accurate
information at these tracepoints, as the wrong information could send us
down the wrong path when debugging problems.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 include/trace/events/btrfs.h | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index c7237317a8b9..a87953e74573 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -2037,7 +2037,7 @@ TRACE_EVENT(btrfs_convert_extent_bit,
 );
 
 DECLARE_EVENT_CLASS(btrfs_dump_space_info,
-	TP_PROTO(const struct btrfs_fs_info *fs_info,
+	TP_PROTO(struct btrfs_fs_info *fs_info,
 		 const struct btrfs_space_info *sinfo),
 
 	TP_ARGS(fs_info, sinfo),
@@ -2057,6 +2057,8 @@ DECLARE_EVENT_CLASS(btrfs_dump_space_info,
 		__field(	u64,	delayed_refs_reserved	)
 		__field(	u64,	delayed_reserved	)
 		__field(	u64,	free_chunk_space	)
+		__field(	u64,	delalloc_bytes		)
+		__field(	u64,	ordered_bytes		)
 	),
 
 	TP_fast_assign_btrfs(fs_info,
@@ -2074,6 +2076,8 @@ DECLARE_EVENT_CLASS(btrfs_dump_space_info,
 		__entry->delayed_refs_reserved	=	fs_info->delayed_refs_rsv.reserved;
 		__entry->delayed_reserved	=	fs_info->delayed_block_rsv.reserved;
 		__entry->free_chunk_space	=	atomic64_read(&fs_info->free_chunk_space);
+		__entry->delalloc_bytes		=	percpu_counter_sum_positive(&fs_info->delalloc_bytes);
+		__entry->ordered_bytes		=	percpu_counter_sum_positive(&fs_info->ordered_bytes);
 	),
 
 	TP_printk_btrfs("flags=%s total_bytes=%llu bytes_used=%llu "
@@ -2081,7 +2085,8 @@ DECLARE_EVENT_CLASS(btrfs_dump_space_info,
 			"bytes_may_use=%llu bytes_readonly=%llu "
 			"reclaim_size=%llu clamp=%d global_reserved=%llu "
 			"trans_reserved=%llu delayed_refs_reserved=%llu "
-			"delayed_reserved=%llu chunk_free_space=%llu",
+			"delayed_reserved=%llu chunk_free_space=%llu "
+			"delalloc_bytes=%llu ordered_bytes=%llu",
 			__print_flags(__entry->flags, "|", BTRFS_GROUP_FLAGS),
 			__entry->total_bytes, __entry->bytes_used,
 			__entry->bytes_pinned, __entry->bytes_reserved,
@@ -2089,11 +2094,12 @@ DECLARE_EVENT_CLASS(btrfs_dump_space_info,
 			__entry->reclaim_size, __entry->clamp,
 			__entry->global_reserved, __entry->trans_reserved,
 			__entry->delayed_refs_reserved,
-			__entry->delayed_reserved, __entry->free_chunk_space)
+			__entry->delayed_reserved, __entry->free_chunk_space,
+			__entry->delalloc_bytes, __entry->ordered_bytes)
 );
 
 DEFINE_EVENT(btrfs_dump_space_info, btrfs_done_preemptive_reclaim,
-	TP_PROTO(const struct btrfs_fs_info *fs_info,
+	TP_PROTO(struct btrfs_fs_info *fs_info,
 		 const struct btrfs_space_info *sinfo),
 	TP_ARGS(fs_info, sinfo)
 );
-- 
2.26.3