Re: [PATCH] btrfs: reject unknown mount options early

[David Sterba <dsterba@suse.cz>]

On Wed, Sep 27, 2023 at 10:43:15AM +0930, Qu Wenruo wrote:
> [BUG]
> The following script would allow invalid mount options to be specified
> (although such invalid options would just be ignored):
> 
>  # mkfs.btrfs -f $dev
>  # mount $dev $mnt1		<<< Successful mount expected
>  # mount $dev $mnt2 -o junk	<<< Failed mount expected
>  # echo $?
>  0
> 
> [CAUSE]
> For the 2nd mount, since the fs is already mounted, we won't go through
> open_ctree() thus no btrfs_parse_options(), but only through
> btrfs_parse_subvol_options().
> 
> However we do not treat unrecognized options from valid but irrelevant
> options, thus those invalid options would just be ignored by
> btrfs_parse_subvol_options().
> 
> [FIX]
> Add the handling for Opt_error to handle invalid options and error out,
> while still ignore other valid options inside
> btrfs_parse_subvol_options().
> 
> Reported-by: Anand Jain <anand.jain@oracle.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Added to misc-next, thanks.