Re: [PATCH RESEND] ubifs: Introduce a mount option of force_atime.

[Dongsheng Yang <yangds.fnst@cn.fujitsu.com>]

On 06/09/2015 01:00 PM, Dongsheng Yang wrote:
> On 06/09/2015 11:24 AM, Dongsheng Yang wrote:
>> On 06/09/2015 06:55 AM, Richard Weinberger wrote:
>>> Am 08.06.2015 um 12:07 schrieb Dongsheng Yang:
>>>> -    ubifs_assert(mutex_is_locked(&ui->ui_mutex));
>>>>       if (!ui->dirty) {
>>>> +        if (!locked) {
>>>> +            /*
>>>> +             * It's a little tricky here, there is only one
>>>> +             * possible user of ubifs_dirty_inode did not do
>>>> +             * a budget for this inode. At the same time, this
>>>> +             * user is not holding the ui->ui_mutex. Then if
>>>> +             * we found ui->ui_mutex is not locked, we can say:
>>>> +             * we need to do a budget in ubifs_dirty_inode here.
>>>> +             */
>>>> +            struct ubifs_budget_req req = { .dirtied_ino = 1,
>>>> +                    .dirtied_ino_d = ALIGN(ui->data_len, 8) };
>>>> +
>>>> +            ret = ubifs_budget_space(c, &req);
>>>> +            if (ret)
>>>> +                goto out;
>>>> +        }
>>>
>>> So, this is the new case when ->dirty_inode() is called via
>>> generic_update_time()?
>>> Did you research whether you can detect that case also by looking at
>>> the flags parameter?
>>> I'd give I_DIRTY_TIME a try. This way you could get at least rid of
>>> the mutex_is_locked()
>>> usage.
>>
>> Okey, after a reading, I'm afraid I can not think a better idea
>> out. The flags between *old* cases and the *new* case can possiblly
>> be same. Then we can't use the flags to filter the new case from old
>> cases.
>
> Oops, sorry, my bad!!
>
> generic_upadte_time() is the only way to use I_DIRTY_TIME here currently.

But there is another problem, if we are going to try to support
lazytime, we have to set the I_DIRTY_TIME in the *old* cases. Then
we can not use the flags to distinguish them in drity_inode().

> You are right!. we can get rid of mutex_is_locked() at least.
>
> Thanx
> Yang
>>
>> But I think I can append a patch to add a support for lazytime here:
>>      if (flags == I_DIRTY_TIME)
>>          return;
>>
>> Thanx
>> Yang
>>
>>>
>>> Thanks,
>>> //richard
>>> .
>>>
>>
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