[PATCH v2 1/2] md-cluster: fix hanging issue while a new disk adding

[PATCH v2 1/2] md-cluster: fix hanging issue while a new disk adding

[Heming Zhao]

The commit 1bbe254e4336 ("md-cluster: check for timeout while a
new disk adding") is correct in terms of code syntax but not
suite real clustered code logic.

When a timeout occurs while adding a new disk, if recv_daemon()
bypasses the unlock for ack_lockres:CR, another node will be waiting
to grab EX lock. This will cause the cluster to hang indefinitely.

How to fix:

1. In dlm_lock_sync(), change the wait behaviour from forever to a
   timeout, This could avoid the hanging issue when another node
   fails to handle cluster msg. Another result of this change is
   that if another node receives an unknown msg (e.g. a new msg_type),
   the old code will hang, whereas the new code will timeout and fail.
   This could help cluster_md handle new msg_type from different
   nodes with different kernel/module versions (e.g. The user only
   updates one leg's kernel and monitors the stability of the new
   kernel).
2. The old code for __sendmsg() always returns 0 (success) under the
   design (must successfully unlock ->message_lockres). This commit
   makes this function return an error number when an error occurs.

Fixes: 1bbe254e4336 ("md-cluster: check for timeout while a new disk adding")
Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Su Yue <glass.su@suse.com>
---
v1 -> v2:
- use define WAIT_DLM_LOCK_TIMEOUT instead of hard code
- change timeout value from 60s to 30s
- follow Kuai's suggestion to use while loop to unlock message_lockres
---
 drivers/md/md-cluster.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 8e36a0feec09..b5a802ae17bb 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -15,6 +15,7 @@
 
 #define LVB_SIZE	64
 #define NEW_DEV_TIMEOUT 5000
+#define WAIT_DLM_LOCK_TIMEOUT (30 * HZ)
 
 struct dlm_lock_resource {
 	dlm_lockspace_t *ls;
@@ -130,8 +131,13 @@ static int dlm_lock_sync(struct dlm_lock_resource *res, int mode)
 			0, sync_ast, res, res->bast);
 	if (ret)
 		return ret;
-	wait_event(res->sync_locking, res->sync_locking_done);
+	ret = wait_event_timeout(res->sync_locking, res->sync_locking_done,
+				WAIT_DLM_LOCK_TIMEOUT);
 	res->sync_locking_done = false;
+	if (!ret) {
+		pr_err("locking DLM '%s' timeout!\n", res->name);
+		return -EBUSY;
+	}
 	if (res->lksb.sb_status == 0)
 		res->mode = mode;
 	return res->lksb.sb_status;
@@ -743,7 +749,7 @@ static void unlock_comm(struct md_cluster_info *cinfo)
  */
 static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
 {
-	int error;
+	int error, unlock_error;
 	int slot = cinfo->slot_number - 1;
 
 	cmsg->slot = cpu_to_le32(slot);
@@ -751,7 +757,7 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
 	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;
+		return error;
 	}
 
 	memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg,
@@ -781,14 +787,10 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
 	}
 
 failed_ack:
-	error = dlm_unlock_sync(cinfo->message_lockres);
-	if (unlikely(error != 0)) {
+	while ((unlock_error = dlm_unlock_sync(cinfo->message_lockres)))
 		pr_err("md-cluster: failed convert to NL on MESSAGE(%d)\n",
-			error);
-		/* in case the message can't be released due to some reason */
-		goto failed_ack;
-	}
-failed_message:
+			unlock_error);
+
 	return error;
 }
 
-- 
2.35.3

[PATCH v2 2/2] md-cluster: fix no recovery job when adding/re-adding a disk

[Heming Zhao]

The commit db5e653d7c9f ("md: delay choosing sync action to
md_start_sync()") delays the start of the sync action. In a
clustered environment, this will cause another node to first
activate the spare disk and skip recovery. As a result, no
nodes will perform recovery when a disk is added or re-added.

