1 files changed, 24 insertions, 3 deletions

diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index 10e149ae5e3a..68b668b0e60a 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -97,13 +97,14 @@ static int ocfs2_stack_driver_request(const char *stack_name,
                 goto out;
         }
 
-        /* Ok, the stack is pinned */
-        p->sp_count++;
         active_stack = p;
-
         rc = 0;
 
 out:
+        /* If we found it, pin it */
+        if (!rc)
+                active_stack->sp_count++;
+
         spin_unlock(&ocfs2_stack_lock);
         return rc;
 }
@@ -287,6 +288,26 @@ void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
 }
 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 
+int ocfs2_stack_supports_plocks(void)
+{
+        return active_stack && active_stack->sp_ops->plock;
+}
+EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
+
+/*
+ * ocfs2_plock() can only be safely called if
+ * ocfs2_stack_supports_plocks() returned true
+ */
+int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
+                struct file *file, int cmd, struct file_lock *fl)
+{
+        WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
+        if (active_stack->sp_ops->plock)
+                return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
+        return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(ocfs2_plock);
+
 int ocfs2_cluster_connect(const char *stack_name,
                           const char *group,
                           int grouplen,