ocfs2: old mle put and release after the function dlm_add_migration_mle called

If the old mle is found after the dlm_add_migration_mle called, it should
be put once.  If the return value is not - EEXIST and its type is BLOCK,
it should be put again to release it to avoid memory leak, for it had been
unhashed from the map.

Link: http://lkml.kernel.org/r/71604351584F6A4EBAE558C676F37CA4A3D4B7FE@H3CMLB12-EX.srv.huawei-3com.com
Signed-off-by: Guozhonghua <guozhonghua@h3c.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 44 insertions, 18 deletions

diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 3e04279446e8..4438671c4ac3 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -2612,20 +2612,45 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
 	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;
+	}
+
+	/* If an old one mle found, it should be put. if its type is BLOCK,
+	 * it should be put again. Because it had been unhasded from the map
+	 * in the function dlm_add_migration_mle.
+	 * otherwise the memory will be leaked. It will not found it again from
+	 * the hash map.
+	 */
+	if (oldmle) {
+		/* master is known, detach if not already detached */
+		__dlm_mle_detach_hb_events(dlm, oldmle);
+		__dlm_put_mle(oldmle);
+
+		/* if the type of the mle is BLOCK, should put it once for release.
+		 * otherwise memory leak may be caused because oldmle had been unhashed
+		 * from the hash map, it will not be found anymore.
+		 */
+		if (oldmle->type == DLM_MLE_BLOCK)
+			__dlm_put_mle(oldmle);
+       }
+
 	/* get an extra reference on the mle.
 	 * otherwise the assert_master from the new
 	 * master will destroy this.
 	 */
 	dlm_get_mle_inuse(mle);
+	mle_added = 1;
+
 	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;
-
 	/*
 	 * set the MIGRATING flag and flush asts
 	 * if we fail after this we need to re-dirty the lockres
@@ -2642,12 +2667,6 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
 	}
 
 fail:
-	if (ret != -EEXIST && oldmle) {
-		/* master is known, detach if not already detached */
-		dlm_mle_detach_hb_events(dlm, oldmle);
-		dlm_put_mle(oldmle);
-	}
-
 	if (ret < 0) {
 		if (mle_added) {
 			dlm_mle_detach_hb_events(dlm, mle);
@@ -3182,16 +3201,23 @@ int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
 	if (ret < 0)
 		kmem_cache_free(dlm_mle_cache, mle);
 
+	/* If an old one mle found, it should be put. if its type is BLOCK,
+	 * it should be put again. Because it had been unhasded from the map
+	 * in the function dlm_add_migration_mle.
+	 * otherwise the memory will be leaked. It will not found it again from
+	 * the hash map.
+	 */
+	if (oldmle) {
+		__dlm_mle_detach_hb_events(dlm, oldmle);
+		__dlm_put_mle(oldmle);
+		if (ret >= 0 && oldmle->type == DLM_MLE_BLOCK)
+			__dlm_put_mle(oldmle);
+	}
+
 	spin_unlock(&dlm->master_lock);
 unlock:
 	spin_unlock(&dlm->spinlock);
 
-	if (oldmle) {
-		/* master is known, detach if not already detached */
-		dlm_mle_detach_hb_events(dlm, oldmle);
-		dlm_put_mle(oldmle);
-	}
-
 	if (res)
 		dlm_lockres_put(res);
 leave: