On Tue, Mar 26, 2024 at 12:04:56PM +0800, Hongbo Li wrote:
> 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);
Please include the assertions too :)
> Fixes: c65c13f0eac6 ("bcachefs: Run btree key cache shrinker less
> aggressively")
> Signed-off-by: Hongbo Li <[email protected]>
> ---
> 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
>