Before db5e653d7c9f:

```
   node1                                node2
----------------------------------------------------------------
md_check_recovery
 + md_update_sb
 |  sendmsg: METADATA_UPDATED
 + md_choose_sync_action           process_metadata_update
 |  remove_and_add_spares           //node1 has not finished adding
 + call mddev->sync_work            //the spare disk:do nothing

md_start_sync
 starts md_do_sync

md_do_sync
 + grabbed resync_lockres:DLM_LOCK_EX
 + do syncing job

md_check_recovery
 sendmsg: METADATA_UPDATED
                                 process_metadata_update
                                   //activate spare disk

                                 ... ...

                                 md_do_sync
                                  waiting to grab resync_lockres:EX
```

After db5e653d7c9f:

(note: if 'cmd:idle' sets MD_RECOVERY_INTR after md_check_recovery
starts md_start_sync, setting the INTR action will exacerbate the
delay in node1 calling the md_do_sync function.)

```
   node1                                node2
----------------------------------------------------------------
md_check_recovery
 + md_update_sb
 |  sendmsg: METADATA_UPDATED
 + calls mddev->sync_work         process_metadata_update
                                   //node1 has not finished adding
                                   //the spare disk:do nothing

md_start_sync
 + md_choose_sync_action
 |  remove_and_add_spares
 + calls md_do_sync

md_check_recovery
 md_update_sb
  sendmsg: METADATA_UPDATED
                                  process_metadata_update
                                    //activate spare disk

  ... ...                         ... ...

                                  md_do_sync
                                   + grabbed resync_lockres:EX
                                   + raid1_sync_request skip sync under
				     conf->fullsync:0
md_do_sync
 1. waiting to grab resync_lockres:EX
 2. when node1 could grab EX lock,
    node1 will skip resync under recovery_offset:MaxSector
```

How to trigger:

```(commands @node1)
 # to easily watch the recovery status
echo 2000 > /proc/sys/dev/raid/speed_limit_max
ssh root@node2 "echo 2000 > /proc/sys/dev/raid/speed_limit_max"

mdadm -CR /dev/md0 -l1 -b clustered -n 2 /dev/sda /dev/sdb --assume-clean
ssh root@node2 mdadm -A /dev/md0 /dev/sda /dev/sdb
mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda
mdadm --manage /dev/md0 --add /dev/sdc

=== "cat /proc/mdstat" on both node, there are no recovery action. ===
```

How to fix:

because md layer code logic is hard to restore for speeding up sync job
on local node, we add new cluster msg to pending the another node to
active disk.

Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Su Yue <glass.su@suse.com>
---
v1 -> v2: no change in this patch
---
 drivers/md/md-cluster.c | 27 +++++++++++++++++++++++++++
 drivers/md/md-cluster.h |  2 ++
 drivers/md/md.c         | 17 ++++++++++++++---
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index b5a802ae17bb..bf6a0dd8dac7 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -57,6 +57,7 @@ struct resync_info {
 #define		MD_CLUSTER_ALREADY_IN_CLUSTER		6
 #define		MD_CLUSTER_PENDING_RECV_EVENT		7
 #define 	MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD		8
+#define		MD_CLUSTER_WAITING_FOR_SYNC		9
 
 struct md_cluster_info {
 	struct mddev *mddev; /* the md device which md_cluster_info belongs to */
@@ -92,6 +93,7 @@ struct md_cluster_info {
 	sector_t sync_hi;
 };
 
+/* For compatibility, add the new msg_type at the end. */
 enum msg_type {
 	METADATA_UPDATED = 0,
 	RESYNCING,
@@ -101,6 +103,7 @@ enum msg_type {
 	BITMAP_NEEDS_SYNC,
 	CHANGE_CAPACITY,
 	BITMAP_RESIZE,
+	RESYNCING_START,
 };
 
 struct cluster_msg {
@@ -461,6 +464,7 @@ static void process_suspend_info(struct mddev *mddev,
 		clear_bit(MD_RESYNCING_REMOTE, &mddev->recovery);
 		remove_suspend_info(mddev, slot);
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		clear_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
 		md_wakeup_thread(mddev->thread);
 		return;
 	}
@@ -531,6 +535,7 @@ static int process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
 		res = -1;
 	}
 	clear_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
+	set_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
 	return res;
 }
 
