Ocfs2 devel - Sep 2016 - MLE process bugs and its patch for review.

Hi, All

In the function dlm_migrate_lockres, as the return value is -EEXIST, the mle
should not be added because it had not been initialized. And the oldmle should
be put.
Same as in function dlm_migrate_request_handler, when the return val is -EEIST,
the mle should cache freed, otherwise memory lead may be occurred.


*** ocfs2.org/dlm/dlmmaster.c   2016-09-01 15:46:16.163140295 +0800
--- ocfs2/dlm/dlmmaster.c       2016-09-01 18:56:21.211442107 +0800
*************** static int dlm_is_lockres_migrateable(st
*** 2592,2599 ****
  /*
   * DLM_MIGRATE_LOCKRES
   */
-
-
  static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
                               struct dlm_lock_resource *res, u8 target)
  {
--- 2592,2597 ----
*************** static int dlm_migrate_lockres(struct dl
*** 2640,2645 ****
--- 2638,2654 ----
        spin_lock(&dlm->master_lock);
        ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
                                    namelen, target, dlm->node_num);
+
+       if (ret == -EEXIST) {
+               if(oldmle)
+                       dlm_put_mle(oldmle);
+
+               spin_unlock(&dlm->master_lock);
+               spin_unlock(&dlm->spinlock);
+               mlog(0, "another process is already migrating it\n");
+               goto fail;
+       }
+
        /* get an extra reference on the mle.
         * otherwise the assert_master from the new
         * master will destroy this.
*************** static int dlm_migrate_lockres(struct dl
*** 2648,2657 ****
        spin_unlock(&dlm->master_lock);
        spin_unlock(&dlm->spinlock);

-       if (ret == -EEXIST) {
-               mlog(0, "another process is already migrating it\n");
-               goto fail;
-       }
        mle_added = 1;

        /*
--- 2657,2662 ----
*************** int dlm_migrate_request_handler(struct o
*** 3206,3211 ****
--- 3211,3218 ----
                                    name, namelen,
                                    migrate->new_master,
                                    migrate->master);
+       if (ret < 0)
+               kmem_cache_free(dlm_mle_cache, mle);

        spin_unlock(&dlm->master_lock);
  unlock:
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