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

[Gao Xiang]

Hi Linxuan,

On 2025/1/17 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.

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 <chenlinx...@uniontech.com>

I think the default branch is actually deadcode here, see
erofs_fc_parse_param() -> fs_parse() -> fs_lookup_key() -> -ENOPARAM

then vfs_parse_fs_param() will show "Unknown parameter".

Maybe we could just kill `default:` branch...

Thanks,
Gao Xiang

---
  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;
  }