Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
MIME-Version: 1.0
References: <20231124060553.GA575483@ZenIV> <20231124060644.576611-1-viro@zeniv.linux.org.uk>
 <20231124060644.576611-9-viro@zeniv.linux.org.uk>
In-Reply-To: <20231124060644.576611-9-viro@zeniv.linux.org.uk>
From:   Amir Goldstein <amir73il@gmail.com>
Date:   Fri, 24 Nov 2023 09:37:16 +0200
Message-ID: <CAOQ4uxgRiQCG_Q5TP+05_N4V=iFTemzGTd62ePgAgotK52EAAQ@mail.gmail.com>
Subject: Re: [PATCH 09/20] [software coproarchaeology] dentry.h: kill a
 mysterious comment
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     linux-fsdevel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Christian Brauner <brauner@kernel.org>,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, Nov 24, 2023 at 8:07=E2=80=AFAM Al Viro <viro@zeniv.linux.org.uk> w=
rote:
>
> there's a strange comment in front of d_lookup() declaration:
>
> /* appendix may either be NULL or be used for transname suffixes */
>
> Looks like nobody had been curious enough to track its history;
> it predates git, it predates bitkeeper and if you look through
> the pre-BK trees, you finally arrive at this in 2.1.44-for-davem:
>   /* appendix may either be NULL or be used for transname suffixes */
>  -extern struct dentry * d_lookup(struct inode * dir, struct qstr * name,
>  -                               struct qstr * appendix);
>  +extern struct dentry * d_lookup(struct dentry * dir, struct qstr * name=
);
> In other words, it refers to the third argument d_lookup() used to have
> back then.  It had been introduced in 2.1.43-pre, on June 12 1997,
> along with d_lookup(), only to be removed by July 4 1997, presumably
> when the Cthulhu-awful thing it used to be used for (look for
> CONFIG_TRANS_NAMES in 2.1.43-pre, and keep a heavy-duty barfbag
> ready) had been, er, noticed and recognized for what it had been.
>
> Despite the appendectomy, the comment remained.  Some things really
> need to be put out of their misery...
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  include/linux/dcache.h | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/include/linux/dcache.h b/include/linux/dcache.h
> index 9706bf1dc5de..a5e5e274eee0 100644
> --- a/include/linux/dcache.h
> +++ b/include/linux/dcache.h
> @@ -270,7 +270,6 @@ extern void d_move(struct dentry *, struct dentry *);
>  extern void d_exchange(struct dentry *, struct dentry *);
>  extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
>
> -/* appendix may either be NULL or be used for transname suffixes */
>  extern struct dentry *d_lookup(const struct dentry *, const struct qstr =
*);
>  extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
>

Al,

Since you like pre-git archeology...

Mind digging up what this comment in fs.h is about:

/* needed for stackable file system support */
extern loff_t default_llseek(struct file *file, loff_t offset, int whence);

Or we can just remove it without digging up what the comment used
to refer to ;)

Thanks,
Amir.