Re: Suggested fix to mountlist.c: Define fuse.portal, devtmpfs and squashfs mounts as dummy

[Pádraig Brady]

On 13/02/2021 01:40, Daniel Bonner wrote:
> Hi gnulib developers,
> At present many gnulib users encounter this error:
> Running 'df' as user (not root) causes results in output that includes
> this error message:
> "df: /run/user/1000/doc: Operation not permitted"
> I would like to pass on to you a suggested fix:
> @@ -164,7 +164,10 @@
>   #define ME_DUMMY_0(Fs_name, Fs_type)            \
>     (strcmp (Fs_type, "autofs") == 0              \
> +   || strcmp (Fs_type, "devtmpfs") == 0         \
> +   || strcmp (Fs_type, "fuse.portal") == 0      \
>      || strcmp (Fs_type, "proc") == 0             \
> +   || strcmp (Fs_type, "squashfs") == 0         \
>      || strcmp (Fs_type, "subfs") == 0            \
>      /* for Linux 2.6/3.x */                      \
>      || strcmp (Fs_type, "debugfs") == 0          \
> Julian Klode, from Ubuntu, deserves credit for this suggested fix. He
> published a patch that has been included in the Ubuntu Hirsute 21.04
> package: coreutils 8.32-4ubuntu2.  See
> 1. https://bugs.launchpad.net/ubuntu/+source/xdg-desktop-portal/+bug/19056232.
> 2. 
> https://launchpadlibrarian.net/510003931/coreutils_8.32-4ubuntu1_8.32-4ubuntu2.diff.gz
> I have cc'ed Julian in this email.
> The patch addresses a problem that particularly affects gnulib users
> with fuse.portal mounts, such as users who have installed Flatpak.
> This is a significant problem for users who depend on df not returning
> an error exit code in their scripts.  Julian's  bug report said:
> "/run/user/1000/doc is a fuse.portal mount point, but statfs() return
> EPERM, hence df produces an error message. Maybe statfs() is not
> implemented, but it would be good to quieten this down (df even does
> not allow me to ignore it, probably because it looks at statfs to find
> out fs type, so my fs type ignoring doesn't work)."
> This problem has also been reported on Fedora 32 here:
> flatpak/xdg-desktop-portal#512
> Kind regards,
> Daniel

I'll look into this in a bit more detail to see if it's general enough.
I.e. that there are no cases where these file system types may
have usable space.  squashfs is read-only so that is probably ok.

thanks!
Pádraig