diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 024eb5d..f7aa49d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8535,220 +8535,6 @@ reada:
 	wc->reada_slot = slot;
 }
 
-static int account_leaf_items(struct btrfs_trans_handle *trans,
-			      struct btrfs_root *root,
-			      struct extent_buffer *eb)
-{
-	int nr = btrfs_header_nritems(eb);
-	int i, extent_type, ret;
-	struct btrfs_key key;
-	struct btrfs_file_extent_item *fi;
-	u64 bytenr, num_bytes;
-
-	/* We can be called directly from walk_up_proc() */
-	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
-		return 0;
-
-	for (i = 0; i < nr; i++) {
-		btrfs_item_key_to_cpu(eb, &key, i);
-
-		if (key.type != BTRFS_EXTENT_DATA_KEY)
-			continue;
-
-		fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
-		/* filter out non qgroup-accountable extents  */
-		extent_type = btrfs_file_extent_type(eb, fi);
-
-		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
-			continue;
-
-		bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
-		if (!bytenr)
-			continue;
-
-		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
-
-		ret = btrfs_qgroup_trace_extent(trans, root->fs_info,
-						bytenr, num_bytes, GFP_NOFS);
-		if (ret)
-			return ret;
-	}
-	return 0;
-}
-
-/*
- * Walk up the tree from the bottom, freeing leaves and any interior
- * nodes which have had all slots visited. If a node (leaf or
- * interior) is freed, the node above it will have it's slot
- * incremented. The root node will never be freed.
- *
- * At the end of this function, we should have a path which has all
- * slots incremented to the next position for a search. If we need to
- * read a new node it will be NULL and the node above it will have the
- * correct slot selected for a later read.
- *
- * If we increment the root nodes slot counter past the number of
- * elements, 1 is returned to signal completion of the search.
- */
-static int adjust_slots_upwards(struct btrfs_root *root,
-				struct btrfs_path *path, int root_level)
-{
-	int level = 0;
-	int nr, slot;
-	struct extent_buffer *eb;
-
-	if (root_level == 0)
-		return 1;
-
-	while (level <= root_level) {
-		eb = path->nodes[level];
-		nr = btrfs_header_nritems(eb);
-		path->slots[level]++;
-		slot = path->slots[level];
-		if (slot >= nr || level == 0) {
-			/*
-			 * Don't free the root -  we will detect this
-			 * condition after our loop and return a
-			 * positive value for caller to stop walking the tree.
-			 */
-			if (level != root_level) {
-				btrfs_tree_unlock_rw(eb, path->locks[level]);
-				path->locks[level] = 0;
-
-				free_extent_buffer(eb);
-				path->nodes[level] = NULL;
-				path->slots[level] = 0;
-			}
-		} else {
-			/*
-			 * We have a valid slot to walk back down
-			 * from. Stop here so caller can process these
-			 * new nodes.
-			 */
-			break;
-		}
-
-		level++;
-	}
-
-	eb = path->nodes[root_level];
-	if (path->slots[root_level] >= btrfs_header_nritems(eb))
-		return 1;
-
-	return 0;
-}
-
-/*
- * root_eb is the subtree root and is locked before this function is called.
- */
-static int account_shared_subtree(struct btrfs_trans_handle *trans,
-				  struct btrfs_root *root,
-				  struct extent_buffer *root_eb,
-				  u64 root_gen,
-				  int root_level)
-{
-	int ret = 0;
-	int level;
-	struct extent_buffer *eb = root_eb;
-	struct btrfs_path *path = NULL;
-
-	BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
-	BUG_ON(root_eb == NULL);
-
-	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
-		return 0;
-
-	if (!extent_buffer_uptodate(root_eb)) {
-		ret = btrfs_read_buffer(root_eb, root_gen);
-		if (ret)
-			goto out;
-	}
-
-	if (root_level == 0) {
-		ret = account_leaf_items(trans, root, root_eb);
-		goto out;
-	}
-
-	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
-
-	/*
-	 * Walk down the tree.  Missing extent blocks are filled in as
-	 * we go. Metadata is accounted every time we read a new
-	 * extent block.
-	 *
-	 * When we reach a leaf, we account for file extent items in it,
-	 * walk back up the tree (adjusting slot pointers as we go)
-	 * and restart the search process.
