3 files changed, 36 insertions, 6 deletions

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 21a75771763..da7419ed01b 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -529,8 +529,8 @@ static noinline void add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
         ref->is_head = 0;
         ref->in_tree = 1;
 
-        if (is_fstree(ref_root))
-                seq = btrfs_inc_tree_mod_seq(fs_info);
+        if (need_ref_seq(for_cow, ref_root))
+                seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
         ref->seq = seq;
 
         full_ref = btrfs_delayed_node_to_tree_ref(ref);
@@ -588,8 +588,8 @@ static noinline void add_delayed_data_ref(struct btrfs_fs_info *fs_info,
         ref->is_head = 0;
         ref->in_tree = 1;
 
-        if (is_fstree(ref_root))
-                seq = btrfs_inc_tree_mod_seq(fs_info);
+        if (need_ref_seq(for_cow, ref_root))
+                seq = btrfs_get_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
         ref->seq = seq;
 
         full_ref = btrfs_delayed_node_to_data_ref(ref);
@@ -662,10 +662,12 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
         add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
                                    num_bytes, parent, ref_root, level, action,
                                    for_cow);
-        if (!is_fstree(ref_root) &&
+        if (!need_ref_seq(for_cow, ref_root) &&
             waitqueue_active(&fs_info->tree_mod_seq_wait))
                 wake_up(&fs_info->tree_mod_seq_wait);
         spin_unlock(&delayed_refs->lock);
+        if (need_ref_seq(for_cow, ref_root))
+                btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 
         return 0;
 }
@@ -711,10 +713,12 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
         add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
                                    num_bytes, parent, ref_root, owner, offset,
                                    action, for_cow);
-        if (!is_fstree(ref_root) &&
+        if (!need_ref_seq(for_cow, ref_root) &&
             waitqueue_active(&fs_info->tree_mod_seq_wait))
                 wake_up(&fs_info->tree_mod_seq_wait);
         spin_unlock(&delayed_refs->lock);
+        if (need_ref_seq(for_cow, ref_root))
+                btrfs_qgroup_record_ref(trans, &ref->node, extent_op);
 
         return 0;
 }
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 2b5cb27f986..0d7c90c366b 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -180,6 +180,25 @@ int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
                             u64 seq);
 
 /*
+ * delayed refs with a ref_seq > 0 must be held back during backref walking.
+ * this only applies to items in one of the fs-trees. for_cow items never need
+ * to be held back, so they won't get a ref_seq number.
+ */
+static inline int need_ref_seq(int for_cow, u64 rootid)
+{
+        if (for_cow)
+                return 0;
+
+        if (rootid == BTRFS_FS_TREE_OBJECTID)
+                return 1;
+
+        if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
+                return 1;
+
+        return 0;
+}
+
+/*
  * a node might live in a head or a regular ref, this lets you
  * test for the proper type to use.
  */
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index d20d2e24f8d..21c768cb443 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -795,6 +795,13 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
         ret = btrfs_run_dev_stats(trans, root->fs_info);
         BUG_ON(ret);
 
+        ret = btrfs_run_qgroups(trans, root->fs_info);
+        BUG_ON(ret);
+
+        /* run_qgroups might have added some more refs */
+        ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+        BUG_ON(ret);
+
         while (!list_empty(&fs_info->dirty_cowonly_roots)) {
                 next = fs_info->dirty_cowonly_roots.next;
                 list_del_init(next);