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Message-ID: <144922ad-66a3-27e8-df85-4a58c175a630@linux.alibaba.com>
Date:   Fri, 13 Jan 2023 15:41:21 +0800
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Subject: Re: [PATCH 1/2] erofs: clean up erofs_iget()
To:     Gao Xiang <hsiangkao@linux.alibaba.com>,
        linux-erofs@lists.ozlabs.org, Chao Yu <chao@kernel.org>,
        Yue Hu <huyue2@coolpad.com>
Cc:     LKML <linux-kernel@vger.kernel.org>
References: <20230113065226.68801-1-hsiangkao@linux.alibaba.com>
Content-Language: en-US
From:   Jingbo Xu <jefflexu@linux.alibaba.com>
In-Reply-To: <20230113065226.68801-1-hsiangkao@linux.alibaba.com>
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On 1/13/23 2:52 PM, Gao Xiang wrote:
> Move inode hash function into inode.c and simplify erofs_iget().
> 
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> ---
>  fs/erofs/inode.c    | 40 +++++++++++++++++++++-------------------
>  fs/erofs/internal.h |  9 ---------
>  2 files changed, 21 insertions(+), 28 deletions(-)
> 
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index d3b8736fa124..57328691582e 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -308,47 +308,49 @@ static int erofs_fill_inode(struct inode *inode)
>  }
>  
>  /*
> - * erofs nid is 64bits, but i_ino is 'unsigned long', therefore
> - * we should do more for 32-bit platform to find the right inode.
> + * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
> + * so that it will fit.
>   */
> -static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
> +static ino_t erofs_squash_ino(erofs_nid_t nid)
>  {
> -	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
> +	ino_t ino = (ino_t)nid;
> +
> +	if (sizeof(ino_t) < sizeof(erofs_nid_t))
> +		ino ^= nid >> (sizeof(erofs_nid_t) - sizeof(ino_t)) * 8;

Shouldn't we do:

	ino ^= nid >> sizeof(ino_t) * 8
?


-- 
Thanks,
Jingbo