Wakeup down-convert thread just after clearing OCFS2_LOCK_UPCONVERT_FINISHING -v2

In down convert thread, when the ocfs2_lock_res is in OCFS2_LOCK_UPCONVERT_FINISHING state, it is requeued for next run of ocfs2_downconvert_thread_do_work(). If not waked up, the DC thread just sleep there without even there are ocfs2_lock_res' left in the list.

So when clearing the OCFS2_LOCK_UPCONVERT_FINISHING flag, we need also to wake up dc thread accordingly.

Signed-off-by Wengang Wang<[email protected]>

---
  fs/ocfs2/dlmglue.c |    2 ++
  1 files changed, 2 insertions(+), 0 deletions(-)

fs/ocfs2/dlmglue.c +2 -0

index 7642d7c..a2e8278 100644
@@ -1206,6 +1206,7 @@ static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
  	spin_unlock_irqrestore(&lockres->l_lock, flags);
 
  	wake_up(&lockres->l_event);
+	ocfs2_wake_downconvert_thread(ocfs2_get_lockres_osb(lockres));
  }
 
  /* Note: If we detect another process working on the lock (i.e.,

@@ -1502,6 +1503,7 @@ unlock:
  	lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
 
  	spin_unlock_irqrestore(&lockres->l_lock, flags);
+	ocfs2_wake_downconvert_thread(osb);
  out:
  	/*
  	 * This is helping work around a lock inversion between the page lock

A better description would be:
=====================================
When the lockres state UPCONVERT_FINISHING is cleared, we should wake up the downconvert thread incase that lockres is in the blocked queue. Currently we are not doing so and thus are at the mercy of another event waking up the dc thread.
======================================

With that in mind, can you do the following with the lock...

kick = (lockres->l_flags & OCFS2_LOCK_BLOCKED);

...

and this at the end of both functions.

if (kick)

     ocfs2_wake_downconvert_thread(ocfs2_get_lockres_osb(lockres));

Be careful in cluster_lock.

Quoted 33 lines · Wengang Wang

In down convert thread, when the ocfs2_lock_res is in OCFS2_LOCK_UPCONVERT_FINISHING state, it is requeued for next run of ocfs2_downconvert_thread_do_work(). If not waked up, the DC thread just sleep there without even there are ocfs2_lock_res' left in the list.

So when clearing the OCFS2_LOCK_UPCONVERT_FINISHING flag, we need also to wake up dc thread accordingly.

Signed-off-by Wengang Wang<[email protected]>

---
 fs/ocfs2/dlmglue.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

fs/ocfs2/dlmglue.c +2 -0

index 7642d7c..a2e8278 100644
@@ -1206,6 +1206,7 @@ static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
 	spin_unlock_irqrestore(&lockres->l_lock, flags);
 
 	wake_up(&lockres->l_event);
+	ocfs2_wake_downconvert_thread(ocfs2_get_lockres_osb(lockres));
 }
 
 /* Note: If we detect another process working on the lock (i.e.,

@@ -1502,6 +1503,7 @@ unlock:
 	lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
 
 	spin_unlock_irqrestore(&lockres->l_lock, flags);
+	ocfs2_wake_downconvert_thread(osb);
 out:
 	/*
 	 * This is helping work around a lock inversion between the page lock