Re: [PATCH 09/20] [software coproarchaeology] dentry.h: kill a mysterious comment

[Amir Goldstein]

On Fri, Nov 24, 2023 at 8:07 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxxxxxxxx>
> ---
>  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.