Re: [PATCH] erofs: add error log in erofs_fc_parse_param

[Ian Kent <raven@themaw.net>]

On 17/1/25 16:52, Chen Linxuan wrote:
> While reading erofs code, I notice that `erofs_fc_parse_param` will
> return -ENOPARAM, which means that erofs do not support this option,
> without report anything when `fs_parse` return an unknown `opt`.
>
> But if an option is unknown to erofs, I mean that option not in
> `erofs_fs_parameters` at all, `fs_parse` will return -ENOPARAM,
> which means that `erofs_fs_parameters` should has returned earlier.

I'm pretty sure than the vfs deals with reporting unknown options

and returns -EINVAL already.


I think the caller oferofs_fc_parse_param() is vfs_parse_fs_param()

and for an -ENOPARAM return will ultimately do this:

return invalf(fc, "%s: Unknown parameter '%s'", fc->fs_type->name, 
param->key);

which does this.

The thing about this is the mount API macro deals with (or it should,

although I'm not sure that's completely sorted out yet) logging the

message to the console log as well as possibly making it available to

mount api system calls. I'm pretty sure this change will prevent the

error message being available for mount api system calls to retrieve.

Ian

>
> Entering `default` means `fs_parse` return something we unexpected.
> I am not sure about it but I think we should return -EINVAL here,
> just like `xfs_fs_parse_param`.
>
> Signed-off-by: Chen Linxuan <chenlinxuan@uniontech.com>
> ---
>   fs/erofs/super.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 1fc5623c3a4d..67fc4c1deb98 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -509,7 +509,8 @@ static int erofs_fc_parse_param(struct fs_context *fc,
>   #endif
>   		break;
>   	default:
> -		return -ENOPARAM;
> +		errorfc(fc, "%s option not supported", param->key);
> +		return -EINVAL;
>   	}
>   	return 0;
>   }