Re: [PATCH 04/12] container quota: introduce container disk quota data header file.

[Jeff Liu <jeff.liu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

On 05/31/2012 05:10 PM, Glauber Costa wrote:

>> +
>> +/* Operations for quota control */
>> +struct ns_quotactl_ops {
>> +    int (*quota_on)(struct mnt_namespace *, int);
>> +    int (*quota_off)(struct mnt_namespace *, int);
>> +    int (*get_info)(struct mnt_namespace *, int, struct if_dqinfo *);
>> +    int (*set_info)(struct mnt_namespace *, int, struct if_dqinfo *);
>> +    int (*get_dqblk)(struct mnt_namespace *, int, qid_t,
>> +             struct fs_disk_quota *);
>> +    int (*set_dqblk)(struct mnt_namespace *, int, qid_t,
>> +             struct fs_disk_quota *);
>> +};
>> +
> 
> That is quite bad. Just have the same signature. Which namespace you
> belong to can *always* be derived from the calling process, you should
> never need to specify that in any interface. It is of course fine to do
> that in functions internal to the kernel, but not this.

Exactly, "struct mnt_namespace" should not be presented at any quota
operation interface, retrieve it through current->nsproxy->mnt_ns should
be fine.

> You should rethink the whole ns_quota thing. Some of it I believe will
> have to stay, I doubt we'll be able to be completely transparent. But
> the core of your changes have to be making sure a hierarchical walk over
> the valid quotas work well, finding out what are those valid quotas, etc.

> The interface should be kept as unchanged as possible, and this can be
> achieved by things like automatic discover of the current namespace, and
> pre-operational container setup for the relevant files.

Thanks for teaching me that,  let me try to refactor ns_quota to make
the change as little as possible.

-Jeff

> 
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