btrfs: don't run delayed references while we are creating the free space tree

This is a short term solution to make sure btrfs_run_delayed_refs()
doesn't change the extent tree while we are scanning it to create the
free space tree.

Longer term we need to synchronize scanning the block groups one by one,
similar to what happens during a balance.

Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 12 insertions, 12 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 823c1ce87e2e..dc6b73a95342 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3065,6 +3065,18 @@ retry_root_backup:
         if (sb->s_flags & MS_RDONLY)
                 return 0;
 
+        if (btrfs_test_opt(tree_root, FREE_SPACE_TREE) &&
+            !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
+                pr_info("BTRFS: creating free space tree\n");
+                ret = btrfs_create_free_space_tree(fs_info);
+                if (ret) {
+                        pr_warn("BTRFS: failed to create free space tree %d\n",
+                                ret);
+                        close_ctree(tree_root);
+                        return ret;
+                }
+        }
+
         down_read(&fs_info->cleanup_work_sem);
         if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
             (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
@@ -3102,18 +3114,6 @@ retry_root_backup:
                 }
         }
 
-        if (btrfs_test_opt(tree_root, FREE_SPACE_TREE) &&
-            !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
-                pr_info("BTRFS: creating free space tree\n");
-                ret = btrfs_create_free_space_tree(fs_info);
-                if (ret) {
-                        pr_warn("BTRFS: failed to create free space tree %d\n",
-                                ret);
-                        close_ctree(tree_root);
-                        return ret;
-                }
-        }
-
         if (!fs_info->uuid_root) {
                 pr_info("BTRFS: creating UUID tree\n");
                 ret = btrfs_create_uuid_tree(fs_info);