[CRIU] [PATCH v2 26/36] ns: Add ns_owner

[Kirill Tkhai]

On 07.02.2017 01:40, Andrei Vagin wrote:
> On Fri, Feb 03, 2017 at 07:15:26PM +0300, Kirill Tkhai wrote:
>> Add a struct ns_id member to store information,
>> where the ns copy may be obtained.
>>
>> It's "/proc/[pid]/fd/[fd]", or "/proc/[pid]/ns/[ns]"
>> in dependence of ns_owner::fd value.
> 
> https://patchwork.criu.org/patch/3457/
> 
> Have you seen this patch? Maybe it will be useful for this task.
> 
> This patch adds a new subsystem which is called fdstore and it
> allows to create a storage for file descriptors and this storage
> are shared between processes. It will work faster that opening a file
> descriptor via usernsd.

I think it wouldn't be a problem to rebase on fdstore, when it's in criu.
 
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> ---
>>  criu/include/namespaces.h |    8 ++++++++
>>  criu/namespaces.c         |    2 ++
>>  2 files changed, 10 insertions(+)
>>
>> diff --git a/criu/include/namespaces.h b/criu/include/namespaces.h
>> index 21dc8beb7..546de7c5d 100644
>> --- a/criu/include/namespaces.h
>> +++ b/criu/include/namespaces.h
>> @@ -81,6 +81,13 @@ enum ns_type {
>>  	NS_OTHER,
>>  };
>>  
>> +struct ns_owner {
>> +	struct {
>> +		pid_t pid;	/* Owner pid */
>> +		int fd; 	/* Owner fd, or -1 if it's /proc/[pid]/ns/[ns] file */
>> +	};
>> +};
>> +
>>  struct ns_id {
>>  	unsigned int kid;
>>  	unsigned int id;
>> @@ -90,6 +97,7 @@ struct ns_id {
>>  	struct list_head children;
>>  	struct list_head siblings;
>>  	struct ns_id *user_ns;
>> +	struct ns_owner owner;
>>  	struct ns_id *next;
>>  	enum ns_type type;
>>  
>> diff --git a/criu/namespaces.c b/criu/namespaces.c
>> index 538074ab9..6151219d8 100644
>> --- a/criu/namespaces.c
>> +++ b/criu/namespaces.c
>> @@ -302,6 +302,8 @@ struct ns_id *rst_new_ns_id(unsigned int id, pid_t pid,
>>  		nsid->type = type;
>>  		nsid_add(nsid, nd, id, pid);
>>  		nsid->ns_populated = false;
>> +		nsid->owner.pid = -1;
>> +		nsid->owner.fd = -1;
>>  		INIT_LIST_HEAD(&nsid->children);
>>  		INIT_LIST_HEAD(&nsid->siblings);
>>  	}
>>
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