2 files changed, 35 insertions, 6 deletions

diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 1f939631ab74..dc8ea666efdb 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -176,6 +176,7 @@ struct dlm_mig_lockres_priv
 {
         struct dlm_lock_resource *lockres;
         u8 real_master;
+        u8 extra_ref;
 };
 
 struct dlm_assert_master_priv
diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
index db17727594ab..f94683552420 100644
--- a/fs/ocfs2/dlm/dlmrecovery.c
+++ b/fs/ocfs2/dlm/dlmrecovery.c
@@ -1327,6 +1327,7 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
                 (struct dlm_migratable_lockres *)msg->buf;
         int ret = 0;
         u8 real_master;
+        u8 extra_refs = 0;
         char *buf = NULL;
         struct dlm_work_item *item = NULL;
         struct dlm_lock_resource *res = NULL;
@@ -1404,16 +1405,28 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
                 __dlm_insert_lockres(dlm, res);
                 spin_unlock(&dlm->spinlock);
 
+                /* Add an extra ref for this lock-less lockres lest the
+                 * dlm_thread purges it before we get the chance to add
+                 * locks to it */
+                dlm_lockres_get(res);
+
+                /* There are three refs that need to be put.
+                 * 1. Taken above.
+                 * 2. kref_init in dlm_new_lockres()->dlm_init_lockres().
+                 * 3. dlm_lookup_lockres()
+                 * The first one is handled at the end of this function. The
+                 * other two are handled in the worker thread after locks have
+                 * been attached. Yes, we don't wait for purge time to match
+                 * kref_init. The lockres will still have atleast one ref
+                 * added because it is in the hash __dlm_insert_lockres() */
+                extra_refs++;
+
                 /* now that the new lockres is inserted,
                  * make it usable by other processes */
                 spin_lock(&res->spinlock);
                 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
                 spin_unlock(&res->spinlock);
                 wake_up(&res->wq);
-
-                /* add an extra ref for just-allocated lockres 
-                 * otherwise the lockres will be purged immediately */
-                dlm_lockres_get(res);
         }
 
         /* at this point we have allocated everything we need,
@@ -1443,12 +1456,17 @@ int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
         dlm_init_work_item(dlm, item, dlm_mig_lockres_worker, buf);
         item->u.ml.lockres = res; /* already have a ref */
         item->u.ml.real_master = real_master;
+        item->u.ml.extra_ref = extra_refs;
         spin_lock(&dlm->work_lock);
         list_add_tail(&item->list, &dlm->work_list);
         spin_unlock(&dlm->work_lock);
         queue_work(dlm->dlm_worker, &dlm->dispatched_work);
 
 leave:
+        /* One extra ref taken needs to be put here */
+        if (extra_refs)
+                dlm_lockres_put(res);
+
         dlm_put(dlm);
         if (ret < 0) {
                 if (buf)
@@ -1464,17 +1482,19 @@ leave:
 
 static void dlm_mig_lockres_worker(struct dlm_work_item *item, void *data)
 {
-        struct dlm_ctxt *dlm = data;
+        struct dlm_ctxt *dlm;
         struct dlm_migratable_lockres *mres;
         int ret = 0;
         struct dlm_lock_resource *res;
         u8 real_master;
+        u8 extra_ref;
 
         dlm = item->dlm;
         mres = (struct dlm_migratable_lockres *)data;
 
         res = item->u.ml.lockres;
         real_master = item->u.ml.real_master;
+        extra_ref = item->u.ml.extra_ref;
 
         if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
                 /* this case is super-rare. only occurs if
@@ -1517,6 +1537,12 @@ again:
         }
 
 leave:
+        /* See comment in dlm_mig_lockres_handler() */
+        if (res) {
+                if (extra_ref)
+                        dlm_lockres_put(res);
+                dlm_lockres_put(res);
+        }
         kfree(data);
         mlog_exit(ret);
 }
@@ -1644,7 +1670,8 @@ int dlm_master_requery_handler(struct o2net_msg *msg, u32 len, void *data,
                                 /* retry!? */
                                 BUG();
                         }
-                }
+                } else /* put.. incase we are not the master */
+                        dlm_lockres_put(res);
                 spin_unlock(&res->spinlock);
         }
         spin_unlock(&dlm->spinlock);
@@ -1921,6 +1948,7 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
                      "Recovering res %s:%.*s, is already on recovery list!\n",
                      dlm->name, res->lockname.len, res->lockname.name);
                 list_del_init(&res->recovering);
+                dlm_lockres_put(res);
         }
         /* We need to hold a reference while on the recovery list */
         dlm_lockres_get(res);