Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <babdb60b-227a-ac37-8fda-367556987c3f@bytedance.com>
Date:   Tue, 13 Sep 2022 12:35:58 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
 Gecko/20100101 Thunderbird/91.13.0
Subject: Re: [External] Re: [PATCH V2 3/5] erofs: add 'domain_id' prefix when
 register sysfs
To:     JeffleXu <jefflexu@linux.alibaba.com>,
        linux-erofs@lists.ozlabs.org, xiang@kernel.org, chao@kernel.org
Cc:     linux-fsdevel@vger.kernel.org, huyue2@coolpad.com,
        linux-kernel@vger.kernel.org, yinxin.x@bytedance.com
References: <20220902105305.79687-1-zhujia.zj@bytedance.com>
 <20220902105305.79687-4-zhujia.zj@bytedance.com>
 <539dcc26-a250-5bf4-0f3c-a3f7cdc2ce48@linux.alibaba.com>
 <fc63c7ed-bffe-4127-7622-a7ce0c4b4378@linux.alibaba.com>
From:   Jia Zhu <zhujia.zj@bytedance.com>
In-Reply-To: <fc63c7ed-bffe-4127-7622-a7ce0c4b4378@linux.alibaba.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2022/9/9 17:26, JeffleXu 写道:
> 
> 
> On 9/9/22 5:23 PM, JeffleXu wrote:
>>
>>
>> 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;
>> }
> 
> Another choice:
> 
> if (erofs_is_fscache_mode(sb)) {
> 	if (sbi->opt.domain_id) {
> 		str = kasprintf(GFP_KERNEL, "%s,%s", sbi->opt.domain_id, sbi->opt.fsid);
> 		name = str;
> 	} else {
> 		name = sbi->opt.fsid;
> 	}
> } else {
> 	name = sb->s_id;
> }
> 
> 
Thanks for your advise, this version looks more intuitive. I'll apply it
in next version.
> 
> 
>>
>>
>>>   	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;
>>
>