Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <e388f379-cd11-a5d2-db82-aa1aa518a582@redhat.com>
 <05a0f4fd-7f62-8fbc-378d-886ccd5b3f11@redhat.com> <20201201173905.GI143045@magnolia>
 <20201201205243.GK2842436@dread.disaster.area> <9ab51770-1917-fc05-ff57-7677f17b6e44@sandeen.net>
In-Reply-To: <9ab51770-1917-fc05-ff57-7677f17b6e44@sandeen.net>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 1 Dec 2020 14:12:19 -0800
Message-ID: <CAHk-=wjymrd42E6XfiXwR3NF5Fs4EhTzhUukCojEWpz0Vagvtw@mail.gmail.com>
Subject: Re: [PATCH 2/2] statx: move STATX_ATTR_DAX attribute handling to filesystems
To:     Eric Sandeen <sandeen@sandeen.net>
Cc:     Dave Chinner <david@fromorbit.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Eric Sandeen <sandeen@redhat.com>,
        Miklos Szeredi <mszeredi@redhat.com>,
        Ira Weiny <ira.weiny@intel.com>,
        David Howells <dhowells@redhat.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-man <linux-man@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        xfs <linux-xfs@vger.kernel.org>,
        Ext4 Developers List <linux-ext4@vger.kernel.org>,
        Xiaoli Feng <xifeng@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Dec 1, 2020 at 2:03 PM Eric Sandeen <sandeen@sandeen.net> wrote:
>
> That's why I was keen to just add DAX unconditionally at this point, and if we want
> to invent/refine meanings for the mask, we can still try to do that?

Oh Gods.  Let's *not* make this some "random filesystem choice" where
now semantics depends on what some filesystem decided to do, and
different filesystems have very subtly different semantics.

This all screams "please keep this in the VFS layer" so that we at
least have _one_ place where these kinds of decisions are made.

I suspect very very few people actually end up caring about any of the
STATX flags at all, of course. The fact that the DAX one was
apparently entirely the wrong bit argues that this isn't all that
important.

               Linus