From 2e655e6de202d891f0232cfd3c56b8f8c176cf99 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Mon, 12 Jul 2021 23:52:49 -0400
Subject: [PATCH] bcachefs: Add open_buckets to sysfs

This is to help debug a rare shutdown deadlock in the allocator code -
the btree code is leaking open_buckets.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
 fs/bcachefs/alloc_background.c | 19 +++++++++++++++++++
 fs/bcachefs/alloc_background.h |  2 ++
 fs/bcachefs/sysfs.c            |  7 +++++++
 3 files changed, 28 insertions(+)

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 15f9adf0876a9..fc20649b19cf4 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -1232,3 +1232,22 @@ void bch2_fs_allocator_background_init(struct bch_fs *c)
 {
 	spin_lock_init(&c->freelist_lock);
 }
+
+void bch2_open_buckets_to_text(struct printbuf *out, struct bch_fs *c)
+{
+	struct open_bucket *ob;
+
+	for (ob = c->open_buckets;
+	     ob < c->open_buckets + ARRAY_SIZE(c->open_buckets);
+	     ob++) {
+		spin_lock(&ob->lock);
+		if (ob->valid && !ob->on_partial_list) {
+			pr_buf(out, "%zu ref %u type %s\n",
+			       ob - c->open_buckets,
+			       atomic_read(&ob->pin),
+			       bch2_data_types[ob->type]);
+		}
+		spin_unlock(&ob->lock);
+	}
+
+}
diff --git a/fs/bcachefs/alloc_background.h b/fs/bcachefs/alloc_background.h
index 9cadfdb5b83df..a4f6bf56b18f6 100644
--- a/fs/bcachefs/alloc_background.h
+++ b/fs/bcachefs/alloc_background.h
@@ -132,4 +132,6 @@ int bch2_dev_allocator_start(struct bch_dev *);
 int bch2_alloc_write(struct bch_fs *, unsigned);
 void bch2_fs_allocator_background_init(struct bch_fs *);
 
+void bch2_open_buckets_to_text(struct printbuf *, struct bch_fs *);
+
 #endif /* _BCACHEFS_ALLOC_BACKGROUND_H */
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index 84a7acb04d01b..9b1ffbf96e147 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -171,6 +171,7 @@ read_attribute(btree_cache);
 read_attribute(btree_key_cache);
 read_attribute(btree_transactions);
 read_attribute(stripes_heap);
+read_attribute(open_buckets);
 
 read_attribute(internal_uuid);
 
@@ -409,6 +410,11 @@ SHOW(bch2_fs)
 		return out.pos - buf;
 	}
 
+	if (attr == &sysfs_open_buckets) {
+		bch2_open_buckets_to_text(&out, c);
+		return out.pos - buf;
+	}
+
 	if (attr == &sysfs_compression_stats) {
 		bch2_compression_stats_to_text(&out, c);
 		return out.pos - buf;
@@ -567,6 +573,7 @@ struct attribute *bch2_fs_internal_files[] = {
 	&sysfs_btree_key_cache,
 	&sysfs_btree_transactions,
 	&sysfs_stripes_heap,
+	&sysfs_open_buckets,
 
 	&sysfs_read_realloc_races,
 	&sysfs_extent_migrate_done,
-- 
2.30.2