diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 35cfa388dc0bab640f6dce31fb167582b6520bd5..6cac5ab8d5e0fc625c07ac1088782472b1a3a86f 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -40,265 +40,6 @@ struct extent_inode_elem {
 	struct extent_inode_elem *next;
 };
 
-/*
- * ref_root is used as the root of the ref tree that hold a collection
- * of unique references.
- */
-struct ref_root {
-	struct rb_root rb_root;
-
-	/*
-	 * The unique_refs represents the number of ref_nodes with a positive
-	 * count stored in the tree. Even if a ref_node (the count is greater
-	 * than one) is added, the unique_refs will only increase by one.
-	 */
-	unsigned int unique_refs;
-};
-
-/* ref_node is used to store a unique reference to the ref tree. */
-struct ref_node {
-	struct rb_node rb_node;
-
-	/* For NORMAL_REF, otherwise all these fields should be set to 0 */
-	u64 root_id;
-	u64 object_id;
-	u64 offset;
-
-	/* For SHARED_REF, otherwise parent field should be set to 0 */
-	u64 parent;
-
-	/* Ref to the ref_mod of btrfs_delayed_ref_node */
-	int ref_mod;
-};
-
-/* Dynamically allocate and initialize a ref_root */
-static struct ref_root *ref_root_alloc(void)
-{
-	struct ref_root *ref_tree;
-
-	ref_tree = kmalloc(sizeof(*ref_tree), GFP_NOFS);
-	if (!ref_tree)
-		return NULL;
-
-	ref_tree->rb_root = RB_ROOT;
-	ref_tree->unique_refs = 0;
-
-	return ref_tree;
-}
-
-/* Free all nodes in the ref tree, and reinit ref_root */
-static void ref_root_fini(struct ref_root *ref_tree)
-{
-	struct ref_node *node;
-	struct rb_node *next;
-
-	while ((next = rb_first(&ref_tree->rb_root)) != NULL) {
-		node = rb_entry(next, struct ref_node, rb_node);
-		rb_erase(next, &ref_tree->rb_root);
-		kfree(node);
-	}
-
-	ref_tree->rb_root = RB_ROOT;
-	ref_tree->unique_refs = 0;
-}
-
-static void ref_root_free(struct ref_root *ref_tree)
-{
-	if (!ref_tree)
-		return;
-
-	ref_root_fini(ref_tree);
-	kfree(ref_tree);
-}
-
-/*
- * Compare ref_node with (root_id, object_id, offset, parent)
- *
- * The function compares two ref_node a and b. It returns an integer less
- * than, equal to, or greater than zero , respectively, to be less than, to
- * equal, or be greater than b.
- */
-static int ref_node_cmp(struct ref_node *a, struct ref_node *b)
-{
-	if (a->root_id < b->root_id)
-		return -1;
-	else if (a->root_id > b->root_id)
-		return 1;
-
-	if (a->object_id < b->object_id)
-		return -1;
-	else if (a->object_id > b->object_id)
-		return 1;
-
-	if (a->offset < b->offset)
-		return -1;
-	else if (a->offset > b->offset)
-		return 1;
-
-	if (a->parent < b->parent)
-		return -1;
-	else if (a->parent > b->parent)
-		return 1;
-
-	return 0;
-}
-
-/*
- * Search ref_node with (root_id, object_id, offset, parent) in the tree
- *
- * if found, the pointer of the ref_node will be returned;
- * if not found, NULL will be returned and pos will point to the rb_node for
- * insert, pos_parent will point to pos'parent for insert;
-*/
-static struct ref_node *__ref_tree_search(struct ref_root *ref_tree,
-					  struct rb_node ***pos,
-					  struct rb_node **pos_parent,
-					  u64 root_id, u64 object_id,
-					  u64 offset, u64 parent)
-{
-	struct ref_node *cur = NULL;
-	struct ref_node entry;
-	int ret;
-
-	entry.root_id = root_id;
-	entry.object_id = object_id;