@@ -599,6 +604,9 @@ static int process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
 	case CHANGE_CAPACITY:
 		set_capacity_and_notify(mddev->gendisk, mddev->array_sectors);
 		break;
+	case RESYNCING_START:
+		clear_bit(MD_CLUSTER_WAITING_FOR_SYNC, &mddev->cluster_info->state);
+		break;
 	case RESYNCING:
 		set_bit(MD_RESYNCING_REMOTE, &mddev->recovery);
 		process_suspend_info(mddev, le32_to_cpu(msg->slot),
@@ -1345,6 +1353,23 @@ static void resync_info_get(struct mddev *mddev, sector_t *lo, sector_t *hi)
 	spin_unlock_irq(&cinfo->suspend_lock);
 }
 
+static int resync_status_get(struct mddev *mddev)
+{
+	struct md_cluster_info *cinfo = mddev->cluster_info;
+
+	return test_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
+}
+
+static int resync_start_notify(struct mddev *mddev)
+{
+	struct md_cluster_info *cinfo = mddev->cluster_info;
+	struct cluster_msg cmsg = {0};
+
+	cmsg.type = cpu_to_le32(RESYNCING_START);
+
+	return sendmsg(cinfo, &cmsg, 0);
+}
+
 static int resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
 {
 	struct md_cluster_info *cinfo = mddev->cluster_info;
@@ -1579,6 +1604,8 @@ static struct md_cluster_operations cluster_ops = {
 	.resync_start = resync_start,
 	.resync_finish = resync_finish,
 	.resync_info_update = resync_info_update,
+	.resync_start_notify = resync_start_notify,
+	.resync_status_get = resync_status_get,
 	.resync_info_get = resync_info_get,
 	.metadata_update_start = metadata_update_start,
 	.metadata_update_finish = metadata_update_finish,
diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
index a78e3021775d..470bf18ffde5 100644
--- a/drivers/md/md-cluster.h
+++ b/drivers/md/md-cluster.h
@@ -14,6 +14,8 @@ struct md_cluster_operations {
 	int (*leave)(struct mddev *mddev);
 	int (*slot_number)(struct mddev *mddev);
 	int (*resync_info_update)(struct mddev *mddev, sector_t lo, sector_t hi);
+	int (*resync_start_notify)(struct mddev *mddev);
+	int (*resync_status_get)(struct mddev *mddev);
 	void (*resync_info_get)(struct mddev *mddev, sector_t *lo, sector_t *hi);
 	int (*metadata_update_start)(struct mddev *mddev);
 	int (*metadata_update_finish)(struct mddev *mddev);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index aff9118ff697..e393df55fc8b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8907,7 +8907,8 @@ void md_do_sync(struct md_thread *thread)
 	 * This will mean we have to start checking from the beginning again.
 	 *
 	 */
-
+	if (mddev_is_clustered(mddev))
+		md_cluster_ops->resync_start_notify(mddev);
 	do {
 		int mddev2_minor = -1;
 		mddev->curr_resync = MD_RESYNC_DELAYED;
@@ -9968,8 +9969,18 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
 			 */
 			if (rdev2->raid_disk == -1 && role != MD_DISK_ROLE_SPARE &&
 			    !(le32_to_cpu(sb->feature_map) &
-			      MD_FEATURE_RESHAPE_ACTIVE)) {
-				rdev2->saved_raid_disk = role;
+			      MD_FEATURE_RESHAPE_ACTIVE) &&
+			    !md_cluster_ops->resync_status_get(mddev)) {
+				/*
+				 * -1 to make raid1_add_disk() set conf->fullsync
+				 * to 1. This could avoid skipping sync when the
+				 * remote node is down during resyncing.
+				 */
+				if ((le32_to_cpu(sb->feature_map)
+				    & MD_FEATURE_RECOVERY_OFFSET))
+					rdev2->saved_raid_disk = -1;
+				else
+					rdev2->saved_raid_disk = role;
 				ret = remove_and_add_spares(mddev, rdev2);
 				pr_info("Activated spare: %pg\n",
 					rdev2->bdev);
-- 
2.35.3

