ocfs2/dlm: Fix race during lockres mastery

[linux-2.6-omap-h63xx.git] / fs / ocfs2 / dlm / dlmmaster.c

diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index cbf3abe24cdb4e899184be9e72db442cb695d61a..54e182a27caf81a86b96fb9cc133b5776346e028 100644 (file)
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -732,14 +732,21 @@ lookup:
        if (tmpres) {
                int dropping_ref = 0;
 
+               spin_unlock(&dlm->spinlock);
+
                spin_lock(&tmpres->spinlock);
+               /* We wait for the other thread that is mastering the resource */
+               if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
+                       __dlm_wait_on_lockres(tmpres);
+                       BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
+               }
+
                if (tmpres->owner == dlm->node_num) {
                        BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF);
                        dlm_lockres_grab_inflight_ref(dlm, tmpres);
                } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF)
                        dropping_ref = 1;
                spin_unlock(&tmpres->spinlock);
-               spin_unlock(&dlm->spinlock);
 
                /* wait until done messaging the master, drop our ref to allow
                 * the lockres to be purged, start over. */