Re: [PATCH v2 6/6] fuse: support FSCONFIG_SET_FD for "fd" option

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Mar 12, 2026 at 08:40:04PM +0100, Miklos Szeredi wrote:
> This is not only cleaner to use in userspace (no need to sprintf the fd to
> a string) but also allows userspace to detect that the devfd can be closed
> after the fsconfig call.

Heh, I was just about to reply to the previous revision with "hey, have
you thought about converting to fsparam_fd?" :)

> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Looks fine to me -- the fuse dev file points to a fud, and the the fud
won't outlast the fd so the fget/fput look right to me.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/fuse/inode.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index f951f8d69e47..5608ed5ba000 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -788,7 +788,7 @@ enum {
>  
>  static const struct fs_parameter_spec fuse_fs_parameters[] = {
>  	fsparam_string	("source",		OPT_SOURCE),
> -	fsparam_u32	("fd",			OPT_FD),
> +	fsparam_fd	("fd",			OPT_FD),
>  	fsparam_u32oct	("rootmode",		OPT_ROOTMODE),
>  	fsparam_uid	("user_id",		OPT_USER_ID),
>  	fsparam_gid	("group_id",		OPT_GROUP_ID),
> @@ -800,9 +800,8 @@ static const struct fs_parameter_spec fuse_fs_parameters[] = {
>  	{}
>  };
>  
> -static int fuse_opt_fd(struct fs_context *fsc, int fd)
> +static int fuse_opt_fd(struct fs_context *fsc, struct file *file)
>  {
> -	struct file *file __free(fput) = fget(fd);
>  	struct fuse_fs_context *ctx = fsc->fs_private;
>  
>  	if (file->f_op != &fuse_dev_operations)
> @@ -859,7 +858,11 @@ static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
>  		return 0;
>  
>  	case OPT_FD:
> -		return fuse_opt_fd(fsc, result.uint_32);
> +		if (param->type == fs_value_is_file)
> +			return fuse_opt_fd(fsc, param->file);
> +
> +		struct file *file __free(fput) = fget(result.uint_32);
> +		return fuse_opt_fd(fsc, file);
>  
>  	case OPT_ROOTMODE:
>  		if (!fuse_valid_type(result.uint_32))
> -- 
> 2.53.0
> 
>