ocfs2: Check the owner of a lockres inside the spinlock

The checking of lockres owner in dlm_update_lvb() is not inside spinlock
protection. I don't see problem in current call path of dlm_update_lvb().
But just for code robustness.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/fs/ocfs2/dlm/dlmast.c b/fs/ocfs2/dlm/dlmast.c
index dccc439fa087..b7a25ef18e2a 100644
--- a/fs/ocfs2/dlm/dlmast.c
+++ b/fs/ocfs2/dlm/dlmast.c
@@ -185,9 +185,8 @@ static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
         BUG_ON(!lksb);
 
         /* only updates if this node masters the lockres */
+        spin_lock(&res->spinlock);
         if (res->owner == dlm->node_num) {
-
-                spin_lock(&res->spinlock);
                 /* check the lksb flags for the direction */
                 if (lksb->flags & DLM_LKSB_GET_LVB) {
                         mlog(0, "getting lvb from lockres for %s node\n",
@@ -202,8 +201,8 @@ static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
                  * here. In the future we might want to clear it at the time
                  * the put is actually done.
                  */
-                spin_unlock(&res->spinlock);
         }
+        spin_unlock(&res->spinlock);
 
         /* reset any lvb flags on the lksb */
         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);