2 files changed, 37 insertions, 6 deletions

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 21262f2b1654..953f4eb75fa7 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -861,8 +861,13 @@ static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lo
          * We set the OCFS2_LOCK_UPCONVERT_FINISHING flag before clearing
          * the OCFS2_LOCK_BUSY flag to prevent the dc thread from
          * downconverting the lock before the upconvert has fully completed.
+         * Do not prevent the dc thread from downconverting if NONBLOCK lock
+         * had already returned.
          */
-        lockres_or_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
+        if (!(lockres->l_flags & OCFS2_LOCK_NONBLOCK_FINISHED))
+                lockres_or_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
+        else
+                lockres_clear_flags(lockres, OCFS2_LOCK_NONBLOCK_FINISHED);
 
         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
 }
@@ -1324,13 +1329,12 @@ static void lockres_add_mask_waiter(struct ocfs2_lock_res *lockres,
 
 /* returns 0 if the mw that was removed was already satisfied, -EBUSY
  * if the mask still hadn't reached its goal */
-static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
+static int __lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
                                       struct ocfs2_mask_waiter *mw)
 {
-        unsigned long flags;
         int ret = 0;
 
-        spin_lock_irqsave(&lockres->l_lock, flags);
+        assert_spin_locked(&lockres->l_lock);
         if (!list_empty(&mw->mw_item)) {
                 if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
                         ret = -EBUSY;
@@ -1338,6 +1342,18 @@ static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
                 list_del_init(&mw->mw_item);
                 init_completion(&mw->mw_complete);
         }
+
+        return ret;
+}
+
+static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
+                                      struct ocfs2_mask_waiter *mw)
+{
+        unsigned long flags;
+        int ret = 0;
+
+        spin_lock_irqsave(&lockres->l_lock, flags);
+        ret = __lockres_remove_mask_waiter(lockres, mw);
         spin_unlock_irqrestore(&lockres->l_lock, flags);
 
         return ret;
@@ -1373,6 +1389,7 @@ static int __ocfs2_cluster_lock(struct ocfs2_super *osb,
         unsigned long flags;
         unsigned int gen;
         int noqueue_attempted = 0;
+        int dlm_locked = 0;
 
         ocfs2_init_mask_waiter(&mw);
 
@@ -1481,6 +1498,7 @@ again:
                         ocfs2_recover_from_dlm_error(lockres, 1);
                         goto out;
                 }
+                dlm_locked = 1;
 
                 mlog(0, "lock %s, successful return from ocfs2_dlm_lock\n",
                      lockres->l_name);
@@ -1514,10 +1532,17 @@ out:
         if (wait && arg_flags & OCFS2_LOCK_NONBLOCK &&
             mw.mw_mask & (OCFS2_LOCK_BUSY|OCFS2_LOCK_BLOCKED)) {
                 wait = 0;
-                if (lockres_remove_mask_waiter(lockres, &mw))
+                spin_lock_irqsave(&lockres->l_lock, flags);
+                if (__lockres_remove_mask_waiter(lockres, &mw)) {
+                        if (dlm_locked)
+                                lockres_or_flags(lockres,
+                                        OCFS2_LOCK_NONBLOCK_FINISHED);
+                        spin_unlock_irqrestore(&lockres->l_lock, flags);
                         ret = -EAGAIN;
-                else
+                } else {
+                        spin_unlock_irqrestore(&lockres->l_lock, flags);
                         goto again;
+                }
         }
         if (wait) {
                 ret = ocfs2_wait_for_mask(&mw);
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index bbec539230fd..7d6b7d090452 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -144,6 +144,12 @@ enum ocfs2_unlock_action {
                                                      * before the upconvert
                                                      * has completed */
 
+#define OCFS2_LOCK_NONBLOCK_FINISHED (0x00001000) /* NONBLOCK cluster
+                                                   * lock has already
+                                                   * returned, do not block
+                                                   * dc thread from
+                                                   * downconverting */
+
 struct ocfs2_lock_res_ops;
 
 typedef void (*ocfs2_lock_callback)(int status, unsigned long data);