On Wed, 1 Jun 2022 at 03:11, Daniil Lunev <dlunev@xxxxxxxxxxxx> wrote:
>
> From: Daniil Lunev <dlunev@xxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxx>
>
> Signed-off-by: Daniil Lunev <dlunev@xxxxxxxxxx>
Why the double sign-off?
> ---
>
> (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);
And this is called for both block and non-block supers. Which means
that the bdi will be unregistered, yet the sb could still be reused
(see fuse_test_super()).
Thanks,
Miklos
