[libvirt] [PATCH] storage: Inherit permissions of parent pool if they are not specified

[Osier Yang]

于 2011年09月21日 03:27, Eric Blake 写道:
> On 09/20/2011 11:05 AM, Laine Stump wrote:
>> On 09/20/2011 04:38 AM, Osier Yang wrote:
>>> If permissions (mode, uid, gid) are not specified, a new created vol
>>> will get the permissions like:
>>>
>>> mode = 0600
>>> uid = -1
>>> gid = -1
>>>
>>> This will be a bit surprised if the user define the pool with a
>>> non-root uid/gid, but the new created vol is still defined as
>>> root/root.
>>>
>>> This patch changes the behaviour so that the new created vol will
>>> inherit the permissions of parent pool if permission are not
>>> specified.
>>
>> Should this behavior maybe be changed later on when the definition is
>> used, rather than during parsing? I tend to not like modifying the
>> incoming data as part of a parse (although I know we're already doing
>> that in some other places).
>>
>> (Of course other people may have a different opinion, or there may be a
>> reason why my suggestion isn't feasible...)
>
> I actually like the idea of keeping the user's data intact as long as 
> possible, so I agree with Laine on refactoring the patch to delay the 
> inheritance to the point of use when uid is still -1 (rather than 
> reassigning uid at the time of parse).
>

Agreed.

So I guess it's time to introduce some flags for virStorageVolumeCreateXML.
Such as:

typedef enum {
VIR_STORAGE_VOL_CREATE_INHERIT_PERMS_GRACEFUL (1 << 0),
VIR_STORAGE_VOL_CREATE_INHERIT_PERMS_FORCE (1 << 1),
} virStorageVolCreateFlags;

If *_INHERIT_PERMS_GRACEFULL is specified, the new created vol will
inherit permissions of parent's pool only when the perms are not specified.
E.g. A vol XML contains perms XML like:

<target>
<permissions>
<mode>0755</mode>
<gid>500</gid>
</permissions>
</target>

Then only *uid* will inherit from parent pool.

If *_INHERIT_PERMS_FORCE is specified, the new created vol will inherit
permissions of parent's pool anyway. This gives a choice for the user
who always want to inherite perms.

Thoughts?

Thanks
Osier