-	entry.offset = offset;
-	entry.parent = parent;
-
-	*pos = &ref_tree->rb_root.rb_node;
-
-	while (**pos) {
-		*pos_parent = **pos;
-		cur = rb_entry(*pos_parent, struct ref_node, rb_node);
-
-		ret = ref_node_cmp(cur, &entry);
-		if (ret > 0)
-			*pos = &(**pos)->rb_left;
-		else if (ret < 0)
-			*pos = &(**pos)->rb_right;
-		else
-			return cur;
-	}
-
-	return NULL;
-}
-
-/*
- * Insert a ref_node to the ref tree
- * @pos used for specifiy the position to insert
- * @pos_parent for specifiy pos's parent
- *
- * success, return 0;
- * ref_node already exists, return -EEXIST;
-*/
-static int ref_tree_insert(struct ref_root *ref_tree, struct rb_node **pos,
-			   struct rb_node *pos_parent, struct ref_node *ins)
-{
-	struct rb_node **p = NULL;
-	struct rb_node *parent = NULL;
-	struct ref_node *cur = NULL;
-
-	if (!pos) {
-		cur = __ref_tree_search(ref_tree, &p, &parent, ins->root_id,
-					ins->object_id, ins->offset,
-					ins->parent);
-		if (cur)
-			return -EEXIST;
-	} else {
-		p = pos;
-		parent = pos_parent;
-	}
-
-	rb_link_node(&ins->rb_node, parent, p);
-	rb_insert_color(&ins->rb_node, &ref_tree->rb_root);
-
-	return 0;
-}
-
-/* Erase and free ref_node, caller should update ref_root->unique_refs */
-static void ref_tree_remove(struct ref_root *ref_tree, struct ref_node *node)
-{
-	rb_erase(&node->rb_node, &ref_tree->rb_root);
-	kfree(node);
-}
-
-/*
- * Update ref_root->unique_refs
- *
- * Call __ref_tree_search
- *	1. if ref_node doesn't exist, ref_tree_insert this node, and update
- *	ref_root->unique_refs:
- *		if ref_node->ref_mod > 0, ref_root->unique_refs++;
- *		if ref_node->ref_mod < 0, do noting;
- *
- *	2. if ref_node is found, then get origin ref_node->ref_mod, and update
- *	ref_node->ref_mod.
- *		if ref_node->ref_mod is equal to 0,then call ref_tree_remove
- *
- *		according to origin_mod and new_mod, update ref_root->items
- *		+----------------+--------------+-------------+
- *		|		 |new_count <= 0|new_count > 0|
- *		+----------------+--------------+-------------+
- *		|origin_count < 0|       0      |      1      |
- *		+----------------+--------------+-------------+
- *		|origin_count > 0|      -1      |      0      |
- *		+----------------+--------------+-------------+
- *
- * In case of allocation failure, -ENOMEM is returned and the ref_tree stays
- * unaltered.
- * Success, return 0
- */
-static int ref_tree_add(struct ref_root *ref_tree, u64 root_id, u64 object_id,
-			u64 offset, u64 parent, int count)
-{
-	struct ref_node *node = NULL;
-	struct rb_node **pos = NULL;
-	struct rb_node *pos_parent = NULL;
-	int origin_count;
-	int ret;
-
-	if (!count)
-		return 0;
-
-	node = __ref_tree_search(ref_tree, &pos, &pos_parent, root_id,
-				 object_id, offset, parent);
-	if (node == NULL) {
-		node = kmalloc(sizeof(*node), GFP_NOFS);
-		if (!node)
-			return -ENOMEM;
-
-		node->root_id = root_id;
-		node->object_id = object_id;
-		node->offset = offset;
-		node->parent = parent;
-		node->ref_mod = count;
-
-		ret = ref_tree_insert(ref_tree, pos, pos_parent, node);
-		ASSERT(!ret);
-		if (ret) {
-			kfree(node);
-			return ret;
-		}
-
-		ref_tree->unique_refs += node->ref_mod > 0 ? 1 : 0;
-
-		return 0;
-	}
-
-	origin_count = node->ref_mod;
-	node->ref_mod += count;
-
