Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
MIME-Version: 1.0
References: <CAHk-=wixObEhBXM22JDopRdt7Z=tGGuizq66g4RnUmG9toA2DA@mail.gmail.com>
 <d6162230b83359d3ed1ee706cc1cb6eacfb12a4f.camel@kernel.org>
 <CAHk-=wiKJgOg_3z21Sy9bu+3i_34S86r8fd6ngvJpZDwa-ww8Q@mail.gmail.com>
 <5f96e69d438ab96099bb67d16b77583c99911caa.camel@kernel.org>
 <20231019-fluor-skifahren-ec74ceb6c63e@brauner> <0a1a847af4372e62000b259e992850527f587205.camel@kernel.org>
 <ZTGncMVw19QVJzI6@dread.disaster.area> <eb3b9e71ee9c6d8e228b0927dec3ac9177b06ec6.camel@kernel.org>
 <ZTWfX3CqPy9yCddQ@dread.disaster.area> <61b32a4093948ae1ae8603688793f07de764430f.camel@kernel.org>
 <ZTcBI2xaZz1GdMjX@dread.disaster.area> <CAHk-=whphyjjLwDcEthOOFXXfgwGrtrMnW2iyjdQioV6YSMEPw@mail.gmail.com>
 <2c74660bc44557dba8391758535e4012cbea3724.camel@kernel.org>
In-Reply-To: <2c74660bc44557dba8391758535e4012cbea3724.camel@kernel.org>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 24 Oct 2023 09:40:08 -1000
Message-ID: <CAHk-=wibJqQGBXAr2S69FifUXdJJ=unAQT5ag0qRSQNxGk31Lw@mail.gmail.com>
Subject: Re: [PATCH RFC 2/9] timekeeping: new interfaces for multigrain
 timestamp handing
To:     Jeff Layton <jlayton@kernel.org>
Cc:     Dave Chinner <david@fromorbit.com>,
        Kent Overstreet <kent.overstreet@linux.dev>,
        Christian Brauner <brauner@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        John Stultz <jstultz@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Stephen Boyd <sboyd@kernel.org>,
        Chandan Babu R <chandan.babu@oracle.com>,
        "Darrick J. Wong" <djwong@kernel.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>,
        Hugh Dickins <hughd@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Amir Goldstein <amir73il@gmail.com>, Jan Kara <jack@suse.de>,
        David Howells <dhowells@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-btrfs@vger.kernel.org, linux-mm@kvack.org,
        linux-nfs@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, 24 Oct 2023 at 09:07, Jeff Layton <jlayton@kernel.org> wrote:
>
> The new flag idea is a good one. The catch though is that there are no
> readers of i_version in-kernel other than NFSD and IMA, so there would
> be no in-kernel users of I_VERSION_QUERIED_STRICT.

I actually see that as an absolute positive.

I think we should *conceptually* do those two flags, but then realize
that there are no users of the STRICT version, and just skip it.

So practically speaking, we'd end up with just a weaker version of
I_VERSION_QUERIED that is that "I don't care about atime" case.

I really can't find any use that would *want* to see i_version updates
for any atime updates. Ever.

We may have had historical user interfaces for i_version, but I can't
find any currently.

But to be very very clear: I've only done some random grepping, and I
may have missed something. I'm not dismissing Dave's worries, and he
may well be entirely correct.

Somebody would need to do a much more careful check than my "I can't
find anything".

             Linus