linux-kernel - Re: [GIT PULL] timestamp fixes

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Message-ID: <CAHk-=wiTNktN1k+D-3uJ-jGOMw8nxf45xSHHf8TzpjKj6HaYqQ@mail.gmail.com>
Date:   Mon, 18 Sep 2023 11:24:26 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Christian Brauner <brauner@...nel.org>,
        Jeff Layton <jlayton@...nel.org>, Jan Kara <jack@...e.cz>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [GIT PULL] timestamp fixes

On Mon, 18 Sept 2023 at 04:54, Christian Brauner <brauner@...nel.org> wrote:
>
> * Only update the atime if "now" is later than the current value. This
>   can happen when the atime gets updated with a fine-grained timestamp
>   and then later gets updated using a coarse-grained timestamp.

I pulled this, and then I unpulled it again.

I think this is fundamentally wrong.

If somebody has set the time into the future (for whatever reason -
maybe the clocks were wrong at some point), afaik accessing a file
should reset it, and very much used to do that.

Am I missing something? Because this really seems *horribly* broken garbage.

Any "go from fine-grained back to coarse-grained" situation needs to
explicitly test *that* case.

Not some kind of completely broken "don't update to past value" like this.

               Linus