From: Li Chen <chenl311@chinatelecom.cn>

pcache_meta_find_latest() leaves whatever it last copied into the
caller’s buffer even when it returns NULL. For cache_info_init(),
that meant cache->cache_info could still contain CRC-bad garbage when
no valid metadata exists, leading later initialization paths to read
bogus flags.

Explicitly memset cache->cache_info in cache_info_init_default()
so new-cache paths start from a clean slate. The default sequence
number assignment becomes redundant with this reset, so it drops out.

Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
---
 drivers/md/dm-pcache/cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
index d516d4904227..698697a7a73c 100644
--- a/drivers/md/dm-pcache/cache.c
+++ b/drivers/md/dm-pcache/cache.c
@@ -181,7 +181,7 @@ static void cache_info_init_default(struct pcache_cache *cache)
 {
 	struct pcache_cache_info *cache_info = &cache->cache_info;
 
-	cache_info->header.seq = 0;
+	memset(cache_info, 0, sizeof(*cache_info));
 	cache_info->n_segs = cache->cache_dev->seg_num;
 	cache_info_set_gc_percent(cache_info, PCACHE_CACHE_GC_PERCENT_DEFAULT);
 }
-- 
2.51.0

在 11/11/2025 8:13 PM, Li Chen 写道:
> From: Li Chen <chenl311@chinatelecom.cn>
>
> pcache_meta_find_latest() leaves whatever it last copied into the
> caller’s buffer even when it returns NULL. For cache_info_init(),
> that meant cache->cache_info could still contain CRC-bad garbage when
> no valid metadata exists, leading later initialization paths to read
> bogus flags.
>
> Explicitly memset cache->cache_info in cache_info_init_default()
> so new-cache paths start from a clean slate. The default sequence
> number assignment becomes redundant with this reset, so it drops out.
>
> Signed-off-by: Li Chen <chenl311@chinatelecom.cn>

Reviewed-by： Dongsheng Yang <dongsheng.yang@linux.dev>

> ---
>   drivers/md/dm-pcache/cache.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
> index d516d4904227..698697a7a73c 100644
> --- a/drivers/md/dm-pcache/cache.c
> +++ b/drivers/md/dm-pcache/cache.c
> @@ -181,7 +181,7 @@ static void cache_info_init_default(struct pcache_cache *cache)
>   {
>   	struct pcache_cache_info *cache_info = &cache->cache_info;
>   
> -	cache_info->header.seq = 0;
> +	memset(cache_info, 0, sizeof(*cache_info));
>   	cache_info->n_segs = cache->cache_dev->seg_num;
>   	cache_info_set_gc_percent(cache_info, PCACHE_CACHE_GC_PERCENT_DEFAULT);
>   }

On Tue, Nov 11, 2025 at 8:14 PM Li Chen <me@linux.beauty> wrote:
>
> From: Li Chen <chenl311@chinatelecom.cn>
>
> pcache_meta_find_latest() leaves whatever it last copied into the
> caller’s buffer even when it returns NULL. For cache_info_init(),
> that meant cache->cache_info could still contain CRC-bad garbage when
> no valid metadata exists, leading later initialization paths to read
> bogus flags.
>
> Explicitly memset cache->cache_info in cache_info_init_default()
> so new-cache paths start from a clean slate. The default sequence
> number assignment becomes redundant with this reset, so it drops out.
>
> Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
> ---
>  drivers/md/dm-pcache/cache.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-pcache/cache.c b/drivers/md/dm-pcache/cache.c
> index d516d4904227..698697a7a73c 100644
> --- a/drivers/md/dm-pcache/cache.c
> +++ b/drivers/md/dm-pcache/cache.c
> @@ -181,7 +181,7 @@ static void cache_info_init_default(struct pcache_cache *cache)
>  {
>         struct pcache_cache_info *cache_info = &cache->cache_info;
>
> -       cache_info->header.seq = 0;
> +       memset(cache_info, 0, sizeof(*cache_info));
>         cache_info->n_segs = cache->cache_dev->seg_num;
>         cache_info_set_gc_percent(cache_info, PCACHE_CACHE_GC_PERCENT_DEFAULT);
>  }
> --
> 2.51.0
>
It looks good to me.

Reviewed-by:  Zheng Gu <cengku@gmail.com>