Re: [PATCH] hfsplus: fix the bug that cannot recognize files with hangul file name

["Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>]

On Fri, Nov 17, 2017 at 04:20:05PM +0800, Ting-Chang Hou wrote:
> The unicode of hangul from macOS is decomposed. There has a bug that
> mistake decomposed unicode for composed when change unicode to ascii,
> so it cannot recognize the hangul correctly.
> 
> Signed-off-by: Ting-Chang Hou <tchou@synology.com>
> ---
>  fs/hfsplus/unicode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
> index dfa90c2..2daf7b0 100644
> --- a/fs/hfsplus/unicode.c
> +++ b/fs/hfsplus/unicode.c
> @@ -135,7 +135,7 @@ int hfsplus_uni2asc(struct super_block *sb,
>  	ustrlen = be16_to_cpu(ustr->length);
>  	len = *len_p;
>  	ce1 = NULL;
> -	compose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
> +	compose = test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);

I'm not sure this is a mistake. The developers probably wanted the
filenames to be recomposed before being presented in utf8. With your patch,
if you try the following (with the default mount options):

  touch Á
  ls | hexdump -C

the utf8 output filename will be using the combining accent (CC 81) instead
of the Á character (C3 81). This is a bit annoying because it won't print
correctly in my terminal anymore.

What is it exactly that you are trying to fix? You mention an issue with
hangul characters, but I failed to trigger it. Could you expand on that?

>  	while (ustrlen > 0) {
>  		c0 = be16_to_cpu(*ip++);
> -- 
> 2.7.4
>