btrfs: handle errors in reference count manipulation in replace_path

If any of the reference count manipulation stuff fails in replace_path
we need to abort the transaction, as we've modified the blocks already.
We can simply break at this point and everything will be cleaned up.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/relocation.c

@@ -1367,27 +1367,39 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		ref.skip_qgroup = true;
 		btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
 		ret = btrfs_inc_extent_ref(trans, &ref);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			break;
+		}
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
 				       blocksize, 0);
 		ref.skip_qgroup = true;
 		btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
 		ret = btrfs_inc_extent_ref(trans, &ref);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			break;
+		}
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
 				       blocksize, path->nodes[level]->start);
 		btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
 		ref.skip_qgroup = true;
 		ret = btrfs_free_extent(trans, &ref);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			break;
+		}
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
 				       blocksize, 0);
 		btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
 		ref.skip_qgroup = true;
 		ret = btrfs_free_extent(trans, &ref);
-		BUG_ON(ret);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			break;
+		}
 
 		btrfs_unlock_up_safe(path, 0);