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From: Hongbo Li <lihongbo22@huawei.com>
To: <kent.overstreet@linux.dev>, <bfoster@redhat.com>
Cc: <linux-bcachefs@vger.kernel.org>, <lihongbo22@huawei.com>
Subject: [PATCH] bcachefs: fix the count of nr_freed_pcpu after changing bc->freed_nonpcpu list
Date: Tue, 26 Mar 2024 12:04:56 +0800	[thread overview]
Message-ID: <20240326040456.2587357-1-lihongbo22@huawei.com> (raw)

When allocating bkey_cached from bc->freed_pcpu list, it missed
decreasing the count of nr_freed_pcpu which would cause the mismatch
between the value of nr_freed_pcpu and the list items. This problem
also exists in moving new bkey_cached to bc->freed_pcpu list.
If these happened, the bug info may appear in
bch2_fs_btree_key_cache_exit by the follow code:

   BUG_ON(list_count_nodes(&bc->freed_pcpu) != bc->nr_freed_pcpu);
   BUG_ON(list_count_nodes(&bc->freed_nonpcpu) != bc->nr_freed_nonpcpu);

Fixes: c65c13f0eac6 ("bcachefs: Run btree key cache shrinker less aggressively")
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
 fs/bcachefs/btree_key_cache.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/bcachefs/btree_key_cache.c b/fs/bcachefs/btree_key_cache.c
index 581edcb0911b..e1031b9ba3f4 100644
--- a/fs/bcachefs/btree_key_cache.c
+++ b/fs/bcachefs/btree_key_cache.c
@@ -169,6 +169,7 @@ static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
 	} else {
 		mutex_lock(&bc->lock);
 		list_move_tail(&ck->list, &bc->freed_pcpu);
+		bc->nr_freed_pcpu++;
 		mutex_unlock(&bc->lock);
 	}
 }
@@ -245,6 +246,7 @@ bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
 		if (!list_empty(&bc->freed_pcpu)) {
 			ck = list_last_entry(&bc->freed_pcpu, struct bkey_cached, list);
 			list_del_init(&ck->list);
+			bc->nr_freed_pcpu--;
 		}
 		mutex_unlock(&bc->lock);
 	}
-- 
2.34.1


             reply	other threads:[~2024-03-26  4:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-26  4:04 Hongbo Li [this message]
2024-03-26  4:17 ` [PATCH] bcachefs: fix the count of nr_freed_pcpu after changing bc->freed_nonpcpu list Kent Overstreet
2024-03-26  6:04   ` Hongbo Li
2024-03-26 19:40     ` Kent Overstreet
2024-03-27  2:15       ` Hongbo Li

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