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: Lidong Zhong <lzhong@xxxxxxxx>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
drivers/md/md-cluster.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 617ffee..259d4c2 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -55,6 +55,23 @@ 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)
@@ -286,6 +303,63 @@ 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;
@@ -372,6 +446,26 @@ 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("Joined cluster %s slot %d\n", str, cinfo->slot_number);
@@ -395,6 +489,9 @@ 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)
@@ -411,6 +508,10 @@ 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);
--
2.1.2
--
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