btrfs: rename werr and err to ret in btrfs_write_marked_extents()

Rename the function's local variable werr and err to ret.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
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/transaction.c

@@ -1118,8 +1118,7 @@ int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
 			       struct extent_io_tree *dirty_pages, int mark)
 {
-	int err = 0;
-	int werr = 0;
+	int ret = 0;
 	struct address_space *mapping = fs_info->btree_inode->i_mapping;
 	struct extent_state *cached_state = NULL;
 	u64 start = 0;
@@ -1129,7 +1128,7 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
 				     mark, &cached_state)) {
 		bool wait_writeback = false;
 
-		err = convert_extent_bit(dirty_pages, start, end,
+		ret = convert_extent_bit(dirty_pages, start, end,
 					 EXTENT_NEED_WAIT,
 					 mark, &cached_state);
 		/*
@@ -1145,24 +1144,22 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
 		 * We cleanup any entries left in the io tree when committing
 		 * the transaction (through extent_io_tree_release()).
 		 */
-		if (err == -ENOMEM) {
-			err = 0;
+		if (ret == -ENOMEM) {
+			ret = 0;
 			wait_writeback = true;
 		}
-		if (!err)
-			err = filemap_fdatawrite_range(mapping, start, end);
-		if (err)
-			werr = err;
-		else if (wait_writeback)
-			werr = filemap_fdatawait_range(mapping, start, end);
+		if (!ret)
+			ret = filemap_fdatawrite_range(mapping, start, end);
+		if (!ret && wait_writeback)
+			ret = filemap_fdatawait_range(mapping, start, end);
 		free_extent_state(cached_state);
-		if (werr)
+		if (ret)
 			break;
 		cached_state = NULL;
 		cond_resched();
 		start = end + 1;
 	}
-	return werr;
+	return ret;
 }
 
 /*