ocfs2/dlm: clear migration_pending when migration target goes down

PATCH New xuejiufei 2 participants 2 messages Dec 24, 2015 OCFS2

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2015-12-24 07:20 UTC #0 lore raw

PATCH v2 1/1 ocfs2/dlm: clear migration_pending when migration target goes down

We have found a BUG on res->migration_pending when migrating lock resources. The situation is as follows.

dlm_mark_lockres_migration
res->migration_pending = 1;
__dlm_lockres_reserve_ast
dlm_lockres_release_ast returns with res->migration_pending remains
because other threads reserve asts
wait dlm_migration_can_proceed returns 1

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o2hb found that target goes down and remove target

from domain_map
dlm_migration_can_proceed returns 1 dlm_mark_lockres_migrating returns -ESHOTDOWN with

      res->migration_pending still remains.

When reentering dlm_mark_lockres_migrating(), it will trigger the BUG_ON with res->migration_pending. So clear migration_pending when target is down.

Signed-off-by Jiufei Xue <[email protected]>

---
 fs/ocfs2/dlm/dlmmaster.c | 2 ++
 1 file changed, 2 insertions(+)

fs/ocfs2/dlm/dlmmaster.c +2 -0

index c43da7f..936e11b 100644
@@ -2843,6 +2843,8 @@ again:
 	res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
 	if (!ret)
 		BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
+	else
+		res->migration_pending = 0;
 	spin_unlock(&res->spinlock);
 
 	/*

Signature · 1 line

1.8.4.3

Joseph Qi

2015-12-24 07:48 UTC #1 lore raw

PATCH v2 1/1 ocfs2/dlm: clear migration_pending when migration target goes down

Quoted 13 lines · xuejiufei

We have found a BUG on res->migration_pending when migrating lock resources. The situation is as follows.
dlm_mark_lockres_migration
res->migration_pending = 1;
__dlm_lockres_reserve_ast
dlm_lockres_release_ast returns with res->migration_pending remains
because other threads reserve asts
wait dlm_migration_can_proceed returns 1
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o2hb found that target goes down and remove target
from domain_map
dlm_migration_can_proceed returns 1 dlm_mark_lockres_migrating returns -ESHOTDOWN with

Quoted 7 lines

      res->migration_pending still remains.
When reentering dlm_mark_lockres_migrating(), it will trigger the BUG_ON with res->migration_pending. So clear migration_pending when target is down.
Signed-off-by Jiufei Xue <[email protected]>

Reviewed-by Joseph Qi <[email protected]>

Quoted 18 lines

---
 fs/ocfs2/dlm/dlmmaster.c | 2 ++
 1 file changed, 2 insertions(+)

fs/ocfs2/dlm/dlmmaster.c +2 -0

index c43da7f..936e11b 100644
@@ -2843,6 +2843,8 @@ again:
 	res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
 	if (!ret)
 		BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
+	else
+		res->migration_pending = 0;
 	spin_unlock(&res->spinlock);
 
 	/*