Re: [PATCH v2 1/2] md-cluster: fix hanging issue while a new disk adding

[Yu Kuai]

在 2024/07/09 18:41, Heming Zhao 写道:
> The commit 1bbe254e4336 ("md-cluster: check for timeout while a
> new disk adding") is correct in terms of code syntax but not
> suite real clustered code logic.
> 
> When a timeout occurs while adding a new disk, if recv_daemon()
> bypasses the unlock for ack_lockres:CR, another node will be waiting
> to grab EX lock. This will cause the cluster to hang indefinitely.
> 
> How to fix:
> 
> 1. In dlm_lock_sync(), change the wait behaviour from forever to a
>     timeout, This could avoid the hanging issue when another node
>     fails to handle cluster msg. Another result of this change is
>     that if another node receives an unknown msg (e.g. a new msg_type),
>     the old code will hang, whereas the new code will timeout and fail.
>     This could help cluster_md handle new msg_type from different
>     nodes with different kernel/module versions (e.g. The user only
>     updates one leg's kernel and monitors the stability of the new
>     kernel).
> 2. The old code for __sendmsg() always returns 0 (success) under the
>     design (must successfully unlock ->message_lockres). This commit
>     makes this function return an error number when an error occurs.
> 
> Fixes: 1bbe254e4336 ("md-cluster: check for timeout while a new disk adding")
> Signed-off-by: Heming Zhao <heming.zhao@suse.com>
> Reviewed-by: Su Yue <glass.su@suse.com>

Thanks for the patch.

Acked-by: Yu Kuai <yukuai3@huawei.com>
> ---
> v1 -> v2:
> - use define WAIT_DLM_LOCK_TIMEOUT instead of hard code
> - change timeout value from 60s to 30s
> - follow Kuai's suggestion to use while loop to unlock message_lockres
> ---
>   drivers/md/md-cluster.c | 22 ++++++++++++----------
>   1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
> index 8e36a0feec09..b5a802ae17bb 100644
> --- a/drivers/md/md-cluster.c
> +++ b/drivers/md/md-cluster.c
> @@ -15,6 +15,7 @@
>   
>   #define LVB_SIZE	64
>   #define NEW_DEV_TIMEOUT 5000
> +#define WAIT_DLM_LOCK_TIMEOUT (30 * HZ)
>   
>   struct dlm_lock_resource {
>   	dlm_lockspace_t *ls;
> @@ -130,8 +131,13 @@ static int dlm_lock_sync(struct dlm_lock_resource *res, int mode)
>   			0, sync_ast, res, res->bast);
>   	if (ret)
>   		return ret;
> -	wait_event(res->sync_locking, res->sync_locking_done);
> +	ret = wait_event_timeout(res->sync_locking, res->sync_locking_done,
> +				WAIT_DLM_LOCK_TIMEOUT);
>   	res->sync_locking_done = false;
> +	if (!ret) {
> +		pr_err("locking DLM '%s' timeout!\n", res->name);
> +		return -EBUSY;
> +	}
>   	if (res->lksb.sb_status == 0)
>   		res->mode = mode;
>   	return res->lksb.sb_status;
> @@ -743,7 +749,7 @@ static void unlock_comm(struct md_cluster_info *cinfo)
>    */
>   static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
>   {
> -	int error;
> +	int error, unlock_error;
>   	int slot = cinfo->slot_number - 1;
>   
>   	cmsg->slot = cpu_to_le32(slot);
> @@ -751,7 +757,7 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
>   	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;
> +		return error;
>   	}
>   
>   	memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg,
> @@ -781,14 +787,10 @@ static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
>   	}
>   
>   failed_ack:
> -	error = dlm_unlock_sync(cinfo->message_lockres);
> -	if (unlikely(error != 0)) {
> +	while ((unlock_error = dlm_unlock_sync(cinfo->message_lockres)))
>   		pr_err("md-cluster: failed convert to NL on MESSAGE(%d)\n",
> -			error);
> -		/* in case the message can't be released due to some reason */
> -		goto failed_ack;
> -	}
> -failed_message:
> +			unlock_error);
> +
>   	return error;
>   }
>   
> 

