linux-kernel - Re: [PATCH 3/8] erofs: move preparation logic into z_erofs_pcluster

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Message-ID: <48235010-25e4-341f-77a3-a3399af3b6be@kernel.org>
Date:   Wed, 23 Aug 2023 23:05:05 +0800
From:   Chao Yu <chao@...nel.org>
To:     Gao Xiang <hsiangkao@...ux.alibaba.com>,
        linux-erofs@...ts.ozlabs.org
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/8] erofs: move preparation logic into
 z_erofs_pcluster_begin()

On 2023/8/17 16:28, Gao Xiang wrote:
> Some preparation logic should be part of z_erofs_pcluster_begin()
> instead of z_erofs_do_read_page().  Let's move now.
> 
> Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
> ---
>   fs/erofs/zdata.c | 59 +++++++++++++++++++++---------------------------
>   1 file changed, 26 insertions(+), 33 deletions(-)
> 
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 4ed99346c4e1..30ecdfe41836 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -852,7 +852,10 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
>   static int z_erofs_pcluster_begin(struct z_erofs_decompress_frontend *fe)
>   {
>   	struct erofs_map_blocks *map = &fe->map;
> +	struct super_block *sb = fe->inode->i_sb;
> +	erofs_blk_t blknr = erofs_blknr(sb, map->m_pa);
>   	struct erofs_workgroup *grp = NULL;
> +	void *mptr;
>   	int ret;
>   
>   	DBG_BUGON(fe->pcl);
> @@ -861,8 +864,7 @@ static int z_erofs_pcluster_begin(struct z_erofs_decompress_frontend *fe)
>   	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_NIL);
>   
>   	if (!(map->m_flags & EROFS_MAP_META)) {
> -		grp = erofs_find_workgroup(fe->inode->i_sb,
> -					   map->m_pa >> PAGE_SHIFT);
> +		grp = erofs_find_workgroup(sb, blknr);
>   	} else if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
>   		DBG_BUGON(1);
>   		return -EFSCORRUPTED;
> @@ -881,9 +883,24 @@ static int z_erofs_pcluster_begin(struct z_erofs_decompress_frontend *fe)
>   	} else if (ret) {
>   		return ret;
>   	}
> +
>   	z_erofs_bvec_iter_begin(&fe->biter, &fe->pcl->bvset,
>   				Z_EROFS_INLINE_BVECS, fe->pcl->vcnt);
> -	/* since file-backed online pages are traversed in reverse order */
> +	if (!z_erofs_is_inline_pcluster(fe->pcl)) {
> +		/* bind cache first when cached decompression is preferred */
> +		z_erofs_bind_cache(fe);
> +	} else {

Nitpick, mptr can be defined here.

Reviewed-by: Chao Yu <chao@...nel.org>

Thanks,

> +		mptr = erofs_read_metabuf(&map->buf, sb, blknr, EROFS_NO_KMAP);
> +		if (IS_ERR(mptr)) {
> +			ret = PTR_ERR(mptr);
> +			erofs_err(sb, "failed to get inline data %d", ret);
> +			return ret;
> +		}
> +		get_page(map->buf.page);
> +		WRITE_ONCE(fe->pcl->compressed_bvecs[0].page, map->buf.page);
> +		fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
> +	}
> +	/* file-backed inplace I/O pages are traversed in reverse order */
>   	fe->icur = z_erofs_pclusterpages(fe->pcl);
>   	return 0;
>   }
> @@ -982,39 +999,15 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
>   		err = z_erofs_map_blocks_iter(inode, map, 0);
>   		if (err)
>   			goto out;
> -	} else {
> -		if (fe->pcl)
> -			goto hitted;
> -		/* didn't get a valid pcluster previously (very rare) */
> -	}
> -
> -	if (!(map->m_flags & EROFS_MAP_MAPPED) ||
> -	    map->m_flags & EROFS_MAP_FRAGMENT)
> +	} else if (fe->pcl) {
>   		goto hitted;
> +	}
>   
> -	err = z_erofs_pcluster_begin(fe);
> -	if (err)
> -		goto out;
> -
> -	if (z_erofs_is_inline_pcluster(fe->pcl)) {
> -		void *mp;
> -
> -		mp = erofs_read_metabuf(&fe->map.buf, inode->i_sb,
> -					erofs_blknr(inode->i_sb, map->m_pa),
> -					EROFS_NO_KMAP);
> -		if (IS_ERR(mp)) {
> -			err = PTR_ERR(mp);
> -			erofs_err(inode->i_sb,
> -				  "failed to get inline page, err %d", err);
> +	if ((map->m_flags & EROFS_MAP_MAPPED) &&
> +	    !(map->m_flags & EROFS_MAP_FRAGMENT)) {
> +		err = z_erofs_pcluster_begin(fe);
> +		if (err)
>   			goto out;
> -		}
> -		get_page(fe->map.buf.page);
> -		WRITE_ONCE(fe->pcl->compressed_bvecs[0].page,
> -			   fe->map.buf.page);
> -		fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
> -	} else {
> -		/* bind cache first when cached decompression is preferred */
> -		z_erofs_bind_cache(fe);
>   	}
>   hitted:
>   	/*