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

[Richard Weinberger]

Am 09.06.2015 um 08:36 schrieb Artem Bityutskiy:
> On Mon, 2015-06-08 at 18:07 +0800, Dongsheng Yang wrote:
>> Currently, ubifs does not support access time anyway. I understand
>> that there is a overhead to update inode in each access from user.
>>
>> But for the following two reasons, I think we can make it optional
>> to user.
>>
>> (1). More and more flash storage in server are trying to use ubifs,
>> it is not only for a device such as mobile phone any more, we want
>> to use it in more and more generic way. Then we need to compete
>> with some other main filesystems. From this point, access time is
>> necessary to us, at least as a choice to user currently.
>>
>> (2). The default mount option about atime is relatime currently,
>> it's much relaxy compared with strictatime. Then we don't update
>> the inode in any accessing. So the overhead is not too much.
>> It's really acceptable.
>>
>> Signed-off-by: Dongsheng Yang <yangds.fnst at cn.fujitsu.com>
>> ---
>> 	It's a RESEND patch to cc to fsdevel as Artem suggested.
>> I would rename force_atime to enable_atime in next version.
> 
> Why do you need to introduce a custom "force_atime" option if there are
> already standard "atime" and "noatime" mount option? I am fine with
> adding atime support to UBIFS in general, and I'd expect this behavior
> then.

I think the rationale behind force_atime was "I know atime can hurt my NAND and I know what
I'm doing". :-)
Such that possible users think of the consequences.

Thanks,
//richard