linux-kernel - Re: [PATCH v3 2/3] splice: fsnotify_access(fd)/fsnotify

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Date:   Tue, 27 Jun 2023 21:11:35 +0300
From:   Amir Goldstein <amir73il@...il.com>
To:     Ahelenia Ziemiańska 
        <nabijaczleweli@...ijaczleweli.xyz>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <brauner@...nel.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jan Kara <jack@...e.cz>,
        Chung-Chiang Cheng <cccheng@...ology.com>, ltp@...r.kernel.org
Subject: Re: [PATCH v3 2/3] splice: fsnotify_access(fd)/fsnotify_modify(fd) in vmsplice

On Tue, Jun 27, 2023 at 7:55 PM Ahelenia Ziemiańska
<nabijaczleweli@...ijaczleweli.xyz> wrote:
>
> Same logic applies here: this can fill up the pipe and pollers that rely
> on getting IN_MODIFY notifications never wake up.
>
> Fixes: 983652c69199 ("splice: report related fsnotify events")
> Link: https://lore.kernel.org/linux-fsdevel/jbyihkyk5dtaohdwjyivambb2gffyjs3dodpofafnkkunxq7bu@jngkdxx65pux/t/#u
> Link: https://bugs.debian.org/1039488
> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@...ijaczleweli.xyz>

Reviewed-by: Amir Goldstein <amir73il@...il.com>

> ---
>  fs/splice.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/splice.c b/fs/splice.c
> index e16f4f032d2f..0eb36e93c030 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1346,6 +1346,9 @@ static long vmsplice_to_user(struct file *file, struct iov_iter *iter,
>                 pipe_unlock(pipe);
>         }
>
> +       if (ret > 0)
> +               fsnotify_access(file);
> +
>         return ret;
>  }
>
> @@ -1375,8 +1378,10 @@ static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter,
>         if (!ret)
>                 ret = iter_to_pipe(iter, pipe, buf_flag);
>         pipe_unlock(pipe);
> -       if (ret > 0)
> +       if (ret > 0) {
>                 wakeup_pipe_readers(pipe);
> +               fsnotify_modify(file);
> +       }
>         return ret;
>  }
>
> --
> 2.39.2
>