Re: [PATCH v2 2/2] md-cluster: fix no recovery job when adding/re-adding a disk

[Yu Kuai]

在 2024/07/09 18:41, Heming Zhao 写道:
> The commit db5e653d7c9f ("md: delay choosing sync action to
> md_start_sync()") delays the start of the sync action. In a
> clustered environment, this will cause another node to first
> activate the spare disk and skip recovery. As a result, no
> nodes will perform recovery when a disk is added or re-added.
> 
> Before db5e653d7c9f:
> 
> ```
>     node1                                node2
> ----------------------------------------------------------------
> md_check_recovery
>   + md_update_sb
>   |  sendmsg: METADATA_UPDATED
>   + md_choose_sync_action           process_metadata_update
>   |  remove_and_add_spares           //node1 has not finished adding
>   + call mddev->sync_work            //the spare disk:do nothing
> 
> md_start_sync
>   starts md_do_sync
> 
> md_do_sync
>   + grabbed resync_lockres:DLM_LOCK_EX
>   + do syncing job
> 
> md_check_recovery
>   sendmsg: METADATA_UPDATED
>                                   process_metadata_update
>                                     //activate spare disk
> 
>                                   ... ...
> 
>                                   md_do_sync
>                                    waiting to grab resync_lockres:EX
> ```
> 
> After db5e653d7c9f:
> 
> (note: if 'cmd:idle' sets MD_RECOVERY_INTR after md_check_recovery
> starts md_start_sync, setting the INTR action will exacerbate the
> delay in node1 calling the md_do_sync function.)
> 
> ```
>     node1                                node2
> ----------------------------------------------------------------
> md_check_recovery
>   + md_update_sb
>   |  sendmsg: METADATA_UPDATED
>   + calls mddev->sync_work         process_metadata_update
>                                     //node1 has not finished adding
>                                     //the spare disk:do nothing
> 
> md_start_sync
>   + md_choose_sync_action
>   |  remove_and_add_spares
>   + calls md_do_sync
> 
> md_check_recovery
>   md_update_sb
>    sendmsg: METADATA_UPDATED
>                                    process_metadata_update
>                                      //activate spare disk
> 
>    ... ...                         ... ...
> 
>                                    md_do_sync
>                                     + grabbed resync_lockres:EX
>                                     + raid1_sync_request skip sync under
> 				     conf->fullsync:0
> md_do_sync
>   1. waiting to grab resync_lockres:EX
>   2. when node1 could grab EX lock,
>      node1 will skip resync under recovery_offset:MaxSector
> ```
> 
> How to trigger:
> 
> ```(commands @node1)
>   # to easily watch the recovery status
> echo 2000 > /proc/sys/dev/raid/speed_limit_max
> ssh root@node2 "echo 2000 > /proc/sys/dev/raid/speed_limit_max"
> 
> mdadm -CR /dev/md0 -l1 -b clustered -n 2 /dev/sda /dev/sdb --assume-clean
> ssh root@node2 mdadm -A /dev/md0 /dev/sda /dev/sdb
> mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda
> mdadm --manage /dev/md0 --add /dev/sdc
> 
> === "cat /proc/mdstat" on both node, there are no recovery action. ===
> ```
> 
> How to fix:
> 
> because md layer code logic is hard to restore for speeding up sync job
> on local node, we add new cluster msg to pending the another node to
> active disk.

