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Message-ID: <539dcc26-a250-5bf4-0f3c-a3f7cdc2ce48@linux.alibaba.com>
Date:   Fri, 9 Sep 2022 17:23:12 +0800
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Subject: Re: [PATCH V2 3/5] erofs: add 'domain_id' prefix when register sysfs
Content-Language: en-US
To:     Jia Zhu <zhujia.zj@bytedance.com>, linux-erofs@lists.ozlabs.org,
        xiang@kernel.org, chao@kernel.org
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        yinxin.x@bytedance.com, huyue2@coolpad.com
References: <20220902105305.79687-1-zhujia.zj@bytedance.com>
 <20220902105305.79687-4-zhujia.zj@bytedance.com>
From:   JeffleXu <jefflexu@linux.alibaba.com>
In-Reply-To: <20220902105305.79687-4-zhujia.zj@bytedance.com>
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On 9/2/22 6:53 PM, Jia Zhu wrote:
> In shared domain mount procedure, add 'domain_id' prefix to register
> sysfs entry. Thus we could distinguish mounts that don't use shared
> domain.
> 
> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
> ---
>  fs/erofs/sysfs.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
> index c1383e508bbe..c0031d7bd817 100644
> --- a/fs/erofs/sysfs.c
> +++ b/fs/erofs/sysfs.c
> @@ -201,12 +201,21 @@ static struct kobject erofs_feat = {
>  int erofs_register_sysfs(struct super_block *sb)
>  {
>  	struct erofs_sb_info *sbi = EROFS_SB(sb);
> +	char *name = NULL;
>  	int err;
>  
> +	if (erofs_is_fscache_mode(sb)) {
> +		name = kasprintf(GFP_KERNEL, "%s%s%s", sbi->opt.domain_id ?
> +				sbi->opt.domain_id : "", sbi->opt.domain_id ? "," : "",
> +				sbi->opt.fsid);
> +		if (!name)
> +			return -ENOMEM;
> +	}


How about:

name = erofs_is_fscache_mode(sb) ? sbi->opt.fsid : sb->s_id;
if (sbi->opt.domain_id) {
	str = kasprintf(GFP_KERNEL, "%s,%s", sbi->opt.domain_id, sbi->opt.fsid);
	name = str;
}


>  	sbi->s_kobj.kset = &erofs_root;
>  	init_completion(&sbi->s_kobj_unregister);
>  	err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s",
> -			erofs_is_fscache_mode(sb) ? sbi->opt.fsid : sb->s_id);
> +			name ? name : sb->s_id);

	kobject_init_and_add(..., "%s", name);
	kfree(str);

though it's still not such straightforward...

Any better idea?


> +	kfree(name);
>  	if (err)
>  		goto put_sb_kobj;
>  	return 0;

-- 
Thanks,
Jingbo