From ae6907623cddfccd906b73e6dbd45079eff5b762 Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Tue, 1 May 2018 08:51:45 -0700
Subject: [PATCH] scoutfs: add btree rw error traces and counters

Add some trivial traces and counters around btree block IO errors.

Signed-off-by: Zach Brown <zab@versity.com>
---
 kmod/src/btree.c         |  6 +++++-
 kmod/src/counters.h      |  2 ++
 kmod/src/scoutfs_trace.h | 21 +++++++++++++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/kmod/src/btree.c b/kmod/src/btree.c
index aead4756..565474df 100644
--- a/kmod/src/btree.c
+++ b/kmod/src/btree.c
@@ -674,6 +674,8 @@ static int get_ref_block(struct super_block *sb, int flags,
 retry:
 		bh = sb_bread(sb, le64_to_cpu(ref->blkno));
 		if (!bh) {
+			trace_scoutfs_btree_read_error(sb, ref);
+			scoutfs_inc_counter(sb, btree_read_error);
 			ret = -EIO;
 			goto out;
 		}
@@ -1671,8 +1673,10 @@ int scoutfs_btree_write_dirty(struct super_block *sb)
 	ret = 0;
 	for_each_dirty_bh(bti, bh, tmp) {
 		wait_on_buffer(bh);
-		if (!buffer_uptodate(bh))
+		if (!buffer_uptodate(bh)) {
+			scoutfs_inc_counter(sb, btree_write_error);
 			ret = -EIO;
+		}
 	}
 
 out:
diff --git a/kmod/src/counters.h b/kmod/src/counters.h
index 6ecbd8e5..adae0a23 100644
--- a/kmod/src/counters.h
+++ b/kmod/src/counters.h
@@ -14,7 +14,9 @@
 #define EXPAND_EACH_COUNTER					\
 	EXPAND_COUNTER(alloc_alloc)				\
 	EXPAND_COUNTER(alloc_free)				\
+	EXPAND_COUNTER(btree_read_error)			\
 	EXPAND_COUNTER(btree_stale_read)			\
+	EXPAND_COUNTER(btree_write_error)			\
 	EXPAND_COUNTER(compact_operations)			\
 	EXPAND_COUNTER(compact_segment_moved)			\
 	EXPAND_COUNTER(compact_segment_read)			\
diff --git a/kmod/src/scoutfs_trace.h b/kmod/src/scoutfs_trace.h
index 81baeb1f..537f2a3c 100644
--- a/kmod/src/scoutfs_trace.h
+++ b/kmod/src/scoutfs_trace.h
@@ -2065,6 +2065,27 @@ TRACE_EVENT(scoutfs_get_name,
 		  __get_str(name))
 );
 
+TRACE_EVENT(scoutfs_btree_read_error,
+	TP_PROTO(struct super_block *sb, struct scoutfs_btree_ref *ref),
+
+	TP_ARGS(sb, ref),
+
+	TP_STRUCT__entry(
+		__field(__u64, fsid)
+		__field(__u64, blkno)
+		__field(__u64, seq)
+	),
+
+	TP_fast_assign(
+		__entry->fsid = FSID_ARG(sb);
+		__entry->blkno = le64_to_cpu(ref->blkno);
+		__entry->seq = le64_to_cpu(ref->seq);
+	),
+
+	TP_printk("fsid "FSID_FMT" blkno %llu seq %llu",
+		  __entry->fsid, __entry->blkno, __entry->seq)
+);
+
 #endif /* _TRACE_SCOUTFS_H */
 
 /* This part must be outside protection */