Re: [PATCH v4 06/10] ext4: Log error when lookup of encoded dentry fails

[Eric Biggers <ebiggers@kernel.org>]

On Wed, May 11, 2022 at 03:31:42PM -0400, Gabriel Krisman Bertazi wrote:
> If the volume is in strict mode, ext4_ci_compare can report a broken
> encoding name.  This will not trigger on a bad lookup, which is caught
> earlier, only if the actual disk name is bad.
> 
> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
> 
> ---
> 
> Changes since v1:
>   - reword error message "file in directory" -> "filename" (Eric)
> ---
>  fs/ext4/namei.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index cebbcabf0ff0..708811525411 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -1458,6 +1458,9 @@ static bool ext4_match(struct inode *parent,
>  			 * only case where it happens is on a disk
>  			 * corruption or ENOMEM.
>  			 */
> +			if (ret == -EINVAL)
> +				EXT4_ERROR_INODE(parent,
> +						 "Bad encoded filename");

This message is still quite vague; perhaps it should be more specific about what
a "bad" filename is?  Maybe something like: "Directory contains filename that is
not valid UTF-8" (or whatever the encoding being enforced is).

- Eric