Re: [PATCH 07/10] mount: clarify kernel_opts vs mnt_opts vs flags in fuse_kern_fsmount

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

On Fri, May 08, 2026 at 06:39:10PM +0200, Bernd Schubert via B4 Relay wrote:
> From: Bernd Schubert <bernd@bsbernd.com>
> 
> Just code/API updates, as these mount options can be rather confusing.
> 
> Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
> ---
>  lib/mount_i_linux.h | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/mount_i_linux.h b/lib/mount_i_linux.h
> index ab83e30b..112c365e 100644
> --- a/lib/mount_i_linux.h
> +++ b/lib/mount_i_linux.h
> @@ -36,13 +36,20 @@ int fuse_kern_mount_get_base_mnt_opts(const struct mount_opts *mo, char **mnt_op
>  /**
>   * Mount using the new Linux mount API (fsopen/fsconfig/fsmount/move_mount)
>   * @mnt: mountpoint
> - * @flags: mount flags (MS_NOSUID, MS_NODEV, etc.)
> + * @flags: MS_* bits (ro/rw, nosuid, nodev, sync, dirsync, ...) -
> + *         translated by set_ms_flags() into fsconfig(SET_FLAG) and/or
> + *         fsmount(MOUNT_ATTR_*); never carried via the strings below.

I wonder if this parameter ought to be renamed ms_flags?

>   * @blkdev: 1 for fuseblk, 0 for fuse
>   * @fsname: filesystem name (or NULL)
>   * @subtype: filesystem subtype (or NULL)
>   * @source_dev: device name for building source string
> - * @kernel_opts: kernel mount options string
> - * @mnt_opts: additional mount options to pass to the kernel
> + * @kernel_opts: FUSE-kernel options parsed from -o args
> + *               (e.g. "allow_other,max_read=65536,default_permissions")
> + * @mnt_opts:    extras the caller layers on
> + *               (e.g. "fd=7,rootmode=40000,user_id=1000,group_id=1000")

Oh, the "caller" here is libfuse.  Could that be clarified a bit?

      @mnt_opts:    internal mount options added by libfuse
                    (e.g. "fd=7,rootmode=40000,user_id=1000,group_id=1000")

--D

> + *
> + * @kernel_opts and @mnt_opts are both applied via fsconfig() in order;
> + * overlap is tolerated.
>   *
>   * Returns: 0 on success, -1 on failure with errno set
>   */
> 
> -- 
> 2.53.0
> 
>