btrfs: handle __add_reloc_root failures in btrfs_recover_relocation

We can already handle errors appropriately from this function, deal with
an error coming from __add_reloc_root appropriately.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/relocation.c

@@ -4059,7 +4059,12 @@ int btrfs_recover_relocation(struct btrfs_root *root)
 		}
 
 		err = __add_reloc_root(reloc_root);
-		BUG_ON(err < 0); /* -ENOMEM or logic error */
+		if (err) {
+			list_add_tail(&reloc_root->root_list, &reloc_roots);
+			btrfs_put_root(fs_root);
+			btrfs_end_transaction(trans);
+			goto out_unset;
+		}
 		fs_root->reloc_root = btrfs_grab_root(reloc_root);
 		btrfs_put_root(fs_root);
 	}
@@ -4274,7 +4279,11 @@ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
 		return PTR_ERR(reloc_root);
 
 	ret = __add_reloc_root(reloc_root);
-	BUG_ON(ret < 0);
+	if (ret) {
+		/* Pairs with create_reloc_root */
+		btrfs_put_root(reloc_root);
+		return ret;
+	}
 	new_root->reloc_root = btrfs_grab_root(reloc_root);
 
 	if (rc->create_reloc_tree)