Re: [PATCH 1/3] erofs-utils: get rid of useless nr_dup

[Yue Hu <zbestahu@gmail.com>]

On Wed,  1 Mar 2023 02:54:57 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:

> Also refine the longest detection.
> 
> Fixes: 990c7e383795 ("erofs-utils: mkfs: support fragment deduplication")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Yue Hu <huyue2@coolpad.com>

> ---
>  lib/fragments.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/fragments.c b/lib/fragments.c
> index c67c1bb..1e41485 100644
> --- a/lib/fragments.c
> +++ b/lib/fragments.c
> @@ -26,7 +26,7 @@
>  
>  struct erofs_fragment_dedupe_item {
>  	struct list_head	list;
> -	unsigned int		length, nr_dup;
> +	unsigned int		length;
>  	erofs_off_t		pos;
>  	u8			data[];
>  };
> @@ -53,7 +53,7 @@ static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
>  	struct erofs_fragment_dedupe_item *cur, *di = NULL;
>  	struct list_head *head;
>  	u8 *data;
> -	unsigned int length, e2;
> +	unsigned int length, e2, deduped;
>  	int ret;
>  
>  	head = &dupli_frags[FRAGMENT_HASH(crc)];
> @@ -83,6 +83,7 @@ static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
>  
>  	DBG_BUGON(length <= EROFS_TOF_HASHLEN);
>  	e2 = length - EROFS_TOF_HASHLEN;
> +	deduped = 0;
>  
>  	list_for_each_entry(cur, head, list) {
>  		unsigned int e1, mn, i = 0;
> @@ -97,22 +98,22 @@ static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
>  		while (i < mn && cur->data[e1 - i - 1] == data[e2 - i - 1])
>  			++i;
>  
> -		if (i && (!di || i + EROFS_TOF_HASHLEN > di->nr_dup)) {
> -			cur->nr_dup = i + EROFS_TOF_HASHLEN;
> +		if (!di || i + EROFS_TOF_HASHLEN > deduped) {
> +			deduped = i + EROFS_TOF_HASHLEN;
>  			di = cur;
>  
>  			/* full match */
> -			if (i == mn)
> +			if (i == e2)
>  				break;
>  		}
>  	}
>  	if (!di)
>  		goto out;
>  
> -	DBG_BUGON(di->length < di->nr_dup);
> +	DBG_BUGON(di->length < deduped);
>  
> -	inode->fragment_size = di->nr_dup;
> -	inode->fragmentoff = di->pos + di->length - di->nr_dup;
> +	inode->fragment_size = deduped;
> +	inode->fragmentoff = di->pos + di->length - deduped;
>  
>  	erofs_dbg("Dedupe %u tail data at %llu", inode->fragment_size,
>  		  inode->fragmentoff | 0ULL);
> @@ -161,7 +162,6 @@ static int z_erofs_fragments_dedupe_insert(void *data, unsigned int len,
>  	memcpy(di->data, data, len);
>  	di->length = len;
>  	di->pos = pos;
> -	di->nr_dup = 0;
>  
>  	list_add_tail(&di->list, &dupli_frags[FRAGMENT_HASH(crc)]);
>  	return 0;