On Thu, Dec 4, 2025 at 10:57 AM Dongsheng Yang <[email protected]> wrote:
>
> From: Li Chen <[email protected]>
>
> The on-media cache_info index used sizeof(struct) instead of the
> 4K metadata stride, so gc_percent updates from dmsetup message
> were written between slots and lost after reboot. Use
> PCACHE_CACHE_INFO_SIZE in get_cache_info_addr() and align
> info_index with the slot returned by pcache_meta_find_latest().
>
> Signed-off-by: Li Chen <[email protected]>
> Signed-off-by: Dongsheng Yang <[email protected]>
> ---
>  drivers/md/dm-pcache/cache.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
> index 9289c016b7c9..bcc4e509aa69 100644
> --- a/drivers/md/dm-pcache/cache.c
> +++ b/drivers/md/dm-pcache/cache.c
> @@ -8,9 +8,11 @@
>
>  struct kmem_cache *key_cache;
>
> -static inline struct pcache_cache_info *get_cache_info_addr(struct 
> pcache_cache *cache)
> +static inline struct pcache_cache_info *
> +get_cache_info_addr(struct pcache_cache *cache)
>  {
> -       return cache->cache_info_addr + cache->info_index;
> +       return (struct pcache_cache_info *)((char *)cache->cache_info_addr +
> +                                               (size_t)cache->info_index * 
> PCACHE_CACHE_INFO_SIZE);
>  }
>
>  static void cache_info_write(struct pcache_cache *cache)
> @@ -49,6 +51,8 @@ static int cache_info_init(struct pcache_cache *cache, 
> struct pcache_cache_optio
>                         return -EINVAL;
>                 }
>
> +               cache->info_index = ((char *)cache_info_addr - (char 
> *)cache->cache_info_addr) / PCACHE_CACHE_INFO_SIZE;
> +
>                 return 0;
>         }
>
> --
> 2.43.0
>

Reviewed-by:  Zheng Gu <[email protected]>

Regards,
Gu

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