Re: [PATCH v2 2/2] erofs: use get_tree_bdev_flags() to avoid misleading messages

[Christoph Hellwig]

On Wed, Oct 09, 2024 at 11:31:51AM +0800, Gao Xiang wrote:
> Users can pass in an arbitrary source path for the proper type of
> a mount then without "Can't lookup blockdev" error message.
> 
> Reported-by: Allison Karlitskaya <allison.karlitskaya@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/CAOYeF9VQ8jKVmpy5Zy9DNhO6xmWSKMB-DO8yvBB0XvBE7=3Ugg@xxxxxxxxxxxxxx
> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
> ---
> changes since v1:
>  - use new get_tree_bdev_flags().
> 
>  fs/erofs/super.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 666873f745da..b89836a8760d 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -705,7 +705,9 @@ static int erofs_fc_get_tree(struct fs_context *fc)
>  	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
>  		return get_tree_nodev(fc, erofs_fc_fill_super);
>  
> -	ret = get_tree_bdev(fc, erofs_fc_fill_super);
> +	ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
> +		IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
> +			GET_TREE_BDEV_QUIET_LOOKUP : 0);

Why not pass it unconditionally and provide your own more useful
error message at the end of the function if you could not find any
source?