From 096b2ef83c87d7a7e0d2838f7f1391c74fdad0e6 Mon Sep 17 00:00:00 2001 From: Xue jiufei Date: Wed, 3 Jul 2013 15:00:56 -0700 Subject: [PATCH] ocfs2: dlmlock_master() should return DLM_NORMAL after adding lock to blocked list dlmlock_master() returns DLM_RECOVERING/DLM_MIGRATING/ DLM_FORWAR after adding lock to blocked list if lockres has the state DLM_LOCK_RES_RECOVERING/DLM_LOCK_RES_MIGRATING/ DLM_LOCK_RES_IN_PROGRESS. so it will retry in dlmlock(). And this may cause dlm_thread fall into an infinite loop Thread1 dlm_thread calls dlm_lock->dlmlock_master, if lockresA is in state DLM_LOCK_RES_RECOVERING, calls __dlm_wait_on_lockres() and waits until others threads clear this state; If cannot grant this lock, adding lock to blocked list, and return DLM_RECOVERING; Grant this lock and move it to grant list; After a while, retry and calls list_add_tail(), adding lock to blocked list again. Granted and blocked list of this lockres will become the following conditions: lock_res->granted.next = dlm_lock->list_head; lock_res->blocked.next = dlm_lock->list_head; dlm_lock->list_head.next = dlm_lock_resource->blocked; When dlm_thread traverses the granted list, it will fall into an endless loop, checking dlm_lock.list_head, dlm_lock->list_head.next (i.e.lock_res->blocked), lock_res->blocked.next(i.e.dlm_lock.list_head again) ..... Signed-off-by: joyce Reviewed-by: jensen Cc: Jeff Liu Acked-by: Sunil Mushran Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/dlm/dlmlock.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c index 975810b..47e67c2 100644 --- a/fs/ocfs2/dlm/dlmlock.c +++ b/fs/ocfs2/dlm/dlmlock.c @@ -178,6 +178,7 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm, lock->ml.node); } } else { + status = DLM_NORMAL; dlm_lock_get(lock); list_add_tail(&lock->list, &res->blocked); kick_thread = 1; -- 2.7.4