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From:   Daniil Lunev <dlunev@chromium.org>
Date:   Wed, 13 Jul 2022 08:24:11 +1000
Message-ID: <CAONX=-faZGmOe_=y_kG=erkQOR6fYdwXuF0HoFJVwMUdemxk0g@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] FUSE: Retire superblock on force unmount
To:     miklos@szeredi.hu
Cc:     linux-kernel@vger.kernel.org, fuse-devel@lists.sourceforge.net,
        Daniil Lunev <dlunev@google.com>,
        linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
        hch@infradead.org, tytso@mit.edu
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Hi Miklos,
Can you please take a look at the current patchset and see if you are
ok with it?
Thanks,
Daniil

On Wed, Jun 1, 2022 at 11:11 AM Daniil Lunev <dlunev@chromium.org> wrote:
>
> From: Daniil Lunev <dlunev@chromium.org>
>
> Force unmount of FUSE severes the connection with the user space, even
> if there are still open files. Subsequent remount tries to re-use the
> superblock held by the open files, which is meaningless in the FUSE case
> after disconnect - reused super block doesn't have userspace counterpart
> attached to it and is incapable of doing any IO.
>
> Signed-off-by: Daniil Lunev <dlunev@chromium.org>
>
> Signed-off-by: Daniil Lunev <dlunev@google.com>
> ---
>
> (no changes since v3)
>
> Changes in v3:
> - No changes
>
> Changes in v2:
> - Use an exported function instead of directly modifying superblock
>
>  fs/fuse/inode.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index 8c0665c5dff88..8875361544b2a 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -476,8 +476,11 @@ static void fuse_umount_begin(struct super_block *sb)
>  {
>         struct fuse_conn *fc = get_fuse_conn_super(sb);
>
> -       if (!fc->no_force_umount)
> -               fuse_abort_conn(fc);
> +       if (fc->no_force_umount)
> +               return;
> +
> +       fuse_abort_conn(fc);
> +       retire_super(sb);
>  }
>
>  static void fuse_send_destroy(struct fuse_mount *fm)
> --
> 2.31.0
>