On 04/12/2015 09:27 PM, Guoqing Jiang wrote:

Goldwyn Rodrigues wrote:

quoted

Signed-off-by: Goldwyn Rodrigues <redacted>
---
  drivers/md/md-cluster.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
  drivers/md/md-cluster.h |  1 +
  drivers/md/md.c         | 24 +++++++++++++++---------
  drivers/md/md.h         |  1 +
  4 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 96679b2..d036c83 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c

@@ -72,6 +72,7 @@ enum msg_type {
  	METADATA_UPDATED = 0,
  	RESYNCING,
  	NEWDISK,
+	REMOVE,
  };

  struct cluster_msg {

@@ -186,6 +187,20 @@ static char *pretty_uuid(char *dest, char *src)
  	return dest;
  }

+static struct md_rdev *find_rdev_uuid(struct mddev *mddev, char *uuid)
+{
+	struct md_rdev *rdev;
+	struct mdp_superblock_1 *sb;
+
+	rdev_for_each_rcu(rdev, mddev) {
+		sb = page_address(rdev->sb_page);
+		if (!strncmp(uuid, sb->device_uuid, 16)) {
+			return rdev;
+		}
+	}
+	return NULL;
+}
+
  static void add_resync_info(struct mddev *mddev, struct dlm_lock_resource *lockres,
  		sector_t lo, sector_t hi)
  {

@@ -401,6 +416,17 @@ static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg
  	dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
  }

+static void process_remove_disk(struct mddev *mddev, struct cluster_msg *msg)
+{
+	struct md_rdev *rdev = find_rdev_uuid(mddev, msg->uuid);
+	char uuid[32];
+
+	if (rdev)
+		md_kick_rdev_from_array(rdev);
+	else
+		pr_warn("%s: %d Could not find disk with uuid: %s", __func__, __LINE__, pretty_uuid(uuid, msg->uuid));
+}
+
  static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
  {
  	switch (msg->type) {

@@ -419,6 +445,15 @@ static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
  		pr_info("%s: %d Received message: NEWDISK from %d\n",
  			__func__, __LINE__, msg->slot);
  		process_add_new_disk(mddev, msg);
+		break;
+	case REMOVE:
+		pr_info("%s: %d Received REMOVE from %d\n",
+			__func__, __LINE__, msg->slot);
+		process_remove_disk(mddev, msg);
+		break;
+	default:
+		pr_warn("%s:%d Received unknown message from %d\n",
+			__func__, __LINE__, msg->slot);
  	};
  }

@@ -854,6 +889,17 @@ static int new_disk_ack(struct mddev *mddev, bool ack)
  	return 0;
  }

+static int remove_disk(struct mddev *mddev, struct md_rdev *rdev)
+{
+	struct cluster_msg cmsg;
+	struct md_cluster_info *cinfo = mddev->cluster_info;
+	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
+	char *uuid = sb->device_uuid;
+	cmsg.type = REMOVE;
+	memcpy(cmsg.uuid, uuid, 16);
+	return __sendmsg(cinfo, &cmsg);
+}
+
  static struct md_cluster_operations cluster_ops = {
  	.join   = join,
  	.leave  = leave,

@@ -868,6 +914,7 @@ static struct md_cluster_operations cluster_ops = {
  	.add_new_disk_start = add_new_disk_start,
  	.add_new_disk_finish = add_new_disk_finish,
  	.new_disk_ack = new_disk_ack,
+	.remove_disk = remove_disk,
  };

  static int __init cluster_init(void)

diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
index 7417133..71e5143 100644
--- a/drivers/md/md-cluster.h
+++ b/drivers/md/md-cluster.h

@@ -22,6 +22,7 @@ struct md_cluster_operations {
  	int (*add_new_disk_start)(struct mddev *mddev, struct md_rdev *rdev);
  	int (*add_new_disk_finish)(struct mddev *mddev);
  	int (*new_disk_ack)(struct mddev *mddev, bool ack);
+	int (*remove_disk)(struct mddev *mddev, struct md_rdev *rdev);
  };

  #endif /* _MD_CLUSTER_H */

diff --git a/drivers/md/md.c b/drivers/md/md.c
index bc11551..0c65e51 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -2291,11 +2291,12 @@ static void export_rdev(struct md_rdev * rdev)
  	kobject_put(&rdev->kobj);
  }

-static void kick_rdev_from_array(struct md_rdev * rdev)
+void md_kick_rdev_from_array(struct md_rdev * rdev)
  {
  	unbind_rdev_from_array(rdev);
  	export_rdev(rdev);
  }
+EXPORT_SYMBOL_GPL(md_kick_rdev_from_array);

  static void export_array(struct mddev *mddev)
  {

@@ -2306,7 +2307,7 @@ static void export_array(struct mddev *mddev)
  			MD_BUG();
  			continue;
  		}
-		kick_rdev_from_array(rdev);
+		md_kick_rdev_from_array(rdev);
  	}
  	if (!list_empty(&mddev->disks))
  		MD_BUG();

@@ -2750,9 +2751,11 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
  			err = -EBUSY;
  		else {
  			struct mddev *mddev = rdev->mddev;
-			if (mddev_is_clustered(mddev))
+			if (mddev_is_clustered(mddev)) {
  				md_cluster_ops->metadata_update_start(mddev);
-			kick_rdev_from_array(rdev);
+				md_cluster_ops->remove_disk(mddev, rdev);
+			}
+			md_kick_rdev_from_array(rdev);

For md-cluster, seems it is possible that md_kick_rdev_from_array could
be called twice,
is this what you want? Thanks.

No, it would be called only once. There are two types of nodes in this 
case: one is  sender and other received. The sender calls 
md_kick_rdev_from_array() in the regular flow of 
state_store/hot_remove_disk() while the receiver calls 
md_kick_rdev_from_array() in the process_remove_disk().

Or am I missing something?

-- 
Goldwyn