EXT4_IO_END_FAILED
#define EXT4_IO_END_DEFER_COMPLETION (EXT4_IO_END_UNWRITTEN | EXT4_IO_END_FAILED)
if (unlikely(io_end->flag & EXT4_IO_END_FAILED)) {
io_end->flag & EXT4_IO_END_FAILED &&
io_end->flag |= EXT4_IO_END_FAILED;