linux-ext4 - Re: [PATCH] ext4: remove set but rewrite variables

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Message-Id: <CCD53C8F-7A5B-40B4-9FB8-6D17F352AAFD@gmail.com>
Date:   Mon, 17 May 2021 12:18:20 +0300
From:   Благодаренко Артём 
        <artem.blagodarenko@...il.com>
To:     "tiantao (H)" <tiantao6@...wei.com>
Cc:     Tian Tao <tiantao6@...ilicon.com>,
        "Theodore Y. Ts'o" <tytso@....edu>, adilger.kernel@...ger.ca,
        linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext4: remove set but rewrite variables

It looks like it is always reset just after “again:”  label. So, yes, your fix does not change the logic.

Feel free to add:
Reviewed-by: Artem Blagodarenko <artem.blagodarenko@...il.com>

Best regards,
Artem Blagodarenko
> On 17 May 2021, at 11:44, tiantao (H) <tiantao6@...wei.com> wrote:
> 
> 
> 在 2021/5/17 16:05, Благодаренко Артём 写道:
>> 
>>> On 17 May 2021, at 05:56, Tian Tao <tiantao6@...ilicon.com> wrote:
>>> 
>>> In line 2500 of the ext4_dx_add_entry function, the at variable is
>>> assigned but not used, and it is reassigned in line 2449, so delete
>>> the assignment of the at variable in line 2500.
>>> 
>>> Signed-off-by: Tian Tao <tiantao6@...ilicon.com>
>>> ---
>>> fs/ext4/namei.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>> 
>>> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
>>> index afb9d05..18bbf15 100644
>>> --- a/fs/ext4/namei.c
>>> +++ b/fs/ext4/namei.c
>>> @@ -2497,7 +2497,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
>>> 
>>> 			/* Which index block gets the new entry? */
>>> 			if (at - entries >= icount1) {
>>> -				frame->at = at = at - entries - icount1 + entries2;
>>> +				frame->at = at - entries - icount1 + entries2;
>>> 				frame->entries = entries = entries2;
>>> 				swap(frame->bh, bh2);
>>> 			}
>>> -- 
>>> 2.7.4
>>> 
>> 
>> Hello Tian,
>> 
>> Thank you for the patch.
>> 
>> Please, clarify, do you think the logic not changed after you patch if "while (frame > frames) {“ loop is not executed or terminated by “break:” in " if (dx_get_count((frame - 1)->entries) < ...“ block?
> 
> yes, it's reported by svace. and I check the code it's not change the logic. myabe I was wrong:-P
> 
>> Also I am not sure code lines numbers in the description are useful for future readers, because they can be changed.
> I can update the commit message at v2.
>> 
>> Thank you..