On 05/20, Stanislav Kinsbursky wrote:
>
> 20.05.2013 17:57, Oleg Nesterov пишет:
>>
>> Why do we need the new member/arguments?
>>
>>> @@ -215,6 +216,9 @@ static int ____call_usermodehelper(void *data)
>>> */
>>> set_user_nice(current, 0);
>>>
>>> + if (sub_info->root)
>>> + set_fs_root(current->fs, sub_info->root);
>>
>> Can't subprocess_info->init() do this? You can pass root as ->data.
>>
>> IOW, unless I missed something, nfs can do this without any changes
>> in kmod.c.
>>
>> Oleg.
>>
>
> Thanks for the comment.
> Yes, it definitely can. But, NFS server in the the only place. Usermode
> helper in
> called from NFS client code and thus the same functionality is required there
> as well.
Not sure I understand... OK, and why NFS client can't use the same
functionality?
> Moreover, set_fs_root() is not exported.
Then it should be exported, I think ;)
Or you can export the new helper.
> And adding an ability of a root swap to usermode helper looks quite logical.
> At least from the
> "containers" point of view, which usually have it's own root.
But it is not logical to uglify the code, imho.
OK, why nfs can't simply use this code
static int umh_set_fs_root(struct subprocess_info *info, struct cred
*new)
{
set_fs_root(current->fs, sub_info->data);
return 0;
}
int call_usermodehelper_root(char *path, char **argv, char **envp, int
wait,
struct path *root)
{
struct subprocess_info *info;
info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
umh_set_fs_root, NULL,
root);
if (info == NULL)
return -ENOMEM;
return call_usermodehelper_exec(info, wait);
}
? Why do you want to add the new member, the new arguments, the new helpers?
Oleg.
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