From fdbc9c390ade238383f5a24e4b32e49550dc90e4 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon, 19 Aug 2024 15:33:38 -0400
Subject: [PATCH] bcachefs: bch2_time_stats_reset()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/sysfs.c      |  9 ++++++++-
 fs/bcachefs/time_stats.c | 14 ++++++++++++++
 fs/bcachefs/time_stats.h |  3 ++-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index 7ff9afcb37b2..6791540d6a4a 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -233,7 +233,7 @@ write_attribute(perf_test);
 
 #define x(_name)						\
 	static struct attribute sysfs_time_stat_##_name =		\
-		{ .name = #_name, .mode = 0444 };
+		{ .name = #_name, .mode = 0644 };
 	BCH_TIME_STATS()
 #undef x
 
@@ -722,6 +722,13 @@ SHOW(bch2_fs_time_stats)
 
 STORE(bch2_fs_time_stats)
 {
+	struct bch_fs *c = container_of(kobj, struct bch_fs, time_stats);
+
+#define x(name)								\
+	if (attr == &sysfs_time_stat_##name)				\
+		bch2_time_stats_reset(&c->times[BCH_TIME_##name]);
+	BCH_TIME_STATS()
+#undef x
 	return size;
 }
 SYSFS_OPS(bch2_fs_time_stats);
diff --git a/fs/bcachefs/time_stats.c b/fs/bcachefs/time_stats.c
index 4508e9dcbee2..3fe82757f93a 100644
--- a/fs/bcachefs/time_stats.c
+++ b/fs/bcachefs/time_stats.c
@@ -151,6 +151,20 @@ void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end)
 	}
 }
 
+void bch2_time_stats_reset(struct bch2_time_stats *stats)
+{
+	spin_lock_irq(&stats->lock);
+	unsigned offset = offsetof(struct bch2_time_stats, min_duration);
+	memset((void *) stats + offset, 0, sizeof(*stats) - offset);
+
+	if (stats->buffer) {
+		int cpu;
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(stats->buffer, cpu)->nr = 0;
+	}
+	spin_unlock_irq(&stats->lock);
+}
+
 void bch2_time_stats_exit(struct bch2_time_stats *stats)
 {
 	free_percpu(stats->buffer);
diff --git a/fs/bcachefs/time_stats.h b/fs/bcachefs/time_stats.h
index 5df61403744b..dc6493f7bbab 100644
--- a/fs/bcachefs/time_stats.h
+++ b/fs/bcachefs/time_stats.h
@@ -70,6 +70,7 @@ struct time_stat_buffer {
 struct bch2_time_stats {
 	spinlock_t	lock;
 	bool		have_quantiles;
+	struct time_stat_buffer __percpu *buffer;
 	/* all fields are in nanoseconds */
 	u64             min_duration;
 	u64		max_duration;
@@ -87,7 +88,6 @@ struct bch2_time_stats {
 
 	struct mean_and_variance_weighted duration_stats_weighted;
 	struct mean_and_variance_weighted freq_stats_weighted;
-	struct time_stat_buffer __percpu *buffer;
 };
 
 struct bch2_time_stats_quantiles {
@@ -142,6 +142,7 @@ static inline bool track_event_change(struct bch2_time_stats *stats, bool v)
 	return false;
 }
 
+void bch2_time_stats_reset(struct bch2_time_stats *);
 void bch2_time_stats_exit(struct bch2_time_stats *);
 void bch2_time_stats_init(struct bch2_time_stats *);