-	 */
-	extent_buffer_get(root_eb); /* For path */
-	path->nodes[root_level] = root_eb;
-	path->slots[root_level] = 0;
-	path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
-walk_down:
-	level = root_level;
-	while (level >= 0) {
-		if (path->nodes[level] == NULL) {
-			int parent_slot;
-			u64 child_gen;
-			u64 child_bytenr;
-
-			/* We need to get child blockptr/gen from
-			 * parent before we can read it. */
-			eb = path->nodes[level + 1];
-			parent_slot = path->slots[level + 1];
-			child_bytenr = btrfs_node_blockptr(eb, parent_slot);
-			child_gen = btrfs_node_ptr_generation(eb, parent_slot);
-
-			eb = read_tree_block(root, child_bytenr, child_gen);
-			if (IS_ERR(eb)) {
-				ret = PTR_ERR(eb);
-				goto out;
-			} else if (!extent_buffer_uptodate(eb)) {
-				free_extent_buffer(eb);
-				ret = -EIO;
-				goto out;
-			}
-
-			path->nodes[level] = eb;
-			path->slots[level] = 0;
-
-			btrfs_tree_read_lock(eb);
-			btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
-			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
-
-			ret = btrfs_qgroup_trace_extent(trans,
-					root->fs_info, child_bytenr,
-					root->nodesize, GFP_NOFS);
-			if (ret)
-				goto out;
-		}
-
-		if (level == 0) {
-			ret = account_leaf_items(trans, root, path->nodes[level]);
-			if (ret)
-				goto out;
-
-			/* Nonzero return here means we completed our search */
-			ret = adjust_slots_upwards(root, path, root_level);
-			if (ret)
-				break;
-
-			/* Restart search with new slots */
-			goto walk_down;
-		}
-
-		level--;
-	}
-
-	ret = 0;
-out:
-	btrfs_free_path(path);
-
-	return ret;
-}
-
 /*
  * helper to process tree block while walking down the tree.
  *
@@ -8977,8 +8763,8 @@ skip:
 		}
 
 		if (need_account) {
-			ret = account_shared_subtree(trans, root, next,
-						     generation, level - 1);
+			ret = btrfs_qgroup_trace_subtree(trans, root, next,
+							 generation, level - 1);
 			if (ret) {
 				btrfs_err_rl(root->fs_info,
 					     "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
@@ -9075,7 +8861,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
 			else
 				ret = btrfs_dec_ref(trans, root, eb, 0);
 			BUG_ON(ret); /* -ENOMEM */
-			ret = account_leaf_items(trans, root, eb);
+			ret = btrfs_qgroup_trace_leaf_items(trans, root, eb);
 			if (ret) {
 				btrfs_err_rl(root->fs_info,
 					     "error %d accounting leaf items. Quota is out of sync, rescan required.",
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index e73eea3..e97f304 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1510,6 +1510,217 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  struct extent_buffer *eb)
+{
+	int nr = btrfs_header_nritems(eb);
+	int i, extent_type, ret;
+	struct btrfs_key key;
+	struct btrfs_file_extent_item *fi;
+	u64 bytenr, num_bytes;
+
+	/* We can be called directly from walk_up_proc() */
+	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
+		return 0;
+
+	for (i = 0; i < nr; i++) {
+		btrfs_item_key_to_cpu(eb, &key, i);
+
+		if (key.type != BTRFS_EXTENT_DATA_KEY)
+			continue;
+
+		fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
+		/* filter out non qgroup-accountable extents  */
+		extent_type = btrfs_file_extent_type(eb, fi);
+
+		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+			continue;
+
+		bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
+		if (!bytenr)
+			continue;
+
+		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
+
+		ret = btrfs_qgroup_trace_extent(trans, root->fs_info,
+						bytenr, num_bytes, GFP_NOFS);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/*
+ * Walk up the tree from the bottom, freeing leaves and any interior
+ * nodes which have had all slots visited. If a node (leaf or
+ * interior) is freed, the node above it will have it's slot
+ * incremented. The root node will never be freed.
+ *
+ * At the end of this function, we should have a path which has all
+ * slots incremented to the next position for a search. If we need to
+ * read a new node it will be NULL and the node above it will have the
+ * correct slot selected for a later read.
+ *
+ * If we increment the root nodes slot counter past the number of
+ * elements, 1 is returned to signal completion of the search.
+ */
+static int adjust_slots_upwards(struct btrfs_root *root,
+				struct btrfs_path *path, int root_level)
+{
+	int level = 0;
+	int nr, slot;
+	struct extent_buffer *eb;
+
+	if (root_level == 0)
+		return 1;
+
+	while (level <= root_level) {
+		eb = path->nodes[level];
+		nr = btrfs_header_nritems(eb);
+		path->slots[level]++;
+		slot = path->slots[level];
+		if (slot >= nr || level == 0) {
+			/*
+			 * Don't free the root -  we will detect this
+			 * condition after our loop and return a
+			 * positive value for caller to stop walking the tree.