Acked-by: Yu Kuai <yukuai3@huawei.com>
> 
> Signed-off-by: Heming Zhao <heming.zhao@suse.com>
> Reviewed-by: Su Yue <glass.su@suse.com>
> ---
> v1 -> v2: no change in this patch
> ---
>   drivers/md/md-cluster.c | 27 +++++++++++++++++++++++++++
>   drivers/md/md-cluster.h |  2 ++
>   drivers/md/md.c         | 17 ++++++++++++++---
>   3 files changed, 43 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
> index b5a802ae17bb..bf6a0dd8dac7 100644
> --- a/drivers/md/md-cluster.c
> +++ b/drivers/md/md-cluster.c
> @@ -57,6 +57,7 @@ struct resync_info {
>   #define		MD_CLUSTER_ALREADY_IN_CLUSTER		6
>   #define		MD_CLUSTER_PENDING_RECV_EVENT		7
>   #define 	MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD		8
> +#define		MD_CLUSTER_WAITING_FOR_SYNC		9
>   
>   struct md_cluster_info {
>   	struct mddev *mddev; /* the md device which md_cluster_info belongs to */
> @@ -92,6 +93,7 @@ struct md_cluster_info {
>   	sector_t sync_hi;
>   };
>   
> +/* For compatibility, add the new msg_type at the end. */
>   enum msg_type {
>   	METADATA_UPDATED = 0,
>   	RESYNCING,
> @@ -101,6 +103,7 @@ enum msg_type {
>   	BITMAP_NEEDS_SYNC,
>   	CHANGE_CAPACITY,
>   	BITMAP_RESIZE,
> +	RESYNCING_START,
>   };
>   
>   struct cluster_msg {
> @@ -461,6 +464,7 @@ static void process_suspend_info(struct mddev *mddev,
>   		clear_bit(MD_RESYNCING_REMOTE, &mddev->recovery);
>   		remove_suspend_info(mddev, slot);
>   		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> +		clear_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
>   		md_wakeup_thread(mddev->thread);
>   		return;
>   	}
> @@ -531,6 +535,7 @@ static int process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
>   		res = -1;
>   	}
>   	clear_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
> +	set_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
>   	return res;
>   }
>   
> @@ -599,6 +604,9 @@ static int process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
>   	case CHANGE_CAPACITY:
>   		set_capacity_and_notify(mddev->gendisk, mddev->array_sectors);
>   		break;
> +	case RESYNCING_START:
> +		clear_bit(MD_CLUSTER_WAITING_FOR_SYNC, &mddev->cluster_info->state);
> +		break;
>   	case RESYNCING:
>   		set_bit(MD_RESYNCING_REMOTE, &mddev->recovery);
>   		process_suspend_info(mddev, le32_to_cpu(msg->slot),
> @@ -1345,6 +1353,23 @@ static void resync_info_get(struct mddev *mddev, sector_t *lo, sector_t *hi)
>   	spin_unlock_irq(&cinfo->suspend_lock);
>   }
>   
> +static int resync_status_get(struct mddev *mddev)
> +{
> +	struct md_cluster_info *cinfo = mddev->cluster_info;
> +
> +	return test_bit(MD_CLUSTER_WAITING_FOR_SYNC, &cinfo->state);
> +}
> +
> +static int resync_start_notify(struct mddev *mddev)
> +{
> +	struct md_cluster_info *cinfo = mddev->cluster_info;
> +	struct cluster_msg cmsg = {0};
> +
> +	cmsg.type = cpu_to_le32(RESYNCING_START);
> +
> +	return sendmsg(cinfo, &cmsg, 0);
> +}
> +
>   static int resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
>   {
>   	struct md_cluster_info *cinfo = mddev->cluster_info;
> @@ -1579,6 +1604,8 @@ static struct md_cluster_operations cluster_ops = {
>   	.resync_start = resync_start,
>   	.resync_finish = resync_finish,
>   	.resync_info_update = resync_info_update,
> +	.resync_start_notify = resync_start_notify,
> +	.resync_status_get = resync_status_get,
>   	.resync_info_get = resync_info_get,
>   	.metadata_update_start = metadata_update_start,
>   	.metadata_update_finish = metadata_update_finish,
> diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
> index a78e3021775d..470bf18ffde5 100644
> --- a/drivers/md/md-cluster.h
> +++ b/drivers/md/md-cluster.h
> @@ -14,6 +14,8 @@ struct md_cluster_operations {
>   	int (*leave)(struct mddev *mddev);
>   	int (*slot_number)(struct mddev *mddev);
>   	int (*resync_info_update)(struct mddev *mddev, sector_t lo, sector_t hi);
> +	int (*resync_start_notify)(struct mddev *mddev);
> +	int (*resync_status_get)(struct mddev *mddev);
>   	void (*resync_info_get)(struct mddev *mddev, sector_t *lo, sector_t *hi);
>   	int (*metadata_update_start)(struct mddev *mddev);
>   	int (*metadata_update_finish)(struct mddev *mddev);
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index aff9118ff697..e393df55fc8b 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -8907,7 +8907,8 @@ void md_do_sync(struct md_thread *thread)
>   	 * This will mean we have to start checking from the beginning again.
>   	 *
>   	 */
> -
> +	if (mddev_is_clustered(mddev))
> +		md_cluster_ops->resync_start_notify(mddev);
>   	do {
>   		int mddev2_minor = -1;
>   		mddev->curr_resync = MD_RESYNC_DELAYED;
> @@ -9968,8 +9969,18 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
>   			 */
>   			if (rdev2->raid_disk == -1 && role != MD_DISK_ROLE_SPARE &&
>   			    !(le32_to_cpu(sb->feature_map) &
> -			      MD_FEATURE_RESHAPE_ACTIVE)) {
> -				rdev2->saved_raid_disk = role;
> +			      MD_FEATURE_RESHAPE_ACTIVE) &&
> +			    !md_cluster_ops->resync_status_get(mddev)) {
> +				/*
> +				 * -1 to make raid1_add_disk() set conf->fullsync
> +				 * to 1. This could avoid skipping sync when the
> +				 * remote node is down during resyncing.
> +				 */
> +				if ((le32_to_cpu(sb->feature_map)
> +				    & MD_FEATURE_RECOVERY_OFFSET))
> +					rdev2->saved_raid_disk = -1;
> +				else
> +					rdev2->saved_raid_disk = role;
>   				ret = remove_and_add_spares(mddev, rdev2);
>   				pr_info("Activated spare: %pg\n",
>   					rdev2->bdev);
> 

