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-rw-r--r--drivers/md/md-cluster.c73
1 files changed, 63 insertions, 10 deletions
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index b659ef7b8daf..ad3ec7df1547 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -48,12 +48,26 @@ struct resync_info {
#define MD_CLUSTER_SUSPEND_READ_BALANCING 2
#define MD_CLUSTER_BEGIN_JOIN_CLUSTER 3
+/* Lock the send communication. This is done through
+ * bit manipulation as opposed to a mutex in order to
+ * accomodate lock and hold. See next comment.
+ */
+#define MD_CLUSTER_SEND_LOCK 4
+/* If cluster operations must lock the communication channel,
+ * so as to perform extra operations (and no other operation
+ * is allowed on the MD, such as adding a disk. Token needs
+ * to be locked and held until the operation completes with
+ * a md_update_sb(), which would eventually release the lock.
+ */
+#define MD_CLUSTER_SEND_LOCKED_ALREADY 5
+
struct md_cluster_info {
/* dlm lock space and resources for clustered raid. */
dlm_lockspace_t *lockspace;
int slot_number;
struct completion completion;
+ struct mutex recv_mutex;
struct dlm_lock_resource *bitmap_lockres;
struct dlm_lock_resource **other_bitmap_lockres;
struct dlm_lock_resource *resync_lockres;
@@ -68,6 +82,7 @@ struct md_cluster_info {
struct dlm_lock_resource *no_new_dev_lockres;
struct md_thread *recv_thread;
struct completion newdisk_completion;
+ wait_queue_head_t wait;
unsigned long state;
};
@@ -508,9 +523,11 @@ static void recv_daemon(struct md_thread *thread)
struct cluster_msg msg;
int ret;
+ mutex_lock(&cinfo->recv_mutex);
/*get CR on Message*/
if (dlm_lock_sync(message_lockres, DLM_LOCK_CR)) {
pr_err("md/raid1:failed to get CR on MESSAGE\n");
+ mutex_unlock(&cinfo->recv_mutex);
return;
}
@@ -534,33 +551,45 @@ static void recv_daemon(struct md_thread *thread)
ret = dlm_unlock_sync(message_lockres);
if (unlikely(ret != 0))
pr_info("unlock msg failed return %d\n", ret);
+ mutex_unlock(&cinfo->recv_mutex);
}
-/* lock_comm()
+/* lock_token()
* Takes the lock on the TOKEN lock resource so no other
* node can communicate while the operation is underway.
- * If called again, and the TOKEN lock is alread in EX mode
- * return success. However, care must be taken that unlock_comm()
- * is called only once.
*/
-static int lock_comm(struct md_cluster_info *cinfo)
+static int lock_token(struct md_cluster_info *cinfo)
{
int error;
- if (cinfo->token_lockres->mode == DLM_LOCK_EX)
- return 0;
-
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);
+
+ /* Lock the receive sequence */
+ mutex_lock(&cinfo->recv_mutex);
return error;
}
+/* lock_comm()
+ * Sets the MD_CLUSTER_SEND_LOCK bit to lock the send channel.
+ */
+static int lock_comm(struct md_cluster_info *cinfo)
+{
+ wait_event(cinfo->wait,
+ !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state));
+
+ return lock_token(cinfo);
+}
+
static void unlock_comm(struct md_cluster_info *cinfo)
{
WARN_ON(cinfo->token_lockres->mode != DLM_LOCK_EX);
+ mutex_unlock(&cinfo->recv_mutex);
dlm_unlock_sync(cinfo->token_lockres);
+ clear_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state);
+ wake_up(&cinfo->wait);
}
/* __sendmsg()
@@ -713,6 +742,8 @@ static int join(struct mddev *mddev, int nodes)
spin_lock_init(&cinfo->suspend_lock);
init_completion(&cinfo->completion);
set_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state);
+ init_waitqueue_head(&cinfo->wait);
+ mutex_init(&cinfo->recv_mutex);
mddev->cluster_info = cinfo;
@@ -843,9 +874,25 @@ static int slot_number(struct mddev *mddev)
return cinfo->slot_number - 1;
}
+/*
+ * Check if the communication is already locked, else lock the communication
+ * channel.
+ * If it is already locked, token is in EX mode, and hence lock_token()
+ * should not be called.
+ */
static int metadata_update_start(struct mddev *mddev)
{
- return lock_comm(mddev->cluster_info);
+ struct md_cluster_info *cinfo = mddev->cluster_info;
+
+ wait_event(cinfo->wait,
+ !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state) ||
+ test_and_clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state));
+
+ /* If token is already locked, return 0 */
+ if (cinfo->token_lockres->mode == DLM_LOCK_EX)
+ return 0;
+
+ return lock_token(cinfo);
}
static int metadata_update_finish(struct mddev *mddev)
@@ -870,6 +917,7 @@ static int metadata_update_finish(struct mddev *mddev)
ret = __sendmsg(cinfo, &cmsg);
} else
pr_warn("md-cluster: No good device id found to send\n");
+ clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
unlock_comm(cinfo);
return ret;
}
@@ -877,6 +925,7 @@ static int metadata_update_finish(struct mddev *mddev)
static void metadata_update_cancel(struct mddev *mddev)
{
struct md_cluster_info *cinfo = mddev->cluster_info;
+ clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
unlock_comm(cinfo);
}
@@ -970,14 +1019,18 @@ static int add_new_disk(struct mddev *mddev, struct md_rdev *rdev)
ret = -ENOENT;
if (ret)
unlock_comm(cinfo);
- else
+ else {
dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
+ set_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
+ wake_up(&cinfo->wait);
+ }
return ret;
}
static void add_new_disk_cancel(struct mddev *mddev)
{
struct md_cluster_info *cinfo = mddev->cluster_info;
+ clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
unlock_comm(cinfo);
}