在 2018年4月19日，上午3:42，Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> 写道：
>
> On Tue, 17 Apr 2018 15:05:32 +0800 Chengguang Xu <cgxu519@xxxxxxx> wrote:
>
>> When specifying iocharset/codepage multiple times in a mount,
>> current option parsing will cause inaccurate refcount of nls
>> module. Hence, call unload_nls for previous one in this case.
>>
>> ...
>>
>> --- a/fs/hfs/super.c
>> +++ b/fs/hfs/super.c
>> @@ -329,8 +329,10 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
>> return 0;
>> }
>> p = match_strdup(&args[0]);
>> - if (p)
>> + if (p) {
>> + unload_nls(hsb->nls_disk);
>> hsb->nls_disk = load_nls(p);
>> + }
>> if (!hsb->nls_disk) {
>> pr_err("unable to load codepage \"%s\"\n", p);
>> kfree(p);
>> @@ -344,8 +346,10 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
>> return 0;
>> }
>> p = match_strdup(&args[0]);
>> - if (p)
>> + if (p) {
>> + unload_nls(hsb->nls_io);
>> hsb->nls_io = load_nls(p);
>> + }
>> if (!hsb->nls_io) {
>> pr_err("unable to load iocharset \"%s\"\n", p);
>> kfree(p);
>
> Confused.
>
> break;
> : case opt_codepage:
> : if (hsb->nls_disk) {
> : pr_err("unable to change codepage\n");
> : return 0;
> : }
>
> Here, hsb->nls_disk is known to be zero.
>
> : p = match_strdup(&args[0]);
> : if (p) {
> : unload_nls(hsb->nls_disk);
>
> So this will always do unload_nls(0).
>
> : hsb->nls_disk = load_nls(p);
> : }
>
> And the same applies to your opt_iocharset change.
You are right. Sorry I just misread this part, please just drop the patch.
Thanks.
