linux-kernel - Re: [PATCH v3 3/3] vfs: use the new debug macros in inode_set_cached

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Message-ID: <CAMuHMdWgjrYVoMyLHWa6YUhrEpQ9uk6rWj30i=4sxGxXaV4zNQ@mail.gmail.com>
Date: Mon, 10 Feb 2025 09:21:23 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Mateusz Guzik <mjguzik@...il.com>
Cc: brauner@...nel.org, viro@...iv.linux.org.uk, jack@...e.cz, 
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] vfs: use the new debug macros in inode_set_cached_link()

Hi Mateusz,

On Sat, 8 Feb 2025 at 17:27, Mateusz Guzik <mjguzik@...il.com> wrote:
> Signed-off-by: Mateusz Guzik <mjguzik@...il.com>

Thanks for your patch!

> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -792,19 +792,8 @@ struct inode {
>
>  static inline void inode_set_cached_link(struct inode *inode, char *link, int linklen)
>  {
> -       int testlen;
> -
> -       /*
> -        * TODO: patch it into a debug-only check if relevant macros show up.
> -        * In the meantime, since we are suffering strlen even on production kernels
> -        * to find the right length, do a fixup if the wrong value got passed.
> -        */
> -       testlen = strlen(link);
> -       if (testlen != linklen) {
> -               WARN_ONCE(1, "bad length passed for symlink [%s] (got %d, expected %d)",
> -                         link, linklen, testlen);
> -               linklen = testlen;

This is a (undocumented) change in behavior.

> -       }
> +       VFS_WARN_ON_INODE(strlen(link) != linklen, inode);

This change matches the one-line patch summary.

> +       VFS_WARN_ON_INODE(inode->i_opflags & IOP_CACHED_LINK, inode);

This (unrelated?) change is not described in the patch description.

>         inode->i_link = link;
>         inode->i_linklen = linklen;
>         inode->i_opflags |= IOP_CACHED_LINK;

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds