linux-kernel - Re: [PATCH] fuse: invalidate the page cache after direct write

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Message-ID: <5b9fd5cb-2494-4dbd-8779-82525cb46bf4@linux.alibaba.com>
Date: Fri, 9 Jan 2026 10:13:57 +0800
From: Jingbo Xu <jefflexu@...ux.alibaba.com>
To: Bernd Schubert <bernd@...ernd.com>, miklos@...redi.hu,
 linux-fsdevel@...r.kernel.org, bschubert@....com
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fuse: invalidate the page cache after direct write



On 1/9/26 12:16 AM, Bernd Schubert wrote:
> 
> The side effect should only come without FOPEN_DIRECT_IO. Could you add
> this diff to avoid it?
> 
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index d6ae3b4652f8..c04296316a82 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -1177,7 +1177,13 @@ static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
>         written = ia->write.out.size;
>         if (!err && written > count)
>                 err = -EIO;
> -       if (!err && written && mapping->nrpages) {
> +
> +       /*
> +        * without FOPEN_DIRECT_IO generic_file_direct_write() does the
> +        * invalidation for us
> +        */
> +       if (!err && written && mapping->nrpages &&
> +           (ff->open_flags & FOPEN_DIRECT_IO)) {
>                 /*
>                  * As in generic_file_direct_write(), invalidate after the
>                  * write, to invalidate read-ahead cache that may have competed
> 

Actually I think it's more complicated:

```
/*
 * without FOPEN_DIRECT_IO generic_file_direct_write() does the
 * invalidation for synchronous write.
 */
if (!err && written && mapping->nrpages &&
    ((ff->open_flags & FOPEN_DIRECT_IO) || !io->blocking)) {
```

I will send v2 soon if you feel good about the above diff.

-- 
Thanks,
Jingbo