Re: [PATCH v3] exfat: integrates dir-entry getting and validation

From: Tetsuhiro Kohada <kohada.t2@gmail.com>
To: Namjae Jeon <namjae.jeon@samsung.com>
Cc: kohada.tetsuhiro@dc.mitsubishielectric.co.jp,
	mori.takahiro@ab.mitsubishielectric.co.jp,
	motai.hirotaka@aj.mitsubishielectric.co.jp,
	'Sungjong Seo' <sj1557.seo@samsung.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] exfat: integrates dir-entry getting and validation
Date: Wed, 12 Aug 2020 22:25:34 +0900	[thread overview]
Message-ID: <ca3b2b52-1abc-939c-aa11-8c7d12e4eb2e@gmail.com> (raw)
In-Reply-To: <003c01d66edc$edbb1690$c93143b0$@samsung.com>

Thank you for your reply.

>> @@ -171,7 +174,9 @@ struct exfat_entry_set_cache {
>>   	unsigned int start_off;
>>   	int num_bh;
>>   	struct buffer_head *bh[DIR_CACHE_SIZE];
>> -	unsigned int num_entries;
>> +	int num_entries;
>> +	struct exfat_de_file *de_file;
>> +	struct exfat_de_stream *de_stream;
> I prefer to assign validated entries to **de and use it using enum value.
> 	struct exfat_dentry **de;

I've tried several implementations that add a struct exfat_dentry type.(*de0 & *de1;  *de[2]; etc...)
The problem with the struct exfat_dentry type is that it is too flexible for type.
This means weak typing.
Therefore, when using them,
	de[XXX_FILE]->dentry.file.zzz ...
It is necessary to re-specify the type. (against the DRY principle)
Strong typing prevents use with wrong type, at compiling.

I think the approach of using de_file/de_stream could be strongly typed.
I don't think we need excessive flexibility.

BR
---
Tetsuhiro Kohada <kohada.t2@gmail.com>