+			 */
+			if (level != root_level) {
+				btrfs_tree_unlock_rw(eb, path->locks[level]);
+				path->locks[level] = 0;
+
+				free_extent_buffer(eb);
+				path->nodes[level] = NULL;
+				path->slots[level] = 0;
+			}
+		} else {
+			/*
+			 * We have a valid slot to walk back down
+			 * from. Stop here so caller can process these
+			 * new nodes.
+			 */
+			break;
+		}
+
+		level++;
+	}
+
+	eb = path->nodes[root_level];
+	if (path->slots[root_level] >= btrfs_header_nritems(eb))
+		return 1;
+
+	return 0;
+}
+
+int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       struct extent_buffer *root_eb,
+			       u64 root_gen, int root_level)
+{
+	int ret = 0;
+	int level;
+	struct extent_buffer *eb = root_eb;
+	struct btrfs_path *path = NULL;
+
+	BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
+	BUG_ON(root_eb == NULL);
+
+	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
+		return 0;
+
+	if (!extent_buffer_uptodate(root_eb)) {
+		ret = btrfs_read_buffer(root_eb, root_gen);
+		if (ret)
+			goto out;
+	}
+
+	if (root_level == 0) {
+		ret = btrfs_qgroup_trace_leaf_items(trans, root, root_eb);
+		goto out;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	/*
+	 * Walk down the tree.  Missing extent blocks are filled in as
+	 * we go. Metadata is accounted every time we read a new
+	 * extent block.
+	 *
+	 * When we reach a leaf, we account for file extent items in it,
+	 * walk back up the tree (adjusting slot pointers as we go)
+	 * and restart the search process.
+	 */
+	extent_buffer_get(root_eb); /* For path */
+	path->nodes[root_level] = root_eb;
+	path->slots[root_level] = 0;
+	path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
+walk_down:
+	level = root_level;
+	while (level >= 0) {
+		if (path->nodes[level] == NULL) {
+			int parent_slot;
+			u64 child_gen;
+			u64 child_bytenr;
+
+			/* We need to get child blockptr/gen from
+			 * parent before we can read it. */
+			eb = path->nodes[level + 1];
+			parent_slot = path->slots[level + 1];
+			child_bytenr = btrfs_node_blockptr(eb, parent_slot);
+			child_gen = btrfs_node_ptr_generation(eb, parent_slot);
+
+			eb = read_tree_block(root, child_bytenr, child_gen);
+			if (IS_ERR(eb)) {
+				ret = PTR_ERR(eb);
+				goto out;
+			} else if (!extent_buffer_uptodate(eb)) {
+				free_extent_buffer(eb);
+				ret = -EIO;
+				goto out;
+			}
+
+			path->nodes[level] = eb;
+			path->slots[level] = 0;
+
+			btrfs_tree_read_lock(eb);
+			btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
+			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
+
+			ret = btrfs_qgroup_trace_extent(trans,
+					root->fs_info, child_bytenr,
+					root->nodesize, GFP_NOFS);
+			if (ret)
+				goto out;
+		}
+
+		if (level == 0) {
+			ret = btrfs_qgroup_trace_leaf_items(trans, root,
+					path->nodes[level]);
+			if (ret)
+				goto out;
+
+			/* Nonzero return here means we completed our search */
+			ret = adjust_slots_upwards(root, path, root_level);
+			if (ret)
+				break;
+
+			/* Restart search with new slots */
+			goto walk_down;
+		}
+
+		level--;
+	}
+
+	ret = 0;
+out:
+	btrfs_free_path(path);
+
+	return ret;
+}
+
 #define UPDATE_NEW	0
 #define UPDATE_OLD	1
 /*
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 9303e09..99c879d 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -122,6 +122,29 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans,
 		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
 		gfp_t gfp_flag);
 
+/*
+ * Inform qgroup to trace all leaf items of data
+ *
+ * Return 0 for success
+ * Return <0 for error(ENOMEM)
+ */
+int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  struct extent_buffer *eb);
+/*
+ * Inform qgroup to trace a whole subtree, including all its child tree
+ * blocks and data.
+ * The root tree block is specified by @root_eb.
+ *
+ * Normally used by relocation(tree block swap) and subvolume deletion.
+ *
+ * Return 0 for success
+ * Return <0 for error(ENOMEM or tree search error)
+ */
+int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       struct extent_buffer *root_eb,
+			       u64 root_gen, int root_level);
 int
 btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
 			    struct btrfs_fs_info *fs_info,
