btrfs: simplify return variables in lookup_extent_data_ref()

First, drop err instead reuse ret, choose to return the error instead of
goto fail and then return the same error. Do not initialize the ret
until where it has to be initialized. Slight logic change in handling
the btrfs_search_slot() and btrfs_next_leaf() return value.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -446,9 +446,8 @@ static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 	struct btrfs_extent_data_ref *ref;
 	struct extent_buffer *leaf;
 	u32 nritems;
-	int ret;
 	int recow;
-	int err = -ENOENT;
+	int ret;
 
 	key.objectid = bytenr;
 	if (parent) {
@@ -462,26 +461,26 @@ static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 again:
 	recow = 0;
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
-	if (ret < 0) {
-		err = ret;
-		goto fail;
-	}
+	if (ret < 0)
+		return ret;
 
 	if (parent) {
-		if (!ret)
+		if (ret)
+			return -ENOENT;
 		return 0;
-		goto fail;
 	}
 
+	ret = -ENOENT;
 	leaf = path->nodes[0];
 	nritems = btrfs_header_nritems(leaf);
 	while (1) {
 		if (path->slots[0] >= nritems) {
 			ret = btrfs_next_leaf(root, path);
-			if (ret < 0)
-				err = ret;
-			if (ret)
-				goto fail;
+			if (ret) {
+				if (ret > 1)
+					return -ENOENT;
+				return ret;
+			}
 
 			leaf = path->nodes[0];
 			nritems = btrfs_header_nritems(leaf);
@@ -502,13 +501,13 @@ static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 				btrfs_release_path(path);
 				goto again;
 			}
-			err = 0;
+			ret = 0;
 			break;
 		}
 		path->slots[0]++;
 	}
 fail:
-	return err;
+	return ret;
 }
 
 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,