The sending part is split in two functions to make sure
atomicity of the operations, such as the MD superblock update.
Signed-off-by: Lidong Zhong <lzhong@xxxxxxxx>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
drivers/md/md-cluster.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 259d4c2..1e11a9b 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -360,6 +360,90 @@ static void recv_daemon(struct md_thread *thread)
dlm_unlock_sync(message_lockres);
}
+/* lock_comm()
+ * Takes the lock on the TOKEN lock resource so no other
+ * node can communicate while the operation is underway.
+ */
+static int lock_comm(struct md_cluster_info *cinfo)
+{
+ int error;
+ error = dlm_lock_sync(cinfo->token_lockres, DLM_LOCK_EX);
+ if (error)
+ pr_err("md-cluster(%s:%d): failed to get EX on "
+ "TOKEN (%d)\n", __func__, __LINE__, error);
+ return error;
+}
+
+static void unlock_comm(struct md_cluster_info *cinfo)
+{
+ dlm_unlock_sync(cinfo->token_lockres);
+}
+
+/* __sendmsg()
+ * This function performs the actual sending of the message. This function is
+ * usually called after performing the encompassing operation
+ * The function:
+ * 1. Grabs the message lockresource in EX mode
+ * 2. Copies the message to the message LVB
+ * 3. Downconverts message lockresource to CR
+ * 4. Upconverts ack lock resource from CR to EX. This forces the BAST on other nodes
+ * and the other nodes read the message. The thread will wait here until all other
+ * nodes have released ack lock resource.
+ * 5. Downconvert ack lockresource to CR
+ */
+static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
+{
+ int error;
+ int slot = cinfo->slot_number - 1;
+ cmsg->slot = cpu_to_le32(slot);
+ /*get EX on Message*/
+ error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_EX);
+ if (error) {
+ pr_err("md-cluster: failed to get EX on MESSAGE (%d)\n", error);
+ goto failed_message;
+ }
+
+ memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg,
+ sizeof(struct cluster_msg));
+ /*down-convert EX to CR on Message*/
+ error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_CR);
+ if (error) {
+ pr_err("md-cluster: failed to convert EX to CR "
+ "on MESSAGE(%d)\n", error);
+ goto failed_message;
+ }
+
+ /*up-convert CR to EX on Ack*/
+ error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_EX);
+ if (error) {
+ pr_err("md-cluster: failed to convert CR to EX "
+ "on ACK(%d)\n", error);
+ goto failed_ack;
+ }
+
+ /*down-convert EX to CR on Ack*/
+ error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR);
+ if (error) {
+ pr_err("md-cluster: failed to convert EX to CR "
+ "on ACK(%d)\n", error);
+ goto failed_ack;
+ }
+
+failed_ack:
+ dlm_unlock_sync(cinfo->message_lockres);
+failed_message:
+ return error;
+}
+
+static int sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
+{
+ int ret;
+ lock_comm(cinfo);
+ ret = __sendmsg(cinfo, cmsg);
+ unlock_comm(cinfo);
+ return ret;
+}
+
static int gather_all_resync_info(struct mddev *mddev, int total_slots)
{
struct md_cluster_info *cinfo = mddev->cluster_info;
--
2.1.2
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