Commit 4664680c authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues
Browse files

Communication Framework: Receiving 



1. receive status

   sender                         receiver                   receiver
   ACK:CR                          ACK:CR                     ACK:CR

2. sender get EX of TOKEN
   sender get EX of MESSAGE
   sender                          receiver                   receiver
   TOKEN:EX                         ACK:CR                     ACK:CR
   MESSAGE:EX
   ACK:CR

3. sender write LVB.
   sender down-convert MESSAGE from EX to CR
   sender try to get EX of ACK
   [ wait until all receiver has *processed* the MESSAGE ]

                                     [ triggered by bast of ACK ]
                                     receiver get CR of MESSAGE
                                     receiver read LVB
                                     receiver processes the message
				     [ wait finish ]
                                     receiver release ACK

   sender                         receiver                   receiver
   TOKEN:EX                       MESSAGE:CR                 MESSAGE:CR
   MESSAGE:CR
   ACK:EX

4. sender down-convert ACK from EX to CR
   sender release MESSAGE
   sender release TOKEN
				  receiver upconvert to EX of MESSAGE
                                  receiver get CR of ACK
				  receiver release MESSAGE

   sender                        receiver                   receiver
   ACK:CR                         ACK:CR                     ACK:CR

Signed-off-by: default avatarLidong Zhong <lzhong@suse.com>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
parent 4b26a08a

drivers/md/md-cluster.c

+102 −0
Original line number Diff line number Diff line
@@ -52,6 +52,23 @@ struct md_cluster_info { 
	spinlock_t suspend_lock;

	struct md_thread *recovery_thread;

	unsigned long recovery_map;

	/* communication loc resources */

	struct dlm_lock_resource *ack_lockres;

	struct dlm_lock_resource *message_lockres;

	struct dlm_lock_resource *token_lockres;

	struct md_thread *recv_thread;

};



enum msg_type {

	METADATA_UPDATED = 0,

	RESYNCING,

};



struct cluster_msg {

	int type;

	int slot;

	sector_t low;

	sector_t high;

};



static void sync_ast(void *arg)
@@ -283,6 +300,64 @@ static const struct dlm_lockspace_ops md_ls_ops = { 
	.recover_done = recover_done,

};



/*

 * The BAST function for the ack lock resource

 * This function wakes up the receive thread in

 * order to receive and process the message.

 */

static void ack_bast(void *arg, int mode)

{

	struct dlm_lock_resource *res = (struct dlm_lock_resource *)arg;

	struct md_cluster_info *cinfo = res->mddev->cluster_info;



	if (mode == DLM_LOCK_EX)

		md_wakeup_thread(cinfo->recv_thread);

}



static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)

{

	switch (msg->type) {

	case METADATA_UPDATED:

		pr_info("%s: %d Received message: METADATA_UPDATE from %d\n",

			__func__, __LINE__, msg->slot);

		break;

	case RESYNCING:

		pr_info("%s: %d Received message: RESYNCING from %d\n",

			__func__, __LINE__, msg->slot);

		break;

	};

}



/*

 * thread for receiving message

 */

static void recv_daemon(struct md_thread *thread)

{

	struct md_cluster_info *cinfo = thread->mddev->cluster_info;

	struct dlm_lock_resource *ack_lockres = cinfo->ack_lockres;

	struct dlm_lock_resource *message_lockres = cinfo->message_lockres;

	struct cluster_msg msg;



	/*get CR on Message*/

	if (dlm_lock_sync(message_lockres, DLM_LOCK_CR)) {

		pr_err("md/raid1:failed to get CR on MESSAGE\n");

		return;

	}



	/* read lvb and wake up thread to process this message_lockres */

	memcpy(&msg, message_lockres->lksb.sb_lvbptr, sizeof(struct cluster_msg));

	process_recvd_msg(thread->mddev, &msg);



	/*release CR on ack_lockres*/

	dlm_unlock_sync(ack_lockres);

	/*up-convert to EX on message_lockres*/

	dlm_lock_sync(message_lockres, DLM_LOCK_EX);

	/*get CR on ack_lockres again*/

	dlm_lock_sync(ack_lockres, DLM_LOCK_CR);

	/*release CR on message_lockres*/

	dlm_unlock_sync(message_lockres);

}



static int gather_all_resync_info(struct mddev *mddev, int total_slots)

{

	struct md_cluster_info *cinfo = mddev->cluster_info;
@@ -368,6 +443,26 @@ static int join(struct mddev *mddev, int nodes) 
		ret = -ENOMEM;

		goto err;

	}

	/* Initiate the communication resources */

	ret = -ENOMEM;

	cinfo->recv_thread = md_register_thread(recv_daemon, mddev, "cluster_recv");

	if (!cinfo->recv_thread) {

		pr_err("md-cluster: cannot allocate memory for recv_thread!\n");

		goto err;

	}

	cinfo->message_lockres = lockres_init(mddev, "message", NULL, 1);

	if (!cinfo->message_lockres)

		goto err;

	cinfo->token_lockres = lockres_init(mddev, "token", NULL, 0);

	if (!cinfo->token_lockres)

		goto err;

	cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);

	if (!cinfo->ack_lockres)

		goto err;

	/* get sync CR lock on ACK. */

	if (dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR))

		pr_err("md-cluster: failed to get a sync CR lock on ACK!(%d)\n",

				ret);



	pr_info("md-cluster: Joined cluster %s slot %d\n", str, cinfo->slot_number);

	snprintf(str, 64, "bitmap%04d", cinfo->slot_number - 1);
@@ -389,6 +484,9 @@ static int join(struct mddev *mddev, int nodes) 


	return 0;

err:

	lockres_free(cinfo->message_lockres);

	lockres_free(cinfo->token_lockres);

	lockres_free(cinfo->ack_lockres);

	lockres_free(cinfo->bitmap_lockres);

	lockres_free(cinfo->sb_lock);

	if (cinfo->lockspace)
@@ -406,6 +504,10 @@ static int leave(struct mddev *mddev) 
	if (!cinfo)

		return 0;

	md_unregister_thread(&cinfo->recovery_thread);

	md_unregister_thread(&cinfo->recv_thread);

	lockres_free(cinfo->message_lockres);

	lockres_free(cinfo->token_lockres);

	lockres_free(cinfo->ack_lockres);

	lockres_free(cinfo->sb_lock);

	lockres_free(cinfo->bitmap_lockres);

	dlm_release_lockspace(cinfo->lockspace, 2);

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