Re: [PATCH 2/2] fat: introduce creation time

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

Chung-Chiang Cheng <shepjeng@gmail.com> writes:

> On Wed, Mar 23, 2022 at 6:57 PM OGAWA Hirofumi
> <hirofumi@mail.parknet.co.jp> wrote:
>>
>> No, a user can change the ctime to arbitrary time, and after the your
>> patch, the changed ctime only hold on a memory inode. So a user sees
>> ctime jump backward and forward when a memory inode is expired. (Of
>> course, this happens just by "cp -a" in real world use case.)
>>
>> I'm pointing about this introduced new behavior by your patch.
>>
>
> As you mentioned, there are still some cases to consider that ctime
> isn't identical to mtime. If so, ctime won't be consistent after
> inode is expired because it will be filled with the value of on-disk
> mtime, which is weird and confusing.
>
> To solve the issue, I propose to keep ctime and mtime always the same
> in memory. If you agree with this approach, I'll send a v2 patch for
> it.

Yes, exactly.

Although I think it is better, in real world userspace, it may got
actual compatibility issue and reported, then we may have to revert even
if I personally think new is better.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>