-	if (node->ref_mod > 0)
-		ref_tree->unique_refs += origin_count > 0 ? 0 : 1;
-	else if (node->ref_mod <= 0)
-		ref_tree->unique_refs += origin_count > 0 ? -1 : 0;
-
-	if (!node->ref_mod)
-		ref_tree_remove(ref_tree, node);
-
-	return 0;
-}
-
 static int check_extent_in_eb(const struct btrfs_key *key,
 			      const struct extent_buffer *eb,
 			      const struct btrfs_file_extent_item *fi,
@@ -964,7 +705,6 @@ static int add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
  */
 static int add_inline_refs(struct btrfs_path *path, u64 bytenr,
 			   int *info_level, struct list_head *prefs,
-			   struct ref_root *ref_tree,
 			   u64 *total_refs, u64 inum)
 {
 	int ret = 0;
@@ -1031,13 +771,6 @@ static int add_inline_refs(struct btrfs_path *path, u64 bytenr,
 			count = btrfs_shared_data_ref_count(leaf, sdref);
 			ret = add_prelim_ref(prefs, 0, NULL, 0, offset,
 					     bytenr, count, GFP_NOFS);
-			if (ref_tree) {
-				if (!ret)
-					ret = ref_tree_add(ref_tree, 0, 0, 0,
-							   bytenr, count);
-				if (!ret && ref_tree->unique_refs > 1)
-					ret = BACKREF_FOUND_SHARED;
-			}
 			break;
 		}
 		case BTRFS_TREE_BLOCK_REF_KEY:
@@ -1065,15 +798,6 @@ static int add_inline_refs(struct btrfs_path *path, u64 bytenr,
 			root = btrfs_extent_data_ref_root(leaf, dref);
 			ret = add_prelim_ref(prefs, root, &key, 0, 0,
 					     bytenr, count, GFP_NOFS);
-			if (ref_tree) {
-				if (!ret)
-					ret = ref_tree_add(ref_tree, root,
-							   key.objectid,
-							   key.offset, 0,
-							   count);
-				if (!ret && ref_tree->unique_refs > 1)
-					ret = BACKREF_FOUND_SHARED;
-			}
 			break;
 		}
 		default:
@@ -1092,8 +816,7 @@ static int add_inline_refs(struct btrfs_path *path, u64 bytenr,
  */
 static int add_keyed_refs(struct btrfs_fs_info *fs_info,
 			  struct btrfs_path *path, u64 bytenr,
-			  int info_level, struct list_head *prefs,
-			  struct ref_root *ref_tree, u64 inum)
+			  int info_level, struct list_head *prefs, u64 inum)
 {
 	struct btrfs_root *extent_root = fs_info->extent_root;
 	int ret;
@@ -1135,13 +858,6 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
 			count = btrfs_shared_data_ref_count(leaf, sdref);
 			ret = add_prelim_ref(prefs, 0, NULL, 0, key.offset,
 					     bytenr, count, GFP_NOFS);
-			if (ref_tree) {
-				if (!ret)
-					ret = ref_tree_add(ref_tree, 0, 0, 0,
-							   bytenr, count);
-				if (!ret && ref_tree->unique_refs > 1)
-					ret = BACKREF_FOUND_SHARED;
-			}
 			break;
 		}
 		case BTRFS_TREE_BLOCK_REF_KEY:
@@ -1170,15 +886,6 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
 			root = btrfs_extent_data_ref_root(leaf, dref);
 			ret = add_prelim_ref(prefs, root, &key, 0, 0,
 					     bytenr, count, GFP_NOFS);
-			if (ref_tree) {
-				if (!ret)
-					ret = ref_tree_add(ref_tree, root,
-							   key.objectid,
-							   key.offset, 0,
-							   count);
-				if (!ret && ref_tree->unique_refs > 1)
-					ret = BACKREF_FOUND_SHARED;
-			}
 			break;
 		}
 		default:
@@ -1205,16 +912,13 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
  * commit root.
  * The special case is for qgroup to search roots in commit_transaction().
  *
- * If check_shared is set to 1, any extent has more than one ref item, will
- * be returned BACKREF_FOUND_SHARED immediately.