Re: [PATCH v2 1/2] md-cluster: fix hanging issue while a new disk adding

[Song Liu]

On Tue, Jul 9, 2024 at 7:06 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> 在 2024/07/09 18:41, Heming Zhao 写道:
> > The commit 1bbe254e4336 ("md-cluster: check for timeout while a
> > new disk adding") is correct in terms of code syntax but not
> > suite real clustered code logic.
> >
> > When a timeout occurs while adding a new disk, if recv_daemon()
> > bypasses the unlock for ack_lockres:CR, another node will be waiting
> > to grab EX lock. This will cause the cluster to hang indefinitely.
> >
> > How to fix:
> >
> > 1. In dlm_lock_sync(), change the wait behaviour from forever to a
> >     timeout, This could avoid the hanging issue when another node
> >     fails to handle cluster msg. Another result of this change is
> >     that if another node receives an unknown msg (e.g. a new msg_type),
> >     the old code will hang, whereas the new code will timeout and fail.
> >     This could help cluster_md handle new msg_type from different
> >     nodes with different kernel/module versions (e.g. The user only
> >     updates one leg's kernel and monitors the stability of the new
> >     kernel).
> > 2. The old code for __sendmsg() always returns 0 (success) under the
> >     design (must successfully unlock ->message_lockres). This commit
> >     makes this function return an error number when an error occurs.
> >
> > Fixes: 1bbe254e4336 ("md-cluster: check for timeout while a new disk adding")
> > Signed-off-by: Heming Zhao <heming.zhao@suse.com>
> > Reviewed-by: Su Yue <glass.su@suse.com>
>
> Thanks for the patch.
>
> Acked-by: Yu Kuai <yukuai3@huawei.com>

Applied to md-6.11. Thanks!

Song