linux-kernel - Re: [PATCH v3 2/4] fs: hide ->i_state handling behind accessors

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Message-ID: <CAGudoHETnk1NJe_7TAsweokKia2xtKH0bLn-V7+hcE1voiqrhw@mail.gmail.com>
Date: Mon, 15 Sep 2025 15:48:29 +0200
From: Mateusz Guzik <mjguzik@...il.com>
To: Christian Brauner <brauner@...nel.org>
Cc: viro@...iv.linux.org.uk, jack@...e.cz, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, josef@...icpanda.com, kernel-team@...com, 
	amir73il@...il.com, linux-btrfs@...r.kernel.org, linux-ext4@...r.kernel.org, 
	linux-xfs@...r.kernel.org, ocfs2-devel@...ts.linux.dev
Subject: Re: [PATCH v3 2/4] fs: hide ->i_state handling behind accessors

On Mon, Sep 15, 2025 at 3:41 PM Christian Brauner <brauner@...nel.org> wrote:
>
> On Mon, Sep 15, 2025 at 03:27:16PM +0200, Mateusz Guzik wrote:
> > On Mon, Sep 15, 2025 at 2:41 PM Christian Brauner <brauner@...nel.org> wrote:
> > >
> > > On Thu, Sep 11, 2025 at 06:55:55AM +0200, Mateusz Guzik wrote:
> > > > Signed-off-by: Mateusz Guzik <mjguzik@...il.com>
> > > > ---
> > >
> > > I would do:
> > >
> > > inode_state()
> > > inode_state_raw()
> > >
> > > Similar to
> > >
> > > rcu_derefence()
> > > rcu_dereference_raw()
> > >
> >
> > I don't follow how to fit this in here.
> >
> > Here is the complete list:
> > inode_state_read
> > inode_state_read_unstable
> >
> > first is a plain read + lockdep assert, second is a READ_ONCE
> >
> > inode_state_add
> > inode_state_add_unchecked
> > inode_state_del
> > inode_state_del_unchecked
> > inode_state_set_unchecked
> >
> > Routine with _unchecked forego asserts, otherwise the op checks lockdep.
> >
> > I guess _unchecked could be _raw, but I don't see how to fit this into
> > the read thing.
>
> _raw() is adapted from rcu which is why I'm very familiar with what it
> means: rcu_dereference() performs checks and rcu_dereference_raw()
> doesn't. It's just a naming convention that we already have and are
> accustomed to.
>
> >
> > Can you just spell out the names you want for all of these?
>
> just use _raw() imho
>

For these no problem:
inode_state_add
inode_state_add_raw
inode_state_del
inode_state_del_raw
inode_state_set_raw

But for the read side:
inode_state_read
inode_state_read_unstable

The _unstable thing makes sure to prevent surprise re-reads
specifically because the lock is not expected to be held.
Giving it the _raw suffix would suggest it is plain inode_state_read
without lockdep, which is imo misleading.

But I'm not going to die on this hill.