- *
  * FIXME some caching might speed things up
  */
 static int find_parent_nodes(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info, u64 bytenr,
 			     u64 time_seq, struct ulist *refs,
 			     struct ulist *roots, const u64 *extent_item_pos,
-			     u64 root_objectid, u64 inum, int check_shared)
+			     u64 root_objectid, u64 inum)
 {
 	struct btrfs_key key;
 	struct btrfs_path *path;
@@ -1226,7 +930,6 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 	struct list_head prefs;
 	struct prelim_ref *ref;
 	struct extent_inode_elem *eie = NULL;
-	struct ref_root *ref_tree = NULL;
 	u64 total_refs = 0;
 
 	INIT_LIST_HEAD(&prefs);
@@ -1258,18 +961,6 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 again:
 	head = NULL;
 
-	if (check_shared) {
-		if (!ref_tree) {
-			ref_tree = ref_root_alloc();
-			if (!ref_tree) {
-				ret = -ENOMEM;
-				goto out;
-			}
-		} else {
-			ref_root_fini(ref_tree);
-		}
-	}
-
 	ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 	if (ret < 0)
 		goto out;
@@ -1314,36 +1005,6 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 		} else {
 			spin_unlock(&delayed_refs->lock);
 		}
-
-		if (check_shared && !list_empty(&prefs_delayed)) {
-			/*
-			 * Add all delay_ref to the ref_tree and check if there
-			 * are multiple ref items added.
-			 */
-			list_for_each_entry(ref, &prefs_delayed, list) {
-				if (ref->key_for_search.type) {
-					ret = ref_tree_add(ref_tree,
-						ref->root_id,
-						ref->key_for_search.objectid,
-						ref->key_for_search.offset,
-						0, ref->count);
-					if (ret)
-						goto out;
-				} else {
-					ret = ref_tree_add(ref_tree, 0, 0, 0,
-						     ref->parent, ref->count);
-					if (ret)
-						goto out;
-				}
-
-			}
-
-			if (ref_tree->unique_refs > 1) {
-				ret = BACKREF_FOUND_SHARED;
-				goto out;
-			}
-
-		}
 	}
 
 	if (path->slots[0]) {
@@ -1358,12 +1019,11 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 		    (key.type == BTRFS_EXTENT_ITEM_KEY ||
 		     key.type == BTRFS_METADATA_ITEM_KEY)) {
 			ret = add_inline_refs(path, bytenr, &info_level,
-					      &prefs, ref_tree, &total_refs,
-					      inum);
+					      &prefs, &total_refs, inum);
 			if (ret)
 				goto out;
 			ret = add_keyed_refs(fs_info, path, bytenr, info_level,
-					     &prefs, ref_tree, inum);
+					     &prefs, inum);
 			if (ret)
 				goto out;
 		}
@@ -1447,7 +1107,6 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 
 out:
 	btrfs_free_path(path);
-	ref_root_free(ref_tree);
 	while (!list_empty(&prefs)) {
 		ref = list_first_entry(&prefs, struct prelim_ref, list);
 		list_del(&ref->list);
@@ -1502,7 +1161,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 
 	ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
-				*leafs, NULL, extent_item_pos, 0, 0, 0);
+				*leafs, NULL, extent_item_pos, 0, 0);
 	if (ret < 0 && ret != -ENOENT) {
 		free_leaf_list(*leafs);
 		return ret;
@@ -1545,7 +1204,7 @@ static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans,
 	ULIST_ITER_INIT(&uiter);
 	while (1) {
 		ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
-					tmp, *roots, NULL, 0, 0, 0);
+					tmp, *roots, NULL, 0, 0);
 		if (ret < 0 && ret != -ENOENT) {
 			ulist_free(tmp);
 			ulist_free(*roots);
@@ -1621,7 +1280,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
 	ULIST_ITER_INIT(&uiter);
 	while (1) {
 		ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
-					roots, NULL, root->objectid, inum, 1);
+					roots, NULL, root->objectid, inum);
 		if (ret == BACKREF_FOUND_SHARED) {
 			/* this is the only condition under which we return 1 */
 			ret = 1;